/*
 *  RapidMiner
 *
 *  Copyright (C) 2001-2011 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.parameter;

import org.w3c.dom.Element;

import com.rapidminer.operator.ports.InputPort;
import com.rapidminer.operator.ports.metadata.MetaData;
import com.rapidminer.tools.XMLException;

/**
 * This attribute type supports the user by letting him define an expression with a
 * user interface known from calculators.
 * 
 * For knowing attribute names before process execution a valid meta data transformation must be performed. Otherwise
 * the user might type in the name, instead of choosing.
 * 
 * @author Ingo Mierswa
 */
public class ParameterTypeExpression extends ParameterTypeString {

    private static final long serialVersionUID = -1938925853519339382L;

    private static final String ATTRIBUTE_INPUT_PORT = "port-name";

    private transient InputPort inPort;

    public ParameterTypeExpression(Element element) throws XMLException {
        super(element);
    }

    /**
     * This constructor will generate a ParameterType that does not
     * use the {@link MetaData} of an associated {@link InputPort} to verify
     * the expressions.
     * @param key
     * @param description
     */
    public ParameterTypeExpression(final String key, String description) {
        this(key, description, null, false);
    }

    public ParameterTypeExpression(final String key, String description, InputPort inPort) {
        this(key, description, inPort, false);
    }

    public ParameterTypeExpression(final String key, String description, InputPort inPort, boolean optional, boolean expert) {
        this(key, description, inPort, optional);
        setExpert(expert);
    }

    public ParameterTypeExpression(final String key, String description, InputPort inPort, boolean optional) {
        super(key, description, optional);
        this.inPort = inPort;
    }

    @Override
    public Object getDefaultValue() {
        return "";
    }

    /**
     * Returns the input port associated with this ParameterType. This might be null!
     */
    public InputPort getInputPort() {
        return inPort;
    }

    @Override
    protected void writeDefinitionToXML(Element typeElement) {
        super.writeDefinitionToXML(typeElement);

        typeElement.setAttribute(ATTRIBUTE_INPUT_PORT, inPort.getName());
    }
}