/*
* Copyright 2001-2009 Stephen Colebourne
*
* 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.facebook.presto.jdbc.internal.joda.time.tz;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.ref.SoftReference;
import java.util.Map;
import java.util.Set;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;
import com.facebook.presto.jdbc.internal.joda.time.DateTimeZone;
/**
* ZoneInfoProvider loads compiled data files as generated by
* {@link ZoneInfoCompiler}.
* <p>
* ZoneInfoProvider is thread-safe and publicly immutable.
*
* @author Brian S O'Neill
* @since 1.0
*/
public class ZoneInfoProvider implements Provider {
/** The directory where the files are held. */
private final File iFileDir;
/** The resource path. */
private final String iResourcePath;
/** The class loader to use. */
private final ClassLoader iLoader;
/** Maps ids to strings or SoftReferences to DateTimeZones. */
private final Map<String, Object> iZoneInfoMap;
/**
* ZoneInfoProvider searches the given directory for compiled data files.
*
* @throws IOException if directory or map file cannot be read
*/
public ZoneInfoProvider(File fileDir) throws IOException {
if (fileDir == null) {
throw new IllegalArgumentException("No file directory provided");
}
if (!fileDir.exists()) {
throw new IOException("File directory doesn't exist: " + fileDir);
}
if (!fileDir.isDirectory()) {
throw new IOException("File doesn't refer to a directory: " + fileDir);
}
iFileDir = fileDir;
iResourcePath = null;
iLoader = null;
iZoneInfoMap = loadZoneInfoMap(openResource("ZoneInfoMap"));
}
/**
* ZoneInfoProvider searches the given ClassLoader resource path for
* compiled data files. Resources are loaded from the ClassLoader that
* loaded this class.
*
* @throws IOException if directory or map file cannot be read
*/
public ZoneInfoProvider(String resourcePath) throws IOException {
this(resourcePath, null, false);
}
/**
* ZoneInfoProvider searches the given ClassLoader resource path for
* compiled data files.
*
* @param loader ClassLoader to load compiled data files from. If null,
* use system ClassLoader.
* @throws IOException if directory or map file cannot be read
*/
public ZoneInfoProvider(String resourcePath, ClassLoader loader)
throws IOException
{
this(resourcePath, loader, true);
}
/**
* @param favorSystemLoader when true, use the system class loader if
* loader null. When false, use the current class loader if loader is null.
*/
private ZoneInfoProvider(String resourcePath,
ClassLoader loader, boolean favorSystemLoader)
throws IOException
{
if (resourcePath == null) {
throw new IllegalArgumentException("No resource path provided");
}
if (!resourcePath.endsWith("/")) {
resourcePath += '/';
}
iFileDir = null;
iResourcePath = resourcePath;
if (loader == null && !favorSystemLoader) {
loader = getClass().getClassLoader();
}
iLoader = loader;
iZoneInfoMap = loadZoneInfoMap(openResource("ZoneInfoMap"));
}
//-----------------------------------------------------------------------
/**
* If an error is thrown while loading zone data, uncaughtException is
* called to log the error and null is returned for this and all future
* requests.
*
* @param id the id to load
* @return the loaded zone
*/
public DateTimeZone getZone(String id) {
if (id == null) {
return null;
}
Object obj = iZoneInfoMap.get(id);
if (obj == null) {
return null;
}
if (id.equals(obj)) {
// Load zone data for the first time.
return loadZoneData(id);
}
if (obj instanceof SoftReference<?>) {
@SuppressWarnings("unchecked")
SoftReference<DateTimeZone> ref = (SoftReference<DateTimeZone>) obj;
DateTimeZone tz = ref.get();
if (tz != null) {
return tz;
}
// Reference cleared; load data again.
return loadZoneData(id);
}
// If this point is reached, mapping must link to another.
return getZone((String)obj);
}
/**
* Gets a list of all the available zone ids.
*
* @return the zone ids
*/
public Set<String> getAvailableIDs() {
// Return a copy of the keys rather than an umodifiable collection.
// This prevents ConcurrentModificationExceptions from being thrown by
// some JVMs if zones are opened while this set is iterated over.
return new TreeSet<String>(iZoneInfoMap.keySet());
}
/**
* Called if an exception is thrown from getZone while loading zone data.
*
* @param ex the exception
*/
protected void uncaughtException(Exception ex) {
Thread t = Thread.currentThread();
t.getThreadGroup().uncaughtException(t, ex);
}
/**
* Opens a resource from file or classpath.
*
* @param name the name to open
* @return the input stream
* @throws IOException if an error occurs
*/
private InputStream openResource(String name) throws IOException {
InputStream in;
if (iFileDir != null) {
in = new FileInputStream(new File(iFileDir, name));
} else {
String path = iResourcePath.concat(name);
if (iLoader != null) {
in = iLoader.getResourceAsStream(path);
} else {
in = ClassLoader.getSystemResourceAsStream(path);
}
if (in == null) {
StringBuffer buf = new StringBuffer(40)
.append("Resource not found: \"")
.append(path)
.append("\" ClassLoader: ")
.append(iLoader != null ? iLoader.toString() : "system");
throw new IOException(buf.toString());
}
}
return in;
}
/**
* Loads the time zone data for one id.
*
* @param id the id to load
* @return the zone
*/
private DateTimeZone loadZoneData(String id) {
InputStream in = null;
try {
in = openResource(id);
DateTimeZone tz = DateTimeZoneBuilder.readFrom(in, id);
iZoneInfoMap.put(id, new SoftReference<DateTimeZone>(tz));
return tz;
} catch (IOException ex) {
uncaughtException(ex);
iZoneInfoMap.remove(id);
return null;
} finally {
try {
if (in != null) {
in.close();
}
} catch (IOException ex) {
}
}
}
//-----------------------------------------------------------------------
/**
* Loads the zone info map.
*
* @param in the input stream
* @return the map
*/
private static Map<String, Object> loadZoneInfoMap(InputStream in) throws IOException {
Map<String, Object> map = new ConcurrentHashMap<String, Object>();
DataInputStream din = new DataInputStream(in);
try {
readZoneInfoMap(din, map);
} finally {
try {
din.close();
} catch (IOException ex) {
}
}
map.put("UTC", new SoftReference<DateTimeZone>(DateTimeZone.UTC));
return map;
}
/**
* Reads the zone info map from file.
*
* @param din the input stream
* @param zimap gets filled with string id to string id mappings
*/
private static void readZoneInfoMap(DataInputStream din, Map<String, Object> zimap) throws IOException {
// Read the string pool.
int size = din.readUnsignedShort();
String[] pool = new String[size];
for (int i=0; i<size; i++) {
pool[i] = din.readUTF().intern();
}
// Read the mappings.
size = din.readUnsignedShort();
for (int i=0; i<size; i++) {
try {
zimap.put(pool[din.readUnsignedShort()], pool[din.readUnsignedShort()]);
} catch (ArrayIndexOutOfBoundsException ex) {
throw new IOException("Corrupt zone info map");
}
}
}
}