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/*
* 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 libcore.util;
/**
* Exploits a weakness in the runtime to throw an arbitrary throwable without
* the traditional declaration. <strong>This is a dangerous API that should be
* used with great caution.</strong> Typically this is useful when rethrowing
* throwables that are of a known range of types.
*
* <p>The following code must enumerate several types to rethrow:
* <pre>
* public void close() throws IOException {
* Throwable thrown = null;
* ...
*
* if (thrown != null) {
* if (thrown instanceof IOException) {
* throw (IOException) thrown;
* } else if (thrown instanceof RuntimeException) {
* throw (RuntimeException) thrown;
* } else if (thrown instanceof Error) {
* throw (Error) thrown;
* } else {
* throw new AssertionError();
* }
* }
* }</pre>
* With SneakyThrow, rethrowing is easier:
* <pre>
* public void close() throws IOException {
* Throwable thrown = null;
* ...
*
* if (thrown != null) {
* SneakyThrow.sneakyThrow(thrown);
* }
* }</pre>
*/
public final class SneakyThrow {
private SneakyThrow() {}
public static void sneakyThrow(Throwable t) {
SneakyThrow.<Error>sneakyThrow2(t);
}
/**
* Exploits unsafety to throw an exception that the compiler wouldn't permit
* but that the runtime doesn't check. See Java Puzzlers #43.
*/
@SuppressWarnings("unchecked")
private static <T extends Throwable> void sneakyThrow2(Throwable t) throws T {
throw (T) t;
}
}
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