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893 lines
32 KiB
Java
893 lines
32 KiB
Java
/*
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* Copyright (c) 2000, 2022, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package javax.imageio.spi;
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import java.security.AccessControlContext;
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import java.security.AccessController;
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import java.security.PrivilegedAction;
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import java.util.ArrayList;
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import java.util.HashMap;
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import java.util.Iterator;
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import java.util.List;
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import java.util.Map;
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import java.util.NoSuchElementException;
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import java.util.Set;
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import java.util.ServiceLoader;
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/**
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* A registry for service provider instances for Image I/O service types.
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*
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* <p> Service providers are stored in one or more <i>categories</i>,
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* each of which is defined by a class or interface (described by a
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* {@code Class} object) that all of its members must implement.
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*
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* <p>The set of categories supported by this class is limited
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* to the following standard Image I/O service types:
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*
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* <ul>
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* <li>{@link ImageInputStreamSpi}
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* <li>{@link ImageOutputStreamSpi}
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* <li>{@link ImageReaderSpi}
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* <li>{@link ImageTranscoderSpi}
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* <li>{@link ImageWriterSpi}
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* </ul>
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*
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* <p>An attempt to load a provider that is not a subtype of one of the
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* above types will result in {@code IllegalArgumentException}.
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* <p> For the general mechanism to load service providers, see
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* {@link java.util.ServiceLoader ServiceLoader}, which is
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* the underlying standard mechanism used by this class.
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*
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* <p> Only a single instance of a given leaf class (that is, the
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* actual class returned by {@code getClass()}, as opposed to any
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* inherited classes or interfaces) may be registered. That is,
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* suppose that the
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* {@code com.mycompany.mypkg.GreenImageReaderProvider} class
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* is a subclass of {@code javax.imageio.spi.ImageReaderSpi}.
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* If a {@code GreenImageReaderProvider} instance is
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* registered, it will be stored in the category defined by the
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* {@code ImageReaderSpi} class. If a new instance of
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* {@code GreenImageReaderProvider} is registered, it will replace
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* the previous instance. In practice, service provider objects are
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* usually singletons so this behavior is appropriate.
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*
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* <p> The service provider classes should be lightweight and
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* quick to load. Implementations of these interfaces should avoid
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* complex dependencies on other classes and on native code. The usual
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* pattern for more complex services is to register a lightweight
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* proxy for the heavyweight service.
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*
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* <p> An application may customize the contents of a registry as it
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* sees fit, so long as it has the appropriate runtime permission.
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*
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* <p> For information on how to create and deploy service providers,
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* refer to the documentation on {@link java.util.ServiceLoader ServiceLoader}
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*
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* @see RegisterableService
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* @see java.util.ServiceLoader
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*/
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public class ServiceRegistry {
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// Class -> Registry
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private Map<Class<?>, SubRegistry> categoryMap = new HashMap<>();
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/**
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* Constructs a {@code ServiceRegistry} instance with a
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* set of categories taken from the {@code categories}
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* argument. The categories must all be members of the set
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* of service types listed in the class specification.
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*
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* @param categories an {@code Iterator} containing
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* {@code Class} objects to be used to define categories.
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*
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* @throws IllegalArgumentException if
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* {@code categories} is {@code null}, or if
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* one of the categories is not an allowed service type.
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*/
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public ServiceRegistry(Iterator<Class<?>> categories) {
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if (categories == null) {
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throw new IllegalArgumentException("categories == null!");
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}
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while (categories.hasNext()) {
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Class<?> category = categories.next();
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checkClassAllowed(category);
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SubRegistry reg = new SubRegistry(this, category);
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categoryMap.put(category, reg);
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}
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}
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/**
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* Searches for implementations of a particular service class
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* using the given class loader.
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*
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* <p>The service class must be one of the service types listed
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* in the class specification. If it is not, {@code IllegalArgumentException}
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* will be thrown.
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*
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* <p> This method transforms the name of the given service class
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* into a provider-configuration filename as described in the
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* class comment and then uses the {@code getResources}
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* method of the given class loader to find all available files
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* with that name. These files are then read and parsed to
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* produce a list of provider-class names. The iterator that is
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* returned uses the given class loader to look up and then
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* instantiate each element of the list.
