/*
 *  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.operator.io;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.List;

import com.rapidminer.operator.IOObject;
import com.rapidminer.operator.Operator;
import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.operator.ResultObject;
import com.rapidminer.operator.UserError;
import com.rapidminer.parameter.ParameterType;
import com.rapidminer.parameter.ParameterTypeFile;
import com.rapidminer.tools.ResultService;


/**
 * This operator can be used at each point in an operator chain. It returns all
 * input it receives without any modification. Every input object which
 * implements the {@link com.rapidminer.operator.ResultObject} interface (which
 * is the case for almost all objects generated by the core RapidMiner operators) will
 * write its results to the file specified by the parameter <var>result_file</var>.
 * If the definition of this parameter is ommited then the global result file parameter
 * with the same name of the ProcessRootOperator 
 * (the root of the process) will be used. If this file is also not specified
 * the results are simply written to the console (standard out).
 * 
 * @author Ingo Mierswa
 * @version $Id: ResultWriter.java,v 1.9 2008/07/07 07:06:38 ingomierswa Exp $
 */
public class ResultWriter extends Operator {


	/** The parameter name for "Appends the descriptions of the input objects to this file. If empty, use the general file defined in the process root operator." */
	public static final String PARAMETER_RESULT_FILE = "result_file";
    private boolean firstRun = true;
    
	public ResultWriter(OperatorDescription description) {
		super(description);
	}

	/**
	 * Use the ResultService to write the results of all input ResultObjects
	 * into the result file.
	 */
	public IOObject[] apply() throws OperatorException {
		IOObject[] input = getInput().getIOObjects();
        File file = getParameterAsFile(PARAMETER_RESULT_FILE);
        if (file != null) {
            PrintWriter out = null;
            try {
                if (firstRun) {
                    out = new PrintWriter(new OutputStreamWriter(new FileOutputStream(file, false), getEncoding()));
                } else {
                    out = new PrintWriter(new OutputStreamWriter(new FileOutputStream(file, true), getEncoding()));
                }
                firstRun = false;
            } catch (IOException e) {
                throw new UserError(this, 301, file);
            }
            if (out != null) {
                ResultService.logResult("Results of ResultWriter '" + getName() + "' [" + getApplyCount() + "]: ", out);
                for (int i = 0; i < input.length; i++) {
                    if (input[i] instanceof ResultObject)
                        ResultService.logResult((ResultObject) input[i], out);
                }
                out.close();
            }
        } else {
            ResultService.logResult("Results of ResultWriter '" + getName() + "' [" + getApplyCount() + "]: ");
            for (int i = 0; i < input.length; i++) {
                if (input[i] instanceof ResultObject)
                    ResultService.logResult((ResultObject) input[i]);
            }
        }
		return new IOObject[0];
	}
	
	public void processStarts() throws OperatorException {
        super.processStarts();
        this.firstRun = true;
    }
    
	/** Returns an empty array. */
	public Class<?>[] getInputClasses() {
		return new Class[0];
	}

	/** Returns an empty array. */
	public Class<?>[] getOutputClasses() {
		return new Class[0];
	}
    
    public List<ParameterType> getParameterTypes() {
        List<ParameterType> types = super.getParameterTypes();
        ParameterType type = new ParameterTypeFile(PARAMETER_RESULT_FILE, "Appends the descriptions of the input objects to this file. If empty, use the general file defined in the process root operator.", "res", true);
        type.setExpert(false);
        types.add(type);
        return types;
    }
}