Commons Collections example source code file (FunctorException.java)

This example Commons Collections source code file (FunctorException.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 Collections tags/keywords

caused, class, functorexception, functorexception, io, jdk_supports_nested, jdk_supports_nested, nosuchmethodexception, printwriter, printwriter, runtimeexception, throwable, throwable

The Commons Collections FunctorException.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.commons.collections;

import java.io.PrintStream;
import java.io.PrintWriter;

/**
 * Runtime exception thrown from functors.
 * If required, a root cause error can be wrapped within this one.
 * 
 * @since Commons Collections 3.0
 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $
 *
 * @author Stephen Colebourne
 */
public class FunctorException extends RuntimeException {
    
    /**
     * Does JDK support nested exceptions
     */
    private static final boolean JDK_SUPPORTS_NESTED;
    
    static {
        boolean flag = false;
        try {
            Throwable.class.getDeclaredMethod("getCause", new Class[0]);
            flag = true;
        } catch (NoSuchMethodException ex) {
            flag = false;
        }
        JDK_SUPPORTS_NESTED = flag;
    }
    
    /**
     * Root cause of the exception
     */
    private final Throwable rootCause;

    /**
     * Constructs a new <code>FunctorException without specified
     * detail message.
     */
    public FunctorException() {
        super();
        this.rootCause = null;
    }

    /**
     * Constructs a new <code>FunctorException with specified
     * detail message.
     *
     * @param msg  the error message.
     */
    public FunctorException(String msg) {
        super(msg);
        this.rootCause = null;
    }

    /**
     * Constructs a new <code>FunctorException with specified
     * nested <code>Throwable root cause.
     *
     * @param rootCause  the exception or error that caused this exception
     *                   to be thrown.
     */
    public FunctorException(Throwable rootCause) {
        super((rootCause == null ? null : rootCause.getMessage()));
        this.rootCause = rootCause;
    }

    /**
     * Constructs a new <code>FunctorException with specified
     * detail message and nested <code>Throwable root cause.
     *
     * @param msg        the error message.
     * @param rootCause  the exception or error that caused this exception
     *                   to be thrown.
     */
    public FunctorException(String msg, Throwable rootCause) {
        super(msg);
        this.rootCause = rootCause;
    }

    /**
     * Gets the cause of this throwable.
     * 
     * @return  the cause of this throwable, or <code>null
     */
    public Throwable getCause() {
        return rootCause;
    }

    /**
     * Prints the stack trace of this exception to the standard error stream.
     */
    public void printStackTrace() {
        printStackTrace(System.err);
    }

    /**
     * Prints the stack trace of this exception to the specified stream.
     *
     * @param out  the <code>PrintStream to use for output
     */
    public void printStackTrace(PrintStream out) {
        synchronized (out) {
            PrintWriter pw = new PrintWriter(out, false);
            printStackTrace(pw);
            // Flush the PrintWriter before it's GC'ed.
            pw.flush();
        }
    }

    /**
     * Prints the stack trace of this exception to the specified writer.
     *
     * @param out  the <code>PrintWriter to use for output
     */
    public void printStackTrace(PrintWriter out) {
        synchronized (out) {
            super.printStackTrace(out);
            if (rootCause != null && JDK_SUPPORTS_NESTED == false) {
                out.print("Caused by: ");
                rootCause.printStackTrace(out);
            }
        }
    }

}