IT. Expert System.

All Implemented Interfaces:

MatchResult

public final class Matcher
extends Object
implements MatchResult

• Method Summary

  Methods

  Modifier and Type	Method and Description
  Matcher	appendReplacement(StringBuffer buffer, String replacement) Appends a literal part of the input plus a replacement for the current match to a given StringBuffer.
  StringBuffer	appendTail(StringBuffer buffer) Appends the (unmatched) remainder of the input to the given StringBuffer.
  int	end() Returns the index of the first character following the text that matched the whole regular expression.
  int	end(int group) Returns the index of the first character following the text that matched a given group.
  protected void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
  boolean	find() Returns the next occurrence of the Pattern in the input.
  boolean	find(int start) Returns true if there is another match in the input, starting from the given position.
  String	group() Returns the text that matched the whole regular expression.
  String	group(int group) Returns the text that matched a given group of the regular expression.
  int	groupCount() Returns the number of groups in the results, which is always equal to the number of groups in the original regular expression.
  boolean	hasAnchoringBounds() Indicates whether this matcher has anchoring bounds enabled.
  boolean	hasTransparentBounds() Indicates whether this matcher has transparent bounds enabled.
  boolean	hitEnd() Indicates whether the last match hit the end of the input.
  boolean	lookingAt() Tries to match the Pattern, starting from the beginning of the region (or the beginning of the input, if no region has been set).
  boolean	matches() Tries to match the Pattern against the entire region (or the entire input, if no region has been set).
  Pattern	pattern() Returns the Pattern instance used inside this matcher.
  static String	quoteReplacement(String s) Returns a replacement string for the given one that has all backslashes and dollar signs escaped.
  Matcher	region(int start, int end) Resets this matcher and sets a region.
  int	regionEnd() Returns this matcher's region end, that is, the first character that is not considered for a match.
  int	regionStart() Returns this matcher's region start, that is, the first character that is considered for a match.
  String	replaceAll(String replacement) Replaces all occurrences of this matcher's pattern in the input with a given string.
  String	replaceFirst(String replacement) Replaces the first occurrence of this matcher's pattern in the input with a given string.
  boolean	requireEnd() Indicates whether more input might change a successful match into an unsuccessful one.
  Matcher	reset() Resets the Matcher.
  Matcher	reset(CharSequence input) Provides a new input and resets the Matcher.
  int	start() Returns the index of the first character of the text that matched the whole regular expression.
  int	start(int group) Returns the index of the first character of the text that matched a given group.
  MatchResult	toMatchResult() Converts the current match into a separate MatchResult instance that is independent from this matcher.
  Matcher	useAnchoringBounds(boolean value) Determines whether this matcher has anchoring bounds enabled or not.
  Matcher	usePattern(Pattern pattern) Sets a new pattern for the Matcher.
  Matcher	useTransparentBounds(boolean value) Determines whether this matcher has transparent bounds enabled or not.

  • Methods inherited from class java.lang.Object

    clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

• Method Detail

  • appendReplacement

    public Matcher appendReplacement(StringBuffer buffer,
                            String replacement)

    Appends a literal part of the input plus a replacement for the current match to a given StringBuffer. The literal part is exactly the part of the input between the previous match and the current match. The method can be used in conjunction with find() and appendTail(StringBuffer) to walk through the input and replace all occurrences of the Pattern with something else.

    Parameters:

    buffer - the StringBuffer to append to.

    replacement - the replacement text.

    Returns:

    the Matcher itself.

    Throws:

    IllegalStateException - if no successful match has been made.

  • reset

    public Matcher reset()

    Resets the Matcher. This results in the region being set to the whole input. Results of a previous find get lost. The next attempt to find an occurrence of the Pattern in the string will start at the beginning of the input.

    Returns:

    the Matcher itself.

  • reset

    public Matcher reset(CharSequence input)

    Provides a new input and resets the Matcher. This results in the region being set to the whole input. Results of a previous find get lost. The next attempt to find an occurrence of the Pattern in the string will start at the beginning of the input.

    Parameters:

    input - the new input sequence.

    Returns:

    the Matcher itself.

  • usePattern

    public Matcher usePattern(Pattern pattern)

    Sets a new pattern for the Matcher. Results of a previous find get lost. The next attempt to find an occurrence of the Pattern in the string will start at the beginning of the input.