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*
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* <p> Because it is possible for extensions to be installed into
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* a running Java virtual machine, this method may return
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* different results each time it is invoked.
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*
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* @param providerClass a {@code Class} object indicating the
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* class or interface of the service providers being detected.
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*
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* @param loader the class loader to be used to load
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* provider-configuration files and instantiate provider classes,
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* or {@code null} if the system class loader (or, failing that
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* the bootstrap class loader) is to be used.
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*
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* @param <T> the type of the providerClass.
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*
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* @return An {@code Iterator} that yields provider objects
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* for the given service, in some arbitrary order. The iterator
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* will throw an {@code Error} if a provider-configuration
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* file violates the specified format or if a provider class
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* cannot be found and instantiated.
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*
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* @throws IllegalArgumentException if
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* {@code providerClass} is {@code null}, or if it is
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* not one of the allowed service types.
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*/
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public static <T> Iterator<T> lookupProviders(Class<T> providerClass,
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ClassLoader loader)
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{
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if (providerClass == null) {
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throw new IllegalArgumentException("providerClass == null!");
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}
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checkClassAllowed(providerClass);
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return ServiceLoader.load(providerClass, loader).iterator();
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}
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/**
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* Locates and incrementally instantiates the available providers
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* of a given service using the context class loader. This
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* convenience method is equivalent to:
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*
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* <pre>
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* ClassLoader cl = Thread.currentThread().getContextClassLoader();
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* return Service.providers(service, cl);
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* </pre>
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*
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* <p>The service class must be one of the service types listed
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* in the class specification. If it is not, {@code IllegalArgumentException}
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* will be thrown.
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*
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* @param providerClass a {@code Class} object indicating the
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* class or interface of the service providers being detected.
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*
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* @param <T> the type of the providerClass.
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*
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* @return An {@code Iterator} that yields provider objects
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* for the given service, in some arbitrary order. The iterator
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* will throw an {@code Error} if a provider-configuration
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* file violates the specified format or if a provider class
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* cannot be found and instantiated.
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*
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* @throws IllegalArgumentException if
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* {@code providerClass} is {@code null}, or if it is
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* not one of the allowed service types.
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*/
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public static <T> Iterator<T> lookupProviders(Class<T> providerClass) {
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if (providerClass == null) {
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throw new IllegalArgumentException("providerClass == null!");
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}
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checkClassAllowed(providerClass);
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return ServiceLoader.load(providerClass).iterator();
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}
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/**
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* Returns an {@code Iterator} of {@code Class} objects
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* indicating the current set of categories. The iterator will be
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* empty if no categories exist.
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*
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* @return an {@code Iterator} containing
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* {@code Class} objects.
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*/
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public Iterator<Class<?>> getCategories() {
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Set<Class<?>> keySet = categoryMap.keySet();
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return keySet.iterator();
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}
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/**
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* Returns an Iterator containing the subregistries to which the
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* provider belongs.
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*/
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private Iterator<SubRegistry> getSubRegistries(Object provider) {
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List<SubRegistry> l = new ArrayList<>();
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for (Class<?> c : categoryMap.keySet()) {
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if (c.isInstance(provider)) {
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l.add(categoryMap.get(c));
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}
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}
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return l.iterator();
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}
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/**
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* Adds a service provider object to the registry. The provider
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* is associated with the given category.
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*
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* <p> If {@code provider} implements the
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* {@code RegisterableService} interface, its
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* {@code onRegistration} method will be called. Its
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* {@code onDeregistration} method will be called each time
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* it is deregistered from a category, for example if a
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* category is removed or the registry is garbage collected.
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*
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* @param provider the service provide object to be registered.
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* @param category the category under which to register the
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* provider.
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* @param <T> the type of the provider.
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*
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* @return true if no provider of the same class was previously
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* registered in the same category category.
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*
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* @throws IllegalArgumentException if {@code provider} is
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* {@code null}.
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* @throws IllegalArgumentException if there is no category
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* corresponding to {@code category}.
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* @throws ClassCastException if provider does not implement
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* the {@code Class} defined by {@code category}.
