Ant example source code file (ScriptDef.java)

This example Ant source code file (ScriptDef.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 - Ant tags/keywords

arraylist, attribute, buildexception, buildexception, hashmap, io, list, map, map, nestedelement, nestedelement, object, scriptrunnerhelper, string, string, util

The ScriptDef.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.tools.ant.taskdefs.optional.script;

import org.apache.tools.ant.AntTypeDefinition;
import org.apache.tools.ant.ComponentHelper;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.MagicNames;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.ProjectHelper;
import org.apache.tools.ant.taskdefs.DefBase;

import java.util.Map;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.Set;
import java.util.HashSet;
import java.io.File;

import org.apache.tools.ant.util.ClasspathUtils;
import org.apache.tools.ant.util.ScriptRunnerBase;
import org.apache.tools.ant.util.ScriptRunnerHelper;

/**
 * Define a task using a script
 *
 * @since Ant 1.6
 */
public class ScriptDef extends DefBase {
    /**
     * script runner helper
     */
    private ScriptRunnerHelper helper = new ScriptRunnerHelper();
    /**
     * script runner.
     */
    /** Used to run the script */
    private ScriptRunnerBase   runner = null;

    /** the name by which this script will be activated */
    private String name;

    /** Attributes definitions of this script */
    private List attributes = new ArrayList();

    /** Nested Element definitions of this script */
    private List nestedElements = new ArrayList();

    /** The attribute names as a set */
    private Set attributeSet;

    /** The nested element definitions indexed by their names */
    private Map nestedElementMap;

    /**
     * Set the project.
     * @param project the project that this def belows to.
     */
    public void setProject(Project project) {
        super.setProject(project);
        helper.setProjectComponent(this);
        helper.setSetBeans(false);
    }

    /**
     * set the name under which this script will be activated in a build
     * file
     *
     * @param name the name of the script
     */
    public void setName(String name) {
        this.name = name;
    }

    /**
     * Indicates whether the task supports a given attribute name
     *
     * @param attributeName the name of the attribute.
     *
     * @return true if the attribute is supported by the script.
     */
    public boolean isAttributeSupported(String attributeName) {
        return attributeSet.contains(attributeName);
    }

    /**
     * Class representing an attribute definition
     */
    public static class Attribute {
        /** The attribute name */
        private String name;

        /**
         * Set the attribute name
         *
         * @param name the attribute name
         */
        public void setName(String name) {
            this.name = name.toLowerCase(Locale.US);
        }
    }

    /**
     * Add an attribute definition to this script.
     *
     * @param attribute the attribute definition.
     */
    public void addAttribute(Attribute attribute) {
        attributes.add(attribute);
    }

    /**
     * Class to represent a nested element definition
     */
    public static class NestedElement {
        /** The name of the neseted element */
        private String name;

        /** The Ant type to which this nested element corresponds. */
        private String type;

        /** The class to be created for this nested element */
        private String className;

        /**
         * set the tag name for this nested element
         *
         * @param name the name of this nested element
         */
        public void setName(String name) {
            this.name = name.toLowerCase(Locale.US);
        }

        /**
         * Set the type of this element. This is the name of an
         * Ant task or type which is to be used when this element is to be
         * created. This is an alternative to specifying the class name directly
         *
         * @param type the name of an Ant type, or task, to use for this nested
         * element.
         */
        public void setType(String type) {
            this.type = type;
        }

        /**
         * Set the classname of the class to be used for the nested element.
         * This specifies the class directly and is an alternative to specifying
         * the Ant type name.
         *
         * @param className the name of the class to use for this nested
         * element.
         */
        public void setClassName(String className) {
            this.className = className;
        }
    }

    /**
     * Add a nested element definition.
     *
     * @param nestedElement the nested element definition.
     */
    public void addElement(NestedElement nestedElement) {
        nestedElements.add(nestedElement);
    }

    /**
     * Define the script.
     */
    public void execute() {
        if (name == null) {
            throw new BuildException("scriptdef requires a name attribute to "
                + "name the script");
        }

        if (helper.getLanguage() == null) {
            throw new BuildException("<scriptdef> requires a language attribute "
                + "to specify the script language");
        }

        // Check if need to set the loader
        if (getAntlibClassLoader() != null || hasCpDelegate()) {
            helper.setClassLoader(createLoader());
        }

