equalitycomparator.java

Java数据结构开发包

/*
  Copyright (c) 1999, 2000 Brown University, Providence, RI
  
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  copyright notice and this permission notice appear in supporting
  documentation, and that the name of Brown University not be used in
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  without specific, written prior permission.
  
  BROWN UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
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  UNIVERSITY BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
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  PERFORMANCE OF THIS SOFTWARE.
*/

package jdsl.core.api;



/**
 * This interface defines an equality comparison on a set of objects. It is up
 * to individual implementations to define the set over which they are
 * valid and to reject those objects which they cannot compare by
 * throwing ClassCastExceptions.
 *
 * @author Maurizio Pizzonia
 * @author Luca Vismara  
 * @version JDSL 2.1.1 
 */
public interface EqualityComparator {

  /** 
   * Allows a container (or any client) to find out whether an object is
   * a member of the ordered set over which this comparator is defined.
   * @param o Any java.lang.Object
   * @return True if and only if this comparator may compare this object.
   */
  public boolean isComparable (Object o);

  
  /** 
   * Tests the two parameter objects in the set over which the comparator is
   * defined for equality.
   * @param a First Object to compare
   * @param b Second Object to compare
   * @return True if and only if a is equal to b
   * @exception ClassCastException If either object passed in as a parameter
   * is not a member of the set over which the comparator is defined.
   */
  public boolean isEqualTo (Object a, Object b) throws ClassCastException;

}