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*/
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public <T> boolean registerServiceProvider(T provider,
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Class<T> category) {
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if (provider == null) {
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throw new IllegalArgumentException("provider == null!");
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}
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SubRegistry reg = categoryMap.get(category);
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if (reg == null) {
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throw new IllegalArgumentException("category unknown!");
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}
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if (!category.isInstance(provider)) {
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throw new ClassCastException();
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}
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return reg.registerServiceProvider(provider);
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}
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/**
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* Adds a service provider object to the registry. The provider
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* is associated within each category present in the registry
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* whose {@code Class} it implements.
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*
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* <p> If {@code provider} implements the
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* {@code RegisterableService} interface, its
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* {@code onRegistration} method will be called once for each
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* category it is registered under. Its
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* {@code onDeregistration} method will be called each time
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* it is deregistered from a category or when the registry is
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* finalized.
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*
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* @param provider the service provider object to be registered.
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*
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* @throws IllegalArgumentException if
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* {@code provider} is {@code null}.
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*/
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public void registerServiceProvider(Object provider) {
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if (provider == null) {
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throw new IllegalArgumentException("provider == null!");
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}
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Iterator<SubRegistry> regs = getSubRegistries(provider);
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while (regs.hasNext()) {
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SubRegistry reg = regs.next();
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reg.registerServiceProvider(provider);
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}
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}
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/**
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* Adds a set of service provider objects, taken from an
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* {@code Iterator} to the registry. Each provider is
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* associated within each category present in the registry whose
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* {@code Class} it implements.
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*
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* <p> For each entry of {@code providers} that implements
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* the {@code RegisterableService} interface, its
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* {@code onRegistration} method will be called once for each
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* category it is registered under. Its
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* {@code onDeregistration} method will be called each time
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* it is deregistered from a category or when the registry is
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* finalized.
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*
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* @param providers an Iterator containing service provider
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* objects to be registered.
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*
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* @throws IllegalArgumentException if {@code providers}
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* is {@code null} or contains a {@code null} entry.
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*/
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public void registerServiceProviders(Iterator<?> providers) {
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if (providers == null) {
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throw new IllegalArgumentException("provider == null!");
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}
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while (providers.hasNext()) {
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registerServiceProvider(providers.next());
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}
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}
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/**
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* Removes a service provider object from the given category. If
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* the provider was not previously registered, nothing happens and
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* {@code false} is returned. Otherwise, {@code true}
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* is returned. If an object of the same class as
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* {@code provider} but not equal (using {@code ==}) to
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* {@code provider} is registered, it will not be
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* deregistered.
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*
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* <p> If {@code provider} implements the
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* {@code RegisterableService} interface, its
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* {@code onDeregistration} method will be called.
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*
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* @param provider the service provider object to be deregistered.
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* @param category the category from which to deregister the
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* provider.
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* @param <T> the type of the provider.
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*
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* @return {@code true} if the provider was previously
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* registered in the same category category,
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* {@code false} otherwise.
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*
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* @throws IllegalArgumentException if {@code provider} is
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* {@code null}.
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* @throws IllegalArgumentException if there is no category
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* corresponding to {@code category}.
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* @throws ClassCastException if provider does not implement
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* the class defined by {@code category}.
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*/
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public <T> boolean deregisterServiceProvider(T provider,
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Class<T> category) {
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if (provider == null) {
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throw new IllegalArgumentException("provider == null!");
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}
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SubRegistry reg = categoryMap.get(category);
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if (reg == null) {
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throw new IllegalArgumentException("category unknown!");
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}
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if (!category.isInstance(provider)) {
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throw new ClassCastException();
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}
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return reg.deregisterServiceProvider(provider);
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}
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/**
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* Removes a service provider object from all categories that
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* contain it.
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*
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* @param provider the service provider object to be deregistered.
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*
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* @throws IllegalArgumentException if {@code provider} is
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* {@code null}.
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*/
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public void deregisterServiceProvider(Object provider) {
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if (provider == null) {
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throw new IllegalArgumentException("provider == null!");
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}
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Iterator<SubRegistry> regs = getSubRegistries(provider);
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while (regs.hasNext()) {
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SubRegistry reg = regs.next();
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reg.deregisterServiceProvider(provider);
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}
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}
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/**
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* Returns {@code true} if {@code provider} is currently
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* registered.
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*
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* @param provider the service provider object to be queried.
