Commons Digester example source code file (ObjectCreateRule.java)

This example Commons Digester source code file (ObjectCreateRule.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 - Commons Digester tags/keywords

class, class, deprecated, deprecated, exception, object, objectcreaterule, objectcreaterule, override, pop, rule, sax, string, string, stringbuffer

The Commons Digester ObjectCreateRule.java source code

/* $Id: ObjectCreateRule.java 992060 2010-09-02 19:09:47Z simonetripodi $
 *
 * 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.commons.digester;


import org.xml.sax.Attributes;


/**
 * Rule implementation that creates a new object and pushes it
 * onto the object stack.  When the element is complete, the
 * object will be popped
 */

public class ObjectCreateRule extends Rule {


    // ----------------------------------------------------------- Constructors


    /**
     * Construct an object create rule with the specified class name.
     *
     * @param digester The associated Digester
     * @param className Java class name of the object to be created
     *
     * @deprecated The digester instance is now set in the {@link Digester#addRule} method. 
     * Use {@link #ObjectCreateRule(String className)} instead.
     */
    @Deprecated
    public ObjectCreateRule(Digester digester, String className) {

        this(className);

    }


    /**
     * Construct an object create rule with the specified class.
     *
     * @param digester The associated Digester
     * @param clazz Java class name of the object to be created
     *
     * @deprecated The digester instance is now set in the {@link Digester#addRule} method. 
     * Use {@link #ObjectCreateRule(Class clazz)} instead.
     */
    @Deprecated
    public ObjectCreateRule(Digester digester, Class<?> clazz) {

        this(clazz);

    }


    /**
     * Construct an object create rule with the specified class name and an
     * optional attribute name containing an override.
     *
     * @param digester The associated Digester
     * @param className Java class name of the object to be created
     * @param attributeName Attribute name which, if present, contains an
     *  override of the class name to create
     *
     * @deprecated The digester instance is now set in the {@link Digester#addRule} method. 
     * Use {@link #ObjectCreateRule(String className, String attributeName)} instead.
     */
    @Deprecated
    public ObjectCreateRule(Digester digester, String className,
                            String attributeName) {

        this (className, attributeName);

    }


    /**
     * Construct an object create rule with the specified class and an
     * optional attribute name containing an override.
     *
     * @param digester The associated Digester
     * @param attributeName Attribute name which, if present, contains an
     * @param clazz Java class name of the object to be created
     *  override of the class name to create
     *
     * @deprecated The digester instance is now set in the {@link Digester#addRule} method. 
     * Use {@link #ObjectCreateRule(String attributeName, Class clazz)} instead.
     */
    @Deprecated
    public ObjectCreateRule(Digester digester,
                            String attributeName,
                            Class<?> clazz) {

        this(attributeName, clazz);

    }

    /**
     * Construct an object create rule with the specified class name.
     *
     * @param className Java class name of the object to be created
     */
    public ObjectCreateRule(String className) {

        this(className, (String) null);

    }


    /**
     * Construct an object create rule with the specified class.
     *
     * @param clazz Java class name of the object to be created
     */
    public ObjectCreateRule(Class<?> clazz) {

        this(clazz.getName(), (String) null);

    }


    /**
     * Construct an object create rule with the specified class name and an
     * optional attribute name containing an override.
     *
     * @param className Java class name of the object to be created
     * @param attributeName Attribute name which, if present, contains an
     *  override of the class name to create
     */
    public ObjectCreateRule(String className,
                            String attributeName) {

        this.className = className;
        this.attributeName = attributeName;

    }


    /**
     * Construct an object create rule with the specified class and an
     * optional attribute name containing an override.
     *
     * @param attributeName Attribute name which, if present, contains an
     * @param clazz Java class name of the object to be created
     *  override of the class name to create
     */
    public ObjectCreateRule(String attributeName,
                            Class<?> clazz) {

        this(clazz.getName(), attributeName);

    }

    // ----------------------------------------------------- Instance Variables


    /**
     * The attribute containing an override class name if it is present.
     */
    protected String attributeName = null;


    /**
     * The Java class name of the object to be created.
     */
    protected String className = null;


    // --------------------------------------------------------- Public Methods


    /**
     * Process the beginning of this element.
     *
     * @param attributes The attribute list of this element
     */
    @Override
    public void begin(Attributes attributes) throws Exception {

        // Identify the name of the class to instantiate
        String realClassName = className;
        if (attributeName != null) {
            String value = attributes.getValue(attributeName);
            if (value != null) {
                realClassName = value;
            }
        }
        if (digester.log.isDebugEnabled()) {
            digester.log.debug("[ObjectCreateRule]{" + digester.match +
                    "}New " + realClassName);
        }

        // Instantiate the new object and push it on the context stack
        Class<?> clazz = digester.getClassLoader().loadClass(realClassName);
        Object instance = clazz.newInstance();
        digester.push(instance);

    }


    /**
     * Process the end of this element.
     */
    @Override
    public void end() throws Exception {

        Object top = digester.pop();
        if (digester.log.isDebugEnabled()) {
            digester.log.debug("[ObjectCreateRule]{" + digester.match +
                    "} Pop " + top.getClass().getName());
        }

    }


    /**
     * Render a printable version of this Rule.
     */
    @Override
    public String toString() {

        StringBuffer sb = new StringBuffer("ObjectCreateRule[");
        sb.append("className=");
        sb.append(className);
        sb.append(", attributeName=");
        sb.append(attributeName);
        sb.append("]");
        return (sb.toString());

    }


}