        // Now create the scriptRunner
        runner = helper.getScriptRunner();

        attributeSet = new HashSet();
        for (Iterator i = attributes.iterator(); i.hasNext();) {
            Attribute attribute = (Attribute) i.next();
            if (attribute.name == null) {
                throw new BuildException("scriptdef <attribute> elements "
                    + "must specify an attribute name");
            }

            if (attributeSet.contains(attribute.name)) {
                throw new BuildException("scriptdef <" + name + "> declares "
                    + "the " + attribute.name + " attribute more than once");
            }
            attributeSet.add(attribute.name);
        }

        nestedElementMap = new HashMap();
        for (Iterator i = nestedElements.iterator(); i.hasNext();) {
            NestedElement nestedElement = (NestedElement) i.next();
            if (nestedElement.name == null) {
                throw new BuildException("scriptdef <element> elements "
                    + "must specify an element name");
            }
            if (nestedElementMap.containsKey(nestedElement.name)) {
                throw new BuildException("scriptdef <" + name + "> declares "
                    + "the " + nestedElement.name + " nested element more "
                    + "than once");
            }

            if (nestedElement.className == null
                && nestedElement.type == null) {
                throw new BuildException("scriptdef <element> elements "
                    + "must specify either a classname or type attribute");
            }
            if (nestedElement.className != null
                && nestedElement.type != null) {
                throw new BuildException("scriptdef <element> elements "
                    + "must specify only one of the classname and type "
                    + "attributes");
            }


            nestedElementMap.put(nestedElement.name, nestedElement);
        }

        // find the script repository - it is stored in the project
        Map scriptRepository = null;
        Project p = getProject();
        synchronized (p) {
            scriptRepository =
                (Map) p.getReference(MagicNames.SCRIPT_REPOSITORY);
            if (scriptRepository == null) {
                scriptRepository = new HashMap();
                p.addReference(MagicNames.SCRIPT_REPOSITORY,
                    scriptRepository);
            }
        }

        name = ProjectHelper.genComponentName(getURI(), name);
        scriptRepository.put(name, this);
        AntTypeDefinition def = new AntTypeDefinition();
        def.setName(name);
        def.setClass(ScriptDefBase.class);
        ComponentHelper.getComponentHelper(
            getProject()).addDataTypeDefinition(def);
    }

    /**
     * Create a nested element to be configured.
     *
     * @param elementName the name of the nested element.
     * @return object representing the element name.
     */
    public Object createNestedElement(String elementName) {
        NestedElement definition
            = (NestedElement) nestedElementMap.get(elementName);
        if (definition == null) {
            throw new BuildException("<" + name + "> does not support "
                + "the <" + elementName + "> nested element");
        }

        Object instance = null;
        String classname = definition.className;
        if (classname == null) {
            instance = getProject().createTask(definition.type);
            if (instance == null) {
                instance = getProject().createDataType(definition.type);
            }
        } else {
            /*
            // try the context classloader
            ClassLoader loader
                = Thread.currentThread().getContextClassLoader();
            */
            ClassLoader loader = createLoader();

            try {
                instance = ClasspathUtils.newInstance(classname, loader);
            } catch (BuildException e) {
                instance = ClasspathUtils.newInstance(classname, ScriptDef.class.getClassLoader());
            }

            getProject().setProjectReference(instance);
        }

        if (instance == null) {
            throw new BuildException("<" + name + "> is unable to create "
                + "the <" + elementName + "> nested element");
        }
        return instance;
    }

    /**
     * Execute the script.
     *
     * @param attributes collection of attributes
     * @param elements a list of nested element values.
     * @deprecated since 1.7.
     *             Use executeScript(attribute, elements, instance) instead.
     */
    public void executeScript(Map attributes, Map elements) {
        executeScript(attributes, elements, null);
    }

    /**
     * Execute the script.
     * This is called by the script instance to execute the script for this
     * definition.
     *
     * @param attributes collection of attributes
     * @param elements   a list of nested element values.
     * @param instance   the script instance; can be null
     */
    public void executeScript(Map attributes, Map elements, ScriptDefBase instance) {
        runner.addBean("attributes", attributes);
        runner.addBean("elements", elements);
        runner.addBean("project", getProject());
        if (instance != null) {
            runner.addBean("self", instance);
        }
        runner.executeScript("scriptdef_" + name);
    }

    /**
     * Defines the manager.
     *
     * @param manager the scripting manager.
     */
    public void setManager(String manager) {
        helper.setManager(manager);
    }

    /**
     * Defines the language (required).
     *
     * @param language the scripting language name for the script.
     */
    public void setLanguage(String language) {
        helper.setLanguage(language);
    }

    /**
     * Load the script from an external file ; optional.
     *
     * @param file the file containing the script source.
     */
    public void setSrc(File file) {
        helper.setSrc(file);
    }

    /**
     * Set the script text.
     *
     * @param text a component of the script text to be added.
     */
    public void addText(String text) {
        helper.addText(text);
    }
}