/*

 * Copyright (c) 2007-2008 Nokia Corporation and/or its subsidiary(-ies).

 * All rights reserved.

 * This component and the accompanying materials are made available

 * under the terms of the License "Eclipse Public License v1.0"

 * which accompanies this distribution, and is available

 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

 *

 * Initial Contributors:

 * Nokia Corporation - initial contribution.

 *

 * Contributors:

 *

 * Description:  

 *

 */

package com.nokia.helium.metadata.ant.types;

import java.util.Hashtable;

import java.util.Map;

import javax.persistence.EntityManager;

import com.nokia.helium.metadata.model.metadata.Component;

import com.nokia.helium.metadata.model.metadata.LogFile;

/**

 * LogMetaDataInput which implements some abstract component handling. 

 *

 */

public abstract class AbstractComponentBaseMetadataInput extends LogMetaDataInput {

    protected static final String DEFAULT_COMPONENT = "Default";

    private Map<String, Component> components = new Hashtable<String, Component>();

    private Component defaultComponent;

    /**

     * Provides an entity manager to manipulate the data.

     * @return

     */

    protected abstract EntityManager getEntityManager();

    /**

     * Defines the name of the default component.

     * @return a String with the name of the default component.

     */

    protected String getDefaultComponentName() {

        return DEFAULT_COMPONENT;

    }

    /**

     * Get the default component instance from the database.

     * Or create it if needed.

     * @param logFile logFile to associate the component to.

     * @return the Component instance. 

     */

    protected Component getDefaultComponent(LogFile logFile) {

        if (defaultComponent == null) {

            defaultComponent = getComponent(getDefaultComponentName(), logFile);

        }

        return defaultComponent;

    }

    /**

     * Get the database instance for the name component.

     * @param name the name of the component

     * @param logFile logFile to associate the component to.

     * @return the Component instance.

     */

    protected Component getComponent(String name, LogFile logFile) {

        if (!components.containsKey(name)) {

            Component component = createComponent(name, logFile);

            components.put(name, component);

            return component;

        }

        return components.get(name);

    }

    /**

     * Creates a new component. This method is called by the 

     * getComponent method if the component entity is not found

     * in the cache.

     * @param name the name of the component

     * @param logFile logFile to associate the component to.

     * @return the Component instance.

     */

    protected Component createComponent(String name, LogFile logFile) {

        Component component = new Component();

        component.setComponent(name);

        component.setLogFile(logFile);

        getEntityManager().getTransaction().begin();

        getEntityManager().persist(component);

        getEntityManager().getTransaction().commit();

        return component;

    }

    /**

     * Clear the components cache.

     */

    protected void clear() {

        components = new Hashtable<String, Component>();

        defaultComponent = null;

    }

}