Ant example source code file (RuntimeConfigurable.java)

This example Ant source code file (RuntimeConfigurable.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, attributelist, buildexception, buildexception, hashtable, io, object, runtimeconfigurable, runtimeconfigurable, sax, string, string, stringbuffer, stringbuffer, task, typeadapter, util

The RuntimeConfigurable.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;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Iterator;

import org.apache.tools.ant.util.CollectionUtils;
import org.xml.sax.AttributeList;
import org.xml.sax.helpers.AttributeListImpl;

/**
 * Wrapper class that holds the attributes of an element, its children, and
 * any text within it. It then takes care of configuring that element at
 * runtime.
 *
 */
public class RuntimeConfigurable implements Serializable {

    /** Empty Hashtable. */
    private static final Hashtable EMPTY_HASHTABLE = new Hashtable(0);

    /** Name of the element to configure. */
    private String elementTag = null;

    /** List of child element wrappers. */
    private List/*<RuntimeConfigurable>*/ children = null;

    /** The element to configure. It is only used during
     * maybeConfigure.
     */
    private transient Object wrappedObject = null;

    /** the creator used to make the wrapped object */
    private transient IntrospectionHelper.Creator creator;

    /**
     * XML attributes for the element.
     * @deprecated since 1.6.x
     */
    private transient AttributeList attributes;

    /** Attribute names and values. While the XML spec doesn't require
     *  preserving the order ( AFAIK ), some ant tests do rely on the
     *  exact order. The following code is copied from AttributeImpl.
     *  We could also just use SAX2 Attributes and convert to SAX1 ( DOM
     *  attribute Nodes can also be stored in SAX2 Attributes )
     *  XXX under JDK 1.4 you can just use a LinkedHashMap for this purpose -jglick
     * The only exception to this order is the treatment of
     * refid. A number of datatypes check if refid is set
     * when other attributes are set. This check will not
     * work if the build script has the other attribute before
     * the "refid" attribute, so now (ANT 1.7) the refid
     * attribute will be processed first.
     */
    private List/*<String>*/ attributeNames = null;

    /** Map of attribute names to values */
    private Map/*<String,String>*/ attributeMap = null;

    /** Text appearing within the element. */
    private StringBuffer characters = null;

    /** Indicates if the wrapped object has been configured */
    private boolean proxyConfigured = false;

    /** the polymorphic type */
    private String polyType = null;

    /** the "id" of this Element if it has one */
    private String id = null;

    /**
     * Sole constructor creating a wrapper for the specified object.
     *
     * @param proxy The element to configure. Must not be <code>null.
     * @param elementTag The tag name generating this element.
     */
    public RuntimeConfigurable(Object proxy, String elementTag) {
        setProxy(proxy);
        setElementTag(elementTag);
        // Most likely an UnknownElement
        if (proxy instanceof Task) {
            ((Task) proxy).setRuntimeConfigurableWrapper(this);
        }
    }

    /**
     * Sets the element to configure.
     *
     * @param proxy The element to configure. Must not be <code>null.
     */
    public synchronized void setProxy(Object proxy) {
        wrappedObject = proxy;
        proxyConfigured = false;
    }

    /**
     * Sets the creator of the element to be configured
     * used to store the element in the parent.
     *
     * @param creator the creator object.
     */
    synchronized void setCreator(IntrospectionHelper.Creator creator) {
        this.creator = creator;
    }

    /**
     * Get the object for which this RuntimeConfigurable holds the configuration
     * information.
     *
     * @return the object whose configure is held by this instance.
     */
    public synchronized Object getProxy() {
        return wrappedObject;
    }

    /**
     * Returns the id for this element.
     * @return the id.
     */
    public synchronized String getId() {
        return id;
    }

    /**
     * Get the polymorphic type for this element.
     * @return the ant component type name, null if not set.
     */
    public synchronized String getPolyType() {
        return polyType;
    }

    /**
     * Set the polymorphic type for this element.
     * @param polyType the ant component type name, null if not set.
     */
    public synchronized void setPolyType(String polyType) {
        this.polyType = polyType;
    }