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*
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* @return {@code true} if the given provider has been
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* registered.
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*
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* @throws IllegalArgumentException if {@code provider} is
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* {@code null}.
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*/
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public boolean contains(Object provider) {
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if (provider == null) {
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throw new IllegalArgumentException("provider == null!");
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}
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Iterator<SubRegistry> regs = getSubRegistries(provider);
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while (regs.hasNext()) {
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SubRegistry reg = regs.next();
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if (reg.contains(provider)) {
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return true;
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}
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}
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return false;
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}
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/**
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* Returns an {@code Iterator} containing all registered
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* service providers in the given category. If
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* {@code useOrdering} is {@code false}, the iterator
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* will return all of the server provider objects in an arbitrary
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* order. Otherwise, the ordering will respect any pairwise
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* orderings that have been set. If the graph of pairwise
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* orderings contains cycles, any providers that belong to a cycle
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* will not be returned.
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*
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* @param category the category to be retrieved from.
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* @param useOrdering {@code true} if pairwise orderings
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* should be taken account in ordering the returned objects.
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* @param <T> the type of the category.
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*
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* @return an {@code Iterator} containing service provider
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* objects from the given category, possibly in order.
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*
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* @throws IllegalArgumentException if there is no category
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* corresponding to {@code category}.
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*/
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public <T> Iterator<T> getServiceProviders(Class<T> category,
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boolean useOrdering) {
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SubRegistry reg = categoryMap.get(category);
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if (reg == null) {
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throw new IllegalArgumentException("category unknown!");
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}
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@SuppressWarnings("unchecked")
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Iterator<T> it = (Iterator<T>)reg.getServiceProviders(useOrdering);
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return it;
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}
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/**
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* A simple filter interface used by
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* {@code ServiceRegistry.getServiceProviders} to select
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* providers matching an arbitrary criterion. Classes that
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* implement this interface should be defined in order to make use
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* of the {@code getServiceProviders} method of
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* {@code ServiceRegistry} that takes a {@code Filter}.
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*
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* @see ServiceRegistry#getServiceProviders(Class, ServiceRegistry.Filter, boolean)
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*/
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public interface Filter {
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/**
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* Returns {@code true} if the given
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* {@code provider} object matches the criterion defined
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* by this {@code Filter}.
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*
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* @param provider a service provider {@code Object}.
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*
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* @return true if the provider matches the criterion.
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*/
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boolean filter(Object provider);
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}
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/**
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* Returns an {@code Iterator} containing service provider
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* objects within a given category that satisfy a criterion
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* imposed by the supplied {@code ServiceRegistry.Filter}
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* object's {@code filter} method.
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*
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* <p> The {@code useOrdering} argument controls the
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* ordering of the results using the same rules as
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* {@code getServiceProviders(Class, boolean)}.
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*
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* @param category the category to be retrieved from.
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* @param filter an instance of {@code ServiceRegistry.Filter}
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* whose {@code filter} method will be invoked.
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* @param useOrdering {@code true} if pairwise orderings
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* should be taken account in ordering the returned objects.
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* @param <T> the type of the category.
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*
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* @return an {@code Iterator} containing service provider
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* objects from the given category, possibly in order.
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*
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* @throws IllegalArgumentException if there is no category
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* corresponding to {@code category}.
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*/
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public <T> Iterator<T> getServiceProviders(Class<T> category,
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Filter filter,
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boolean useOrdering) {
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SubRegistry reg = categoryMap.get(category);
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if (reg == null) {
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throw new IllegalArgumentException("category unknown!");
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}
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Iterator<T> iter = getServiceProviders(category, useOrdering);
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return new FilterIterator<>(iter, filter);
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}
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/**
|
|
* Returns the currently registered service provider object that
|
|
* is of the given class type. At most one object of a given
|
|
* class is allowed to be registered at any given time. If no
|
|
* registered object has the desired class type, {@code null}
|
|
* is returned.
|
|
*
|
|
* @param providerClass the {@code Class} of the desired
|
|
* service provider object.
|
|
* @param <T> the type of the provider.
|
|
*
|
|
* @return a currently registered service provider object with the
|
|
* desired {@code Class} type, or {@code null} is none is
|
|
* present.
