stringsubstitution.java

jakarta-oro-2.0.8 正则表达式 引擎 源代码

/*
 * $Id: StringSubstitution.java,v 1.8 2003/11/07 20:16:25 dfs Exp $
 *
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package org.apache.oro.text.regex;


/**
 * StringSubstitution implements a Substitution consisting of a simple
 * literal string.  This class is intended for use with
 * {@link Util#substitute Util.substitute}.
 *
 * @version @version@
 * @since 1.1
 * @see Substitution
 * @see Util
 * @see Util#substitute
 * @see Substitution
 * @see Perl5Substitution
 */
public class StringSubstitution implements Substitution {
  int _subLength;
  String _substitution;

  /**
   * Default constructor initializing substitution to a zero length
   * String.
   */
  public StringSubstitution() {
    this("");
  }

  /**
   * Creates a StringSubstitution representing the given string.
   * <p>
   * @param substitution The string to use as a substitution.
   */
  public StringSubstitution(String substitution) {
    setSubstitution(substitution);
  }


  /**
   * Sets the substitution represented by this StringSubstitution.  You
   * should use this method in order to avoid repeatedly allocating new
   * StringSubstitutions.  It is recommended that you allocate a single
   * StringSubstitution and reuse it by using this method when appropriate.
   * <p>
   * @param substitution The string to use as a substitution.
   */
  public void setSubstitution(String substitution) {
    _substitution = substitution;
    _subLength = substitution.length();
  }

  /**
   * Returns the string substitution represented by this object.
   * <p>
   * @return The string substitution represented by this object.
   */
  public String getSubstitution() { return _substitution; }

  /**
   * Returns the same value as {@link #getSubstitution()}.
   * <p>
   * @return The string substitution represented by this object.
   */
  public String toString() { return getSubstitution(); }

  /**
   * Appends the substitution to a buffer containing the original input
   * with substitutions applied for the pattern matches found so far.
   * See 
   * {@link Substitution#appendSubstitution Substitution.appendSubstition()}
   * for more details regarding the expected behavior of this method.
   * <p>
   * @param appendBuffer The buffer containing the new string resulting
   * from performing substitutions on the original input.
   * @param match The current match causing a substitution to be made. 
   * @param substitutionCount  The number of substitutions that have been
   *  performed so far by Util.substitute.
   * @param originalInput The original input upon which the substitutions are
   * being performed.  This is a read-only parameter and is not modified.
   * @param matcher The PatternMatcher used to find the current match.
   * @param pattern The Pattern used to find the current match.
   */
  public void appendSubstitution(StringBuffer appendBuffer, MatchResult match,
				 int substitutionCount,
				 PatternMatcherInput originalInput, 
				 PatternMatcher matcher, Pattern pattern)
  {
    if(_subLength == 0) 
      return;
    appendBuffer.append(_substitution);
  }
}