/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2008, Open Source Geospatial Foundation (OSGeo)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License.
*
* This library 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
* Lesser General Public License for more details.
*/
package org.geotools.data.shapefile;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.net.URL;
import java.nio.channels.FileChannel;
import java.util.Arrays;
import java.util.SortedSet;
import java.util.TreeSet;
import java.util.logging.Level;
import org.geotools.data.DataUtilities;
/**
* Encapsulates the idea of a file for writing data to and then later updating the original.
*
* @author jesse
*
* @source $URL$
*/
public final class StorageFile implements Comparable<StorageFile>, FileWriter {
private final ShpFiles shpFiles;
private final File tempFile;
private final ShpFileType type;
public StorageFile( ShpFiles shpFiles, File tempFile, ShpFileType type ) {
this.shpFiles = shpFiles;
this.tempFile = tempFile;
this.type = type;
}
/**
* Returns the storage file
*
* @return the storage file
*/
public File getFile() {
return tempFile;
}
public FileChannel getWriteChannel() throws IOException {
return new RandomAccessFile(tempFile, "rw").getChannel();
}
/**
* Replaces the file that the temporary file is acting as a transactional type cache for. Acts
* similar to a commit.
*
* @see #replaceOriginals(StorageFile...)
* @throws IOException
*/
public void replaceOriginal() throws IOException {
replaceOriginals(this);
}
/**
* Takes a collection of StorageFiles and performs the replace functionality described in
* {@link #replaceOriginal()}. However, all files that are part of the same {@link ShpFiles}
* are done within a lock so all of the updates for all the Files of a Shapefile can be updated
* within a single lock.
*
* @param storageFiles files to execute the replace functionality.
* @throws IOException
*/
public static void replaceOriginals( StorageFile... storageFiles ) throws IOException {
SortedSet<StorageFile> files = new TreeSet<StorageFile>(Arrays.asList(storageFiles));
ShpFiles currentShpFiles = null;
URL shpURL = null;
StorageFile locker = null;
for( StorageFile storageFile : files ) {
if (currentShpFiles != storageFile.shpFiles) {
// there's a new set of files so unlock old and lock new.
unlock(currentShpFiles, shpURL, locker);
locker = storageFile;
currentShpFiles = storageFile.shpFiles;
shpURL = currentShpFiles.acquireWrite(ShpFileType.SHP, storageFile);
}
File storage = storageFile.getFile();
URL url = storageFile.getSrcURLForWrite();
try {
File dest = DataUtilities.urlToFile(url);
if (storage.equals(dest))
return;
if (dest.exists()) {
if (!dest.delete()){
ShapefileDataStoreFactory.LOGGER.severe("Unable to delete the file: "+dest+" when attempting to replace with temporary copy.");
if( storageFile.shpFiles.numberOfLocks()>0 ){
ShapefileDataStoreFactory.LOGGER.severe("The problem is almost certainly caused by the fact that there are still locks being held on the shapefiles. Probably a reader or writer was left unclosed");
storageFile.shpFiles.logCurrentLockers(Level.SEVERE);
}
// throw new IOException("Unable to delete original file: " + url);
}
}
if (storage.exists() && !storage.renameTo(dest)) {
ShapefileDataStoreFactory.LOGGER.finer("Unable to rename temporary file to the file: "+dest+" when attempting to replace with temporary copy");
copyFile(storage, url, dest);
if (!storage.delete()) {
storage.deleteOnExit();
}
}
} finally {
storageFile.unlockWriteURL(url);
if (storage.exists()) {
storage.delete();
}
}
}
unlock(currentShpFiles, shpURL, locker);
}
private static void copyFile( File storage, URL url, File dest ) throws FileNotFoundException,
IOException {
FileChannel in = null;
FileChannel out = null;
try {
in = new FileInputStream(storage).getChannel();
out = new FileOutputStream(dest).getChannel();
// magic number for Windows, 64Mb - 32Kb)
int maxCount = (64 * 1024 * 1024) - (32 * 1024);
long size = in.size();
long position = 0;
while( position < size ) {
position += in.transferTo(position, maxCount, out);
}
} finally {
if (in != null) {
in.close();
}
if (out != null) {
out.close();
}
}
}
private URL getSrcURLForWrite() {
return shpFiles.acquireWrite(type, this);
}
private void unlockWriteURL( URL url ) {
shpFiles.unlockWrite(url, this);
}
private static void unlock( ShpFiles currentShpFiles, URL shpURL, StorageFile locker ) {
// no lock to be unlocked
if (currentShpFiles == null) {
return;
}
currentShpFiles.unlockWrite(shpURL, locker);
}
/**
* Just groups together files that have the same ShpFiles instance
*/
public int compareTo( StorageFile o ) {
// group togheter files that have the same shpefile instance
if (this == o) {
return 0;
}
// assume two StorageFile that do not share the same ShpFiles
// are not given the same temp file
return getFile().compareTo(o.getFile());
}
@Override
public String toString() {
return id();
}
public String id() {
return getClass().getSimpleName() + ": " + tempFile.getName();
}
}