IT. Expert System.

Java Enterprise Edition (EE)

Message


javax.jms
Interface Message

All Known Subinterfaces:
BytesMessage, MapMessage, ObjectMessage, StreamMessage, TextMessage
public interface Message

The Message interface is the root interface of all JMS messages. It defines the message header and the acknowledge method used for all messages.

Most message-oriented middleware (MOM) products treat messages as lightweight entities that consist of a header and a payload. The header contains fields used for message routing and identification; the payload contains the application data being sent.

Within this general form, the definition of a message varies significantly across products. It would be quite difficult for the JMS API to support all of these message models.

With this in mind, the JMS message model has the following goals:

  • Provide a single, unified message API
  • Provide an API suitable for creating messages that match the format used by provider-native messaging applications
  • Support the development of heterogeneous applications that span operating systems, machine architectures, and computer languages
  • Support messages containing objects in the Java programming language ("Java objects")
  • Support messages containing Extensible Markup Language (XML) pages

JMS messages are composed of the following parts:

  • Header - All messages support the same set of header fields. Header fields contain values used by both clients and providers to identify and route messages.
  • Properties - Each message contains a built-in facility for supporting application-defined property values. Properties provide an efficient mechanism for supporting application-defined message filtering.
  • Body - The JMS API defines several types of message body, which cover the majority of messaging styles currently in use.

Message Bodies

The JMS API defines five types of message body:

  • Stream - A StreamMessage object's message body contains a stream of primitive values in the Java programming language ("Java primitives"). It is filled and read sequentially.
  • Map - A MapMessage object's message body contains a set of name-value pairs, where names are String objects, and values are Java primitives. The entries can be accessed sequentially or randomly by name. The order of the entries is undefined.
  • Text - A TextMessage object's message body contains a java.lang.String object. This message type can be used to transport plain-text messages, and XML messages.
  • Object - An ObjectMessage object's message body contains a Serializable Java object.
  • Bytes - A BytesMessage object's message body contains a stream of uninterpreted bytes. This message type is for literally encoding a body to match an existing message format. In many cases, it is possible to use one of the other body types, which are easier to use. Although the JMS API allows the use of message properties with byte messages, they are typically not used, since the inclusion of properties may affect the format.

Message Headers

The JMSCorrelationID header field is used for linking one message with another. It typically links a reply message with its requesting message.

JMSCorrelationID can hold a provider-specific message ID, an application-specific String object, or a provider-native byte[] value.

Message Properties

A Message object contains a built-in facility for supporting application-defined property values. In effect, this provides a mechanism for adding application-specific header fields to a message.

Properties allow an application, via message selectors, to have a JMS provider select, or filter, messages on its behalf using application-specific criteria.

Property names must obey the rules for a message selector identifier. Property names must not be null, and must not be empty strings. If a property name is set and it is either null or an empty string, an IllegalArgumentException must be thrown.

Property values can be boolean, byte, short, int, long, float, double, and String.

Property values are set prior to sending a message. When a client receives a message, its properties are in read-only mode. If a client attempts to set properties at this point, a MessageNotWriteableException is thrown. If clearProperties is called, the properties can now be both read from and written to. Note that header fields are distinct from properties. Header fields are never in read-only mode.

A property value may duplicate a value in a message's body, or it may not. Although JMS does not define a policy for what should or should not be made a property, application developers should note that JMS providers will likely handle data in a message's body more efficiently than data in a message's properties. For best performance, applications should use message properties only when they need to customize a message's header. The primary reason for doing this is to support customized message selection.

Message properties support the following conversion table. The marked cases must be supported. The unmarked cases must throw a JMSException. The String-to-primitive conversions may throw a runtime exception if the primitive's valueOf method does not accept the String as a valid representation of the primitive.

A value written as the row type can be read as the column type.

 |        | boolean byte short int long float double String 
 |----------------------------------------------------------
 |boolean |    X                                       X
 |byte    |          X     X    X   X                  X 
 |short   |                X    X   X                  X 
 |int     |                     X   X                  X 
 |long    |                         X                  X 
 |float   |                               X     X      X 
 |double  |                                     X      X 
 |String  |    X     X     X    X   X     X     X      X 
 |----------------------------------------------------------
 

In addition to the type-specific set/get methods for properties, JMS provides the setObjectProperty and getObjectProperty methods. These support the same set of property types using the objectified primitive values. Their purpose is to allow the decision of property type to made at execution time rather than at compile time. They support the same property value conversions.

The setObjectProperty method accepts values of class Boolean, Byte, Short, Integer, Long, Float, Double, and String. An attempt to use any other class must throw a JMSException.

The getObjectProperty method only returns values of class Boolean, Byte, Short, Integer, Long, Float, Double, and String.

The order of property values is not defined. To iterate through a message's property values, use getPropertyNames to retrieve a property name enumeration and then use the various property get methods to retrieve their values.

A message's properties are deleted by the clearProperties method. This leaves the message with an empty set of properties.

Getting a property value for a name which has not been set returns a null value. Only the getStringProperty and getObjectProperty methods can return a null value. Attempting to read a null value as a primitive type must be treated as calling the primitive's corresponding valueOf(String) conversion method with a null value.

The JMS API reserves the JMSX property name prefix for JMS defined properties. The full set of these properties is defined in the Java Message Service specification. New JMS defined properties may be added in later versions of the JMS API. Support for these properties is optional. The String[] ConnectionMetaData.getJMSXPropertyNames method returns the names of the JMSX properties supported by a connection.

