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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

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package org.wildfly.common.function;

import java.util.ArrayDeque;
import java.util.Deque;

/**
 * A thread local stack data structure. In order to avoid memory churn the underlying
 * ArrayDeque is never freed. If we remove the deque when it is empty then this results
 * in excessive deque allocations.
 */
public class ThreadLocalStack {

    private static final Object NULL_VALUE = new Object();

    private final ThreadLocal> deque = ThreadLocal.withInitial(ArrayDeque::new);

    public void push(E item) {
        Deque st = deque.get();
        if(item == null) {
            st.push(NULL_VALUE);
        } else {
            st.push(item);
        }
    }

    public E peek() {
        Deque st = deque.get();
        Object o =  st.peek();
        if(o == NULL_VALUE) {
            return null;
        } else {
            return (E) o;
        }
    }

    public E pop() {
        Deque st = deque.get();
        Object o =  st.pop();
        if(o == NULL_VALUE) {
            return null;
        } else {
            return (E) o;
        }
    }

    public boolean isEmpty() {
        return deque.get().isEmpty();
    }

}    

    

    

            

    

            



    
    






    
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