net.sourceforge.jabm.spring.SimulationScope.java Source code

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Here is the source code for net.sourceforge.jabm.spring.SimulationScope.java

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/*
 * JABM - Java Agent-Based Modeling Toolkit
 * Copyright (C) 2013 Steve Phelps
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 3 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 */
package net.sourceforge.jabm.spring;

import java.util.HashMap;

import org.apache.log4j.Logger;
import org.springframework.beans.factory.ObjectFactory;
import org.springframework.beans.factory.config.Scope;

/**
 * <p>
 * A custom Spring bean scope used to manage objects which persist
 * throughout a single simulation, but are re-instantiated on each new 
 * independent simulation run.
 * </p>
 * @author Steve Phelps
 */
public class SimulationScope implements Scope {

    /**
     * A mapping from bean names to objects that are bound in this scope.
     */
    protected HashMap<String, Object> boundObjects;

    protected int simulationId = 1;

    protected static SimulationScope singletonInstance;

    static Logger logger = Logger.getLogger(SimulationScope.class);

    /**
     * The string that appears in the scope attribute of a bean definition.
     */
    public static final String ATTRIBUTE_VALUE = "simulation";

    public SimulationScope() {
        boundObjects = new HashMap<String, Object>();
    }

    @Override
    public Object get(String name, ObjectFactory<?> objectFactory) {
        if (logger.isDebugEnabled())
            logger.debug("Looking up bean " + name);
        Object result = boundObjects.get(name);
        if (result == null) {
            result = objectFactory.getObject();
            boundObjects.put(name, result);
        }
        if (logger.isDebugEnabled()) {
            logger.debug("Returning " + result + " with hash " + result.hashCode() + " for " + name);
        }
        return result;
    }

    @Override
    public Object remove(String name) {
        return boundObjects.remove(name);
    }

    @Override
    public void registerDestructionCallback(String name, Runnable callback) {
        // TODO Auto-generated method stub
    }

    @Override
    public Object resolveContextualObject(String key) {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public String getConversationId() {
        return simulationId + "";
    }

    /**
     * Invoked to indicate that a new simulation has begun and that a fresh
     * scope is required.
     */
    public void startNewSimulation() {
        boundObjects.clear();
        simulationId++;
    }

    public static SimulationScope getSingletonInstance() {
        if (singletonInstance == null) {
            singletonInstance = new SimulationScope();
        }
        return singletonInstance;
    }

}