JMSX properties may be referenced in message selectors whether or not they are supported by a connection. If they are not present in a message, they are treated like any other absent property.

JMSX properties defined in the specification as "set by provider on send" are available to both the producer and the consumers of the message. JMSX properties defined in the specification as "set by provider on receive" are available only to the consumers.

JMSXGroupID and JMSXGroupSeq are standard properties that clients should use if they want to group messages. All providers must support them. Unless specifically noted, the values and semantics of the JMSX properties are undefined.

The JMS API reserves the JMS_vendor_name property name prefix for provider-specific properties. Each provider defines its own value for vendor_name. This is the mechanism a JMS provider uses to make its special per-message services available to a JMS client.

The purpose of provider-specific properties is to provide special features needed to integrate JMS clients with provider-native clients in a single JMS application. They should not be used for messaging between JMS clients.

Provider Implementations of JMS Message Interfaces

The JMS API provides a set of message interfaces that define the JMS message model. It does not provide implementations of these interfaces.

Each JMS provider supplies a set of message factories with its Session object for creating instances of messages. This allows a provider to use message implementations tailored to its specific needs.

A provider must be prepared to accept message implementations that are not its own. They may not be handled as efficiently as its own implementation; however, they must be handled.

Note the following exception case when a provider is handling a foreign message implementation. If the foreign message implementation contains a JMSReplyTo header field that is set to a foreign destination implementation, the provider is not required to handle or preserve the value of this header field.

Message Selectors

A JMS message selector allows a client to specify, by header field references and property references, the messages it is interested in. Only messages whose header and property values match the selector are delivered. What it means for a message not to be delivered depends on the MessageConsumer being used (see QueueReceiver and TopicSubscriber).

Message selectors cannot reference message body values.

A message selector matches a message if the selector evaluates to true when the message's header field values and property values are substituted for their corresponding identifiers in the selector.

A message selector is a String whose syntax is based on a subset of the SQL92 conditional expression syntax. If the value of a message selector is an empty string, the value is treated as a null and indicates that there is no message selector for the message consumer.

The order of evaluation of a message selector is from left to right within precedence level. Parentheses can be used to change this order.

Predefined selector literals and operator names are shown here in uppercase; however, they are case insensitive.

A selector can contain:

  • Literals:
    • A string literal is enclosed in single quotes, with a single quote represented by doubled single quote; for example, 'literal' and 'literal''s'. Like string literals in the Java programming language, these use the Unicode character encoding.
    • An exact numeric literal is a numeric value without a decimal point, such as 57, -957, and +62; numbers in the range of long are supported. Exact numeric literals use the integer literal syntax of the Java programming language.
    • An approximate numeric literal is a numeric value in scientific notation, such as 7E3 and -57.9E2, or a numeric value with a decimal, such as 7., -95.7, and +6.2; numbers in the range of double are supported. Approximate literals use the floating-point literal syntax of the Java programming language.
    • The boolean literals TRUE and FALSE.
  • Identifiers:
    • An identifier is an unlimited-length sequence of letters and digits, the first of which must be a letter. A letter is any character for which the method Character.isJavaLetter returns true. This includes '_' and '$'. A letter or digit is any character for which the method Character.isJavaLetterOrDigit returns true.
    • Identifiers cannot be the names NULL, TRUE, and FALSE.
    • Identifiers cannot be NOT, AND, OR, BETWEEN, LIKE, IN, IS, or ESCAPE.
    • Identifiers are either header field references or property references. The type of a property value in a message selector corresponds to the type used to set the property. If a property that does not exist in a message is referenced, its value is NULL.
    • The conversions that apply to the get methods for properties do not apply when a property is used in a message selector expression. For example, suppose you set a property as a string value, as in the following:
      myMessage.setStringProperty("NumberOfOrders", "2");
      The following expression in a message selector would evaluate to false, because a string cannot be used in an arithmetic expression:
      "NumberOfOrders > 1"
    • Identifiers are case-sensitive.
    • Message header field references are restricted to JMSDeliveryMode, JMSPriority, JMSMessageID, JMSTimestamp, JMSCorrelationID, and JMSType. JMSMessageID, JMSCorrelationID, and JMSType values may be null and if so are treated as a NULL value.
    • Any name beginning with 'JMSX' is a JMS defined property name.
    • Any name beginning with 'JMS_' is a provider-specific property name.
    • Any name that does not begin with 'JMS' is an application-specific property name.
  • White space is the same as that defined for the Java programming language: space, horizontal tab, form feed, and line terminator.
  • Expressions:
    • A selector is a conditional expression; a selector that evaluates to true matches; a selector that evaluates to false or unknown does not match.
    • Arithmetic expressions are composed of themselves, arithmetic operations, identifiers (whose value is treated as a numeric literal), and numeric literals.
    • Conditional expressions are composed of themselves, comparison operations, and logical operations.
  • Standard bracketing () for ordering expression evaluation is supported.
  • Logical operators in precedence order: NOT, AND, OR
  • Comparison operators: =, >, >=, <</CODE>, <=< /code="/code">, (not equal)
    • Only like type values can be compared. One exception is that it is valid to compare exact numeric values and approximate numeric values; the type conversion required is defined by the rules of numeric promotion in the Java programming language. If the comparison of non-like type values is attempted, the value of the operation is false. If either of the type values evaluates to NULL, the value of the expression is unknown.
    • String and boolean comparison is restricted to = and . Two strings are equal if and only if they contain the same sequence of characters.
  • Arithmetic operators in precedence order:
    • +, - (unary)
    • *, / (multiplication and division)
    • +, - (addition and subtraction)
    • Arithmetic operations must use numeric promotion in the Java programming language.
  • arithmetic-expr1 [NOT] BETWEEN arithmetic-expr2 AND arithmetic-expr3 (comparison operator)
    • "age BETWEEN 15 AND 19" is equivalent to "age >= 15 AND age <= 19"< /code="/code">
    • "age NOT BETWEEN 15 AND 19" is equivalent to "age < 15 or age > 19"
  • identifier [NOT] IN (string-literal1, string-literal2,...) (comparison operator where identifier has a String or NULL value)
    • "Country IN (' UK', 'US', 'France')" is true for 'UK' and false for 'Peru'; it is equivalent to the expression "(Country = ' UK') OR (Country = ' US') OR (Country = ' France')"
    • "Country NOT IN (' UK', 'US', 'France')" is false for 'UK' and true for 'Peru'; it is equivalent to the expression "NOT ((Country = ' UK') OR (Country = ' US') OR (Country = ' France'))"
    • If identifier of an IN or NOT IN operation is NULL, the value of the operation is unknown.
  • identifier [NOT] LIKE pattern-value [ESCAPE escape-character] (comparison operator, where identifier has a String value; pattern-value is a string literal where '_' stands for any single character; '%' stands for any sequence of characters, including the empty sequence; and all other characters stand for themselves. The optional escape-character is a single-character string literal whose character is used to escape the special meaning of the '_' and '%' in pattern-value.)
    • "phone LIKE '12%3'" is true for '123' or '12993' and false for '1234'
    • "word LIKE 'l_se'" is true for 'lose' and false for 'loose'
    • "underscored LIKE '\_%' ESCAPE '\'" is true for '_foo' and false for 'bar'
    • "phone NOT LIKE '12%3'" is false for '123' or '12993' and true for '1234'
    • If identifier of a LIKE or NOT LIKE operation is NULL, the value of the operation is unknown.
  • identifier IS NULL (comparison operator that tests for a null header field value or a missing property value)
    • "prop_name IS NULL"
  • identifier IS NOT NULL (comparison operator that tests for the existence of a non-null header field value or a property value)
    • "prop_name IS NOT NULL"

