DistanceToExpression.java

/**
 * Copyright (C) 2008 - 2014 52°North Initiative for Geospatial Open Source
 * Software GmbH
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 *
 * If the program is linked with libraries which are licensed under one of
 * the following licenses, the combination of the program with the linked
 * library is not considered a "derivative work" of the program:
 *
 *     - Apache License, version 2.0
 *     - Apache Software License, version 1.0
 *     - GNU Lesser General Public License, version 3
 *     - Mozilla Public License, versions 1.0, 1.1 and 2.0
 *     - Common Development and Distribution License (CDDL), version 1.0
 *
 * Therefore the distribution of the program linked with libraries licensed
 * under the aforementioned licenses, is permitted by the copyright holders
 * if the distribution is compliant with both the GNU General Public
 * icense version 2 and the aforementioned licenses.
 *
 * 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.
 */
package org.n52.ses.eml.v002.filter.expression;

import java.util.HashSet;

import org.apache.xmlbeans.XmlObject;
import org.n52.ses.eml.v002.filterlogic.esper.customFunctions.MethodNames;


/**
 * 
 * @author Thomas Everding
 *
 */
public class DistanceToExpression extends ABinaryFilterExpression{
	
	private boolean initialized = false;
	
	/**
	 * 
	 * Constructor for OGC filter encoding 2 mul functions
	 * 
	 * @param args arguments of the addition function.
	 * @param propertyNames name of the known event properties
	 */
	public DistanceToExpression(XmlObject[] args, HashSet<Object> propertyNames) {
		//check arguments
		if (args.length < 2) {
			throw new RuntimeException("illegal argument count for distance to function");
		}
		XmlObject firstArg = args[0];
		XmlObject secondArg = args[1];
		
		//initialize
		if (firstArg != null && secondArg != null) {
			this.initialize(firstArg, secondArg, propertyNames);
			this.initialized = true;
		}
	}

	@Override
	public String createExpressionString(boolean complexPatternGuard) {
		String result = "";
		
		if (this.initialized) {
			StringBuilder sb = new StringBuilder();
			sb.append(MethodNames.SPATIAL_METHODS_PREFIX);
			sb.append("distanceTo(");
			sb.append(this.first.createExpressionString(complexPatternGuard));
			sb.append(", ");
			sb.append(this.second.createExpressionString(complexPatternGuard));
			sb.append(")"); //distance to
			
			result = sb.toString();
		}
		return result;
	}

}