    /**
     * Sets the attributes for the wrapped element.
     *
     * @deprecated since 1.6.x.
     * @param attributes List of attributes defined in the XML for this
     *                   element. May be <code>null.
     */
    public synchronized void setAttributes(AttributeList attributes) {
        this.attributes = new AttributeListImpl(attributes);
        for (int i = 0; i < attributes.getLength(); i++) {
            setAttribute(attributes.getName(i), attributes.getValue(i));
        }
    }

    /**
     * Set an attribute to a given value.
     *
     * @param name the name of the attribute.
     * @param value the attribute's value.
     */
    public synchronized void setAttribute(String name, String value) {
        if (name.equalsIgnoreCase(ProjectHelper.ANT_TYPE)) {
            this.polyType = value;
        } else {
            if (attributeNames == null) {
                attributeNames = new ArrayList();
                attributeMap = new HashMap();
            }
            if (name.toLowerCase(Locale.US).equals("refid")) {
                attributeNames.add(0, name);
            } else {
                attributeNames.add(name);
            }
            attributeMap.put(name, value);
            if (name.equals("id")) {
                this.id = value;
            }
        }
    }

    /**
     * Delete an attribute.  Not for the faint of heart.
     * @param name the name of the attribute to be removed.
     */
    public synchronized void removeAttribute(String name) {
        attributeNames.remove(name);
        attributeMap.remove(name);
    }

    /**
     * Return the attribute map.
     *
     * @return Attribute name to attribute value map.
     * @since Ant 1.6
     */
    public synchronized Hashtable getAttributeMap() {
        return (attributeMap == null)
            ? EMPTY_HASHTABLE : new Hashtable(attributeMap);
    }

    /**
     * Returns the list of attributes for the wrapped element.
     *
     * @deprecated Deprecated since Ant 1.6 in favor of {@link #getAttributeMap}.
     * @return An AttributeList representing the attributes defined in the
     *         XML for this element. May be <code>null.
     */
    public synchronized AttributeList getAttributes() {
        return attributes;
    }

    /**
     * Adds a child element to the wrapped element.
     *
     * @param child The child element wrapper to add to this one.
     *              Must not be <code>null.
     */
    public synchronized void addChild(RuntimeConfigurable child) {
        children = (children == null) ? new ArrayList() : children;
        children.add(child);
    }

    /**
     * Returns the child wrapper at the specified position within the list.
     *
     * @param index The index of the child to return.
     *
     * @return The child wrapper at position <code>index within the
     *         list.
     */
    synchronized RuntimeConfigurable getChild(int index) {
        return (RuntimeConfigurable) children.get(index);
    }

    /**
     * Returns an enumeration of all child wrappers.
     * @return an enumeration of the child wrappers.
     * @since Ant 1.6
     */
    public synchronized Enumeration getChildren() {
        return (children == null) ? new CollectionUtils.EmptyEnumeration()
            : Collections.enumeration(children);
    }

    /**
     * Adds characters from #PCDATA areas to the wrapped element.
     *
     * @param data Text to add to the wrapped element.
     *        Should not be <code>null.
     */
    public synchronized void addText(String data) {
        if (data.length() == 0) {
            return;
        }
        characters = (characters == null)
            ? new StringBuffer(data) : characters.append(data);
    }

    /**
     * Adds characters from #PCDATA areas to the wrapped element.
     *
     * @param buf A character array of the text within the element.
     *            Must not be <code>null.
     * @param start The start element in the array.
     * @param count The number of characters to read from the array.
     *
     */
    public synchronized void addText(char[] buf, int start, int count) {
        if (count == 0) {
            return;
        }
        characters = ((characters == null)
            ? new StringBuffer(count) : characters).append(buf, start, count);
    }

    /**
     * Get the text content of this element. Various text chunks are
     * concatenated, there is no way ( currently ) of keeping track of
     * multiple fragments.
     *
     * @return the text content of this element.
     * @since Ant 1.6
     */
    public synchronized StringBuffer getText() {
        return (characters == null) ? new StringBuffer(0) : characters;
    }

    /**
     * Set the element tag.
     * @param elementTag The tag name generating this element.
     */
    public synchronized void setElementTag(String elementTag) {
        this.elementTag = elementTag;
    }