    JMS providers are required to verify the syntactic correctness of a message selector at the time it is presented. A method that provides a syntactically incorrect selector must result in a JMSException. JMS providers may also optionally provide some semantic checking at the time the selector is presented. Not all semantic checking can be performed at the time a message selector is presented, because property types are not known.

    The following message selector selects messages with a message type of car and color of blue and weight greater than 2500 pounds:

    "JMSType = 'car' AND color = 'blue' AND weight > 2500"

    Null Values

    As noted above, property values may be NULL. The evaluation of selector expressions containing NULL values is defined by SQL92 NULL semantics. A brief description of these semantics is provided here.

    SQL treats a NULL value as unknown. Comparison or arithmetic with an unknown value always yields an unknown value.

    The IS NULL and IS NOT NULL operators convert an unknown value into the respective TRUE and FALSE values.

    The boolean operators use three-valued logic as defined by the following tables:

    The definition of the AND operator

     | AND  |   T   |   F   |   U
     +------+-------+-------+-------
     |  T   |   T   |   F   |   U
     |  F   |   F   |   F   |   F
     |  U   |   U   |   F   |   U
     +------+-------+-------+-------
     

    The definition of the OR operator

     | OR   |   T   |   F   |   U
     +------+-------+-------+--------
     |  T   |   T   |   T   |   T
     |  F   |   T   |   F   |   U
     |  U   |   T   |   U   |   U
     +------+-------+-------+------- 
     

    The definition of the NOT operator

     | NOT
     +------+------
     |  T   |   F
     |  F   |   T
     |  U   |   U
     +------+-------
     

    Special Notes

    When used in a message selector, the JMSDeliveryMode header field is treated as having the values 'PERSISTENT' and 'NON_PERSISTENT'.

    Date and time values should use the standard long millisecond value. When a date or time literal is included in a message selector, it should be an integer literal for a millisecond value. The standard way to produce millisecond values is to use java.util.Calendar.

    Although SQL supports fixed decimal comparison and arithmetic, JMS message selectors do not. This is the reason for restricting exact numeric literals to those without a decimal (and the addition of numerics with a decimal as an alternate representation for approximate numeric values).

    SQL comments are not supported.

    See Also:
    MessageConsumer.receive(), MessageConsumer.receive(long), MessageConsumer.receiveNoWait(), MessageListener.onMessage(Message), BytesMessage, MapMessage, ObjectMessage, StreamMessage, TextMessage

    Field Summary
    static int DEFAULT_DELIVERY_MODE
              The message producer's default delivery mode is PERSISTENT.
    static int DEFAULT_PRIORITY
              The message producer's default priority is 4.
    static long DEFAULT_TIME_TO_LIVE
              The message producer's default time to live is unlimited; the message never expires.
     
