antliscence/src/main/org/apache/tools/ant/RuntimeConfigurable.java

/*
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2000-2003 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "Ant" and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
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 * 5. Products derived from this software may not be called "Apache"
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

package org.apache.tools.ant;

import java.util.Enumeration;
import java.util.Locale;
import java.util.Vector;
import java.util.Hashtable;
import java.io.Serializable;

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.
 *
 * @author Stefan Bodewig
 */
public class RuntimeConfigurable implements Serializable {

    /** Name of the element to configure. */
    private String elementTag = null;
    
    /** List of child element wrappers. */
    private Vector children = new Vector();
    
    /** The element to configure. It is only used during
     * maybeConfigure.
     */
    private transient Object wrappedObject = null;

    /** 
     * @deprecated
     * XML attributes for the element. 
     */
    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 Attributges )
     */
    private Vector attributeNames = new Vector();
    
    /** Map of attribute names to values */
    private Hashtable attributeMap = new Hashtable();

    /** Text appearing within the element. */
    private StringBuffer characters = new StringBuffer();
    
    /** Indicates if the wrapped object has been configured */
    private boolean proxyConfigured = false;

    /**
     * Sole constructor creating a wrapper for the specified object.
     *
     * @param proxy The element to configure. Must not be <code>null</code>.
     * @param elementTag The tag name generating this element.
     *                   Should not be <code>null</code>.
     */
    public RuntimeConfigurable(Object proxy, String elementTag) {
        wrappedObject = proxy;
        this.elementTag = elementTag;
        proxyConfigured = false;
        // 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</code>.
     */
    void setProxy(Object proxy) {
        wrappedObject = proxy;
        proxyConfigured = false;
    }

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

    /**
     * Sets the attributes for the wrapped element.
     *
     * @deprecated
     * @param attributes List of attributes defined in the XML for this
     *                   element. May be <code>null</code>.
     */
    public 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 void setAttribute(String name, String value) {
        attributeNames.addElement(name);
        attributeMap.put(name, value);
    }

    /** Return the attribute map.
     *
     * @return Attribute name to attribute value map
     */
    public Hashtable getAttributeMap() {
        return attributeMap;
    }

    /**
     * Returns the list of attributes for the wrapped element.
     *
     * @deprecated
     * @return An AttributeList representing the attributes defined in the
     *         XML for this element. May be <code>null</code>.
     */
    public 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</code>.
     */
    public void addChild(RuntimeConfigurable child) {
        children.addElement(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</code> within the
     *         list.
     */
    RuntimeConfigurable getChild(int index) {
        return (RuntimeConfigurable) children.elementAt(index);
    }

    /**
     * Returns an enumeration of all child wrappers.
     *
     * @since Ant 1.5.1
     */
    Enumeration getChildren() {
        return children.elements();
    }

    /**
     * Adds characters from #PCDATA areas to the wrapped element.
     *
     * @param data Text to add to the wrapped element.
     *        Should not be <code>null</code>.
     */
    public void addText(String 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</code>.
     * @param start The start element in the array.
     * @param count The number of characters to read from the array.
     *
     */
    public void addText(char[] buf, int start, int count) {
        addText(new String(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.
     */
    public StringBuffer getText() {
        return characters;
    }

    /**
     * Returns the tag name of the wrapped element.
     *
     * @return The tag name of the wrapped element. This is unlikely
     *         to be <code>null</code>, but may be.
     */
    public 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</code> attribute, a reference
     * is added to the project as well.
     *
     * @param p The project containing the wrapped element.
     *          Must not be <code>null</code>.
     *
     * @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</code> attribute, a reference
     * is added to the project as well.
     *
     * @param p The project containing the wrapped element.
     *          Must not be <code>null</code>.
     *
     * @param configureChildren Whether to configure child elements as
     * well.  if true, child elements will be configured after the
     * wrapped element.
     *
     * @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, boolean configureChildren)
        throws BuildException {
        String id = null;

        if (proxyConfigured) {
            return;
        }

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

        //PropertyHelper ph=PropertyHelper.getPropertyHelper(p);
        IntrospectionHelper ih =
            IntrospectionHelper.getHelper(p, target.getClass());

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

            // reflect these into the target
            value = p.replaceProperties(value);
            try {
                ih.setAttribute(p, target,
                        name.toLowerCase(Locale.US), value);
            } catch (BuildException be) {
                // id attribute must be set externally
                if (!name.equals("id")) {
                    throw be;
                }
            }
        }
        id = (String) attributeMap.get("id");

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

        Enumeration enum = children.elements();
        while (enum.hasMoreElements()) {
            RuntimeConfigurable child
                    = (RuntimeConfigurable) enum.nextElement();
            if (child.wrappedObject instanceof Task) {
                Task childTask = (Task) child.wrappedObject;
                childTask.setRuntimeConfigurableWrapper(child);
            }

            if (configureChildren) {
                /*
                 * backwards compatibility - element names of nested
                 * elements have been all lower-case in Ant, except for
                 * TaskContainers
                 */

                /* XXX
                 *
                 * For some reason we don't throw an exception here if
                 * we find the nested element is unsupported, probably
                 * because this will happen somewhere else.
                 */
                String tag = child.getElementTag();
                if (ih.supportsNestedElement(tag.toLowerCase(Locale.US))) {
                    tag = tag.toLowerCase(Locale.US);
                } else if (!ih.supportsNestedElement(tag)) {
                    continue;
                }
                
                child.maybeConfigure(p);
                ProjectHelper.storeChild(p, target, child.wrappedObject,
                                         tag);
            }
        }

        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);
    }
}