io.fabric8.kubernetes.client.Adapters Maven / Gradle / Ivy

Go to download
/**
 * Copyright (C) 2015 Red Hat, Inc.
 *
 * 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 io.fabric8.kubernetes.client;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.ServiceLoader;
import java.util.Set;

public final class Adapters {

  private static final Set CLASS_LOADERS = new HashSet<>();
  private static final Map EXTENSION_ADAPTER_MAP = new HashMap<>();

  private Adapters() {
    //Utility
  }

  static {
    //Register adapters
    discoverServices(Adapters.class.getClassLoader());
  }

  public static  void register(ExtensionAdapter adapter) {
    EXTENSION_ADAPTER_MAP.put(adapter.getExtensionType(), adapter);
  }

  public static  void unregister(ExtensionAdapter adapter) {
    EXTENSION_ADAPTER_MAP.remove(adapter.getExtensionType());
  }

  public static  ExtensionAdapter get(Class type) {
    if (EXTENSION_ADAPTER_MAP.containsKey(type)) {
      return EXTENSION_ADAPTER_MAP.get(type);
    } else {
      for (ExtensionAdapter adapter : ServiceLoader.load(ExtensionAdapter.class, type.getClassLoader())) {
        if (adapter.getExtensionType().equals(type)) {
          return adapter;
        }
      }
      for (ExtensionAdapter adapter : ServiceLoader.load(ExtensionAdapter.class, Thread.currentThread().getContextClassLoader())) {
        if (adapter.getExtensionType().equals(type)) {
          return adapter;
        }
      }
      return null;
    }
  }

  public static  Collection> list(Class type) {
    List> result = new ArrayList<>();
    for (ExtensionAdapter candidate : EXTENSION_ADAPTER_MAP.values()) {
        if (type.isAssignableFrom(candidate.getExtensionType())) {
            result.add(candidate);
        }
    }
    return result;
  }

  private static void discoverServices(ClassLoader classLoader) {
    if (classLoader != null && CLASS_LOADERS.add(classLoader)) {
      for (ExtensionAdapter adapter : ServiceLoader.load(ExtensionAdapter.class, classLoader)) {
        register(adapter);
      }
    }
  }
}