org.hortonmachine.gears.io.disktree.DiskTreeWriter Maven / Gradle / Ivy
/*
* This file is part of HortonMachine (http://www.hortonmachine.org)
* (C) HydroloGIS - www.hydrologis.com
*
* The HortonMachine is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see .
*/
package org.hortonmachine.gears.io.disktree;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.RandomAccessFile;
import com.vividsolutions.jts.JTSVersion;
import com.vividsolutions.jts.geom.Envelope;
import com.vividsolutions.jts.geom.Geometry;
import com.vividsolutions.jts.index.strtree.STRtree;
/**
* Writer for the quadtree disk index.
*
* @author Andrea Antonello (www.hydrologis.com)
* @see IDiskTree
*/
public class DiskTreeWriter implements IDiskTree {
private final String path;
/**
* Constructor.
*
* @param path the path to which the index will be written.
*/
public DiskTreeWriter( String path ) {
this.path = path;
}
/**
* Writes an array of {@link Geometry}s to the disk.
*
* @param geometries the array of geoms to write.
* @throws IOException
*/
public void writeGeometries( Geometry[] geometries ) throws IOException {
File file = new File(path);
RandomAccessFile raf = null;
try {
raf = new RandomAccessFile(file, "rw");
int major = JTSVersion.MAJOR;
int minor = JTSVersion.MINOR;
raf.writeChars("jts");
raf.writeInt(major);
raf.writeInt(minor);
long geometriesStart = INDEX_ADDRESS_POSITION + INDEX_ADDRESS_SIZE + INDEX_LENGTH_SIZE;
raf.seek(geometriesStart);
System.out.println("geometriesStart: " + geometriesStart);
long fileIndex = geometriesStart;
STRtree tree = new STRtree(geometries.length);
for( int i = 0; i < geometries.length; i++ ) {
Geometry geometry = geometries[i];
if (geometry.isEmpty()) {
continue;
}
Envelope envelope = geometry.getEnvelopeInternal();
byte[] geomBytes = serialize(geometry);
raf.write(geomBytes);
/*
* the tree contains the envelope of a geometry
* and the array with the exact position in the file where the
* geometry bytes start + the length.
*/
tree.insert(envelope, new long[]{fileIndex, geomBytes.length});
fileIndex = fileIndex + geomBytes.length;
System.out.println("geom: " + i + " finished at: " + fileIndex);
}
raf.seek(INDEX_ADDRESS_POSITION);
raf.writeLong(fileIndex);
System.out.println("INDEX_ADDRESS_POSITION: " + fileIndex);
/*
* serialize index
*/
byte[] treeBytes = serialize(tree);
long treeSize = treeBytes.length;
raf.seek(fileIndex);
raf.write(treeBytes, 0, (int) treeSize);
System.out.println("treeSize: " + treeSize);
raf.seek(INDEX_ADDRESS_POSITION + INDEX_ADDRESS_SIZE);
raf.writeLong(treeSize);
long length = raf.length();
System.out.println(length);
} finally {
System.out.println("close");
if (raf != null)
raf.close();
}
}
private byte[] serialize( Object obj ) throws IOException {
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ObjectOutputStream out = new ObjectOutputStream(bos);
out.writeObject(obj);
out.close();
return bos.toByteArray();
}
}