    Method Summary
     void acknowledge()
              Acknowledges all consumed messages of the session of this consumed message.
     void clearBody()
              Clears out the message body.
     void clearProperties()
              Clears a message's properties.
     boolean getBooleanProperty(java.lang.String name)
              Returns the value of the boolean property with the specified name.
     byte getByteProperty(java.lang.String name)
              Returns the value of the byte property with the specified name.
     double getDoubleProperty(java.lang.String name)
              Returns the value of the double property with the specified name.
     float getFloatProperty(java.lang.String name)
              Returns the value of the float property with the specified name.
     int getIntProperty(java.lang.String name)
              Returns the value of the int property with the specified name.
     java.lang.String getJMSCorrelationID()
              Gets the correlation ID for the message.
     byte[] getJMSCorrelationIDAsBytes()
              Gets the correlation ID as an array of bytes for the message.
     int getJMSDeliveryMode()
              Gets the DeliveryMode value specified for this message.
     Destination getJMSDestination()
              Gets the Destination object for this message.
     long getJMSExpiration()
              Gets the message's expiration value.
     java.lang.String getJMSMessageID()
              Gets the message ID.
     int getJMSPriority()
              Gets the message priority level.
     boolean getJMSRedelivered()
              Gets an indication of whether this message is being redelivered.
     Destination getJMSReplyTo()
              Gets the Destination object to which a reply to this message should be sent.
     long getJMSTimestamp()
              Gets the message timestamp.
     java.lang.String getJMSType()
              Gets the message type identifier supplied by the client when the message was sent.
     long getLongProperty(java.lang.String name)
              Returns the value of the long property with the specified name.
     java.lang.Object getObjectProperty(java.lang.String name)
              Returns the value of the Java object property with the specified name.
     java.util.Enumeration getPropertyNames()
              Returns an Enumeration of all the property names.
     short getShortProperty(java.lang.String name)
              Returns the value of the short property with the specified name.
     java.lang.String getStringProperty(java.lang.String name)
              Returns the value of the String property with the specified name.
     boolean propertyExists(java.lang.String name)
              Indicates whether a property value exists.
     void setBooleanProperty(java.lang.String name, boolean value)
              Sets a boolean property value with the specified name into the message.
     void setByteProperty(java.lang.String name, byte value)
              Sets a byte property value with the specified name into the message.
     void setDoubleProperty(java.lang.String name, double value)
              Sets a double property value with the specified name into the message.
     void setFloatProperty(java.lang.String name, float value)
              Sets a float property value with the specified name into the message.
     void setIntProperty(java.lang.String name, int value)
              Sets an int property value with the specified name into the message.
     void setJMSCorrelationID(java.lang.String correlationID)
              Sets the correlation ID for the message.
     void setJMSCorrelationIDAsBytes(byte[] correlationID)
              Sets the correlation ID as an array of bytes for the message.
     void setJMSDeliveryMode(int deliveryMode)
              Sets the DeliveryMode value for this message.
     void setJMSDestination(Destination destination)
              Sets the Destination object for this message.
     void setJMSExpiration(long expiration)
              Sets the message's expiration value.
     void setJMSMessageID(java.lang.String id)
              Sets the message ID.
     void setJMSPriority(int priority)
              Sets the priority level for this message.
     void setJMSRedelivered(boolean redelivered)
              Specifies whether this message is being redelivered.
     void setJMSReplyTo(Destination replyTo)
              Sets the Destination object to which a reply to this message should be sent.
     void setJMSTimestamp(long timestamp)
              Sets the message timestamp.
     void setJMSType(java.lang.String type)
              Sets the message type.
     void setLongProperty(java.lang.String name, long value)
              Sets a long property value with the specified name into the message.
     void setObjectProperty(java.lang.String name, java.lang.Object value)
              Sets a Java object property value with the specified name into the message.
     void setShortProperty(java.lang.String name, short value)
              Sets a short property value with the specified name into the message.
     void setStringProperty(java.lang.String name, java.lang.String value)
              Sets a String property value with the specified name into the message.
     

    Field Detail

    DEFAULT_DELIVERY_MODE

    static final int DEFAULT_DELIVERY_MODE
    The message producer's default delivery mode is PERSISTENT.

    See Also:
    DeliveryMode#PERSISTENT, Constant Field Values

    DEFAULT_PRIORITY

    static final int DEFAULT_PRIORITY
    The message producer's default priority is 4.

    See Also:
    Constant Field Values

    DEFAULT_TIME_TO_LIVE

    static final long DEFAULT_TIME_TO_LIVE
    The message producer's default time to live is unlimited; the message never expires.

    See Also:
    Constant Field Values
    Method Detail

    getJMSMessageID

    java.lang.String getJMSMessageID()
                                     throws JMSException
    Gets the message ID.

    The JMSMessageID header field contains a value that uniquely identifies each message sent by a provider.

    When a message is sent, JMSMessageID can be ignored. When the send or publish method returns, it contains a provider-assigned value.

    A JMSMessageID is a String value that should function as a unique key for identifying messages in a historical repository. The exact scope of uniqueness is provider-defined. It should at least cover all messages for a specific installation of a provider, where an installation is some connected set of message routers.

    All JMSMessageID values must start with the prefix 'ID:'. Uniqueness of message ID values across different providers is not required.

    Since message IDs take some effort to create and increase a message's size, some JMS providers may be able to optimize message overhead if they are given a hint that the message ID is not used by an application. By calling the MessageProducer.setDisableMessageID method, a JMS client enables this potential optimization for all messages sent by that message producer. If the JMS provider accepts this hint, these messages must have the message ID set to null; if the provider ignores the hint, the message ID must be set to its normal unique value.

    Returns:
    the message ID
    Throws:
    JMSException - if the JMS provider fails to get the message ID due to some internal error.
    See Also:
    setJMSMessageID(String), MessageProducer.setDisableMessageID(boolean)

    setJMSMessageID

    void setJMSMessageID(java.lang.String id)
                         throws JMSException
    Sets the message ID.

    JMS providers set this field when a message is sent. This method can be used to change the value for a message that has been received.

