ipojo/handler/temporal/temporal-dependency-handler/src/main/java/org/apache/felix/ipojo/handler/temporal/ServiceUsage.java

/* 
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.felix.ipojo.handler.temporal;


/**
 * Object managing thread local copy of required services.
 * 
 * @author <a href="mailto:dev@felix.apache.org">Felix Project Team</a>
 */
public class ServiceUsage extends ThreadLocal {
    
    /**
     * Structure contained in the Thread Local.
     */
    public static class Usage {
        
        /**
         * Stack Size.
         */
        int m_stack = 0;
        /**
         * Object to inject.
         */
        Object m_object;
        
        /**
         * Increment the stack level.
         */
        public void inc() {
            m_stack++;
        }
        
        /**
         * Decrement the stack level.
         * @return  true if the stack is 0 after the decrement.
         */
        public boolean dec() {
            m_stack--;
            return m_stack == 0;
        }
        
        /**
         * Clear the service object array.
         */
        public void clear() {
            m_object = null;
        }
        
    }
    
    /**
     * Initialize the cached object.
     * @return an empty Usage object.
     * @see java.lang.ThreadLocal#initialValue()
     */
    public Object initialValue() {
        return new Usage();
    }   

}