Commons Digester example source code file (PluginAssertionFailure.java)

This example Commons Digester source code file (PluginAssertionFailure.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

override, override, pluginassertionfailure, pluginassertionfailure, runtimeexception, runtimeexception, throwable, throwable

The Commons Digester PluginAssertionFailure.java source code

/* $Id: PluginAssertionFailure.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.plugins;

/**
 * Thrown when a bug is detected in the plugins code.
 * <p>
 * This class is intended to be used in assertion statements, similar to
 * the way that java 1.4's native assertion mechanism is used. However there
 * is a difference: when a java 1.4 assertion fails, an AssertionError
 * is thrown, which is a subclass of Error; here, the PluginAssertionFailure
 * class extends RuntimeException rather than Error.
 * <p>
 * This difference in design is because throwing Error objects is not
 * good in a container-based architecture.
 * <p>
 * Example:
 * <pre>
 *   if (impossibleCondition) {
 *     throw new PluginAssertionFailure(
 *       "internal error: impossible condition is true");
 *   }
 * </pre> 
 * <p>
 * Note that PluginAssertionFailure should <i>not be thrown when user 
 * input is bad, or when code external to the Digester module passes invalid 
 * parameters to a plugins method. It should be used only in checks for 
 * problems which indicate internal bugs within the plugins module.
 *
 * @since 1.6
 */
public class PluginAssertionFailure extends RuntimeException {

    private static final long serialVersionUID = 1L;
    private Throwable cause = null;

    /**
     * @param cause underlying exception that caused this to be thrown
     */
    public PluginAssertionFailure(Throwable cause) {
        this(cause.getMessage());
        this.cause = cause;
    }

    /**
     * @param msg describes the reason this exception is being thrown.
     */
    public PluginAssertionFailure(String msg) {
        super(msg);
    }

    /**
     * @param msg describes the reason this exception is being thrown.
     * @param cause underlying exception that caused this to be thrown
     */
    public PluginAssertionFailure(String msg, Throwable cause) {
        this(msg);
        this.cause = cause;
    }
    
    /**
     * Return the cause of this exception (if any) as specified in the
     * exception constructor.
     * 
     * @since 1.8
     */
    @Override
    public Throwable getCause() {
        return cause;
    }
}