/*
 *  RapidMiner
 *
 *  Copyright (C) 2001-2008 by Rapid-I and the contributors
 *
 *  Complete list of developers available at our web site:
 *
 *       http://rapid-i.com
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero 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 Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see http://www.gnu.org/licenses/.
 */
package com.rapidminer.example.set;

import java.util.Iterator;

import com.rapidminer.example.Attribute;
import com.rapidminer.example.Attributes;
import com.rapidminer.example.Example;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.example.table.DataRow;
import com.rapidminer.example.table.ExampleTable;


/**
 * This view can be used to wrap a single example.
 * 
 * @author Ingo Mierswa
 * @version $Id: SingleExampleExampleSet.java,v 1.6 2008/05/09 19:22:49 ingomierswa Exp $
 */
public class SingleExampleExampleSet extends AbstractExampleSet {

    private static final long serialVersionUID = -4817219403776439504L;

    /** This class is used as a data iterator for the single example example set. */
	private static class SingleExampleIterator extends AbstractExampleReader {

        private boolean nextCalled = false;
        
        private DataRow dataRow;
        
        private SingleExampleExampleSet exampleSet;
        
        public SingleExampleIterator(DataRow dataRow, SingleExampleExampleSet exampleSet) {
            this.dataRow = dataRow;
            this.exampleSet = exampleSet;
        }
        
        public boolean hasNext() {
            return !nextCalled;
        }

        public Example next() {
            if (!nextCalled) {
                nextCalled = true;
                return new Example(dataRow, exampleSet);
            } else {
                return null;
            }
        }
    }
    
    private ExampleSet parent;
    
    private Example example;
    
    
    public SingleExampleExampleSet(ExampleSet exampleSet, Example example) {
        this.parent = (ExampleSet)exampleSet.clone();
        this.example = example;
    }
    
    public SingleExampleExampleSet(SingleExampleExampleSet exampleSet) {
    	this.parent = (ExampleSet)exampleSet.parent.clone();
        this.example = exampleSet.example;
    }
    
    public Iterator<Example> iterator() {
        return new SingleExampleIterator(example.getDataRow(), this);
    }

    public Example getExample(int index) {
        if (index == 0)
            return new Example(example.getDataRow(), this);
        else
            return null;
    }

    public int size() {
        return 1;
    }
  
    public Example getExampleFromId(double id) {
        Attribute idAttribute = getAttributes().getId();
        if (idAttribute != null) {
            Example newExample = new Example(example.getDataRow(), this);
            if (newExample.getValue(idAttribute) == id)
                return newExample;
            else
                return null;
        } else {
            return null;
        }
    }

	public Attributes getAttributes() {
		return parent.getAttributes();
	}

	public ExampleTable getExampleTable() {
		return parent.getExampleTable();
	}
}