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The purpose of this class is to workaround an issue with groovy when running code compiled under jdk1.6 and running it under jdk1.7 (see forum thread: http://groovy.329449.n5.nabble.com/jdk7-and-IncompatibleClassChangeError-for-exception-class-td5714582.html)
/*
* Copyright (c) 2013 Yan Pujante
*
* Licensed 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.linkedin.glu.groovy.utils
import org.codehaus.groovy.runtime.HandleMetaClass
import org.slf4j.Logger
import org.slf4j.LoggerFactory
/**
* The purpose of this class is to workaround an issue with groovy when running code compiled
* under jdk1.6 and running it under jdk1.7 (see forum thread: http://groovy.329449.n5.nabble.com/jdk7-and-IncompatibleClassChangeError-for-exception-class-td5714582.html)
* @author yan@pongasoft.com */
public class ExceptionJdk17Workaround
{
public static final String MODULE = ExceptionJdk17Workaround.class.getName();
public static final Logger log = LoggerFactory.getLogger(MODULE);
static void installWorkaround()
{
if(getJavaVersionAsDouble() >= 1.7)
{
def metaClass = Exception.metaClass
if(metaClass instanceof HandleMetaClass)
metaClass = metaClass.replaceDelegate()
if(metaClass.hasProperty("__gluExceptionJdk17Workaround"))
{
log.info "Running with jdk1.7: groovy Exception workaround already installed"
}
else
{
def field = MetaClassImpl.class.getDeclaredField('constructors')
field.setAccessible(true)
def constructors = field.get(metaClass)
int jdk7ConstructorIdx = -1
constructors.array.eachWithIndex { elt, idx ->
if(elt.cachedConstructor.parameterTypes.size() == 4)
jdk7ConstructorIdx = idx
}
if(jdk7ConstructorIdx != -1)
{
constructors.remove(jdk7ConstructorIdx)
// this has 2 purposes:
// 1) allowing to check the workaround
// 2) making sure that the metaclass is no longer a weak reference, hence is not garbage collected!
metaClass.__gluExceptionJdk17Workaround = true
log.info "Running with jdk1.7: installed groovy Exception workaround"
}
}
// making sure the workaround is in place...
if(!new Exception().__gluExceptionJdk17Workaround)
throw new RuntimeException("groovy exception workaround not set properly!!!")
}
else
{
log.debug "Running with jdk1.6: no workaround necessary"
}
}
static double getJavaVersionAsDouble()
{
def version = System.getProperty("java.version")
try
{
Double.parseDouble(version.split('\\.')[0..1].join('.'))
}
catch(NumberFormatException e)
{
e.printStackTrace()
return 1.6;
}
}
}
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