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 *   https://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 {@link ServiceLoader} mechanism.
029 *
030 * @param <E> The service to load
031 * @since 1.13
032 * @deprecated No longer needed.
033 */
034@Deprecated
035public class ServiceLoaderIterator<E> implements Iterator<E> {
036
037    private E nextServiceLoader;
038    private final Class<E> service;
039    private final Iterator<E> serviceLoaderIterator;
040
041    /**
042     * Constructs a new instance.
043     *
044     * @param service The interface or abstract class representing the service.
045     */
046    public ServiceLoaderIterator(final Class<E> service) {
047        this(service, ClassLoader.getSystemClassLoader());
048    }
049
050    /**
051     * Constructs a new instance.
052     *
053     * @param service     The interface or abstract class representing the service.
054     * @param classLoader The class loader to be used to load provider-configuration files and provider classes, or {@code null} if the system class loader (or,
055     *                    failing that, the bootstrap class loader) is to be used
056     */
057    public ServiceLoaderIterator(final Class<E> service, final ClassLoader classLoader) {
058        this.service = service;
059        this.serviceLoaderIterator = ServiceLoader.load(service, classLoader).iterator();
060    }
061
062    @Override
063    public boolean hasNext() {
064        while (nextServiceLoader == null) {
065            try {
066                if (!serviceLoaderIterator.hasNext()) {
067                    return false;
068                }
069                nextServiceLoader = serviceLoaderIterator.next();
070            } catch (final ServiceConfigurationError e) {
071                if (e.getCause() instanceof SecurityException) {
072                    // Ignore security exceptions
073                    // TODO Log?
074                    continue;
075                }
076                throw e;
077            }
078        }
079        return true;
080    }
081
082    @Override
083    public E next() {
084        if (!hasNext()) {
085            throw new NoSuchElementException("No more elements for service " + service.getName());
086        }
087        final E tempNext = nextServiceLoader;
088        nextServiceLoader = null;
089        return tempNext;
090    }
091
092    @Override
093    public void remove() {
094        throw new UnsupportedOperationException("service=" + service.getName());
095    }
096
097}