standardpipeline.java

业界著名的tomcat服务器的最新6.0的源代码。

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.catalina.core;


import java.util.ArrayList;

import javax.management.ObjectName;

import org.apache.catalina.Contained;
import org.apache.catalina.Container;
import org.apache.catalina.Lifecycle;
import org.apache.catalina.LifecycleException;
import org.apache.catalina.LifecycleListener;
import org.apache.catalina.Pipeline;
import org.apache.catalina.Valve;
import org.apache.catalina.util.LifecycleSupport;
import org.apache.catalina.util.StringManager;
import org.apache.catalina.valves.ValveBase;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import org.apache.tomcat.util.modeler.Registry;


/**
 * Standard implementation of a processing <b>Pipeline</b> that will invoke
 * a series of Valves that have been configured to be called in order.  This
 * implementation can be used for any type of Container.
 *
 * <b>IMPLEMENTATION WARNING</b> - This implementation assumes that no
 * calls to <code>addValve()</code> or <code>removeValve</code> are allowed
 * while a request is currently being processed.  Otherwise, the mechanism
 * by which per-thread state is maintained will need to be modified.
 *
 * @author Craig R. McClanahan
 */

public class StandardPipeline
    implements Pipeline, Contained, Lifecycle 
 {

    private static Log log = LogFactory.getLog(StandardPipeline.class);

    // ----------------------------------------------------------- Constructors


    /**
     * Construct a new StandardPipeline instance with no associated Container.
     */
    public StandardPipeline() {

        this(null);

    }


    /**
     * Construct a new StandardPipeline instance that is associated with the
     * specified Container.
     *
     * @param container The container we should be associated with
     */
    public StandardPipeline(Container container) {

        super();
        setContainer(container);

    }


    // ----------------------------------------------------- Instance Variables


    /**
     * The basic Valve (if any) associated with this Pipeline.
     */
    protected Valve basic = null;


    /**
     * The Container with which this Pipeline is associated.
     */
    protected Container container = null;


    /**
     * Descriptive information about this implementation.
     */
    protected String info = "org.apache.catalina.core.StandardPipeline/1.0";


    /**
     * The lifecycle event support for this component.
     */
    protected LifecycleSupport lifecycle = new LifecycleSupport(this);


    /**
     * The string manager for this package.
     */
    protected static StringManager sm =
        StringManager.getManager(Constants.Package);


    /**
     * Has this component been started yet?
     */
    protected boolean started = false;


    /**
     * The first valve associated with this Pipeline.
     */
    protected Valve first = null;


    // --------------------------------------------------------- Public Methods


    /**
     * Return descriptive information about this implementation class.
     */
    public String getInfo() {

        return (this.info);

    }


    // ------------------------------------------------------ Contained Methods


    /**
     * Return the Container with which this Pipeline is associated.
     */
    public Container getContainer() {

        return (this.container);

    }


    /**
     * Set the Container with which this Pipeline is associated.
     *
     * @param container The new associated container
     */
    public void setContainer(Container container) {

        this.container = container;

    }


    // ------------------------------------------------------ Lifecycle Methods


    /**
     * Add a lifecycle event listener to this component.
     *
     * @param listener The listener to add
     */
    public void addLifecycleListener(LifecycleListener listener) {

        lifecycle.addLifecycleListener(listener);

    }


    /**
     * Get the lifecycle listeners associated with this lifecycle. If this 
     * Lifecycle has no listeners registered, a zero-length array is returned.
     */
    public LifecycleListener[] findLifecycleListeners() {

        return lifecycle.findLifecycleListeners();

    }


    /**
     * Remove a lifecycle event listener from this component.
     *
     * @param listener The listener to remove
     */
    public void removeLifecycleListener(LifecycleListener listener) {

        lifecycle.removeLifecycleListener(listener);

    }

    /**
     * Prepare for active use of the public methods of this Component.
     *
     * @exception LifecycleException if this component detects a fatal error
     *  that prevents it from being started
     */
    public synchronized void start() throws LifecycleException {

        // Validate and update our current component state
        if (started)
            throw new LifecycleException
                (sm.getString("standardPipeline.alreadyStarted"));

        // Notify our interested LifecycleListeners
        lifecycle.fireLifecycleEvent(BEFORE_START_EVENT, null);

        started = true;

        // Start the Valves in our pipeline (including the basic), if any
        Valve current = first;
        if (current == null) {
        	current = basic;
        }
        while (current != null) {
            if (current instanceof Lifecycle)
                ((Lifecycle) current).start();
            registerValve(current);
        	current = current.getNext();
        }

        // Notify our interested LifecycleListeners
        lifecycle.fireLifecycleEvent(START_EVENT, null);

        // Notify our interested LifecycleListeners
        lifecycle.fireLifecycleEvent(AFTER_START_EVENT, null);

    }


    /**
     * Gracefully shut down active use of the public methods of this Component.
     *
     * @exception LifecycleException if this component detects a fatal error
     *  that needs to be reported
     */
    public synchronized void stop() throws LifecycleException {

        // Validate and update our current component state
        if (!started)
            throw new LifecycleException
                (sm.getString("standardPipeline.notStarted"));

        // Notify our interested LifecycleListeners
        lifecycle.fireLifecycleEvent(BEFORE_STOP_EVENT, null);

        // Notify our interested LifecycleListeners
        lifecycle.fireLifecycleEvent(STOP_EVENT, null);
        started = false;

        // Stop the Valves in our pipeline (including the basic), if any
        Valve current = first;
        if (current == null) {
        	current = basic;
        }
        while (current != null) {
            if (current instanceof Lifecycle)
                ((Lifecycle) current).stop();
            unregisterValve(current);
        	current = current.getNext();
        }

        // Notify our interested LifecycleListeners
        lifecycle.fireLifecycleEvent(AFTER_STOP_EVENT, null);
    }

    private void registerValve(Valve valve) {