PatternMatcherInput (Jakarta-ORO 2.0.8 API)
Date: 2019-09-02

org.apache.oro.text.regex

## Class PatternMatcherInput

- java.lang.Object
- - org.apache.oro.text.regex.PatternMatcherInput

-     public final class PatternMatcherInput
      extends java.lang.Object

  The PatternMatcherInput class is used to preserve state across calls to the `contains()` methods of PatternMatcher instances. It is also used to specify that only a subregion of a string should be used as input when looking for a pattern match. All that is meant by preserving state is that the end offset of the last match is remembered, so that the next match is performed from that point where the last match left off. This offset can be accessed from the `getCurrentOffset()` method and can be set with the `setCurrentOffset(int)` method.

  You would use a PatternMatcherInput object when you want to search for more than just the first occurrence of a pattern in a string, or when you only want to search a subregion of the string for a match. An example of its most common use is:

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

  >      compiler = new Perl5Compiler();
  >      matcher  = new Perl5Matcher();

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

  >      input   = new PatternMatcherInput(someStringInput);

  >      while(matcher.contains(input, pattern)) {
  >        result = matcher.getMatch();
  >        // Perform whatever processing on the result you want.
  >      }
  >      // Suppose we want to start searching from the beginning again with
  >      // a different pattern.
  >      // Just set the current offset to the begin offset.
  >      input.setCurrentOffset(input.getBeginOffset());

  >      // Second search omitted

  >      // Suppose we're done with this input, but want to search another string.
  >      // There's no need to create another PatternMatcherInput instance.
  >      // We can just use the setInput() method.
  >      input.setInput(aNewInputString);

  Since:
    1.0
  Version:
    2.0.8
  See Also:
    `PatternMatcher`

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `PatternMatcherInput(char[] input)` Like calling:
    `PatternMatcherInput(char[] input, int begin, int length)` Creates a PatternMatcherInput object, associating a region of a string (represented as a char[]) as input to be used for pattern matching by PatternMatcher objects.
    `PatternMatcherInput(java.lang.String input)` Like calling
    `PatternMatcherInput(java.lang.String input, int begin, int length)` Creates a PatternMatcherInput object, associating a region of a String as input to be used for pattern matching by PatternMatcher objects.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `char` | `charAt(int offset)` Returns the character at a particular offset relative to the begin offset of the input.
    `boolean` | `endOfInput()` Returns whether or not the end of the input has been reached.
    `int` | `getBeginOffset()`
    `char[]` | `getBuffer()` Retrieves the char[] buffer to be used used as input by PatternMatcher implementations to look for matches.
    `int` | `getCurrentOffset()`
    `int` | `getEndOffset()`
    `java.lang.Object` | `getInput()` Retrieves the original input used to initialize the PatternMatcherInput instance.
    `int` | `getMatchBeginOffset()` Returns the offset marking the beginning of the match found by contains().
    `int` | `getMatchEndOffset()` Returns the offset marking the end of the match found by contains().
    `int` | `length()`
    `java.lang.String` | `match()` A convenience method returning the part of the input corresponding to the last match found by a call to a Perl5Matcher `contains` method.
    `java.lang.String` | `postMatch()` A convenience method returning the part of the input occurring after the last match found by a call to a Perl5Matcher `contains` method.
    `java.lang.String` | `preMatch()` A convenience method returning the part of the input occurring before the last match found by a call to a Perl5Matcher `contains` method.
    `void` | `setBeginOffset(int offset)` Sets the offset of the input that should be considered the start of the region to be considered as input by PatternMatcher methods.
    `void` | `setCurrentOffset(int offset)` Sets the offset of the input that should be considered the current offset where PatternMatcher methods should start looking for matches.
    `void` | `setEndOffset(int offset)` Sets the offset of the input that should be considered the end of the region to be considered as input by PatternMatcher methods.
    `void` | `setInput(char[] input)` This method is identical to calling:
    `void` | `setInput(char[] input, int begin, int length)` Associates a region of a string (represented as a char[]) as input to be used for pattern matching by PatternMatcher objects.
    `void` | `setInput(java.lang.String input)` This method is identical to calling:
    `void` | `setInput(java.lang.String input, int begin, int length)` Associates a region of a String as input to be used for pattern matching by PatternMatcher objects.
    `void` | `setMatchOffsets(int matchBeginOffset, int matchEndOffset)` This method is intended for use by PatternMatcher implementations.
    `java.lang.String` | `substring(int beginOffset)` Returns a new string that is a substring of the PatternMatcherInput instance.
    `java.lang.String` | `substring(int beginOffset, int endOffset)` Returns a new string that is a substring of the PatternMatcherInput instance.
    `java.lang.String` | `toString()` Returns the string representation of the input, where the input is considered to start from the begin offset and end at the end offset.