|
|
*
|
|
* @throws IllegalArgumentException if {@code providerClass} is
|
|
* {@code null}.
|
|
*/
|
|
public <T> T getServiceProviderByClass(Class<T> providerClass) {
|
|
if (providerClass == null) {
|
|
throw new IllegalArgumentException("providerClass == null!");
|
|
}
|
|
for (Class<?> c : categoryMap.keySet()) {
|
|
if (c.isAssignableFrom(providerClass)) {
|
|
SubRegistry reg = categoryMap.get(c);
|
|
T provider = reg.getServiceProviderByClass(providerClass);
|
|
if (provider != null) {
|
|
return provider;
|
|
}
|
|
}
|
|
}
|
|
return null;
|
|
}
|
|
|
|
/**
|
|
* Sets a pairwise ordering between two service provider objects
|
|
* within a given category. If one or both objects are not
|
|
* currently registered within the given category, or if the
|
|
* desired ordering is already set, nothing happens and
|
|
* {@code false} is returned. If the providers previously
|
|
* were ordered in the reverse direction, that ordering is
|
|
* removed.
|
|
*
|
|
* <p> The ordering will be used by the
|
|
* {@code getServiceProviders} methods when their
|
|
* {@code useOrdering} argument is {@code true}.
|
|
*
|
|
* @param category a {@code Class} object indicating the
|
|
* category under which the preference is to be established.
|
|
* @param firstProvider the preferred provider.
|
|
* @param secondProvider the provider to which
|
|
* {@code firstProvider} is preferred.
|
|
* @param <T> the type of the category.
|
|
*
|
|
* @return {@code true} if a previously unset ordering
|
|
* was established.
|
|
*
|
|
* @throws IllegalArgumentException if either provider is
|
|
* {@code null} or they are the same object.
|
|
* @throws IllegalArgumentException if there is no category
|
|
* corresponding to {@code category}.
|
|
*/
|
|
public <T> boolean setOrdering(Class<T> category,
|
|
T firstProvider,
|
|
T secondProvider) {
|
|
if (firstProvider == null || secondProvider == null) {
|
|
throw new IllegalArgumentException("provider is null!");
|
|
}
|
|
if (firstProvider == secondProvider) {
|
|
throw new IllegalArgumentException("providers are the same!");
|
|
}
|
|
SubRegistry reg = categoryMap.get(category);
|
|
if (reg == null) {
|
|
throw new IllegalArgumentException("category unknown!");
|
|
}
|
|
if (reg.contains(firstProvider) &&
|
|
reg.contains(secondProvider)) {
|
|
return reg.setOrdering(firstProvider, secondProvider);
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* Sets a pairwise ordering between two service provider objects
|
|
* within a given category. If one or both objects are not
|
|
* currently registered within the given category, or if no
|
|
* ordering is currently set between them, nothing happens
|
|
* and {@code false} is returned.
|
|
*
|
|
* <p> The ordering will be used by the
|
|
* {@code getServiceProviders} methods when their
|
|
* {@code useOrdering} argument is {@code true}.
|
|
*
|
|
* @param category a {@code Class} object indicating the
|
|
* category under which the preference is to be disestablished.
|
|
* @param firstProvider the formerly preferred provider.
|
|
* @param secondProvider the provider to which
|
|
* {@code firstProvider} was formerly preferred.
|
|
* @param <T> the type of the category.
|
|
*
|
|
* @return {@code true} if a previously set ordering was
|
|
* disestablished.
|
|
*
|
|
* @throws IllegalArgumentException if either provider is
|
|
* {@code null} or they are the same object.
|
|
* @throws IllegalArgumentException if there is no category
|
|
* corresponding to {@code category}.
|
|
*/
|
|
public <T> boolean unsetOrdering(Class<T> category,
|
|
T firstProvider,
|
|
T secondProvider) {
|
|
if (firstProvider == null || secondProvider == null) {
|
|
throw new IllegalArgumentException("provider is null!");
|
|
}
|
|
if (firstProvider == secondProvider) {
|
|
throw new IllegalArgumentException("providers are the same!");
|
|
}
|
|
SubRegistry reg = categoryMap.get(category);
|
|
if (reg == null) {
|
|
throw new IllegalArgumentException("category unknown!");
|
|
}
|
|
if (reg.contains(firstProvider) &&
|
|
reg.contains(secondProvider)) {
|
|
return reg.unsetOrdering(firstProvider, secondProvider);
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* Deregisters all service provider object currently registered
|
|
* under the given category.
