/**
 * Copyright 2008-2009 DRIVER PROJECT (ICM UW)
 * Original author: Marek Horst
 *
 * 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.
 */
// $Id: Modifier.java 5865 2008-05-20 13:34:23Z icmdriver $

package org.z3950.zing.cql;

/**
 * Represents a single modifier, consisting of three elements: a type,
 * a comparision and a value.  For example, "distance", "<", "3".  The
 * type is mandatory; either the comparison and value must both occur,
 * or neither must.
 * <P>
 * This class is used only by ModifierSet.
 *
 * @version $Id: Modifier.java 5865 2008-05-20 13:34:23Z icmdriver $
 */
public class Modifier {
    String type;
    String comparison;
    String value;

    /**
     * Creates a new Modifier with the specified type, comparison
     * and value.
     */
    public Modifier(String type, String comparison, String value) {
	this.type = type;
	this.comparison = comparison;
	this.value = value;
	//System.err.println("Made new modifier with " + "type='" + type + "', " + "comparison='" + comparison + "', " + "value='" + value + "',\n");
    }

    /**
     * Creates a new Modifier with the specified type but no
     * comparison or value.
     */
    public Modifier(String type) {
	this.type = type;
	//System.err.println("Made new modifier of type '" + type + "'\n");
    }

    /**
     * Returns the type with which the Modifier was created.
     */
    public String getType() {
	return type;
    }

    /**
     * Returns the comparison with which the Modifier was created.
     */
    public String getComparison() {
	return comparison;
    }

    /**
     * Returns the value with which the Modifier was created.
     */
    public String getValue() {
	return value;
    }

    public String toXCQL(int level, String relationElement) {
	StringBuffer buf = new StringBuffer();

	buf.append(Utils.indent(level) + "<modifier>\n");
	buf.append(Utils.indent(level+1) +
		   "<type>" + Utils.xq(type) + "</type>\n");
	if (value != null) {
	    buf.append(Utils.indent(level+1) + "<" + relationElement + ">" +
		       Utils.xq(comparison) + "</" + relationElement + ">\n");
	    buf.append(Utils.indent(level+1) +
		       "<value>" + Utils.xq(value) + "</value>\n");
	}
	
	buf.append(Utils.indent(level) + "</modifier>\n");
	return buf.toString();
    }

    public String toCQL() {
	StringBuffer buf = new StringBuffer(type);
	if (value != null)
	    buf.append(" " + comparison + " " + value);

	return buf.toString();
    }
}