001    /**
002     * Copyright (C) 2011 rwoo@gmx.de
003     *
004     * Licensed under the Apache License, Version 2.0 (the "License");
005     * you may not use this file except in compliance with the License.
006     * You may obtain a copy of the License at
007     *
008     *         http://www.apache.org/licenses/LICENSE-2.0
009     *
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed under the License is distributed on an "AS IS" BASIS,
012     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013     * See the License for the specific language governing permissions and
014     * limitations under the License.
015     */
016    package com.googlecode.catchexception.throwable.internal;
017    
018    import java.lang.ref.WeakReference;
019    
020    /**
021     * Holds a caught throwable {@link ThreadLocal per Thread}.
022     * 
023     * @author rwoo
024     * 
025     */
026    public class ThrowableHolder {
027    
028        /**
029         * The container for the most recently caught throwable.
030         * <p>
031         * There is no need to use {@link WeakReference weak references} here as all
032         * the code is for testing so that we don't have to care about memory leaks.
033         */
034        private static final ThreadLocal<Throwable> caughtThrowable = new ThreadLocal<Throwable>();
035    
036        /**
037         * Saves the given throwable in {@link #caughtThrowable}.
038         * 
039         * @param <E>
040         *            the type of the caught throwable
041         * @param caughtThrowable
042         *            the caught throwable
043         */
044        public static <E extends Throwable> void set(E caughtThrowable) {
045            ThrowableHolder.caughtThrowable.set(caughtThrowable);
046        }
047    
048        /**
049         * @param <E>
050         *            the type of the caught throwable
051         * @return Returns the caught throwable. Returns null if there is no
052         *         throwable caught.
053         */
054        @SuppressWarnings("unchecked")
055        public static <E extends Throwable> E get() {
056            return (E) caughtThrowable.get();
057        }
058    
059    }