SrtmRegions.java

package org.droidplanner.services.android.impl.core.srtm;

import org.droidplanner.services.android.impl.core.srtm.Srtm.OnProgressListner;

import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

public class SrtmRegions {
	static final String[] REGIONS = { "Eurasia", "Africa", "Australia", "Islands", "North_America",
			"South_America" };
	private Map<String, Integer> regionMap = new HashMap<String, Integer>();
	private String path;

	public SrtmRegions(String path) {
		this.path = path;
	}

	/*
	 * Returns region name for a file
	 */
	public String findRegion(String fname, OnProgressListner listner) throws Exception {
		if (regionMap.isEmpty()) {
			fillRegionData(listner);
		}
		String name = fname.replace(".hgt", "");
		if (regionMap.containsKey(name)) {
			return REGIONS[regionMap.get(name)];
		}
		throw new Exception("Null Region");
	}

	private void fillRegionData(OnProgressListner listner) throws Exception {
		String region;
		for (int i = 0; i < SrtmRegions.REGIONS.length; i++) {
			region = SrtmRegions.REGIONS[i];
			String indexPath = region;
			indexPath = SrtmDownloader.getIndexPath(path) + indexPath;
			File indexDir = new File(indexPath);
			if (!indexDir.exists()) {
				indexDir.mkdirs();
			}
			indexPath += ".index.html";
			File indexFile = new File(indexPath);
			if (!indexFile.exists()) {
				try {
					new SrtmDownloader(listner).downloadRegionIndex(i, path);
				} catch (IOException e) {
					// download error, try again with the next attempt
					regionMap.clear();
					throw new Exception("Null Region");
				}
			}
			Scanner scanner = new Scanner(indexFile);
			while (scanner.hasNext()) {
				String line = scanner.next();
				if (line.contains("href=\"")) {
					int index = line.indexOf(".hgt.zip") - 7;
					if (index >= 0) {
						String srtm = line.substring(index, index + 7);
						regionMap.put(srtm, i);
					} else {
						index = line.indexOf("hgt.zip") - 7;
						if (index >= 0) {
							String srtm = line.substring(index, index + 7);
							regionMap.put(srtm, i);
						}
					}
				}
			}
			scanner.close();
		}
	}
}