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Object Automation library
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/*  Copyright 1999 Vince Via [email protected]
    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/
package com.viaoa.datasource.objectcache;

import java.util.ArrayList;

import com.viaoa.datasource.OADataSourceIterator;
import com.viaoa.object.OAObjectCacheDelegate;
import com.viaoa.util.OAFilter;

/**
 * Used to find and filter objects in OAObjectCache. Note, all queries require that a non-null Filter be used. If filter is null, then no
 * results will be returned.
 *
 * @author vvia
 */
public class ObjectCacheIterator implements OADataSourceIterator {
	protected Class clazz;
	protected OAFilter filter;
	protected T nextObject, lastFetchObject;
	protected ArrayList alFetchObjects = new ArrayList(50);
	protected int posFetchObjects;
	protected boolean bFetchIsDone;
	protected int max;
	private int nextCount;

	public ObjectCacheIterator(Class c) {
		this.clazz = c;
	}

	public ObjectCacheIterator(Class c, OAFilter filter) {
		this.clazz = c;
		this.filter = filter;
	}

	public T next() {
		return getNext();
	}

	private synchronized T getNext() {
		T obj;
		if (nextObject != null) {
			obj = nextObject;
			nextObject = null;
			return obj;
		}
		for (;;) {
			obj = _next();
			if (obj == null) {
				break;
			}
			if (filter == null || filter.isUsed(obj)) {
				break;
			}
		}
		if (obj != null) {
			nextCount++;
		}
		return obj;
	}

	protected T _next() {
		if (max > 0 && nextCount >= max) {
			return null;
		}
		if (posFetchObjects >= alFetchObjects.size()) {
			posFetchObjects = 0;
			alFetchObjects.clear();
			if (bFetchIsDone) {
				return null;
			}
			lastFetchObject = (T) OAObjectCacheDelegate.find(lastFetchObject, clazz, filter, false, false, 50, (ArrayList) alFetchObjects);
			if (lastFetchObject == null) {
				bFetchIsDone = true;
				if (alFetchObjects.size() == 0) {
					return null;
				}
			}
		}
		T obj = alFetchObjects.get(posFetchObjects++);
		return obj;
	}

	public synchronized boolean hasNext() {
		if (nextObject == null) {
			nextObject = getNext();
		}
		return (nextObject != null);
	}

	public void setMax(int x) {
		this.max = x;
	}

	public int getMax() {
		return max;
	}

	public void remove() {
	}

	@Override
	public String getQuery() {
		return null;
	}

	@Override
	public String getQuery2() {
		return null;
	}
}