ordercomparator.java

一个关于Spring框架的示例应用程序,简单使用,可以参考.

/*
 * Copyright 2002-2004 the original author or authors.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */ 

package org.springframework.core;

import java.util.Comparator;

/**
 * Comparator implementation for Ordered objects,
 * sorting by order value ascending (resp. by priority descending).
 *
 * <p>Non-Ordered objects are treated as greatest order values,
 * thus ending up at the end of the list, in arbitrary order
 * (just like same order values of Ordered objects).
 *
 * @author Juergen Hoeller
 * @since 07.04.2003
 * @see Ordered
 */
public class OrderComparator implements Comparator {

  public int compare(Object o1, Object o2) {
    int i1 = (o1 instanceof Ordered ? ((Ordered) o1).getOrder() : Integer.MAX_VALUE);
	  int i2 = (o2 instanceof Ordered ? ((Ordered) o2).getOrder() : Integer.MAX_VALUE);

	  // direct evaluation instead of Integer.compareTo to avoid unnecessary object creation
	  if (i1 < i2)
			return -1;
	  else if (i1 > i2)
		  return 1;
	  else
		  return 0;
  }
}