|
|
*
|
|
* @param category the category to be emptied.
|
|
*
|
|
* @throws IllegalArgumentException if there is no category
|
|
* corresponding to {@code category}.
|
|
*/
|
|
public void deregisterAll(Class<?> category) {
|
|
SubRegistry reg = categoryMap.get(category);
|
|
if (reg == null) {
|
|
throw new IllegalArgumentException("category unknown!");
|
|
}
|
|
reg.clear();
|
|
}
|
|
|
|
/**
|
|
* Deregisters all currently registered service providers from all
|
|
* categories.
|
|
*/
|
|
public void deregisterAll() {
|
|
for (SubRegistry reg : categoryMap.values()) {
|
|
reg.clear();
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Finalizes this object prior to garbage collection. The
|
|
* {@code deregisterAll} method is called to deregister all
|
|
* currently registered service providers. This method should not
|
|
* be called from application code.
|
|
*
|
|
* @throws Throwable if an error occurs during superclass
|
|
* finalization.
|
|
*
|
|
* @deprecated Finalization has been deprecated for removal. See
|
|
* {@link java.lang.Object#finalize} for background information and details
|
|
* about migration options.
|
|
*/
|
|
@Deprecated(since="9", forRemoval=true)
|
|
@SuppressWarnings("removal")
|
|
public void finalize() throws Throwable {
|
|
deregisterAll();
|
|
super.finalize();
|
|
}
|
|
|
|
/**
|
|
* Checks whether the provided class is one of the allowed
|
|
* ImageIO service provider classes. If it is, returns normally.
|
|
* If it is not, throws IllegalArgumentException.
|
|
*
|
|
* @param clazz
|
|
* @throws IllegalArgumentException if clazz is null or is not one of the allowed set
|
|
*/
|
|
private static void checkClassAllowed(Class<?> clazz) {
|
|
if (clazz == null) {
|
|
throw new IllegalArgumentException("class must not be null");
|
|
}
|
|
|
|
if ( clazz != ImageInputStreamSpi.class
|
|
&& clazz != ImageOutputStreamSpi.class
|
|
&& clazz != ImageReaderSpi.class
|
|
&& clazz != ImageTranscoderSpi.class
|
|
&& clazz != ImageWriterSpi.class) {
|
|
throw new IllegalArgumentException(clazz.getName() + " is not an ImageIO SPI class");
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/**
|
|
* A portion of a registry dealing with a single superclass or
|
|
* interface.
|
|
*/
|
|
class SubRegistry {
|
|
|
|
ServiceRegistry registry;
|
|
|
|
Class<?> category;
|
|
|
|
// Provider Objects organized by partial ordering
|
|
final PartiallyOrderedSet<Object> poset = new PartiallyOrderedSet<>();
|
|
|
|
// Class -> Provider Object of that class
|
|
// No way to express heterogeneous map, we want
|
|
// Map<Class<T>, T>, where T is ?
|
|
final Map<Class<?>, Object> map = new HashMap<>();
|
|
@SuppressWarnings("removal")
|
|
final Map<Class<?>, AccessControlContext> accMap = new HashMap<>();
|
|
|
|
public SubRegistry(ServiceRegistry registry, Class<?> category) {
|
|
this.registry = registry;
|
|
this.category = category;
|
|
}
|
|
|
|
@SuppressWarnings("removal")
|
|
public synchronized boolean registerServiceProvider(Object provider) {
|
|
Object oprovider = map.get(provider.getClass());
|
|
boolean present = oprovider != null;
|
|
|
|
if (present) {
|
|
deregisterServiceProvider(oprovider);
|
|
}
|
|
map.put(provider.getClass(), provider);
|
|
accMap.put(provider.getClass(), AccessController.getContext());
|
|
poset.add(provider);
|
|
if (provider instanceof RegisterableService) {
|
|
RegisterableService rs = (RegisterableService)provider;
|
|
try {
|
|
rs.onRegistration(registry, category);
|
|
} catch (Throwable t) {
|
|
System.err.println("Caught and handled this exception :");
|
|
t.printStackTrace();
|
|
}
|
|
}
|
|
|
|
return !present;
|
|
}
|
|
|
|
/**
|
|
* If the provider was not previously registered, do nothing.