    Parameters:

    pattern - the new Pattern.

    Returns:

    the Matcher itself.

  • region

    public Matcher region(int start,
                 int end)

    Resets this matcher and sets a region. Only characters inside the region are considered for a match.

    Parameters:

    start - the first character of the region.

    end - the first character after the end of the region.

    Returns:

    the Matcher itself.

  • appendTail

    public StringBuffer appendTail(StringBuffer buffer)

    Appends the (unmatched) remainder of the input to the given StringBuffer. The method can be used in conjunction with find() and appendReplacement(StringBuffer, String) to walk through the input and replace all matches of the Pattern with something else.

    Parameters:

    buffer - the StringBuffer to append to.

    Returns:

    the StringBuffer.

    Throws:

    IllegalStateException - if no successful match has been made.

  • replaceFirst

    public String replaceFirst(String replacement)

    Replaces the first occurrence of this matcher's pattern in the input with a given string.

    Parameters:

    replacement - the replacement text.

    Returns:

    the modified input string.

  • replaceAll

    public String replaceAll(String replacement)

    Replaces all occurrences of this matcher's pattern in the input with a given string.

    Parameters:

    replacement - the replacement text.

    Returns:

    the modified input string.

  • pattern

    public Pattern pattern()

    Returns the Pattern instance used inside this matcher.

    Returns:

    the Pattern instance.

  • group

    public String group(int group)

    Returns the text that matched a given group of the regular expression. Explicit capturing groups in the pattern are numbered left to right in order of their opening parenthesis, starting at 1. The special group 0 represents the entire match (as if the entire pattern is surrounded by an implicit capturing group). For example, "a((b)c)" matching "abc" would give the following groups:

     0 "abc"
     1 "bc"
     2 "b"
     

    An optional capturing group that failed to match as part of an overall successful match (for example, "a(b)?c" matching "ac") returns null. A capturing group that matched the empty string (for example, "a(b?)c" matching "ac") returns the empty string.

    Specified by:

    group in interface MatchResult

    Parameters:

    group - the group, ranging from 0 to groupCount() - 1, with 0 representing the whole pattern.

    Returns:

    the text that matched the group.

    Throws:

    IllegalStateException - if no successful match has been made.

  • group

    public String group()

    Returns the text that matched the whole regular expression.

    Specified by:

    group in interface MatchResult

    Returns:

    the text.

    Throws:

    IllegalStateException - if no successful match has been made.

  • find

    public boolean find(int start)

    Returns true if there is another match in the input, starting from the given position. The region is ignored.

    Throws:

    IndexOutOfBoundsException - if start < 0 || start > input.length()

  • find

    public boolean find()

    Returns the next occurrence of the Pattern in the input. If a previous match was successful, the method continues the search from the first character following that match in the input. Otherwise it searches either from the region start (if one has been set), or from position 0.

    Returns:

    true if (and only if) a match has been found.

  • lookingAt

    public boolean lookingAt()

    Tries to match the Pattern, starting from the beginning of the region (or the beginning of the input, if no region has been set). Doesn't require the Pattern to match against the whole region.

    Returns:

    true if (and only if) the Pattern matches.

  • matches

    public boolean matches()

    Tries to match the Pattern against the entire region (or the entire input, if no region has been set).

    Returns:

    true if (and only if) the Pattern matches the entire region.

  • start

    public int start(int group)
              throws IllegalStateException

    Returns the index of the first character of the text that matched a given group.

    Specified by:

    start in interface MatchResult

    Parameters:

    group - the group, ranging from 0 to groupCount() - 1, with 0 representing the whole pattern.

    Returns:

    the character index.

    Throws:

    IllegalStateException - if no successful match has been made.

  • end

    public int end(int group)

    Returns the index of the first character following the text that matched a given group.

    Specified by:

    end in interface MatchResult

    Parameters:

    group - the group, ranging from 0 to groupCount() - 1, with 0 representing the whole pattern.

    Returns:

    the character index.

    Throws:

    IllegalStateException - if no successful match has been made.

  • quoteReplacement

    public static String quoteReplacement(String s)

    Returns a replacement string for the given one that has all backslashes and dollar signs escaped.

    Parameters:

    s - the input string.

    Returns:

    the input string, with all backslashes and dollar signs having been escaped.

  • start

    public int start()

    Returns the index of the first character of the text that matched the whole regular expression.