    Parameters:
    id - the ID of the message
    Throws:
    JMSException - if the JMS provider fails to set the message ID due to some internal error.
    See Also:
    getJMSMessageID()

    getJMSTimestamp

    long getJMSTimestamp()
                         throws JMSException
    Gets the message timestamp.

    The JMSTimestamp header field contains the time a message was handed off to a provider to be sent. It is not the time the message was actually transmitted, because the actual send may occur later due to transactions or other client-side queueing of messages.

    When a message is sent, JMSTimestamp is ignored. When the send or publish method returns, it contains a time value somewhere in the interval between the call and the return. The value is in the format of a normal millis time value in the Java programming language.

    Since timestamps take some effort to create and increase a message's size, some JMS providers may be able to optimize message overhead if they are given a hint that the timestamp is not used by an application. By calling the MessageProducer.setDisableMessageTimestamp method, a JMS client enables this potential optimization for all messages sent by that message producer. If the JMS provider accepts this hint, these messages must have the timestamp set to zero; if the provider ignores the hint, the timestamp must be set to its normal value.

    Returns:
    the message timestamp
    Throws:
    JMSException - if the JMS provider fails to get the timestamp due to some internal error.
    See Also:
    setJMSTimestamp(long), MessageProducer.setDisableMessageTimestamp(boolean)

    setJMSTimestamp

    void setJMSTimestamp(long timestamp)
                         throws JMSException
    Sets the message timestamp.

    JMS providers set this field when a message is sent. This method can be used to change the value for a message that has been received.

    Parameters:
    timestamp - the timestamp for this message
    Throws:
    JMSException - if the JMS provider fails to set the timestamp due to some internal error.
    See Also:
    getJMSTimestamp()

    getJMSCorrelationIDAsBytes

    byte[] getJMSCorrelationIDAsBytes()
                                      throws JMSException
    Gets the correlation ID as an array of bytes for the message.

    The use of a byte[] value for JMSCorrelationID is non-portable.

    Returns:
    the correlation ID of a message as an array of bytes
    Throws:
    JMSException - if the JMS provider fails to get the correlation ID due to some internal error.
    See Also:
    setJMSCorrelationID(String), getJMSCorrelationID(), setJMSCorrelationIDAsBytes(byte[])

    setJMSCorrelationIDAsBytes

    void setJMSCorrelationIDAsBytes(byte[] correlationID)
                                    throws JMSException
    Sets the correlation ID as an array of bytes for the message.

    The array is copied before the method returns, so future modifications to the array will not alter this message header.

    If a provider supports the native concept of correlation ID, a JMS client may need to assign specific JMSCorrelationID values to match those expected by native messaging clients. JMS providers without native correlation ID values are not required to support this method and its corresponding get method; their implementation may throw a java.lang.UnsupportedOperationException.

    The use of a byte[] value for JMSCorrelationID is non-portable.

    Parameters:
    correlationID - the correlation ID value as an array of bytes
    Throws:
    JMSException - if the JMS provider fails to set the correlation ID due to some internal error.
    See Also:
    setJMSCorrelationID(String), getJMSCorrelationID(), getJMSCorrelationIDAsBytes()

    setJMSCorrelationID

    void setJMSCorrelationID(java.lang.String correlationID)
                             throws JMSException
    Sets the correlation ID for the message.

    A client can use the JMSCorrelationID header field to link one message with another. A typical use is to link a response message with its request message.

    JMSCorrelationID can hold one of the following:

    • A provider-specific message ID
    • An application-specific String
    • A provider-native byte[] value

    Since each message sent by a JMS provider is assigned a message ID value, it is convenient to link messages via message ID. All message ID values must start with the 'ID:' prefix.

    In some cases, an application (made up of several clients) needs to use an application-specific value for linking messages. For instance, an application may use JMSCorrelationID to hold a value referencing some external information. Application-specified values must not start with the 'ID:' prefix; this is reserved for provider-generated message ID values.

    If a provider supports the native concept of correlation ID, a JMS client may need to assign specific JMSCorrelationID values to match those expected by clients that do not use the JMS API. A byte[] value is used for this purpose. JMS providers without native correlation ID values are not required to support byte[] values. The use of a byte[] value for JMSCorrelationID is non-portable.

    Parameters:
    correlationID - the message ID of a message being referred to
    Throws:
    JMSException - if the JMS provider fails to set the correlation ID due to some internal error.
    See Also:
    getJMSCorrelationID(), getJMSCorrelationIDAsBytes(), setJMSCorrelationIDAsBytes(byte[])

    getJMSCorrelationID

    java.lang.String getJMSCorrelationID()
                                         throws JMSException
    Gets the correlation ID for the message.

    This method is used to return correlation ID values that are either provider-specific message IDs or application-specific String values.

    Returns:
    the correlation ID of a message as a String
    Throws:
    JMSException - if the JMS provider fails to get the correlation ID due to some internal error.
    See Also:
    setJMSCorrelationID(String), getJMSCorrelationIDAsBytes(), setJMSCorrelationIDAsBytes(byte[])

    getJMSReplyTo

    Destination getJMSReplyTo()
                              throws JMSException
    Gets the Destination object to which a reply to this message should be sent.

    Returns:
    Destination to which to send a response to this message
    Throws:
    JMSException - if the JMS provider fails to get the JMSReplyTo destination due to some internal error.
    See Also:
    setJMSReplyTo(Destination)

    setJMSReplyTo

    void setJMSReplyTo(Destination replyTo)
                       throws JMSException
    Sets the Destination object to which a reply to this message should be sent.

