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package com.sun.enterprise.resource.pool.datastructure;

import com.sun.enterprise.resource.allocator.ResourceAllocator;
import com.sun.enterprise.resource.ResourceHandle;
import com.sun.enterprise.resource.pool.ResourceHandler;
import com.sun.enterprise.resource.pool.datastructure.strategy.ResourceSelectionStrategy;
import com.sun.appserv.connectors.internal.api.PoolingException;
import com.sun.logging.LogDomains;

import java.util.concurrent.locks.ReentrantReadWriteLock;
import java.util.Iterator;
import java.util.ArrayList;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * ReadWriteLock based datastructure for pool
 * @author Jagadish Ramu
 */
public class RWLockDataStructure implements DataStructure {

    private ResourceHandler handler;
    private ResourceSelectionStrategy strategy;
    private int maxSize;

    private final ArrayList resources;
    private ReentrantReadWriteLock reentrantLock = new ReentrantReadWriteLock();
    private ReentrantReadWriteLock.ReadLock readLock = reentrantLock.readLock();
    private ReentrantReadWriteLock.WriteLock writeLock = reentrantLock.writeLock();

    protected final static Logger _logger =
            LogDomains.getLogger(RWLockDataStructure.class,LogDomains.RSR_LOGGER);

    public RWLockDataStructure(String parameters, int maxSize,
                                              ResourceHandler handler, String strategyClass) {
        resources = new ArrayList((maxSize > 1000) ? 1000 : maxSize);
        this.maxSize = maxSize;
        this.handler = handler;
        initializeStrategy(strategyClass);
        if(_logger.isLoggable(Level.FINEST)) {
            _logger.log(Level.FINEST, "pool.datastructure.rwlockds.init");
        }
    }

    private void initializeStrategy(String strategyClass) {
        //TODO
    }

    /**
     * {@inheritDoc}
     */
    public int addResource(ResourceAllocator allocator, int count) throws PoolingException {
        int numResAdded = 0;
        writeLock.lock();
        //for now, coarser lock. finer lock needs "resources.size() < maxSize()" once more.
        try {
            for (int i = 0; i < count && resources.size() < maxSize; i++) {
                ResourceHandle handle = handler.createResource(allocator);
                resources.add(handle);
                numResAdded++;
            }
        } catch (Exception e) {
            PoolingException pe = new PoolingException(e.getMessage());
            pe.initCause(e);
            throw pe;
        } finally {
            writeLock.unlock();
        }
        return numResAdded;
    }

    /**
     * {@inheritDoc}
     */
    public ResourceHandle getResource() {
        readLock.lock();
        for(int i=0; i getAllResources() {
        throw new UnsupportedOperationException("Not supported yet.");
    }
}