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org.apache.oro.text.awk
Class AwkMatcher  

java.lang.Object
  org.apache.oro.text.awk.AwkMatcher

All Implemented Interfaces:

org.apache.oro.text.regex.PatternMatcher

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public final class AwkMatcher

extends java.lang.Object

implements org.apache.oro.text.regex.PatternMatcher

The AwkMatcher class is used to match regular expressions (conforming to the Awk regular expression syntax) generated by AwkCompiler. AwkMatcher only supports 8-bit ASCII. Any attempt to match Unicode values greater than 255 will result in undefined behavior. AwkMatcher finds true leftmost-longest matches, so you must take care with how you formulate your regular expression to avoid matching more than you really want.

It is important for you to remember that AwkMatcher does not save parenthesized sub-group information. Therefore the number of groups saved in a MatchResult produced by AwkMatcher will always be 1.

Since:

1.0

Version:

@version@

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Field Summary
private  AwkPattern	__awkPattern
private  int	__beginOffset           A kluge variable to make PatternMatcherInput matches work when their begin offset is non-zero.
private  int	__lastMatchedBufferOffset
private  AwkMatchResult	__lastMatchResult
private  int[]	__offsets
private  AwkStreamInput	__scratchBuffer
private  AwkStreamInput	__streamSearchBuffer

 

Constructor Summary

AwkMatcher()

 

Method Summary
private  int	__streamMatchPrefix()
(package private)  void	_search()
boolean	contains(AwkStreamInput input, org.apache.oro.text.regex.Pattern pattern)           Determines if the contents of an AwkStreamInput, starting from the current offset of the input contains a pattern.
boolean	contains(char[] input, org.apache.oro.text.regex.Pattern pattern)           Determines if a string (represented as a char[]) contains a pattern.
boolean	contains(org.apache.oro.text.regex.PatternMatcherInput input, org.apache.oro.text.regex.Pattern pattern)           Determines if the contents of a PatternMatcherInput, starting from the current offset of the input contains a pattern.
boolean	contains(java.lang.String input, org.apache.oro.text.regex.Pattern pattern)           Determines if a string contains a pattern.
org.apache.oro.text.regex.MatchResult	getMatch()           Fetches the last match found by a call to a matches() or contains() method.
boolean	matches(char[] input, org.apache.oro.text.regex.Pattern pattern)           Determines if a string (represented as a char[]) exactly matches a given pattern.
boolean	matches(org.apache.oro.text.regex.PatternMatcherInput input, org.apache.oro.text.regex.Pattern pattern)           Determines if the contents of a PatternMatcherInput instance exactly matches a given pattern.
boolean	matches(java.lang.String input, org.apache.oro.text.regex.Pattern pattern)           Determines if a string exactly matches a given pattern.
boolean	matchesPrefix(char[] input, org.apache.oro.text.regex.Pattern pattern)           Determines if a prefix of a string (represented as a char[]) matches a given pattern.
boolean	matchesPrefix(char[] input, org.apache.oro.text.regex.Pattern pattern, int offset)           Determines if a prefix of a string (represented as a char[]) matches a given pattern, starting from a given offset into the string.
boolean	matchesPrefix(org.apache.oro.text.regex.PatternMatcherInput input, org.apache.oro.text.regex.Pattern pattern)           Determines if a prefix of a PatternMatcherInput instance matches a given pattern.
boolean	matchesPrefix(java.lang.String input, org.apache.oro.text.regex.Pattern pattern)           Determines if a prefix of a string matches a given pattern.

 

Methods inherited from class java.lang.Object

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

 

Field Detail

__lastMatchedBufferOffset

private int __lastMatchedBufferOffset

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__lastMatchResult

private AwkMatchResult __lastMatchResult

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__scratchBuffer

private AwkStreamInput __scratchBuffer

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__streamSearchBuffer

private AwkStreamInput __streamSearchBuffer

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__awkPattern

private AwkPattern __awkPattern

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__offsets

private int[] __offsets

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__beginOffset

private int __beginOffset

A kluge variable to make PatternMatcherInput matches work when their begin offset is non-zero. This kluge is caused by the misguided notion that AwkStreamInput could be overloaded to do both stream and fixed buffer matches. The whole input representation scheme has to be scrapped and redone. -- dfs 2001/07/10

Constructor Detail

AwkMatcher

public AwkMatcher()

Method Detail

matchesPrefix

public boolean matchesPrefix(char[] input,
                             org.apache.oro.text.regex.Pattern pattern,
                             int offset)

Determines if a prefix of a string (represented as a char[]) matches a given pattern, starting from a given offset into the string. If a prefix of the string matches the pattern, a MatchResult instance representing the match is made accesible via getMatch() 55 .

