org.jboss.weld.injection.ThreadLocalStackService Maven / Gradle / Ivy
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* Copyright 2008, Red Hat, Inc., and individual contributors
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* 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.jboss.weld.injection;
import java.util.EmptyStackException;
import java.util.Stack;
import org.jboss.weld.bootstrap.api.Service;
public class ThreadLocalStackService implements Service {
private final ThreadLocal> threadLocalStack;
public ThreadLocalStackService() {
this.threadLocalStack = new ThreadLocal>();
}
/**
* Replaces (or adds) the current injection point. If a current injection
* point exists, it will be replaced. If no current injection point exists,
* one will be added.
*
* @param item the injection point to use
* @return the injection point added, or null if previous existed did not exist
*/
public void push(T item) {
Stack stack = threadLocalStack.get();
if (stack == null) {
stack = new Stack();
threadLocalStack.set(stack);
}
stack.push(item);
}
public T pop() {
Stack stack = threadLocalStack.get();
if (stack == null) {
throw new EmptyStackException();
}
try {
return stack.pop();
} finally {
if (stack.isEmpty()) {
threadLocalStack.remove();
}
}
}
/**
* The injection point being operated on for this thread
*
* @return the current injection point
*/
public T peek() {
Stack stack = threadLocalStack.get();
if (stack == null) {
return null;
}
if (!stack.empty()) {
return stack.peek();
} else {
return null;
}
}
public void cleanup() {
}
}