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package org.atmosphere.util;


import java.util.concurrent.ConcurrentHashMap;
import java.util.logging.Level;
import org.atmosphere.cpr.Broadcaster;

/**
 * A class that can be used to lookup {@link Broadcaster}
 * based on the returned value of {@link Broadcaster#getID()} and
 * {@link Broadcaster#getScope()}
 *
 * @author Jeanfrancois Arcand
 */
public class BroadcasterLookup{

    private final static ConcurrentHashMap store
            = new ConcurrentHashMap();

    /**
     * Lookup a {@link Broadcaster} instance using {@link Broadcaster#getID()} or ID
     * used when invoking {@link BroadcasterLookup#build(java.lang.Class, java.lang.Object));
     * @param id The Broadcaster's unique ID, or name.
     * @return a Broadcaster, or null if not found.
     */
    public final static Broadcaster lookup(Class c, Object id){
        Broadcaster b = getBroadcaster(id);
        if (b!= null && b.getScope() == Broadcaster.SCOPE.REQUEST){
            throw new IllegalStateException("Broadcaster " + b
                    + " cannot be looked up as its scope is REQUEST");
        }

        if (b!= null && !b.getClass().equals(c)){
            String em = "Invalid BroadcasterLookup class " + c.getName() + ". Cached class is: " + b.getClass().getName();
            LoggerUtils.getLogger().log(Level.WARNING,em);
            throw new IllegalStateException(em);
        }

        return b;
    }

    /**
     * Return a {@link Broadcaster} based on its name.
     * @param name The unique ID
     * @return a {@link Broadcaster}, or null
     */
    static Broadcaster getBroadcaster(Object name){
        return store.get(name);
    }

    /**
     * Add a {@link Broadcaster} to the list.
     * @param b a {@link Broadcaster}
     * @return false if a with the same name {@link Broadcaster} was already stored
     */
    public final static boolean add(Broadcaster b,Object id){
        return (store.putIfAbsent(id,b) == null ? true: false);
    }

    /**
     * Remove a {@link Broadcaster} to the list.
     * @param b a {@link Broadcaster}
     * @return false if wasn't present, or {@link Broadcaster}
     */
    public final static boolean remove(Broadcaster b,Object id){
        return (store.remove(id) == null ? false : true);
    }

    /**
     * Create a new instance of {@link Broadcaster} and store it for
     *
     * @param c The {@link Broadcaster} class instance.
     * @param id The unique ID used to retrieve {@link Broadcaster}
     * @return a new instance of {@link Broadcaster}
     */
    public final static Broadcaster build(Class c, Object id){
        Broadcaster b  = null;
        try {
            b = c.newInstance();
        } catch (InstantiationException ex) {
            LoggerUtils.getLogger().log(Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            LoggerUtils.getLogger().log(Level.SEVERE, null, ex);
        }

        if (id instanceof String){
            b.setID(id.toString());
        }
        store.put(id, b);
        return b;
    }
}