    /**
     * Returns the tag name of the wrapped element.
     *
     * @return The tag name of the wrapped element. This is unlikely
     *         to be <code>null, but may be.
     */
    public synchronized String getElementTag() {
        return elementTag;
    }

    /**
     * Configures the wrapped element and all its children.
     * The attributes and text for the wrapped element are configured,
     * and then each child is configured and added. Each time the
     * wrapper is configured, the attributes and text for it are
     * reset.
     *
     * If the element has an <code>id attribute, a reference
     * is added to the project as well.
     *
     * @param p The project containing the wrapped element.
     *          Must not be <code>null.
     *
     * @exception BuildException if the configuration fails, for instance due
     *            to invalid attributes or children, or text being added to
     *            an element which doesn't accept it.
     */
    public void maybeConfigure(Project p) throws BuildException {
        maybeConfigure(p, true);
    }

    /**
     * Configures the wrapped element.  The attributes and text for
     * the wrapped element are configured.  Each time the wrapper is
     * configured, the attributes and text for it are reset.
     *
     * If the element has an <code>id attribute, a reference
     * is added to the project as well.
     *
     * @param p The project containing the wrapped element.
     *          Must not be <code>null.
     *
     * @param configureChildren ignored.

     *
     * @exception BuildException if the configuration fails, for instance due
     *            to invalid attributes , or text being added to
     *            an element which doesn't accept it.
     */
    public synchronized void maybeConfigure(Project p, boolean configureChildren)
        throws BuildException {

        if (proxyConfigured) {
            return;
        }

        // Configure the object
        Object target = (wrappedObject instanceof TypeAdapter)
            ? ((TypeAdapter) wrappedObject).getProxy() : wrappedObject;

        IntrospectionHelper ih =
            IntrospectionHelper.getHelper(p, target.getClass());

        if (attributeNames != null) {
            for (int i = 0; i < attributeNames.size(); i++) {
                String name = (String) attributeNames.get(i);
                String value = (String) attributeMap.get(name);

                // reflect these into the target
                value = p.replaceProperties(value);
                try {
                    ih.setAttribute(p, target, name, value);
                } catch (UnsupportedAttributeException be) {
                    // id attribute must be set externally
                    if (name.equals("id")) {
                        // Do nothing
                    } else  if (getElementTag() == null) {
                        throw be;
                    } else {
                        throw new BuildException(
                            getElementTag() +  " doesn't support the \""
                            + be.getAttribute() + "\" attribute", be);
                    }
                } catch (BuildException be) {
                    if (name.equals("id")) {
                        // Assume that this is an not supported attribute type
                        // thrown for example by a dymanic attribute task
                        // Do nothing
                    } else {
                        throw be;
                    }
                }
            }
        }

        if (characters != null) {
            ProjectHelper.addText(p, wrappedObject, characters.substring(0));
        }

        if (id != null) {
            p.addReference(id, wrappedObject);
        }
        proxyConfigured = true;
    }

    /**
     * Reconfigure the element, even if it has already been configured.
     *
     * @param p the project instance for this configuration.
     */
    public void reconfigure(Project p) {
        proxyConfigured = false;
        maybeConfigure(p);
    }


    /**
     * Apply presets, attributes and text are set if not currently set.
     * Nested elements are prepended.
     *
     * @param r a <code>RuntimeConfigurable value.
     */
    public void applyPreSet(RuntimeConfigurable r) {
        // Attributes
        if (r.attributeMap != null) {
            for (Iterator i = r.attributeMap.keySet().iterator(); i.hasNext();) {
                String name = (String) i.next();
                if (attributeMap == null || attributeMap.get(name) == null) {
                    setAttribute(name, (String) r.attributeMap.get(name));
                }
            }
        }
        // poly type

        polyType = (polyType == null) ? r.polyType : polyType;

        // Children (this is a shadow of UnknownElement#children)
        if (r.children != null) {
            List newChildren = new ArrayList();
            newChildren.addAll(r.children);
            if (children != null) {
                newChildren.addAll(children);
            }
            children = newChildren;
        }

        // Text
        if (r.characters != null) {
            if (characters == null
                || characters.toString().trim().length() == 0) {
                characters = new StringBuffer(r.characters.toString());
            }
        }
    }
}