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package tim.prune.save;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.util.zip.GZIPInputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import tim.prune.data.DataPoint;
import tim.prune.data.SourceInfo;
/**
* Class to read in a GPX file and cache all the point strings
*/
public class GpxCacher extends DefaultHandler
{
private SourceInfo _sourceInfo = null;
private String _headerString = null;
private String[] _strings = null;
private int _pointNum = 0;
private boolean _insidePoint = false;
private StringBuilder _builder = null;
/**
* Constructor
* @param inSourceInfo source information
*/
public GpxCacher(SourceInfo inInfo)
{
_sourceInfo = inInfo;
_strings = new String[inInfo.getNumPoints()];
_pointNum = 0;
// Should be a gpx file, but might be raw, zipped or gzipped
File gpxFile = inInfo.getFile();
String fileName = gpxFile.getName().toLowerCase();
if (gpxFile.exists() && gpxFile.canRead())
{
try {
SAXParser saxParser = SAXParserFactory.newInstance().newSAXParser();
if (fileName.endsWith(".gpx") || fileName.endsWith(".xml")) {
saxParser.parse(inInfo.getFile(), this);
}
else if (fileName.endsWith(".zip")) {
saxParser.parse(getZipInputStream(inInfo.getFile()), this);
}
else if (fileName.endsWith(".gz")) {
saxParser.parse(new GZIPInputStream(new FileInputStream(inInfo.getFile())), this);
}
else {
System.out.println("GpxCacher unrecognised file type: " + inInfo.getFile().getName());
}
} catch (Exception e) {
// TODO: Handle errors here with a list of warnings?
e.printStackTrace();
}
}
_builder = null;
}
/**
* Receive the start of a tag
*/
public void startElement(String inUri, String inLocalName, String inTagName,
Attributes inAttributes) throws SAXException
{
if (inTagName.equalsIgnoreCase("gpx"))
{
// store initial gpx tag
_builder = new StringBuilder(60);
appendTag(_builder, inTagName, inAttributes);
_headerString = _builder.toString();
}
else
{
if (inTagName.equalsIgnoreCase("wpt") || inTagName.equalsIgnoreCase("trkpt")
|| inTagName.equalsIgnoreCase("rtept"))
{
_insidePoint = true;
_builder = new StringBuilder(60);
}
if (_insidePoint) {
appendTag(_builder, inTagName, inAttributes);
}
}
super.startElement(inUri, inLocalName, inTagName, inAttributes);
}
/**
* Receive characters between tags (inside or outside)
*/
public void characters(char[] inChars, int inStart, int inLength)
throws SAXException
{
if (_insidePoint) {
_builder.append(new String(inChars, inStart, inLength));
}
super.characters(inChars, inStart, inLength);
}
/**
* Receive end of xml tag
*/
public void endElement(String inUri, String inLocalName, String inTagName)
throws SAXException
{
if (_insidePoint) {
_builder.append("</").append(inTagName).append('>');
}
if (inTagName.equalsIgnoreCase("wpt") || inTagName.equalsIgnoreCase("trkpt")
|| inTagName.equalsIgnoreCase("rtept"))
{
_strings[_pointNum] = _builder.toString();
_pointNum++;
_insidePoint = false;
}
super.endElement(inUri, inLocalName, inTagName);
}
/**
* Append the current tag to the supplied StringBuilder
* @param inBuilder Stringbuilder object to append tag to
* @param inTagName name of tag
* @param inAttributes attributes of tag
*/
private static void appendTag(StringBuilder inBuilder, String inTagName, Attributes inAttributes)
{
inBuilder.append('<').append(inTagName);
int numAtts = inAttributes.getLength();
for (int i=0; i<numAtts; i++) {
inBuilder.append(' ').append(inAttributes.getQName(i)).append("=\"")
.append(inAttributes.getValue(i)).append('"');
}
inBuilder.append('>');
}
/**
* @return the header string from the GPX tag
*/
public String getHeaderString()
{
return _headerString;
}
/**
* Get the source string for the given point
* @param inPoint point to retrieve
* @return string if found, otherwise null
*/
public String getSourceString(DataPoint inPoint)
{
int index = _sourceInfo.getIndex(inPoint);
if (index >= 0) {
return _strings[index];
}
return null;
}
/**
* Get an inputstream of a GPX file inside a zip
* @param inFile File object describing zip file
* @return input stream for Xml parser
*/
private static InputStream getZipInputStream(File inFile)
{
try
{
ZipInputStream zis = new ZipInputStream(new FileInputStream(inFile));
while (zis.available() > 0)
{
ZipEntry entry = zis.getNextEntry();
String entryName = entry.toString();
if (entryName != null && entryName.length() > 4)
{
String suffix = entryName.substring(entryName.length()-4).toLowerCase();
if (suffix.equals(".gpx") || suffix.equals(".xml")) {
// First matching file so must be gpx
return zis;
}
}
}
}
catch (Exception e) {} // ignore errors
// not found - error!
return null;
}
}
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