Mega Code Archive
Create a new Exception, setting the cause if possible
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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.
*/
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
/**
* Use this to create a new Exception. This will run under JDK 1.3 or greater.
* However, it running under JDK 1.4 it will set the cause.
*
* @author <a href="mailto:isidore@setgame.com">Llewellyn Falco</a>
* @since 1.5
*/
public class ExceptionUtils
{
private static boolean causesAllowed = true;
/**
* Create a new RuntimeException, setting the cause if possible.
* @param message
* @param cause
* @return A runtime exception object.
*/
public static RuntimeException createRuntimeException(
String message, Throwable cause)
{
return (RuntimeException) createWithCause(
RuntimeException.class, message, cause);
}
/**
* Create a new Exception, setting the cause if possible.
* @param clazz
* @param message
* @param cause
* @return A Throwable.
*/
public static Throwable createWithCause(Class clazz,
String message, Throwable cause)
{
Throwable re = null;
if (causesAllowed)
{
try
{
Constructor constructor = clazz
.getConstructor(new Class[]{String.class,
Throwable.class});
re = (Throwable) constructor
.newInstance(new Object[]{message, cause});
}
catch (RuntimeException e)
{
throw e;
}
catch (Exception e)
{
causesAllowed = false;
}
}
if (re == null)
{
try
{
Constructor constructor = clazz
.getConstructor(new Class[]{String.class});
re = (Throwable) constructor
.newInstance(new Object[]{message
+ " caused by " + cause});
}
catch (RuntimeException e)
{
throw e;
}
catch (Exception e)
{
throw new RuntimeException("Error caused " + e); // should be impossible
}
}
return re;
}
/**
* Set the cause of the Exception. Will detect if this is not allowed.
* @param onObject
* @param cause
*/
public static void setCause(Throwable onObject, Throwable cause)
{
if (causesAllowed)
{
try
{
Method method = onObject.getClass().getMethod("initCause", new Class[]{Throwable.class});
method.invoke(onObject, new Object[]{cause});
}
catch (RuntimeException e)
{
throw e;
}
catch (Exception e)
{
causesAllowed = false;
}
}
}
}
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