001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019
020package org.apache.commons.compress.utils;
021
022import java.util.Iterator;
023import java.util.NoSuchElementException;
024import java.util.ServiceConfigurationError;
025import java.util.ServiceLoader;
026
027/**
028 * Iterates all services for a given class through the standard
029 * {@link ServiceLoader} mechanism.
030 *
031 * @param <E>
032 *            The service to load
033 * @since 1.13
034 * @deprecated No longer needed.
035 */
036@Deprecated
037public class ServiceLoaderIterator<E> implements Iterator<E> {
038
039    private E nextServiceLoader;
040    private final Class<E> service;
041    private final Iterator<E> serviceLoaderIterator;
042
043    public ServiceLoaderIterator(final Class<E> service) {
044        this(service, ClassLoader.getSystemClassLoader());
045    }
046
047    public ServiceLoaderIterator(final Class<E> service, final ClassLoader classLoader) {
048        this.service = service;
049        this.serviceLoaderIterator = ServiceLoader.load(service, classLoader).iterator();
050    }
051
052    @Override
053    public boolean hasNext() {
054        while (nextServiceLoader == null) {
055            try {
056                if (!serviceLoaderIterator.hasNext()) {
057                    return false;
058                }
059                nextServiceLoader = serviceLoaderIterator.next();
060            } catch (final ServiceConfigurationError e) {
061                if (e.getCause() instanceof SecurityException) {
062                    // Ignore security exceptions
063                    // TODO Log?
064                    continue;
065                }
066                throw e;
067            }
068        }
069        return true;
070    }
071
072    @Override
073    public E next() {
074        if (!hasNext()) {
075            throw new NoSuchElementException("No more elements for service " + service.getName());
076        }
077        final E tempNext = nextServiceLoader;
078        nextServiceLoader = null;
079        return tempNext;
080    }
081
082    @Override
083    public void remove() {
084        throw new UnsupportedOperationException("service=" + service.getName());
085    }
086
087}