    The JMSReplyTo header field contains the destination where a reply to the current message should be sent. If it is null, no reply is expected. The destination may be either a Queue object or a Topic object.

    Messages sent with a null JMSReplyTo value may be a notification of some event, or they may just be some data the sender thinks is of interest.

    Messages with a JMSReplyTo value typically expect a response. A response is optional; it is up to the client to decide. These messages are called requests. A message sent in response to a request is called a reply.

    In some cases a client may wish to match a request it sent earlier with a reply it has just received. The client can use the JMSCorrelationID header field for this purpose.

    Parameters:
    replyTo - Destination to which to send a response to this message
    Throws:
    JMSException - if the JMS provider fails to set the JMSReplyTo destination due to some internal error.
    See Also:
    getJMSReplyTo()

    getJMSDestination

    Destination getJMSDestination()
                                  throws JMSException
    Gets the Destination object for this message.

    The JMSDestination header field contains the destination to which the message is being sent.

    When a message is sent, this field is ignored. After completion of the send or publish method, the field holds the destination specified by the method.

    When a message is received, its JMSDestination value must be equivalent to the value assigned when it was sent.

    Returns:
    the destination of this message
    Throws:
    JMSException - if the JMS provider fails to get the destination due to some internal error.
    See Also:
    setJMSDestination(Destination)

    setJMSDestination

    void setJMSDestination(Destination destination)
                           throws JMSException
    Sets the Destination object for this message.

    JMS providers set this field when a message is sent. This method can be used to change the value for a message that has been received.

    Parameters:
    destination - the destination for this message
    Throws:
    JMSException - if the JMS provider fails to set the destination due to some internal error.
    See Also:
    getJMSDestination()

    getJMSDeliveryMode

    int getJMSDeliveryMode()
                           throws JMSException
    Gets the DeliveryMode value specified for this message.

    Returns:
    the delivery mode for this message
    Throws:
    JMSException - if the JMS provider fails to get the delivery mode due to some internal error.
    See Also:
    setJMSDeliveryMode(int), DeliveryMode

    setJMSDeliveryMode

    void setJMSDeliveryMode(int deliveryMode)
                            throws JMSException
    Sets the DeliveryMode value for this message.

    JMS providers set this field when a message is sent. This method can be used to change the value for a message that has been received.

    Parameters:
    deliveryMode - the delivery mode for this message
    Throws:
    JMSException - if the JMS provider fails to set the delivery mode due to some internal error.
    See Also:
    getJMSDeliveryMode(), DeliveryMode

    getJMSRedelivered

    boolean getJMSRedelivered()
                              throws JMSException
    Gets an indication of whether this message is being redelivered.

    If a client receives a message with the JMSRedelivered field set, it is likely, but not guaranteed, that this message was delivered earlier but that its receipt was not acknowledged at that time.

    Returns:
    true if this message is being redelivered
    Throws:
    JMSException - if the JMS provider fails to get the redelivered state due to some internal error.
    See Also:
    setJMSRedelivered(boolean)

    setJMSRedelivered

    void setJMSRedelivered(boolean redelivered)
                           throws JMSException
    Specifies whether this message is being redelivered.

    This field is set at the time the message is delivered. This method can be used to change the value for a message that has been received.

    Parameters:
    redelivered - an indication of whether this message is being redelivered
    Throws:
    JMSException - if the JMS provider fails to set the redelivered state due to some internal error.
    See Also:
    getJMSRedelivered()

    getJMSType

    java.lang.String getJMSType()
                                throws JMSException
    Gets the message type identifier supplied by the client when the message was sent.

    Returns:
    the message type
    Throws:
    JMSException - if the JMS provider fails to get the message type due to some internal error.
    See Also:
    setJMSType(String)

    setJMSType

    void setJMSType(java.lang.String type)
                    throws JMSException
    Sets the message type.

    Some JMS providers use a message repository that contains the definitions of messages sent by applications. The JMSType header field may reference a message's definition in the provider's repository.

    The JMS API does not define a standard message definition repository, nor does it define a naming policy for the definitions it contains.

    Some messaging systems require that a message type definition for each application message be created and that each message specify its type. In order to work with such JMS providers, JMS clients should assign a value to JMSType, whether the application makes use of it or not. This ensures that the field is properly set for those providers that require it.

    To ensure portability, JMS clients should use symbolic values for JMSType that can be configured at installation time to the values defined in the current provider's message repository. If string literals are used, they may not be valid type names for some JMS providers.

    Parameters:
    type - the message type
    Throws:
    JMSException - if the JMS provider fails to set the message type due to some internal error.
    See Also:
    getJMSType()

    getJMSExpiration

    long getJMSExpiration()
                          throws JMSException
    Gets the message's expiration value.

    When a message is sent, the JMSExpiration header field is left unassigned. After completion of the send or publish method, it holds the expiration time of the message. This is the sum of the time-to-live value specified by the client and the GMT at the time of the send or publish.

    If the time-to-live is specified as zero, JMSExpiration is set to zero to indicate that the message does not expire.

    When a message's expiration time is reached, a provider should discard it. The JMS API does not define any form of notification of message expiration.

    Clients should not receive messages that have expired; however, the JMS API does not guarantee that this will not happen.

    Returns:
    the time the message expires, which is the sum of the time-to-live value specified by the client and the GMT at the time of the send
    Throws:
    JMSException - if the JMS provider fails to get the message expiration due to some internal error.
    See Also:
    setJMSExpiration(long)

    setJMSExpiration

    void setJMSExpiration(long expiration)
                          throws JMSException
    Sets the message's expiration value.