|
|
*
|
|
* @return true if the provider was previously registered.
|
|
*/
|
|
public synchronized boolean deregisterServiceProvider(Object provider) {
|
|
Object oprovider = map.get(provider.getClass());
|
|
|
|
if (provider == oprovider) {
|
|
map.remove(provider.getClass());
|
|
accMap.remove(provider.getClass());
|
|
poset.remove(provider);
|
|
if (provider instanceof RegisterableService) {
|
|
RegisterableService rs = (RegisterableService)provider;
|
|
rs.onDeregistration(registry, category);
|
|
}
|
|
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
public synchronized boolean contains(Object provider) {
|
|
Object oprovider = map.get(provider.getClass());
|
|
return oprovider == provider;
|
|
}
|
|
|
|
public synchronized boolean setOrdering(Object firstProvider,
|
|
Object secondProvider) {
|
|
return poset.setOrdering(firstProvider, secondProvider);
|
|
}
|
|
|
|
public synchronized boolean unsetOrdering(Object firstProvider,
|
|
Object secondProvider) {
|
|
return poset.unsetOrdering(firstProvider, secondProvider);
|
|
}
|
|
|
|
public synchronized Iterator<Object> getServiceProviders
|
|
(boolean useOrdering) {
|
|
if (useOrdering) {
|
|
return poset.iterator();
|
|
} else {
|
|
return map.values().iterator();
|
|
}
|
|
}
|
|
|
|
@SuppressWarnings("unchecked")
|
|
public synchronized <T> T getServiceProviderByClass
|
|
(Class<T> providerClass) {
|
|
return (T)map.get(providerClass);
|
|
}
|
|
|
|
@SuppressWarnings("removal")
|
|
public synchronized void clear() {
|
|
Iterator<Object> iter = map.values().iterator();
|
|
while (iter.hasNext()) {
|
|
Object provider = iter.next();
|
|
iter.remove();
|
|
|
|
if (provider instanceof RegisterableService) {
|
|
RegisterableService rs = (RegisterableService)provider;
|
|
AccessControlContext acc = accMap.get(provider.getClass());
|
|
if (acc != null || System.getSecurityManager() == null) {
|
|
AccessController.doPrivileged((PrivilegedAction<Void>) () -> {
|
|
rs.onDeregistration(registry, category);
|
|
return null;
|
|
}, acc);
|
|
}
|
|
}
|
|
}
|
|
poset.clear();
|
|
accMap.clear();
|
|
}
|
|
|
|
@SuppressWarnings("removal")
|
|
public synchronized void finalize() {
|
|
clear();
|
|
}
|
|
}
|
|
|
|
|
|
/**
|
|
* A class for wrapping {@code Iterators} with a filter function.
|
|
* This provides an iterator for a subset without duplication.
|
|
*/
|
|
class FilterIterator<T> implements Iterator<T> {
|
|
|
|
private Iterator<? extends T> iter;
|
|
private ServiceRegistry.Filter filter;
|
|
|
|
private T next = null;
|
|
|
|
public FilterIterator(Iterator<? extends T> iter,
|
|
ServiceRegistry.Filter filter) {
|
|
this.iter = iter;
|
|
this.filter = filter;
|
|
advance();
|
|
}
|
|
|
|
private void advance() {
|
|
while (iter.hasNext()) {
|
|
T elt = iter.next();
|
|
if (filter.filter(elt)) {
|
|
next = elt;
|
|
return;
|
|
}
|
|
}
|
|
|
|
next = null;
|
|
}
|
|
|
|
public boolean hasNext() {
|
|
return next != null;
|
|
}
|
|
|
|
public T next() {
|
|
if (next == null) {
|
|
throw new NoSuchElementException();
|
|
}
|
|
T o = next;
|
|
advance();
|
|
return o;
|
|
}
|
|
|
|
public void remove() {
|
|
throw new UnsupportedOperationException();
|
|
}
|
|
}
|