    Specified by:

    start in interface MatchResult

    Returns:

    the character index.

    Throws:

    IllegalStateException - if no successful match has been made.

  • groupCount

    public int groupCount()

    Returns the number of groups in the results, which is always equal to the number of groups in the original regular expression.

    Specified by:

    groupCount in interface MatchResult

    Returns:

    the number of groups.

  • end

    public int end()

    Returns the index of the first character following the text that matched the whole regular expression.

    Specified by:

    end in interface MatchResult

    Returns:

    the character index.

    Throws:

    IllegalStateException - if no successful match has been made.

  • toMatchResult

    public MatchResult toMatchResult()

    Converts the current match into a separate MatchResult instance that is independent from this matcher. The new object is unaffected when the state of this matcher changes.

    Returns:

    the new MatchResult.

    Throws:

    IllegalStateException - if no successful match has been made.

  • useAnchoringBounds

    public Matcher useAnchoringBounds(boolean value)

    Determines whether this matcher has anchoring bounds enabled or not. When anchoring bounds are enabled, the start and end of the input match the '^' and '$' meta-characters, otherwise not. Anchoring bounds are enabled by default.

    Parameters:

    value - the new value for anchoring bounds.

    Returns:

    the Matcher itself.

  • hasAnchoringBounds

    public boolean hasAnchoringBounds()

    Indicates whether this matcher has anchoring bounds enabled. When anchoring bounds are enabled, the start and end of the input match the '^' and '$' meta-characters, otherwise not. Anchoring bounds are enabled by default.

    Returns:

    true if (and only if) the Matcher uses anchoring bounds.

  • useTransparentBounds

    public Matcher useTransparentBounds(boolean value)

    Determines whether this matcher has transparent bounds enabled or not. When transparent bounds are enabled, the parts of the input outside the region are subject to lookahead and lookbehind, otherwise they are not. Transparent bounds are disabled by default.

    Parameters:

    value - the new value for transparent bounds.

    Returns:

    the Matcher itself.

  • hasTransparentBounds

    public boolean hasTransparentBounds()

    Indicates whether this matcher has transparent bounds enabled. When transparent bounds are enabled, the parts of the input outside the region are subject to lookahead and lookbehind, otherwise they are not. Transparent bounds are disabled by default.

    Returns:

    true if (and only if) the Matcher uses anchoring bounds.

  • regionStart

    public int regionStart()

    Returns this matcher's region start, that is, the first character that is considered for a match.

    Returns:

    the start of the region.

  • regionEnd

    public int regionEnd()

    Returns this matcher's region end, that is, the first character that is not considered for a match.

    Returns:

    the end of the region.

  • requireEnd

    public boolean requireEnd()

    Indicates whether more input might change a successful match into an unsuccessful one.

    Returns:

    true if (and only if) more input might change a successful match into an unsuccessful one.

  • hitEnd

    public boolean hitEnd()

    Indicates whether the last match hit the end of the input.

    Returns:

    true if (and only if) the last match hit the end of the input.

  • finalize

    protected void finalize()
                     throws Throwable

    Description copied from class: Object
    Invoked when the garbage collector has detected that this instance is no longer reachable. The default implementation does nothing, but this method can be overridden to free resources.

    Note that objects that override finalize are significantly more expensive than objects that don't. Finalizers may be run a long time after the object is no longer reachable, depending on memory pressure, so it's a bad idea to rely on them for cleanup. Note also that finalizers are run on a single VM-wide finalizer thread, so doing blocking work in a finalizer is a bad idea. A finalizer is usually only necessary for a class that has a native peer and needs to call a native method to destroy that peer. Even then, it's better to provide an explicit close method (and implement Closeable), and insist that callers manually dispose of instances. This works well for something like files, but less well for something like a BigInteger where typical calling code would have to deal with lots of temporaries. Unfortunately, code that creates lots of temporaries is the worst kind of code from the point of view of the single finalizer thread.

    If you must use finalizers, consider at least providing your own ReferenceQueue and having your own thread process that queue.

    Unlike constructors, finalizers are not automatically chained. You are responsible for calling super.finalize() yourself.

    Uncaught exceptions thrown by finalizers are ignored and do not terminate the finalizer thread. See Effective Java Item 7, "Avoid finalizers" for more.

    Overrides:

    finalize in class Object

    Throws:

    Throwable