    JMS providers set this field when a message is sent. This method can be used to change the value for a message that has been received.

    Parameters:
    expiration - the message's expiration time
    Throws:
    JMSException - if the JMS provider fails to set the message expiration due to some internal error.
    See Also:
    getJMSExpiration()

    getJMSPriority

    int getJMSPriority()
                       throws JMSException
    Gets the message priority level.

    The JMS API defines ten levels of priority value, with 0 as the lowest priority and 9 as the highest. In addition, clients should consider priorities 0-4 as gradations of normal priority and priorities 5-9 as gradations of expedited priority.

    The JMS API does not require that a provider strictly implement priority ordering of messages; however, it should do its best to deliver expedited messages ahead of normal messages.

    Returns:
    the default message priority
    Throws:
    JMSException - if the JMS provider fails to get the message priority due to some internal error.
    See Also:
    setJMSPriority(int)

    setJMSPriority

    void setJMSPriority(int priority)
                        throws JMSException
    Sets the priority level for this message.

    JMS providers set this field when a message is sent. This method can be used to change the value for a message that has been received.

    Parameters:
    priority - the priority of this message
    Throws:
    JMSException - if the JMS provider fails to set the message priority due to some internal error.
    See Also:
    getJMSPriority()

    clearProperties

    void clearProperties()
                         throws JMSException
    Clears a message's properties.

    The message's header fields and body are not cleared.

    Throws:
    JMSException - if the JMS provider fails to clear the message properties due to some internal error.

    propertyExists

    boolean propertyExists(java.lang.String name)
                           throws JMSException
    Indicates whether a property value exists.

    Parameters:
    name - the name of the property to test
    Returns:
    true if the property exists
    Throws:
    JMSException - if the JMS provider fails to determine if the property exists due to some internal error.

    getBooleanProperty

    boolean getBooleanProperty(java.lang.String name)
                               throws JMSException
    Returns the value of the boolean property with the specified name.

    Parameters:
    name - the name of the boolean property
    Returns:
    the boolean property value for the specified name
    Throws:
    JMSException - if the JMS provider fails to get the property value due to some internal error.
    MessageFormatException - if this type conversion is invalid.

    getByteProperty

    byte getByteProperty(java.lang.String name)
                         throws JMSException
    Returns the value of the byte property with the specified name.

    Parameters:
    name - the name of the byte property
    Returns:
    the byte property value for the specified name
    Throws:
    JMSException - if the JMS provider fails to get the property value due to some internal error.
    MessageFormatException - if this type conversion is invalid.

    getShortProperty

    short getShortProperty(java.lang.String name)
                           throws JMSException
    Returns the value of the short property with the specified name.

    Parameters:
    name - the name of the short property
    Returns:
    the short property value for the specified name
    Throws:
    JMSException - if the JMS provider fails to get the property value due to some internal error.
    MessageFormatException - if this type conversion is invalid.

    getIntProperty

    int getIntProperty(java.lang.String name)
                       throws JMSException
    Returns the value of the int property with the specified name.

    Parameters:
    name - the name of the int property
    Returns:
    the int property value for the specified name
    Throws:
    JMSException - if the JMS provider fails to get the property value due to some internal error.
    MessageFormatException - if this type conversion is invalid.

    getLongProperty

    long getLongProperty(java.lang.String name)
                         throws JMSException
    Returns the value of the long property with the specified name.

    Parameters:
    name - the name of the long property
    Returns:
    the long property value for the specified name
    Throws:
    JMSException - if the JMS provider fails to get the property value due to some internal error.
    MessageFormatException - if this type conversion is invalid.

    getFloatProperty

    float getFloatProperty(java.lang.String name)
                           throws JMSException
    Returns the value of the float property with the specified name.

    Parameters:
    name - the name of the float property
    Returns:
    the float property value for the specified name
    Throws:
    JMSException - if the JMS provider fails to get the property value due to some internal error.
    MessageFormatException - if this type conversion is invalid.

    getDoubleProperty

    double getDoubleProperty(java.lang.String name)
                             throws JMSException
    Returns the value of the double property with the specified name.

    Parameters:
    name - the name of the double property
    Returns:
    the double property value for the specified name
    Throws:
    JMSException - if the JMS provider fails to get the property value due to some internal error.
    MessageFormatException - if this type conversion is invalid.

    getStringProperty

    java.lang.String getStringProperty(java.lang.String name)
                                       throws JMSException
    Returns the value of the String property with the specified name.

    Parameters:
    name - the name of the String property
    Returns:
    the String property value for the specified name; if there is no property by this name, a null value is returned
    Throws:
    JMSException - if the JMS provider fails to get the property value due to some internal error.
    MessageFormatException - if this type conversion is invalid.

    getObjectProperty

    java.lang.Object getObjectProperty(java.lang.String name)
                                       throws JMSException
    Returns the value of the Java object property with the specified name.

    This method can be used to return, in objectified format, an object that has been stored as a property in the message with the equivalent setObjectProperty method call, or its equivalent primitive settypeProperty method.

    Parameters:
    name - the name of the Java object property
    Returns:
    the Java object property value with the specified name, in objectified format (for example, if the property was set as an int, an Integer is returned); if there is no property by this name, a null value is returned
    Throws:
    JMSException - if the JMS provider fails to get the property value due to some internal error.

    getPropertyNames

    java.util.Enumeration getPropertyNames()
                                           throws JMSException
    Returns an Enumeration of all the property names.

