and.java

一个关于java 的常用工具包

package org.jutil.predicate;

/**
 * <p>A class of predicates that evaluates to the <code>and</code> of a number
 * of other predicates.</p>
 *
 * <center><img src="doc-files/And.png"/> </center>
 *
 * <p>For efficiency reasons, the conditional and will be computed.</p>
 *
 * @path    $Source: /cvsroot/org-jutil/jutil.org/src/org/jutil/predicate/And.java,v $
 * @version $Revision: 1.3 $
 * @date    $Date: 2002/07/21 16:06:38 $
 * @state   $State: Exp $
 * @author  Marko van Dooren
 * @release $Name:  $
 */
public class And extends CompositePredicate {

  /* The revision of this class */
    public final static String CVS_REVISION ="$Revision: 1.3 $";

	/**
	 * Initialize a new empty And.
	 */
 /*@
	 @ public behavior
	 @
	 @ post nbSubPredicates() == 0;
	 @*/
	public And() {
	}

	/**
	 * Initialize a new And with the given predicates.
	 *
	 * @param first
	 *        The first predicate.
	 * @param second
	 *        The second predicate.
	 */
 /*@
	 @ public behavior
	 @
	 @ pre first != null;
	 @ pre second != null;
	 @
	 @ post predicateAt(1) == first;
	 @ post predicateAt(2) == second;
	 @*/
	public And(Predicate first, Predicate second) {
		add(first);
		add(second);
	}

	/**
	 * Initialize a new And with the given predicates.
	 *
	 * @param predicates
	 *        An array containing the predicates.
	 */
 /*@
	 @ public behavior
	 @
	 @ pre predicates != null;
	 @ pre (\forall int i; i>=0 && i<predicates.length;
	 @       predicates[i] != null);
	 @
	 @ post (\forall int i; i>=0 && i<predicates.length;
	 @        getSubPredicates().get(i) == predicates[i]);
	 @ post nbSubPredicates() == predicates.length;
	 @*/
	public And(Predicate[] predicates) {
		super(predicates);
	}

 /*@
   @ also public behavior
	 @
	 @ post \result == (\forall Predicate p; getSubPredicates().contains(p);
	 @                    p.eval(object));
	 @*/
	public boolean eval(Object object) throws Exception {
		boolean result = true;
		int size = nbSubPredicates();
		int i = 1;
		while ((i <= size) && result) {
			result = predicateAt(i).eval(object);
      i++;
		}
		return result;
	}
}
/*
 * <copyright>Copyright (C) 1997-2001. This software is copyrighted by 
 * the people and entities mentioned after the "@author" tags above, on 
 * behalf of the JUTIL.ORG Project. The copyright is dated by the dates 
 * after the "@date" tags above. All rights reserved.
 * This software is published under the terms of the JUTIL.ORG Software
 * License version 1.1 or later, a copy of which has been included with
 * this distribution in the LICENSE file, which can also be found at
 * http://org-jutil.sourceforge.net/LICENSE. This software is distributed 
 * WITHOUT ANY WARRANTY; without even the implied warranty of 
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
 * See the JUTIL.ORG Software License for more details. For more information,
 * please see http://org-jutil.sourceforge.net/</copyright>
 */