/*
 * 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
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package org.apache.commons.compress.utils;

import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.ServiceConfigurationError;
import java.util.ServiceLoader;

Iterates all services for a given class through the standard ServiceLoader mechanism.
Type parameters:
  • <E> – The service to load
Since:1.13
/** * Iterates all services for a given class through the standard * {@link ServiceLoader} mechanism. * * @param <E> * The service to load * @since 1.13 */
public class ServiceLoaderIterator<E> implements Iterator<E> { private E nextServiceLoader; private final Class<E> service; private final Iterator<E> serviceLoaderIterator; public ServiceLoaderIterator(final Class<E> service) { this(service, ClassLoader.getSystemClassLoader()); } public ServiceLoaderIterator(final Class<E> service, final ClassLoader classLoader) { this.service = service; final ServiceLoader<E> serviceLoader = ServiceLoader.load(service, classLoader); serviceLoaderIterator = serviceLoader.iterator(); nextServiceLoader = null; } private boolean getNextServiceLoader() { while (nextServiceLoader == null) { try { if (!serviceLoaderIterator.hasNext()) { return false; } nextServiceLoader = serviceLoaderIterator.next(); } catch (final ServiceConfigurationError e) { if (e.getCause() instanceof SecurityException) { // Ignore security exceptions // TODO Log? continue; } throw e; } } return true; } @Override public boolean hasNext() { return getNextServiceLoader(); } @Override public E next() { if (!getNextServiceLoader()) { throw new NoSuchElementException("No more elements for service " + service.getName()); } final E tempNext = nextServiceLoader; nextServiceLoader = null; return tempNext; } @Override public void remove() { throw new UnsupportedOperationException("service=" + service.getName()); } }