    - ### Methods inherited from class java.lang.Object

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

- - ### Constructor Detail

    - #### PatternMatcherInput

          public PatternMatcherInput(java.lang.String input,
                                     int begin,
                                     int length)

      Creates a PatternMatcherInput object, associating a region of a String as input to be used for pattern matching by PatternMatcher objects. A copy of the string is not made, therefore you should not modify the string unless you know what you are doing. The current offset of the PatternMatcherInput is set to the begin offset of the region.

      Parameters:
        `input` - The input to associate with the PatternMatcherInput.
        `begin` - The offset into the char[] to use as the beginning of the input.
        `length` - The length of the reegion starting from the begin offset to use as the input for pattern matching purposes.

    - #### PatternMatcherInput

          public PatternMatcherInput(java.lang.String input)

      Like calling

      >      PatternMatcherInput(input, 0, input.length());

      Parameters:
        `input` - The input to associate with the PatternMatcherInput.

    - #### PatternMatcherInput

          public PatternMatcherInput(char[] input,
                                     int begin,
                                     int length)

      Creates a PatternMatcherInput object, associating a region of a string (represented as a char[]) as input to be used for pattern matching by PatternMatcher objects. A copy of the string is not made, therefore you should not modify the string unless you know what you are doing. The current offset of the PatternMatcherInput is set to the begin offset of the region.

      Parameters:
        `input` - The input to associate with the PatternMatcherInput.
        `begin` - The offset into the char[] to use as the beginning of the input.
        `length` - The length of the reegion starting from the begin offset to use as the input for pattern matching purposes.

    - #### PatternMatcherInput

          public PatternMatcherInput(char[] input)

      Like calling:

      >      PatternMatcherInput(input, 0, input.length);

      Parameters:
        `input` - The input to associate with the PatternMatcherInput.

  - ### Method Detail

    - #### length

          public int length()

      Returns:
        The length of the region to be considered input for pattern matching purposes. Essentially this is then end offset minus the begin offset.

    - #### setInput

          public void setInput(java.lang.String input,
                               int begin,
                               int length)

      Associates a region of a String as input to be used for pattern matching by PatternMatcher objects. The current offset of the PatternMatcherInput is set to the begin offset of the region.

      Parameters:
        `input` - The input to associate with the PatternMatcherInput.
        `begin` - The offset into the String to use as the beginning of the input.
        `length` - The length of the reegion starting from the begin offset to use as the input for pattern matching purposes.

    - #### setInput

          public void setInput(java.lang.String input)

      This method is identical to calling:

      >      setInput(input, 0, input.length());

      Parameters:
        `input` - The input to associate with the PatternMatcherInput.

    - #### setInput

          public void setInput(char[] input,
                               int begin,
                               int length)

      Associates a region of a string (represented as a char[]) as input to be used for pattern matching by PatternMatcher objects. A copy of the string is not made, therefore you should not modify the string unless you know what you are doing. The current offset of the PatternMatcherInput is set to the begin offset of the region.

      Parameters:
        `input` - The input to associate with the PatternMatcherInput.
        `begin` - The offset into the char[] to use as the beginning of the input.
        `length` - The length of the reegion starting from the begin offset to use as the input for pattern matching purposes.

    - #### setInput

          public void setInput(char[] input)

      This method is identical to calling:

      >      setInput(input, 0, input.length);

      Parameters:
        `input` - The input to associate with the PatternMatcherInput.

    - #### charAt

          public char charAt(int offset)

      Returns the character at a particular offset relative to the begin offset of the input.

      Parameters:
        `offset` - The offset at which to fetch a character (relative to the beginning offset.
      Returns:
        The character at a particular offset.
      Throws:
        `java.lang.ArrayIndexOutOfBoundsException` - If the offset does not occur within the bounds of the input.

    - #### substring

          public java.lang.String substring(int beginOffset,
                                            int endOffset)

      Returns a new string that is a substring of the PatternMatcherInput instance. The substring begins at the specified beginOffset relative to the begin offset and extends to the specified endOffset - 1 relative to the begin offset of the PatternMatcherInput instance.

      Parameters:
        `beginOffset` - The offset relative to the begin offset of the PatternMatcherInput at which to start the substring (inclusive).
        `endOffset` - The offset relative to the begin offset of the PatternMatcherInput at which to end the substring (exclusive).
      Returns:
        The specified substring.
      Throws:
        `java.lang.ArrayIndexOutOfBoundsException` - If one of the offsets does not occur within the bounds of the input.

    - #### substring

          public java.lang.String substring(int beginOffset)

      Returns a new string that is a substring of the PatternMatcherInput instance. The substring begins at the specified beginOffset relative to the begin offset and extends to the end offset of the PatternMatcherInput.

