/* * Copyright 2016 the original author or authors. * * 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 org.springframework.cloud.deployer.admin.configuration.metadata; import java.net.URLClassLoader; import java.util.ArrayList; import java.util.Arrays; import java.util.Collections; import java.util.List; import org.springframework.boot.configurationmetadata.ConfigurationMetadataProperty; import org.springframework.core.io.Resource; /** * An {@link ApplicationConfigurationMetadataResolver} that tries several delegates in turn, * returning the results of the first one that {@link ApplicationConfigurationMetadataResolver#supports(Resource)} * an app. Returns an empty list of properties as a last resort. * * @author Eric Bottard */ public class DelegatingApplicationConfigurationMetadataResolver extends ApplicationConfigurationMetadataResolver { private List<ApplicationConfigurationMetadataResolver> delegates = new ArrayList<>(); public DelegatingApplicationConfigurationMetadataResolver(ApplicationConfigurationMetadataResolver... delegates) { this.delegates = Arrays.asList(delegates); } @Override public boolean supports(Resource app) { return true; // We're going to return an empty list as a last resort anyway } @Override public List<ConfigurationMetadataProperty> listProperties(Resource app, boolean exhaustive) { for (ApplicationConfigurationMetadataResolver delegate : delegates) { if (delegate.supports(app)) { return delegate.listProperties(app, exhaustive); } } return Collections.emptyList(); } @Override public URLClassLoader createAppClassLoader(Resource app) { for (ApplicationConfigurationMetadataResolver delegate : delegates) { if (delegate.supports(app)) { return delegate.createAppClassLoader(app); } } return super.createAppClassLoader(app); } }