Tomcat example source code file (StandardPipeline.java)

This example Tomcat source code file (StandardPipeline.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 - Tomcat tags/keywords

arraylist, contained, contained, lifecycle, lifecycle, lifecycleexception, lifecycleexception, management, objectname, standardpipeline, string, throwable, util, valve, valve, valvebase

The Tomcat StandardPipeline.java source code

/*
 * 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 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 - This implementation assumes that no
 * calls to <code>addValve() or removeValve 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) {

        if( valve instanceof ValveBase &&
                ((ValveBase)valve).getObjectName()==null ) {
            try {
                
                String domain=((ContainerBase)container).getDomain();
                if( container instanceof StandardContext ) {
                    domain=((StandardContext)container).getEngineName();
                }
                if( container instanceof StandardWrapper) {
                    Container ctx=((StandardWrapper)container).getParent();
                    domain=((StandardContext)ctx).getEngineName();
                }
                ObjectName vname=((ValveBase)valve).createObjectName(
                        domain,
                        ((ContainerBase)container).getJmxName());
                if( vname != null ) {
                    ((ValveBase)valve).setObjectName(vname);
                    Registry.getRegistry(null, null).registerComponent
                        (valve, vname, valve.getClass().getName());
                    ((ValveBase)valve).setController
                        (((ContainerBase)container).getJmxName());
                }
            } catch( Throwable t ) {
                log.info( "Can't register valve " + valve , t );
            }
        }
    }
    
    private void unregisterValve(Valve valve) {
        if( valve instanceof ValveBase ) {
            try {
                ValveBase vb=(ValveBase)valve;
                if( vb.getController()!=null &&
                        vb.getController() == 
                        ((ContainerBase)container).getJmxName() ) {
                    
                    ObjectName vname=vb.getObjectName();
                    Registry.getRegistry(null, null).getMBeanServer()
                        .unregisterMBean(vname);
                    ((ValveBase)valve).setObjectName(null);
                }
            } catch( Throwable t ) {
                log.info( "Can't unregister valve " + valve , t );
            }
        }
    }    

    // ------------------------------------------------------- Pipeline Methods


    /**
     * <p>Return the Valve instance that has been distinguished as the basic
     * Valve for this Pipeline (if any).
     */
    public Valve getBasic() {

        return (this.basic);

    }


    /**
     * <p>Set the Valve instance that has been distinguished as the basic
     * Valve for this Pipeline (if any).  Prioer to setting the basic Valve,
     * the Valve's <code>setContainer() will be called, if it
     * implements <code>Contained, with the owning Container as an
     * argument.  The method may throw an <code>IllegalArgumentException
     * if this Valve chooses not to be associated with this Container, or
     * <code>IllegalStateException if it is already associated with
     * a different Container.</p>
     *
     * @param valve Valve to be distinguished as the basic Valve
     */
    public void setBasic(Valve valve) {

        // Change components if necessary
        Valve oldBasic = this.basic;
        if (oldBasic == valve)
            return;

        // Stop the old component if necessary
        if (oldBasic != null) {
            if (started && (oldBasic instanceof Lifecycle)) {
                try {
                    ((Lifecycle) oldBasic).stop();
                } catch (LifecycleException e) {
                    log.error("StandardPipeline.setBasic: stop", e);
                }
            }
            if (oldBasic instanceof Contained) {
                try {
                    ((Contained) oldBasic).setContainer(null);
                } catch (Throwable t) {
                    ;
                }
            }
        }

        // Start the new component if necessary
        if (valve == null)
            return;
        if (valve instanceof Contained) {
            ((Contained) valve).setContainer(this.container);
        }
        if (valve instanceof Lifecycle) {
            try {
                ((Lifecycle) valve).start();
            } catch (LifecycleException e) {
                log.error("StandardPipeline.setBasic: start", e);
                return;
            }
        }