This method is useful for certain common token identification tasks that are made more difficult without this functionality.

Specified by:

matchesPrefix in interface org.apache.oro.text.regex.PatternMatcher

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matchesPrefix

public boolean matchesPrefix(char[] input,
                             org.apache.oro.text.regex.Pattern pattern)

Determines if a prefix of a string (represented as a char[]) matches a given pattern. If a prefix of the string matches the pattern, a MatchResult instance representing the match is made accesible via getMatch() 55 .

This method is useful for certain common token identification tasks that are made more difficult without this functionality.

Specified by:

matchesPrefix in interface org.apache.oro.text.regex.PatternMatcher

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matchesPrefix

public boolean matchesPrefix(java.lang.String input,
                             org.apache.oro.text.regex.Pattern pattern)

Determines if a prefix of a string matches a given pattern. If a prefix of the string matches the pattern, a MatchResult instance representing the match is made accesible via getMatch() 55 .

This method is useful for certain common token identification tasks that are made more difficult without this functionality.

Specified by:

matchesPrefix in interface org.apache.oro.text.regex.PatternMatcher

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matchesPrefix

public boolean matchesPrefix(org.apache.oro.text.regex.PatternMatcherInput input,
                             org.apache.oro.text.regex.Pattern pattern)

Determines if a prefix of a PatternMatcherInput instance matches a given pattern. If there is a match, a MatchResult instance representing the match is made accesible via getMatch() 55 . Unlike the contains(PatternMatcherInput, Pattern) 55 method, the current offset of the PatternMatcherInput argument is not updated. You should remember that the region starting from the begin offset of the PatternMatcherInput will be tested for a prefix match.

This method is useful for certain common token identification tasks that are made more difficult without this functionality.

Specified by:

matchesPrefix in interface org.apache.oro.text.regex.PatternMatcher

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matches

public boolean matches(char[] input,
                       org.apache.oro.text.regex.Pattern pattern)

Determines if a string (represented as a char[]) exactly matches a given pattern. If there is an exact match, a MatchResult instance representing the match is made accesible via getMatch() 55 . The pattern must be an AwkPattern instance, otherwise a ClassCastException will be thrown. You are not required to, and indeed should NOT try to (for performance reasons), catch a ClassCastException because it will never be thrown as long as you use an AwkPattern as the pattern parameter.

Specified by:

matches in interface org.apache.oro.text.regex.PatternMatcher

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matches

public boolean matches(java.lang.String input,
                       org.apache.oro.text.regex.Pattern pattern)

Determines if a string exactly matches a given pattern. If there is an exact match, a MatchResult instance representing the match is made accesible via getMatch() 55 . The pattern must be a AwkPattern instance, otherwise a ClassCastException will be thrown. You are not required to, and indeed should NOT try to (for performance reasons), catch a ClassCastException because it will never be thrown as long as you use an AwkPattern as the pattern parameter.

Specified by:

matches in interface org.apache.oro.text.regex.PatternMatcher

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matches

public boolean matches(org.apache.oro.text.regex.PatternMatcherInput input,
                       org.apache.oro.text.regex.Pattern pattern)

Determines if the contents of a PatternMatcherInput instance exactly matches a given pattern. If there is an exact match, a MatchResult instance representing the match is made accesible via getMatch() 55 . Unlike the contains(PatternMatcherInput, Pattern) 55 method, the current offset of the PatternMatcherInput argument is not updated. You should remember that the region between the begin and end offsets of the PatternMatcherInput will be tested for an exact match.

The pattern must be an AwkPattern instance, otherwise a ClassCastException will be thrown. You are not required to, and indeed should NOT try to (for performance reasons), catch a ClassCastException because it will never be thrown as long as you use an AwkPattern as the pattern parameter.

Specified by:

matches in interface org.apache.oro.text.regex.PatternMatcher

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contains

public boolean contains(char[] input,
                        org.apache.oro.text.regex.Pattern pattern)

Determines if a string (represented as a char[]) contains a pattern. If the pattern is matched by some substring of the input, a MatchResult instance representing the first such match is made acessible via getMatch() 55 . If you want to access subsequent matches you should either use a PatternMatcherInput object or use the offset information in the MatchResult to create a substring representing the remaining input. Using the MatchResult offset information is the recommended method of obtaining the parts of the string preceeding the match and following the match.

The pattern must be an AwkPattern instance, otherwise a ClassCastException will be thrown. You are not required to, and indeed should NOT try to (for performance reasons), catch a ClassCastException because it will never be thrown as long as you use an AwkPattern as the pattern parameter.

