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PicoContainer example source code file (

This example PicoContainer source code file ( is included in the "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - PicoContainer tags/keywords

error, invocationtargetexception, method, nosuchmethodexception, nosuchmethodexception, object, object, picovisitor, picovisitor, picovisitortraversalexception, picovisitortraversalexception, reflection, runtimeexception, security, throwable, traversal

The PicoContainer source code

 * Copyright (C) PicoContainer Organization. All rights reserved.            *
 * ------------------------------------------------------------------------- *
 * The software in this package is published under the terms of the BSD      *
 * style license a copy of which has been included with this distribution in *
 * the LICENSE.txt file.                                                     *
package org.picocontainer.visitors;

import org.picocontainer.PicoVisitor;
import org.picocontainer.PicoException;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

 * Abstract PicoVisitor implementation. A generic traverse method is implemented, that 
 * accepts any object with a method named "accept", that takes a 
 * {@link PicoVisitor}  as argument and and invokes it. Additionally it provides the 
 * {@link #checkTraversal()} method, that throws a {@link PicoVisitorTraversalException},
 * if currently no traversal is running.
 * @author Jörg Schaible
public abstract class AbstractPicoVisitor implements PicoVisitor {
    private boolean traversal;

    public Object traverse(final Object node) {
        traversal = true;
        Object retval =
                AccessController.doPrivileged(new PrivilegedAction() {
                    public Object run() {
                        try {
                            return node.getClass().getMethod("accept", PicoVisitor.class);
                        } catch (NoSuchMethodException e) {
                            return e;
        try {
            if (retval instanceof NoSuchMethodException) {
                throw (NoSuchMethodException) retval;
            Method accept = (Method) retval;
            accept.invoke(node, this);
            return Void.TYPE;
        } catch (NoSuchMethodException e) {
        } catch (IllegalAccessException e) {
        } catch (InvocationTargetException e) {
            Throwable cause = e.getTargetException();
            if (cause instanceof RuntimeException) {
                throw (RuntimeException)cause;
            } else if (cause instanceof Error) {
                throw (Error)cause;
        } finally {
            traversal = false;
        throw new IllegalArgumentException(node.getClass().getName() + " is not a valid type for traversal");

     * Checks the traversal flag, indicating a currently running traversal of the visitor.
     * @throws PicoVisitorTraversalException if no traversal is active.
    protected void checkTraversal() {
        if (!traversal) {
            throw new PicoVisitorTraversalException(this);

     * Exception for a PicoVisitor, that is dependent on a defined starting point of the traversal.
     * If the traversal is not initiated with a call of {@link PicoVisitor#traverse}
     * @author joehni
    public static class PicoVisitorTraversalException
            extends PicoException {

         * Construct the PicoVisitorTraversalException.
         * @param visitor The visitor casing the exception.
        public PicoVisitorTraversalException(PicoVisitor visitor) {
            super("Traversal for PicoVisitor of type " + visitor.getClass().getName() + " must start with the visitor's traverse method");


Other PicoContainer examples (source code examples)

Here is a short list of links related to this PicoContainer source code file:

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