Java tutorial
/* * 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 maynot 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 applicablelaw 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.phoenix.cache; import com.google.common.cache.CacheBuilder; import com.google.common.cache.CacheLoader; import com.google.common.cache.LoadingCache; import com.google.common.util.concurrent.UncheckedExecutionException; import java.nio.ByteBuffer; import java.util.concurrent.ExecutionException; import java.util.concurrent.TimeUnit; import org.apache.hadoop.hbase.io.ImmutableBytesWritable; import org.apache.hadoop.hbase.util.Bytes; import org.apache.phoenix.schema.IllegalDataException; import org.joda.time.DateTimeZone; public class JodaTimezoneCache { public static final int CACHE_EXPRIRE_TIME_MINUTES = 10; private static final LoadingCache<ByteBuffer, DateTimeZone> cachedJodaTimeZones = createTimezoneCache(); /** * Returns joda's DateTimeZone instance from cache or create new instance and cache it. * * @param timezoneId Timezone Id as accepted by {@code DateTimeZone.forID()}. E.g. Europe/Isle_of_Man * @return joda's DateTimeZone instance * @throws IllegalDataException if unknown timezone id is passed */ public static DateTimeZone getInstance(ByteBuffer timezoneId) { try { return cachedJodaTimeZones.get(timezoneId); } catch (ExecutionException ex) { throw new IllegalDataException(ex); } catch (UncheckedExecutionException e) { throw new IllegalDataException("Unknown timezone " + Bytes.toString(timezoneId.array())); } } /** * Returns joda's DateTimeZone instance from cache or create new instance and cache it. * * @param timezoneId Timezone Id as accepted by {@code DateTimeZone.forID()}. E.g. Europe/Isle_of_Man * @return joda's DateTimeZone instance * @throws IllegalDataException if unknown timezone id is passed */ public static DateTimeZone getInstance(ImmutableBytesWritable timezoneId) { return getInstance(ByteBuffer.wrap(timezoneId.copyBytes())); } /** * Returns joda's DateTimeZone instance from cache or create new instance and cache it. * * @param timezoneId Timezone Id as accepted by {@code DateTimeZone.forID()}. E.g. Europe/Isle_of_Man * @return joda's DateTimeZone instance * @throws IllegalDataException if unknown timezone id is passed */ public static DateTimeZone getInstance(String timezoneId) { return getInstance(ByteBuffer.wrap(Bytes.toBytes(timezoneId))); } private static LoadingCache<ByteBuffer, DateTimeZone> createTimezoneCache() { return CacheBuilder.newBuilder().expireAfterAccess(CACHE_EXPRIRE_TIME_MINUTES, TimeUnit.MINUTES) .build(new CacheLoader<ByteBuffer, DateTimeZone>() { @Override public DateTimeZone load(ByteBuffer timezone) throws Exception { return DateTimeZone.forID(Bytes.toString(timezone.array())); } }); } }