Specified by:

contains in interface org.apache.oro.text.regex.PatternMatcher

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contains

public boolean contains(java.lang.String input,
                        org.apache.oro.text.regex.Pattern pattern)

Determines if a string contains a pattern. If the pattern is matched by some substring of the input, a MatchResult instance representing the first such match is made acessible via getMatch() 55 . If you want to access subsequent matches you should either use a PatternMatcherInput object or use the offset information in the MatchResult to create a substring representing the remaining input. Using the MatchResult offset information is the recommended method of obtaining the parts of the string preceeding the match and following the match.

The pattern must be an AwkPattern instance, otherwise a ClassCastException will be thrown. You are not required to, and indeed should NOT try to (for performance reasons), catch a ClassCastException because it will never be thrown as long as you use an AwkPattern as the pattern parameter.

Specified by:

contains in interface org.apache.oro.text.regex.PatternMatcher

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contains

public boolean contains(org.apache.oro.text.regex.PatternMatcherInput input,
                        org.apache.oro.text.regex.Pattern pattern)

Determines if the contents of a PatternMatcherInput, starting from the current offset of the input contains a pattern. If a pattern match is found, a MatchResult instance representing the first such match is made acessible via getMatch() 55 . The current offset of the PatternMatcherInput is set to the offset corresponding to the end of the match, so that a subsequent call to this method will continue searching where the last call left off. You should remember that the region between the begin and end offsets of the PatternMatcherInput are considered the input to be searched, and that the current offset of the PatternMatcherInput reflects where a search will start from. Matches extending beyond the end offset of the PatternMatcherInput will not be matched. In other words, a match must occur entirely between the begin and end offsets of the input. See PatternMatcherInput for more details.

As a side effect, if a match is found, the PatternMatcherInput match offset information is updated. See the PatternMatcherInput setMatchOffsets(int, int) 55 method for more details.

The pattern must be an AwkPattern instance, otherwise a ClassCastException will be thrown. You are not required to, and indeed should NOT try to (for performance reasons), catch a ClassCastException because it will never be thrown as long as you use an AwkPattern as the pattern parameter.

This method is usually used in a loop as follows:

 PatternMatcher matcher;
 PatternCompiler compiler;
 Pattern pattern;
 PatternMatcherInput input;
 MatchResult result;

 compiler = new AwkCompiler();
 matcher  = new AwkMatcher();

 try {
   pattern = compiler.compile(somePatternString);
 } catch(MalformedPatternException e) {
   System.err.println("Bad pattern.");
   System.err.println(e.getMessage());
   return;
 }

 input   = new PatternMatcherInput(someStringInput);

 while(matcher.contains(input, pattern)) {
   result = matcher.getMatch();  
   // Perform whatever processing on the result you want.
 }

 

Specified by:

contains in interface org.apache.oro.text.regex.PatternMatcher

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contains

public boolean contains(AwkStreamInput input,
                        org.apache.oro.text.regex.Pattern pattern)
                 throws java.io.IOException

Determines if the contents of an AwkStreamInput, starting from the current offset of the input contains a pattern. If a pattern match is found, a MatchResult instance representing the first such match is made acessible via getMatch() 55 . The current offset of the input stream is advanced to the end offset corresponding to the end of the match. Consequently a subsequent call to this method will continue searching where the last call left off. See AwkStreamInput for more details.

Note, patterns matching the null string do NOT match at end of input stream. This is different from the behavior you get from the other contains() methods.

The pattern must be an AwkPattern instance, otherwise a ClassCastException will be thrown. You are not required to, and indeed should NOT try to (for performance reasons), catch a ClassCastException because it will never be thrown as long as you use an AwkPattern as the pattern parameter.

This method is usually used in a loop as follows:

 PatternMatcher matcher;
 PatternCompiler compiler;
 Pattern pattern;
 AwkStreamInput input;
 MatchResult result;

 compiler = new AwkCompiler();
 matcher  = new AwkMatcher();

 try {
   pattern = compiler.compile(somePatternString);
 } catch(MalformedPatternException e) {
   System.err.println("Bad pattern.");
   System.err.println(e.getMessage());
   return;
 }

 input   = new AwkStreamInput(
             new BufferedInputStream(new FileInputStream(someFileName)));

 while(matcher.contains(input, pattern)) {
   result = matcher.getMatch();  
   // Perform whatever processing on the result you want.
 }

 

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__streamMatchPrefix

private int __streamMatchPrefix()
                         throws java.io.IOException

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_search

void _search()
       throws java.io.IOException

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getMatch

public org.apache.oro.text.regex.MatchResult getMatch()

Fetches the last match found by a call to a matches() or contains() method.

Specified by:

getMatch in interface org.apache.oro.text.regex.PatternMatcher

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Overview  Package   Class  Use  Deprecated  Index
Home >> All >> org >> apache >> oro >> text >> [ awk overview ]	PREV CLASS  NEXT CLASS
SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

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