/*

 *  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.

 *

 */

/* * Portion Copyright (c) 2007-2008 Nokia Corporation and/or its subsidiary(-ies). All rights reserved.*/

package com.nokia.ant;

import java.io.IOException;

import java.net.URL;

import java.util.ArrayList;

import java.util.List;

import org.apache.tools.ant.BuildException;

import org.apache.tools.ant.ComponentHelper;

import org.apache.tools.ant.Project;

import org.apache.tools.ant.Task;

import org.apache.tools.ant.UnknownElement;

/**

 * Antlib task. It does not

 * occur in an ant build file. It is the root element

 * an antlib xml file.

 * @ant.task ignore="true"

 * @since Ant 1.6

 */

public class Antlib extends Task implements TaskContainer {

    //

    // Static

    //

    /** The name of this task */

    public static final String TAG = "antlib";

    //

    // Instance

    //

    private ClassLoader classLoader;

    private String      uri = "";

    private List<Task>  tasks = new ArrayList<Task>();

    /**

     * Static method to read an ant lib definition from

     * a url.

     *

     * @param project   the current project

     * @param antlibUrl the url to read the definitions from

     * @param uri       the uri that the antlib is to be placed in

     * @return   the ant lib task

     */

    public static Antlib createAntlib(final Project project, final URL antlibUrl,

                                      final String uri) {

        // Check if we can contact the URL

        try {

            antlibUrl.openConnection().connect();

        } catch (IOException ex) {

            throw new BuildException(

                "Unable to find " + antlibUrl, ex);

        }

        ComponentHelper helper =

            ComponentHelper.getComponentHelper(project);

        helper.enterAntLib(uri);

        try {

            // Should be safe to parse

            ProjectHelper2 parser = new ProjectHelper2();

            UnknownElement ue =

                parser.parseUnknownElement(project, antlibUrl);

            // Check name is "antlib"

            if (!(ue.getTag().equals(TAG))) {

                throw new BuildException(

                    "Unexpected tag " + ue.getTag() + " expecting "

                    + TAG, ue.getLocation());

            }

            Antlib antlib = new Antlib();

            antlib.setProject(project);

            antlib.setLocation(ue.getLocation());

            antlib.setTaskName("antlib");

            antlib.init();

            ue.configure(antlib);

            return antlib;

        } finally {

            helper.exitAntLib();

        }

    }

    /**

     * Set the class loader for this antlib.

     * This class loader is used for any tasks that

     * derive from Definer.

     *

     * @param classLoader the class loader

     */

    protected final void setClassLoader(final ClassLoader classLoader) 

    {

        this.classLoader = classLoader;

    }

    /**

     * Set the URI for this antlib.

     * @param uri the namespace uri

     */

    protected final void  setURI(final String uri) 

    {

        this.uri = uri;

    }

    private ClassLoader getClassLoader() {

        if (classLoader == null) {

            classLoader = Antlib.class.getClassLoader();

        }

        return classLoader;

    }

    /**

     * add a task to the list of tasks

     *

     * @param nestedTask Nested task to execute in antlib

     */

    public final void addTask(final Task nestedTask) {

        tasks.add(nestedTask);

    }

    /**

     * Execute the nested tasks, setting the classloader for

     * any tasks that derive from Definer.

     */

    public final void execute() {

        for (Task task : tasks) {

            if (task instanceof UnknownElement) {

                UnknownElement ue = (UnknownElement)task;

                setLocation(ue.getLocation());

                ue.maybeConfigure();

                Object configuredObject = ue.getRealThing();

                if (configuredObject == null) {

                    continue;

                }

                if (!(configuredObject instanceof AntlibDefinition)) {

                    throw new BuildException(

                            "Invalid task in antlib " + ue.getTag()

                            + " " + configuredObject.getClass() + " does not "

                            + "extend org.apache.tools.ant.taskdefs.AntlibDefinition");

                }

                AntlibDefinition def = (AntlibDefinition) configuredObject;

                def.setURI(uri);

                def.setAntlibClassLoader(getClassLoader());

                def.init();

                def.execute();

            }

        }

    }

}