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 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.jclouds.googlecomputeengine.compute.loaders; import java.util.concurrent.ExecutionException; import javax.inject.Inject; import javax.inject.Singleton; import org.jclouds.googlecomputeengine.GoogleComputeEngineApi; import org.jclouds.googlecomputeengine.compute.domain.internal.RegionAndName; import org.jclouds.googlecomputeengine.domain.Subnetwork; import com.google.common.base.Optional; import com.google.common.cache.CacheLoader; @Singleton public class SubnetworkLoader extends CacheLoader<RegionAndName, Optional<Subnetwork>> { private final GoogleComputeEngineApi api; @Inject SubnetworkLoader(GoogleComputeEngineApi api) { this.api = api; } @Override public Optional<Subnetwork> load(RegionAndName key) throws ExecutionException { try { return Optional.fromNullable(api.subnetworksInRegion(key.regionId()).get(key.name())); } catch (Exception ex) { throw new ExecutionException(message(key, ex), ex); } } public static String message(RegionAndName key, Exception ex) { return String.format("could not find subnet %s in region %s: %s", key.name(), key.regionId(), ex.getMessage()); } }