/**
 * END USER LICENSE AGREEMENT (“EULA”)
 *
 * READ THIS AGREEMENT CAREFULLY (date: 9/13/2011):
 * http://www.akiban.com/licensing/20110913
 *
 * BY INSTALLING OR USING ALL OR ANY PORTION OF THE SOFTWARE, YOU ARE ACCEPTING
 * ALL OF THE TERMS AND CONDITIONS OF THIS AGREEMENT. YOU AGREE THAT THIS
 * AGREEMENT IS ENFORCEABLE LIKE ANY WRITTEN AGREEMENT SIGNED BY YOU.
 *
 * IF YOU HAVE PAID A LICENSE FEE FOR USE OF THE SOFTWARE AND DO NOT AGREE TO
 * THESE TERMS, YOU MAY RETURN THE SOFTWARE FOR A FULL REFUND PROVIDED YOU (A) DO
 * NOT USE THE SOFTWARE AND (B) RETURN THE SOFTWARE WITHIN THIRTY (30) DAYS OF
 * YOUR INITIAL PURCHASE.
 *
 * IF YOU WISH TO USE THE SOFTWARE AS AN EMPLOYEE, CONTRACTOR, OR AGENT OF A
 * CORPORATION, PARTNERSHIP OR SIMILAR ENTITY, THEN YOU MUST BE AUTHORIZED TO SIGN
 * FOR AND BIND THE ENTITY IN ORDER TO ACCEPT THE TERMS OF THIS AGREEMENT. THE
 * LICENSES GRANTED UNDER THIS AGREEMENT ARE EXPRESSLY CONDITIONED UPON ACCEPTANCE
 * BY SUCH AUTHORIZED PERSONNEL.
 *
 * IF YOU HAVE ENTERED INTO A SEPARATE WRITTEN LICENSE AGREEMENT WITH AKIBAN FOR
 * USE OF THE SOFTWARE, THE TERMS AND CONDITIONS OF SUCH OTHER AGREEMENT SHALL
 * PREVAIL OVER ANY CONFLICTING TERMS OR CONDITIONS IN THIS AGREEMENT.
 */

package com.akiban.sql.server;

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

public class ServerCallContextStack
{
    private ServerCallContextStack() {
    }

    private static final ThreadLocal<Deque<ServerQueryContext>> tl = new ThreadLocal<Deque<ServerQueryContext>>() {
        @Override
        protected Deque<ServerQueryContext> initialValue() {
            return new ArrayDeque<ServerQueryContext>();
        }
    };

    public static Deque<ServerQueryContext> stack() {
        return tl.get();
    }
    
    public static ServerQueryContext current() {
        return stack().peekLast();
    }
    
    public static void push(ServerQueryContext call) {
        stack().addLast(call);
    }
    
    public static void pop(ServerQueryContext call) {
        ServerQueryContext last = stack().removeLast();
        assert (call == last);
    }
}

Add a stack of calls.