com.google.gwt.dev.javac.UnitCacheFactory Maven / Gradle / Ivy
/*
* Copyright 2011 Google Inc.
*
* 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 com.google.gwt.dev.javac;
import com.google.gwt.core.ext.TreeLogger;
import com.google.gwt.core.ext.UnableToCompleteException;
import java.io.File;
/**
* Creates a cache for {@link CompilationUnit} instances.
*/
public class UnitCacheFactory {
/**
* The API must be enabled explicitly for persistent caching to be live.
*/
private static final String configPropertyValue = System.getProperty("gwt.persistentunitcache",
"true");
private static final boolean usePersistent = configPropertyValue.length() == 0
|| Boolean.parseBoolean(configPropertyValue);
private static UnitCache instance = null;
/**
* If the cache is enabled, instantiates the cache and begins loading units
* into memory in a background thread. If the cache is not enabled, it clears
* out any old cached files.
*
* Only one instance of the cache is instantiated. If a previously created
* cache exists, the previous instance is returned.
*/
public static synchronized UnitCache get(TreeLogger logger, File cacheDir) {
assert logger != null;
if (instance == null) {
if (usePersistent) {
String dirProp = "gwt.persistentunitcachedir";
String propertyCacheDir = System.getProperty(dirProp);
if (propertyCacheDir != null) {
cacheDir = new File(propertyCacheDir);
} else if (cacheDir == null) {
logger.log(TreeLogger.TRACE, "Persistent caching disabled - no directory specified.\n"
+ "To enable persistent unit caching use -Dgwt.persistentunitcachedir=");
}
if (cacheDir != null) {
try {
instance = new PersistentUnitCache(logger, cacheDir);
return instance;
} catch (UnableToCompleteException ignored) {
}
}
}
// Fallback - use in-memory only cache.
instance = new MemoryUnitCache();
}
return instance;
}
}