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/*
* The MIT License (MIT)
*
* Copyright (c) 2014-2016 Christian Schudt
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package rocks.xmpp.util.cache;
import java.io.IOException;
import java.io.UncheckedIOException;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import java.util.function.BiConsumer;
import java.util.function.Predicate;
import java.util.stream.Collectors;
import java.util.stream.Stream;
/**
* A simple directory based cache for caching of persistent items like avatars or entity capabilities.
*
* @author Christian Schudt
*/
public final class DirectoryCache implements Map<String, byte[]> {
private final Path cacheDirectory;
public DirectoryCache(Path cacheDirectory) {
this.cacheDirectory = cacheDirectory;
}
@Override
public final int size() {
try (final Stream<Path> files = cacheContent()) {
return (int) Math.min(files.count(), Integer.MAX_VALUE);
}
}
@Override
public final boolean isEmpty() {
try (final Stream<Path> files = cacheContent()) {
return files.findAny().map(file -> Boolean.FALSE).orElse(Boolean.TRUE);
}
}
@Override
public final boolean containsKey(Object key) {
return Files.exists(cacheDirectory.resolve(key.toString()));
}
@Override
public final boolean containsValue(Object value) {
throw new UnsupportedOperationException();
}
@Override
public final byte[] get(final Object key) {
return Optional.ofNullable(key).map(Object::toString).filter(((Predicate<String>) String::isEmpty).negate()).map(cacheDirectory::resolve).filter(Files::isReadable).map(file -> {
try {
return Files.readAllBytes(file);
} catch (IOException e) {
throw new UncheckedIOException(e);
}
}).orElse(null);
}
@Override
public final byte[] put(String key, byte[] value) {
// Make sure the directory exists.
byte[] data = get(key);
if (!Arrays.equals(data, value))
try {
if (Files.notExists(cacheDirectory)) {
Files.createDirectories(cacheDirectory);
}
Path file = cacheDirectory.resolve(key);
Files.write(file, value);
} catch (IOException e) {
throw new UncheckedIOException(e);
}
return data;
}
@Override
public final byte[] remove(Object key) {
byte[] data = get(key);
try {
Files.deleteIfExists(cacheDirectory.resolve(key.toString()));
} catch (IOException e) {
throw new UncheckedIOException(e);
}
return data;
}
@Override
public final void putAll(Map<? extends String, ? extends byte[]> m) {
m.forEach(this::put);
}
@Override
public final void clear() {
try {
Files.walkFileTree(cacheDirectory, new SimpleFileVisitor<Path>() {
@Override
public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
Files.deleteIfExists(file);
return FileVisitResult.CONTINUE;
}
@Override
public FileVisitResult postVisitDirectory(Path dir, IOException exc) throws IOException {
// Don't delete the cache directory itself.
if (!Files.isSameFile(dir, cacheDirectory)) {
Files.deleteIfExists(dir);
}
return FileVisitResult.CONTINUE;
}
});
} catch (IOException e) {
throw new UncheckedIOException(e);
}
}
@Override
public final Set<String> keySet() {
try (final Stream<Path> files = Files.list(cacheDirectory)) {
return Collections.unmodifiableSet(files.map(Path::getFileName).map(Path::toString).collect(Collectors.toSet()));
} catch (IOException e) {
throw new UncheckedIOException(e);
}
}
@Override
public final Collection<byte[]> values() {
throw new UnsupportedOperationException();
}
@Override
public final Set<Entry<String, byte[]>> entrySet() {
throw new UnsupportedOperationException();
}
@Override
public final void forEach(final BiConsumer<? super String, ? super byte[]> action) {
if (Files.exists(cacheDirectory))
try (final Stream<Path> files = cacheContent().filter(Files::isReadable)) {
files.forEach(file -> {
try {
action.accept(file.getFileName().toString(), Files.readAllBytes(file));
} catch (final IOException e) {
throw new UncheckedIOException(e);
}
});
}
}
@SuppressWarnings("StreamResourceLeak")
private final Stream<Path> cacheContent() {
try {
return Files.walk(cacheDirectory).filter(Files::isRegularFile);
} catch (final IOException e) {
throw new UncheckedIOException(e);
}
}
}
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