jelly-tags/ant/src/java/org/apache/commons/jelly/tags/ant/JellyPropsHandler.java

package org.apache.commons.jelly.tags.ant;

/*
 * 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.
 */

import java.util.Hashtable;
import java.util.Iterator;

import org.apache.commons.jelly.JellyContext;
import org.apache.commons.jelly.expression.Expression;

/** Implementation of a Commons Grant <code>propsHandler</code>
 *  to resolve through Jelly's context.
 *
 *  @author <a href="mailto:bob@eng.werken.com">Bob McWhirter</a>
 *  @author <a href="mailto:stephenh@chase3000.com">Stephen Haberman</a>
 */
public class JellyPropsHandler extends DefaultPropsHandler {

    /** The JellyContext. */
    private JellyContext context;

    /** Simple constructor with the context to be used.
     *
     *  @param context The context to be used.
     */
    public JellyPropsHandler(JellyContext context) {
        this.context = context;
    }

    /** Set an ant property.
     *
     *  @param name The property name.
     *  @param value The property value.
     */
    public void setProperty(String name, String value) {
        this.context.setVariable(name, value);
    }

    /** Retrieve an ant property.
     *
     *  @param name The property name.
     *
     *  @return The property value.
     */
    public String getProperty(String name) {
        if (name == null) {
            return null;
        }
        Object value = this.context.getVariable(name);
        if (value == null) {
            return null;
        }
        else {
            if ( value instanceof Expression )
            {
                return ( ( Expression ) value ).evaluateAsString( context );
            }
            else
            {
                return value.toString();
            }
        }
    }

    /** Retrieve all ant properties.
     *
     *  @return A <code>Hashtable</code> of all properties.
     */
    public Hashtable getProperties() {
        Hashtable h = new Hashtable();
        for (Iterator i = this.context.getVariableNames(); i.hasNext(); ) {
            String name = (String) i.next();
            String value = getProperty( name );
            if (value != null) {
                h.put(name, value);
            }
        }
        return h;
    }

}