Java tutorial
/* * 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.hive; import com.google.common.collect.ClassToInstanceMap; import com.google.common.collect.ImmutableClassToInstanceMap; import org.apache.hadoop.conf.Configuration; import static com.google.common.base.Preconditions.checkArgument; import static java.util.Objects.requireNonNull; public final class PrestoHadoopConfiguration extends Configuration { private final ClassToInstanceMap<Object> services; public PrestoHadoopConfiguration(ClassToInstanceMap<?> services) { super(false); this.services = ImmutableClassToInstanceMap.copyOf(requireNonNull(services, "services is null")); } public <T> T getService(Class<T> type) { T service = services.getInstance(type); checkArgument(service != null, "service not found: %s", type.getName()); return service; } }