com.streamsets.pipeline.api.impl.CreateByRef Maven / Gradle / Ivy
/*
* Copyright 2017 StreamSets Inc.
*
* 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 com.streamsets.pipeline.api.impl;
import java.util.concurrent.Callable;
public class CreateByRef {
private static final ThreadLocal BY_REF_TL = new ThreadLocal() {
@Override
protected Boolean initialValue() {
return Boolean.FALSE;
}
};
private CreateByRef() {}
public static boolean isByRef() {
return BY_REF_TL.get() == Boolean.TRUE;
}
public static T call(Callable callable) throws Exception{
boolean alreadyByRef = BY_REF_TL.get() == Boolean.TRUE;
try {
if (!alreadyByRef) {
BY_REF_TL.set(Boolean.TRUE);
}
return callable.call();
} finally {
if (!alreadyByRef) {
BY_REF_TL.set(Boolean.FALSE);
}
}
}
}