ObjectPoolSet.java

package org.maltparser.core.pool;

import org.maltparser.core.exception.MaltChainedException;
import org.maltparser.core.helper.HashSet;

public abstract class ObjectPoolSet<T> extends ObjectPool<T> {

    private final HashSet<T> available;
    private final HashSet<T> inuse;

    public ObjectPoolSet() {
        this(Integer.MAX_VALUE);
    }

    public ObjectPoolSet(int keepThreshold) {
        super(keepThreshold);
        available = new HashSet<T>();
        inuse = new HashSet<T>();
    }

    protected abstract T create() throws MaltChainedException;

    public abstract void resetObject(T o) throws MaltChainedException;

    public synchronized T checkOut() throws MaltChainedException {
        if (available.isEmpty()) {
            T t = create();
            inuse.add(t);
            return t;
        } else {
            for (T t : available) {
                inuse.add(t);
                available.remove(t);
                return t;
            }
        }
        return null;
    }

    public synchronized void checkIn(T t) throws MaltChainedException {
        resetObject(t);
        inuse.remove(t);
        if (available.size() < keepThreshold) {
            available.add(t);
        }
    }

    public synchronized void checkInAll() throws MaltChainedException {
        for (T t : inuse) {
            resetObject(t);
            if (available.size() < keepThreshold) {
                available.add(t);
            }
        }
        inuse.clear();
    }

    @Override
    public String toString() {
        final StringBuilder sb = new StringBuilder();
        for (T t : inuse) {
            sb.append(t);
            sb.append(", ");
        }
        return sb.toString();
    }
}