    Note that JMS standard header fields are not considered properties and are not returned in this enumeration.

    Returns:
    an enumeration of all the names of property values
    Throws:
    JMSException - if the JMS provider fails to get the property names due to some internal error.

    setBooleanProperty

    void setBooleanProperty(java.lang.String name,
                            boolean value)
                            throws JMSException
    Sets a boolean property value with the specified name into the message.

    Parameters:
    name - the name of the boolean property
    value - the boolean property value to set
    Throws:
    JMSException - if the JMS provider fails to set the property due to some internal error.
    java.lang.IllegalArgumentException - if the name is null or if the name is an empty string.
    MessageNotWriteableException - if properties are read-only

    setByteProperty

    void setByteProperty(java.lang.String name,
                         byte value)
                         throws JMSException
    Sets a byte property value with the specified name into the message.

    Parameters:
    name - the name of the byte property
    value - the byte property value to set
    Throws:
    JMSException - if the JMS provider fails to set the property due to some internal error.
    java.lang.IllegalArgumentException - if the name is null or if the name is an empty string.
    MessageNotWriteableException - if properties are read-only

    setShortProperty

    void setShortProperty(java.lang.String name,
                          short value)
                          throws JMSException
    Sets a short property value with the specified name into the message.

    Parameters:
    name - the name of the short property
    value - the short property value to set
    Throws:
    JMSException - if the JMS provider fails to set the property due to some internal error.
    java.lang.IllegalArgumentException - if the name is null or if the name is an empty string.
    MessageNotWriteableException - if properties are read-only

    setIntProperty

    void setIntProperty(java.lang.String name,
                        int value)
                        throws JMSException
    Sets an int property value with the specified name into the message.

    Parameters:
    name - the name of the int property
    value - the int property value to set
    Throws:
    JMSException - if the JMS provider fails to set the property due to some internal error.
    java.lang.IllegalArgumentException - if the name is null or if the name is an empty string.
    MessageNotWriteableException - if properties are read-only

    setLongProperty

    void setLongProperty(java.lang.String name,
                         long value)
                         throws JMSException
    Sets a long property value with the specified name into the message.

    Parameters:
    name - the name of the long property
    value - the long property value to set
    Throws:
    JMSException - if the JMS provider fails to set the property due to some internal error.
    java.lang.IllegalArgumentException - if the name is null or if the name is an empty string.
    MessageNotWriteableException - if properties are read-only

    setFloatProperty

    void setFloatProperty(java.lang.String name,
                          float value)
                          throws JMSException
    Sets a float property value with the specified name into the message.

    Parameters:
    name - the name of the float property
    value - the float property value to set
    Throws:
    JMSException - if the JMS provider fails to set the property due to some internal error.
    java.lang.IllegalArgumentException - if the name is null or if the name is an empty string.
    MessageNotWriteableException - if properties are read-only

    setDoubleProperty

    void setDoubleProperty(java.lang.String name,
                           double value)
                           throws JMSException
    Sets a double property value with the specified name into the message.

    Parameters:
    name - the name of the double property
    value - the double property value to set
    Throws:
    JMSException - if the JMS provider fails to set the property due to some internal error.
    java.lang.IllegalArgumentException - if the name is null or if the name is an empty string.
    MessageNotWriteableException - if properties are read-only

    setStringProperty

    void setStringProperty(java.lang.String name,
                           java.lang.String value)
                           throws JMSException
    Sets a String property value with the specified name into the message.

    Parameters:
    name - the name of the String property
    value - the String property value to set
    Throws:
    JMSException - if the JMS provider fails to set the property due to some internal error.
    java.lang.IllegalArgumentException - if the name is null or if the name is an empty string.
    MessageNotWriteableException - if properties are read-only

    setObjectProperty

    void setObjectProperty(java.lang.String name,
                           java.lang.Object value)
                           throws JMSException
    Sets a Java object property value with the specified name into the message.

    Note that this method works only for the objectified primitive object types (Integer, Double, Long ...) and String objects.

    Parameters:
    name - the name of the Java object property
    value - the Java object property value to set
    Throws:
    JMSException - if the JMS provider fails to set the property due to some internal error.
    java.lang.IllegalArgumentException - if the name is null or if the name is an empty string.
    MessageFormatException - if the object is invalid
    MessageNotWriteableException - if properties are read-only

    acknowledge

    void acknowledge()
                     throws JMSException
    Acknowledges all consumed messages of the session of this consumed message.

    All consumed JMS messages support the acknowledge method for use when a client has specified that its JMS session's consumed messages are to be explicitly acknowledged. By invoking acknowledge on a consumed message, a client acknowledges all messages consumed by the session that the message was delivered to.

    Calls to acknowledge are ignored for both transacted sessions and sessions specified to use implicit acknowledgement modes.

    A client may individually acknowledge each message as it is consumed, or it may choose to acknowledge messages as an application-defined group (which is done by calling acknowledge on the last received message of the group, thereby acknowledging all messages consumed by the session.)

    Messages that have been received but not acknowledged may be redelivered.

    Throws:
    JMSException - if the JMS provider fails to acknowledge the messages due to some internal error.
    IllegalStateException - if this method is called on a closed session.
    See Also:
    Session.CLIENT_ACKNOWLEDGE

    clearBody

    void clearBody()
                   throws JMSException
    Clears out the message body. Clearing a message's body does not clear its header values or property entries.

    If this message body was read-only, calling this method leaves the message body in the same state as an empty body in a newly created message.

    Throws:
    JMSException - if the JMS provider fails to clear the message body due to some internal error.


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