/*
* Copyright 2010 the original author or authors.
*
* Licensed 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.gradle.cache.internal;
import org.gradle.api.GradleException;
import org.gradle.internal.Factory;
import org.gradle.cache.PersistentStateCache;
import org.gradle.messaging.serialize.InputStreamBackedDecoder;
import org.gradle.messaging.serialize.OutputStreamBackedEncoder;
import org.gradle.messaging.serialize.Serializer;
import java.io.*;
public class SimpleStateCache<T> implements PersistentStateCache<T> {
private final FileAccess fileAccess;
private final Serializer<T> serializer;
private final File cacheFile;
public SimpleStateCache(File cacheFile, FileAccess fileAccess, Serializer<T> serializer) {
this.cacheFile = cacheFile;
this.fileAccess = fileAccess;
this.serializer = serializer;
}
public T get() {
return fileAccess.readFile(new Factory<T>() {
public T create() {
return deserialize();
}
});
}
public void set(final T newValue) {
fileAccess.writeFile(new Runnable() {
public void run() {
serialize(newValue);
}
});
}
public void update(final UpdateAction<T> updateAction) {
fileAccess.updateFile(new Runnable() {
public void run() {
T oldValue = deserialize();
T newValue = updateAction.update(oldValue);
serialize(newValue);
}
});
}
private void serialize(T newValue) {
try {
OutputStreamBackedEncoder encoder = new OutputStreamBackedEncoder(new BufferedOutputStream(new FileOutputStream(cacheFile)));
try {
serializer.write(encoder, newValue);
} finally {
encoder.close();
}
} catch (Exception e) {
throw new GradleException(String.format("Could not write cache value to '%s'.", cacheFile), e);
}
}
private T deserialize() {
if (!cacheFile.isFile()) {
return null;
}
try {
InputStreamBackedDecoder decoder = new InputStreamBackedDecoder(new BufferedInputStream(new FileInputStream(cacheFile)));
try {
return serializer.read(decoder);
} finally {
decoder.close();
}
} catch (Exception e) {
throw new GradleException(String.format("Could not read cache value from '%s'.", cacheFile), e);
}
}
}