public final class Matcher extends Object implements MatchResult
Pattern
to a given input. See Pattern
for
example uses.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.
|
public Matcher appendReplacement(StringBuffer buffer, String replacement)
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.buffer
- the StringBuffer
to append to.replacement
- the replacement text.Matcher
itself.IllegalStateException
- if no successful match has been made.public Matcher reset()
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.Matcher
itself.public Matcher reset(CharSequence input)
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.input
- the new input sequence.Matcher
itself.public Matcher usePattern(Pattern pattern)
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.pattern
- the new Pattern
.Matcher
itself.public Matcher region(int start, int end)
start
- the first character of the region.end
- the first character after the end of the region.Matcher
itself.public StringBuffer appendTail(StringBuffer buffer)
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.buffer
- the StringBuffer
to append to.StringBuffer
.IllegalStateException
- if no successful match has been made.public String replaceFirst(String replacement)
replacement
- the replacement text.public String replaceAll(String replacement)
replacement
- the replacement text.public Pattern pattern()
Pattern
instance used inside this matcher.Pattern
instance.public String group(int group)
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.
group
in interface MatchResult
group
- the group, ranging from 0 to groupCount() - 1, with 0
representing the whole pattern.IllegalStateException
- if no successful match has been made.public String group()
group
in interface MatchResult
IllegalStateException
- if no successful match has been made.public boolean find(int start)
IndexOutOfBoundsException
- if start < 0 || start > input.length()
public boolean find()
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.public boolean lookingAt()
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.Pattern
matches.public boolean matches()
Pattern
against the entire region (or the
entire input, if no region has been set).Pattern
matches the entire
region.public int start(int group) throws IllegalStateException
start
in interface MatchResult
group
- the group, ranging from 0 to groupCount() - 1, with 0
representing the whole pattern.IllegalStateException
- if no successful match has been made.public int end(int group)
end
in interface MatchResult
group
- the group, ranging from 0 to groupCount() - 1, with 0
representing the whole pattern.IllegalStateException
- if no successful match has been made.public static String quoteReplacement(String s)
s
- the input string.public int start()
start
in interface MatchResult
IllegalStateException
- if no successful match has been made.public int groupCount()
groupCount
in interface MatchResult
public int end()
end
in interface MatchResult
IllegalStateException
- if no successful match has been made.public MatchResult toMatchResult()
MatchResult
instance
that is independent from this matcher. The new object is unaffected when
the state of this matcher changes.MatchResult
.IllegalStateException
- if no successful match has been made.public Matcher useAnchoringBounds(boolean value)
value
- the new value for anchoring bounds.Matcher
itself.public boolean hasAnchoringBounds()
Matcher
uses anchoring bounds.public Matcher useTransparentBounds(boolean value)
value
- the new value for transparent bounds.Matcher
itself.public boolean hasTransparentBounds()
Matcher
uses anchoring bounds.public int regionStart()
public int regionEnd()
public boolean requireEnd()
public boolean hitEnd()
protected void finalize() throws Throwable
Object
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.