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Massive On-line Analysis is an environment for massive data mining. MOA provides a framework for data stream mining and includes tools for evaluation and a collection of machine learning algorithms. Related to the WEKA project, also written in Java, while scaling to more demanding problems.

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/*
 *    CachedInstancesStream.java
 *    Copyright (C) 2007 University of Waikato, Hamilton, New Zealand
 *    @author Richard Kirkby ([email protected])
 *
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 3 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program. If not, see .
 *    
 */
package moa.streams;

import moa.AbstractMOAObject;
import moa.core.InstanceExample;
import com.yahoo.labs.samoa.instances.InstancesHeader;
import com.yahoo.labs.samoa.instances.Instances;

/**
 * Stream generator for representing a stream that is cached in memory.
 * This generator is used with the task CacheShuffledStream that
 * stores and shuffles examples in memory.
 *
 * @author Richard Kirkby ([email protected])
 * @version $Revision: 7 $
 */
public class CachedInstancesStream extends AbstractMOAObject implements
		MultiTargetInstanceStream {

	private static final long serialVersionUID = 1L;

	protected Instances toStream;

	protected int streamPos;

	public CachedInstancesStream(Instances toStream) {
		this.toStream = toStream;
	}

    @Override
	public InstancesHeader getHeader() {
		return new InstancesHeader(this.toStream);
	}

    @Override
	public long estimatedRemainingInstances() {
		return this.toStream.numInstances() - this.streamPos;
	}

    @Override
	public boolean hasMoreInstances() {
		return this.streamPos < this.toStream.numInstances();
	}

    @Override
	public InstanceExample nextInstance() {
		return new InstanceExample(this.toStream.instance(this.streamPos++));
	}

    @Override
	public boolean isRestartable() {
		return true;
	}

    @Override
	public void restart() {
		this.streamPos = 0;
	}

    @Override
	public void getDescription(StringBuilder sb, int indent) {
		// TODO Auto-generated method stub

	}

}