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Spring Framework example source code file (OrderComparator.java)

This example Spring Framework source code file (OrderComparator.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Spring Framework tags/keywords

comparator, comparator, object, object, ordercomparator, ordered, ordered, priorityordered, priorityordered, util

The Spring Framework OrderComparator.java source code

/*
 * Copyright 2002-2007 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;

/**
 * {@link Comparator} implementation for {@link 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 <code>Ordered objects).
 *
 * @author Juergen Hoeller
 * @since 07.04.2003
 * @see Ordered
 * @see java.util.Collections#sort(java.util.List, java.util.Comparator)
 * @see java.util.Arrays#sort(Object[], java.util.Comparator)
 */
public class OrderComparator implements Comparator {

	public int compare(Object o1, Object o2) {
		boolean p1 = (o1 instanceof PriorityOrdered);
		boolean p2 = (o2 instanceof PriorityOrdered);
		if (p1 && !p2) {
			return -1;
		}
		else if (p2 && !p1) {
			return 1;
		}

		// Direct evaluation instead of Integer.compareTo to avoid unnecessary object creation.
		int i1 = getOrder(o1);
		int i2 = getOrder(o2);
		return (i1 < i2) ? -1 : (i1 > i2) ? 1 : 0;
	}

	/**
	 * Determine the order value for the given object.
	 * <p>The default implementation checks against the {@link Ordered}
	 * interface. Can be overridden in subclasses.
	 * @param obj the object to check
	 * @return the order value, or <code>Ordered.LOWEST_PRECEDENCE as fallback
	 */
	protected int getOrder(Object obj) {
		return (obj instanceof Ordered ? ((Ordered) obj).getOrder() : Ordered.LOWEST_PRECEDENCE);
	}

}

Other Spring Framework examples (source code examples)

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