      Parameters:
        `beginOffset` - The offset relative to the begin offset of the PatternMatcherInput at which to start the substring.
      Returns:
        The specified substring.
      Throws:
        `java.lang.ArrayIndexOutOfBoundsException` - If the offset does not occur within the bounds of the input.

    - #### getInput

          public java.lang.Object getInput()

      Retrieves the original input used to initialize the PatternMatcherInput instance. If a String was used, the String instance will be returned. If a char[] was used, a char instance will be returned. This violates data encapsulation and hiding principles, but it is a great convenience for the programmer.

      Returns:
        The String or char[] input used to initialize the PatternMatcherInput instance.

    - #### getBuffer

          public char[] getBuffer()

      Retrieves the char[] buffer to be used used as input by PatternMatcher implementations to look for matches. This array should be treated as read only by the programmer.

      Returns:
        The char[] buffer to be used as input by PatternMatcher implementations.

    - #### endOfInput

          public boolean endOfInput()

      Returns whether or not the end of the input has been reached.

      Returns:
        True if the current offset is greater than or equal to the end offset.

    - #### getBeginOffset

          public int getBeginOffset()

      Returns:
        The offset of the input that should be considered the start of the region to be considered as input by PatternMatcher methods.

    - #### getEndOffset

          public int getEndOffset()

      Returns:
        The offset of the input that should be considered the end of the region to be considered as input by PatternMatcher methods. This offset is actually 1 plus the last offset that is part of the input region.

    - #### getCurrentOffset

          public int getCurrentOffset()

      Returns:
        The offset of the input that should be considered the current offset where PatternMatcher methods should start looking for matches.

    - #### setBeginOffset

          public void setBeginOffset(int offset)

      Sets the offset of the input that should be considered the start of the region to be considered as input by PatternMatcher methods. In other words, everything before this offset is ignored by a PatternMatcher.

      Parameters:
        `offset` - The offset to use as the beginning of the input.

    - #### setEndOffset

          public void setEndOffset(int offset)

      Sets the offset of the input that should be considered the end of the region to be considered as input by PatternMatcher methods. This offset is actually 1 plus the last offset that is part of the input region.

      Parameters:
        `offset` - The offset to use as the end of the input.

    - #### setCurrentOffset

          public void setCurrentOffset(int offset)

      Sets the offset of the input that should be considered the current offset where PatternMatcher methods should start looking for matches. Also resets all match offset information to -1. By calling this method, you invalidate all previous match information. Therefore a PatternMatcher implementation must call this method before setting match offset information.

      Parameters:
        `offset` - The offset to use as the current offset.

    - #### toString

          public java.lang.String toString()

      Returns the string representation of the input, where the input is considered to start from the begin offset and end at the end offset.

      Overrides:
        `toString` in class `java.lang.Object`
      Returns:
        The string representation of the input.

    - #### preMatch

          public java.lang.String preMatch()

      A convenience method returning the part of the input occurring before the last match found by a call to a Perl5Matcher `contains` method.

      Returns:
        The input preceeding a match.

    - #### postMatch

          public java.lang.String postMatch()

      A convenience method returning the part of the input occurring after the last match found by a call to a Perl5Matcher `contains` method.

      Returns:
        The input succeeding a contains() match.

    - #### match

          public java.lang.String match()

      A convenience method returning the part of the input corresponding to the last match found by a call to a Perl5Matcher `contains` method. The method is not called getMatch() so as not to confuse it with Perl5Matcher's getMatch() which returns a MatchResult instance and also for consistency with preMatch() and postMatch().

      Returns:
        The input consisting of the match found by contains().

    - #### setMatchOffsets

          public void setMatchOffsets(int matchBeginOffset,
                                      int matchEndOffset)

      This method is intended for use by PatternMatcher implementations. It is necessary to record the location of the previous match so that consecutive contains() matches involving null string matches are properly handled. If you are not implementing a PatternMatcher, forget this method exists. If you use it outside of its intended context, you will only disrupt the stored state.

      As a note, the preMatch(), postMatch(), and match() methods are provided as conveniences because PatternMatcherInput must store match offset information to completely preserve state for consecutive PatternMatcher contains() matches.

      Parameters:
        `matchBeginOffset` - The begin offset of a match found by contains().
        `matchEndOffset` - The end offset of a match found by contains().

    - #### getMatchBeginOffset

          public int getMatchBeginOffset()

      Returns the offset marking the beginning of the match found by contains().

      Returns:
        The begin offset of a contains() match.

    - #### getMatchEndOffset

          public int getMatchEndOffset()

      Returns the offset marking the end of the match found by contains().

      Returns:
        The end offset of a contains() match.

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