/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.lucene.store;
import java.io.IOException;
import java.nio.file.AtomicMoveNotSupportedException;
import java.nio.file.NoSuchFileException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import org.apache.lucene.util.IOUtils;
/**
* Expert: A Directory instance that switches files between
* two other Directory instances.
* <p>Files with the specified extensions are placed in the
* primary directory; others are placed in the secondary
* directory. The provided Set must not change once passed
* to this class, and must allow multiple threads to call
* contains at once.</p>
*
* <p>Locks with a name having the specified extensions are
* delegated to the primary directory; others are delegated
* to the secondary directory. Ideally, both Directory
* instances should use the same lock factory.</p>
*
* @lucene.experimental
*/
public class FileSwitchDirectory extends Directory {
private final Directory secondaryDir;
private final Directory primaryDir;
private final Set<String> primaryExtensions;
private boolean doClose;
public FileSwitchDirectory(Set<String> primaryExtensions, Directory primaryDir, Directory secondaryDir, boolean doClose) {
this.primaryExtensions = primaryExtensions;
this.primaryDir = primaryDir;
this.secondaryDir = secondaryDir;
this.doClose = doClose;
}
/** Return the primary directory */
public Directory getPrimaryDir() {
return primaryDir;
}
/** Return the secondary directory */
public Directory getSecondaryDir() {
return secondaryDir;
}
@Override
public Lock obtainLock(String name) throws IOException {
return getDirectory(name).obtainLock(name);
}
@Override
public void close() throws IOException {
if (doClose) {
IOUtils.close(primaryDir, secondaryDir);
doClose = false;
}
}
@Override
public String[] listAll() throws IOException {
Set<String> files = new HashSet<>();
// LUCENE-3380: either or both of our dirs could be FSDirs,
// but if one underlying delegate is an FSDir and mkdirs() has not
// yet been called, because so far everything is written to the other,
// in this case, we don't want to throw a NoSuchFileException
NoSuchFileException exc = null;
try {
for(String f : primaryDir.listAll()) {
files.add(f);
}
} catch (NoSuchFileException e) {
exc = e;
}
try {
for(String f : secondaryDir.listAll()) {
files.add(f);
}
} catch (NoSuchFileException e) {
// we got NoSuchFileException from both dirs
// rethrow the first.
if (exc != null) {
throw exc;
}
// we got NoSuchFileException from the secondary,
// and the primary is empty.
if (files.isEmpty()) {
throw e;
}
}
// we got NoSuchFileException from the primary,
// and the secondary is empty.
if (exc != null && files.isEmpty()) {
throw exc;
}
String[] result = files.toArray(new String[files.size()]);
Arrays.sort(result);
return result;
}
/** Utility method to return a file's extension. */
public static String getExtension(String name) {
int i = name.lastIndexOf('.');
if (i == -1) {
return "";
}
return name.substring(i+1, name.length());
}
private Directory getDirectory(String name) {
String ext = getExtension(name);
if (primaryExtensions.contains(ext)) {
return primaryDir;
} else {
return secondaryDir;
}
}
@Override
public void deleteFile(String name) throws IOException {
if (getDirectory(name) == primaryDir) {
primaryDir.deleteFile(name);
} else {
secondaryDir.deleteFile(name);
}
}
@Override
public long fileLength(String name) throws IOException {
return getDirectory(name).fileLength(name);
}
@Override
public IndexOutput createOutput(String name, IOContext context) throws IOException {
return getDirectory(name).createOutput(name, context);
}
@Override
public IndexOutput createTempOutput(String prefix, String suffix, IOContext context) throws IOException {
return getDirectory("."+suffix).createTempOutput(prefix, suffix, context);
}
@Override
public void sync(Collection<String> names) throws IOException {
List<String> primaryNames = new ArrayList<>();
List<String> secondaryNames = new ArrayList<>();
for (String name : names)
if (primaryExtensions.contains(getExtension(name)))
primaryNames.add(name);
else
secondaryNames.add(name);
primaryDir.sync(primaryNames);
secondaryDir.sync(secondaryNames);
}
@Override
public void rename(String source, String dest) throws IOException {
Directory sourceDir = getDirectory(source);
// won't happen with standard lucene index files since pending and commit will
// always have the same extension ("")
if (sourceDir != getDirectory(dest)) {
throw new AtomicMoveNotSupportedException(source, dest, "source and dest are in different directories");
}
sourceDir.rename(source, dest);
}
@Override
public void syncMetaData() throws IOException {
primaryDir.syncMetaData();
secondaryDir.syncMetaData();
}
@Override
public IndexInput openInput(String name, IOContext context) throws IOException {
return getDirectory(name).openInput(name, context);
}
}