Spring Framework example source code file (HandlerExecutionChain.java)

This example Spring Framework source code file (HandlerExecutionChain.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

arraylist, arraylist, handlerexecutionchain, handlerexecutionchain, handlerinterceptor, handlerinterceptor, list, object, object, util

The Spring Framework HandlerExecutionChain.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.web.servlet;

import java.util.ArrayList;
import java.util.List;

import org.springframework.util.CollectionUtils;

/**
 * Handler execution chain, consisting of handler object and any handler interceptors.
 * Returned by HandlerMapping's {@link HandlerMapping#getHandler} method.
 *
 * @author Juergen Hoeller
 * @since 20.06.2003
 * @see HandlerInterceptor
 */
public class HandlerExecutionChain {

	private final Object handler;

	private HandlerInterceptor[] interceptors;

	private List interceptorList;


	/**
	 * Create a new HandlerExecutionChain.
	 * @param handler the handler object to execute
	 */
	public HandlerExecutionChain(Object handler) {
		this(handler, null);
	}

	/**
	 * Create a new HandlerExecutionChain.
	 * @param handler the handler object to execute
	 * @param interceptors the array of interceptors to apply
	 * (in the given order) before the handler itself executes
	 */
	public HandlerExecutionChain(Object handler, HandlerInterceptor[] interceptors) {
		if (handler instanceof HandlerExecutionChain) {
			HandlerExecutionChain originalChain = (HandlerExecutionChain) handler;
			this.handler = originalChain.getHandler();
			this.interceptorList = new ArrayList();
			CollectionUtils.mergeArrayIntoCollection(originalChain.getInterceptors(), this.interceptorList);
			CollectionUtils.mergeArrayIntoCollection(interceptors, this.interceptorList);
		}
		else {
			this.handler = handler;
			this.interceptors = interceptors;
		}
	}


	/**
	 * Return the handler object to execute.
	 * @return the handler object
	 */
	public Object getHandler() {
		return this.handler;
	}

	public void addInterceptor(HandlerInterceptor interceptor) {
		initInterceptorList();
		this.interceptorList.add(interceptor);
	}

	public void addInterceptors(HandlerInterceptor[] interceptors) {
		if (interceptors != null) {
			initInterceptorList();
			for (int i = 0; i < interceptors.length; i++) {
				this.interceptorList.add(interceptors[i]);
			}
		}
	}

	private void initInterceptorList() {
		if (this.interceptorList == null) {
			this.interceptorList = new ArrayList();
		}
		if (this.interceptors != null) {
			for (int i = 0; i < this.interceptors.length; i++) {
				this.interceptorList.add(this.interceptors[i]);
			}
			this.interceptors = null;
		}
	}

	/**
	 * Return the array of interceptors to apply (in the given order).
	 * @return the array of HandlerInterceptors instances (may be <code>null)
	 */
	public HandlerInterceptor[] getInterceptors() {
		if (this.interceptors == null && this.interceptorList != null) {
			this.interceptors = (HandlerInterceptor[])
					this.interceptorList.toArray(new HandlerInterceptor[this.interceptorList.size()]);
		}
		return this.interceptors;
	}

}