        // Update the pipeline
        Valve current = first;
        while (current != null) {
        	if (current.getNext() == oldBasic) {
        		current.setNext(valve);
        		break;
        	}
        	current = current.getNext();
        }
        
        this.basic = valve;

    }


    /**
     * <p>Add a new Valve to the end of the pipeline associated with this
     * Container.  Prior to adding the Valve, the Valve's
     * <code>setContainer() method will be called, if it implements
     * <code>Contained, with the owning Container as an argument.
     * The method may throw an
     * <code>IllegalArgumentException if this Valve chooses not to
     * be associated with this Container, or <code>IllegalStateException
     * if it is already associated with a different Container.</p>
     *
     * @param valve Valve to be added
     *
     * @exception IllegalArgumentException if this Container refused to
     *  accept the specified Valve
     * @exception IllegalArgumentException if the specifie Valve refuses to be
     *  associated with this Container
     * @exception IllegalStateException if the specified Valve is already
     *  associated with a different Container
     */
    public void addValve(Valve valve) {
    
        // Validate that we can add this Valve
        if (valve instanceof Contained)
            ((Contained) valve).setContainer(this.container);

        // Start the new component if necessary
        if (started) {
            if (valve instanceof Lifecycle) {
                try {
                    ((Lifecycle) valve).start();
                } catch (LifecycleException e) {
                    log.error("StandardPipeline.addValve: start: ", e);
                }
            }
            // Register the newly added valve
            registerValve(valve);
        }

        // Add this Valve to the set associated with this Pipeline
        if (first == null) {
        	first = valve;
        	valve.setNext(basic);
        } else {
            Valve current = first;
            while (current != null) {
				if (current.getNext() == basic) {
					current.setNext(valve);
					valve.setNext(basic);
					break;
				}
				current = current.getNext();
			}
        }

    }


    /**
     * Return the set of Valves in the pipeline associated with this
     * Container, including the basic Valve (if any).  If there are no
     * such Valves, a zero-length array is returned.
     */
    public Valve[] getValves() {

    	ArrayList valveList = new ArrayList();
        Valve current = first;
        if (current == null) {
        	current = basic;
        }
        while (current != null) {
        	valveList.add(current);
        	current = current.getNext();
        }

        return ((Valve[]) valveList.toArray(new Valve[0]));

    }

    public ObjectName[] getValveObjectNames() {

    	ArrayList valveList = new ArrayList();
        Valve current = first;
        if (current == null) {
        	current = basic;
        }
        while (current != null) {
        	if (current instanceof ValveBase) {
        		valveList.add(((ValveBase) current).getObjectName());
        	}
        	current = current.getNext();
        }

        return ((ObjectName[]) valveList.toArray(new ObjectName[0]));

    }

    /**
     * Remove the specified Valve from the pipeline associated with this
     * Container, if it is found; otherwise, do nothing.  If the Valve is
     * found and removed, the Valve's <code>setContainer(null) method
     * will be called if it implements <code>Contained.
     *
     * @param valve Valve to be removed
     */
    public void removeValve(Valve valve) {

        Valve current;
        if(first == valve) {
            first = first.getNext();
            current = null;
        } else {
            current = first;
        }
        while (current != null) {
            if (current.getNext() == valve) {
                current.setNext(valve.getNext());
                break;
            }
            current = current.getNext();
        }

        if (first == basic) first = null;

        if (valve instanceof Contained)
            ((Contained) valve).setContainer(null);

        // Stop this valve if necessary
        if (started) {
            if (valve instanceof Lifecycle) {
                try {
                    ((Lifecycle) valve).stop();
                } catch (LifecycleException e) {
                    log.error("StandardPipeline.removeValve: stop: ", e);
                }
            }
            // Unregister the removed valave
            unregisterValve(valve);
        }
    
    }


    public Valve getFirst() {
        if (first != null) {
            return first;
        } else {
            return basic;
        }
    }


}