SearchServer.java

/*******************************************************************************
 * Copyright (c) 2012 Hallvard Tr�tteberg.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     Hallvard Tr�tteberg - initial API and implementation
 ******************************************************************************/

package org.eclipse.nebula.widgets.geomap.jface;

import java.util.AbstractList;
import java.util.ArrayList;
import java.util.List;
import java.util.Stack;

import javax.xml.parsers.SAXParserFactory;

import org.eclipse.nebula.widgets.geomap.PointD;
import org.eclipse.nebula.widgets.geomap.internal.URLService;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

/**
 * An abstract super class for search servers
 * @since 3.3
 *
 */
public abstract class SearchServer extends URLService {

	/**
	 * Initializes the SearchServer with a specific URL and url format
	 * @param url
	 * @param urlFormat
	 */
    public SearchServer(String url, String urlFormat) {
    	super(url, urlFormat);
    }

	/**
	 * Initializes the SearchServer with a specific URL and default url format
	 * @param url
	 */
    public SearchServer(String url) {
    	parseUrl(url, "format=xml&q={0}"); //$NON-NLS-1$
    }

    @Override
    protected Object[] getURLFormatArguments(Object ref) {
    	return new Object[]{ref};
    }
    
    /**
     * Gets the URL used for a specific search
     * @param search
     * @return the URL
     */
    public String getSearchURL(String search) {
    	return getServiceURL(search);
    }

    /**
     * Tries to parse s as a Double, defaulting to Double.NaN
     * @param s the String to parse
     * @return the double or NaN, if the String couldn't be parsed
     */
    protected static double tryDouble(String s) {
        try {
            return Double.valueOf(s);
        } catch (Exception e) {
            return Double.NaN;
        }
    }

    protected boolean checkPath(String[] qNames, AbstractList<String> path) {
    	for (int i = 0; i < qNames.length; i++) {
    		int pathPos = path.size() - i - 1;
			if (pathPos < 0 || (! qNames[qNames.length - i - 1].equals(path.get(pathPos)))) {
				return false;
			}
		}
    	return true;
    }
    
    protected Object startElement(String qName, Stack<String> path, Attributes attributes, Stack<Object> objects) {
    	return null;
    }
    protected Object characters(String qName, Stack<String> path, char[] ch, int start, int length, Stack<Object> objects) {
    	return null;
    }
    protected Object endElement(String qName, Stack<String> path, Stack<Object> objects) {
    	return null;
    }
    
    public Object[] doSearch(String search) {
    	return doSearchInternal(search);
    }

	private Object[] doSearchInternal(String search) {
    	final List<Object> results = new ArrayList<Object>();
        try {
            SAXParserFactory factory = SAXParserFactory.newInstance();
            factory.setValidating(false);
            final Stack<String> path = new Stack<String>();
            final Stack<Object> objects = new Stack<Object>();
            factory.newSAXParser().parse(getSearchURL(search), new DefaultHandler() {
            	private void addResult(Object result) {
            		if (result != null) {
            			results.add(result);
            		}
            	}
                public void startElement(String uri, String localName, String qName, Attributes attributes) {
                	addResult(SearchServer.this.startElement(qName, path, attributes, objects));
                	path.push(qName);
                }
                public void endElement(String uri, String localName, String qName) throws SAXException {
                	addResult(SearchServer.this.endElement(qName, path, objects));
                	path.pop();
                }
                public void characters(char[] ch, int start, int length) throws SAXException {
                	String qName = path.pop();
					addResult(SearchServer.this.characters(qName, path, ch, start, length, objects));
					path.push(qName);
                }
            });
            return (results.size() > 0 ? results.toArray() : null);
        } catch (Exception e) {
        }
        return null;
    }
	
    public static class Result extends Located.Static {

    	private double lon = Double.NaN, lat = Double.NaN;
        private String name, text;

        public PointD getLonLat() {
            return (Double.isNaN(lon) || Double.isNaN(lat) ? null : new PointD(lon, lat));
        }
        public String getName() {
            return name;
        }
        public void setName(String name) {
        	this.name = name.trim();
        }

        public String getText() {
        	return text;
        }
        public void setText(String text) {
        	this.text = text.trim();
        }

		public double getLon() {
			return lon;
		}
		public void setLon(double lon) {
			this.lon = lon;
		}
		public void setLon(String lon) {
			this.lon = tryDouble(lon.trim());
		}

		public double getLat() {
			return lat;
		}
		public void setLat(double lat) {
			this.lat = lat;
		}
		public void setLat(String lat) {
			this.lat = tryDouble(lat.trim());
		}

		public String toString() {
            return "SearchResult [text=" + text + ", location=" + getLonLat() + "]";
        }
    }
}