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.providers; import static com.google.common.collect.Iterables.filter; import static com.google.common.collect.Iterables.find; import static org.jclouds.reflect.Reflection2.typeToken; import java.util.NoSuchElementException; import java.util.ServiceLoader; import org.jclouds.Context; import org.jclouds.View; import org.jclouds.apis.ApiMetadata; import org.jclouds.osgi.ProviderRegistry; import com.google.common.base.Function; import com.google.common.base.Preconditions; import com.google.common.base.Predicates; import com.google.common.collect.ImmutableSet; import com.google.common.reflect.TypeToken; /** * The Providers class provides static methods for accessing providers. * * @author Jeremy Whitlock <jwhitlock@apache.org> */ public class Providers { public static enum IdFunction implements Function<ProviderMetadata, String> { INSTANCE; @Override public String apply(ProviderMetadata input) { return input.getId(); } } public static Function<ProviderMetadata, String> idFunction() { return IdFunction.INSTANCE; } public static class ApiMetadataFunction implements Function<ProviderMetadata, ApiMetadata> { @Override public ApiMetadata apply(ProviderMetadata input) { return input.getApiMetadata(); } } public static Function<ProviderMetadata, ApiMetadata> apiMetadataFunction() { return new ApiMetadataFunction(); } /** * Returns the providers located on the classpath via {@link java.util.ServiceLoader}. * * @return all available providers loaded from classpath via ServiceLoader */ public static Iterable<ProviderMetadata> fromServiceLoader() { return ServiceLoader.load(ProviderMetadata.class); } /** * Returns all available providers. * * @return all available providers */ public static Iterable<ProviderMetadata> all() { return ImmutableSet.<ProviderMetadata>builder().addAll(fromServiceLoader()) .addAll(ProviderRegistry.fromRegistry()).build(); } /** * Returns the first provider with the provided id * * @param id * the id of the provider to return * * @return the provider with the given id * * @throws NoSuchElementException * whenever there are no providers with the provided id */ public static ProviderMetadata withId(String id) throws NoSuchElementException { return find(all(), ProviderPredicates.id(id)); } /** * Returns the providers that are of the provided viewableAs. * * @param viewableAs * the viewableAs to providers to return * * @return the providers of the provided viewableAs */ public static Iterable<ProviderMetadata> viewableAs(TypeToken<? extends View> viewableAs) { return filter(all(), ProviderPredicates.viewableAs(viewableAs)); } public static Iterable<ProviderMetadata> viewableAs(Class<? extends View> viewableAs) { return filter(all(), ProviderPredicates.viewableAs(typeToken(viewableAs))); } /** * Returns the providers that are of the provided api. * * @param api * the api to providers to return * * @return the providers of the provided api */ public static Iterable<ProviderMetadata> apiMetadataAssignableFrom(TypeToken<? extends ApiMetadata> api) { Preconditions.checkNotNull(api, "api must be defined"); return filter(all(), ProviderPredicates.apiMetadataAssignableFrom(api)); } /** * Returns the providers that are of the provided context. * * @param context * the context to providers to return * * @return the providers of the provided context */ public static <C extends Context> Iterable<ProviderMetadata> contextAssignableFrom( TypeToken<? extends Context> context) { Preconditions.checkNotNull(context, "context must be defined"); return filter(all(), new ProviderPredicates.ContextAssignableFrom(context)); } /** * Returns the providers that are bound to the same location as the given ISO 3166 code * regardless of viewableAs. * * @param isoCode * the ISO 3166 code to filter providers by * * @return the providers bound by the given ISO 3166 code */ public static Iterable<ProviderMetadata> boundedByIso3166Code(String iso3166Code) { return filter(all(), ProviderPredicates.boundedByIso3166Code(iso3166Code)); } /** * Returns the providers that are bound to the same location as the given ISO 3166 code and of * the given viewableAs. * * @param iso3166Code * the ISO 3166 code to filter providers by * @param viewableAs * the viewableAs to filter providers by * * @return the providers bound by the given ISO 3166 code and of the proper viewableAs */ public static Iterable<ProviderMetadata> boundedByIso3166Code(String iso3166Code, TypeToken<? extends View> viewableAs) { return filter(all(), Predicates.and(ProviderPredicates.boundedByIso3166Code(iso3166Code), ProviderPredicates.viewableAs(viewableAs))); } public static Iterable<ProviderMetadata> boundedByIso3166Code(String iso3166Code, Class<? extends View> viewableAs) { return boundedByIso3166Code(iso3166Code, typeToken(viewableAs)); } /** * Returns the providers that have at least one common ISO 3166 code in common regardless of * viewableAs. * * @param providerMetadata * the provider metadata to use to filter providers by * * @return the providers that share at least one common ISO 3166 code */ public static Iterable<ProviderMetadata> collocatedWith(ProviderMetadata providerMetadata) { return filter(all(), ProviderPredicates.intersectingIso3166Code(providerMetadata)); } /** * Returns the providers that have at least one common ISO 3166 code and are of the given * viewableAs. * * @param providerMetadata * the provider metadata to use to filter providers by * @param viewableAs * the viewableAs to filter providers by * * @return the providers that share at least one common ISO 3166 code and of the given * viewableAs */ public static Iterable<ProviderMetadata> collocatedWith(ProviderMetadata providerMetadata, TypeToken<? extends View> viewableAs) { return filter(all(), Predicates.and(ProviderPredicates.intersectingIso3166Code(providerMetadata), ProviderPredicates.viewableAs(viewableAs))); } public static Iterable<ProviderMetadata> collocatedWith(ProviderMetadata providerMetadata, Class<? extends View> viewableAs) { return collocatedWith(providerMetadata, typeToken(viewableAs)); } }