Java tutorial
/* * Copyright (c) 2000, 2004, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javax.imageio.spi; import java.util.Locale; import javax.imageio.spi.RegisterableService; import javax.imageio.spi.ServiceRegistry; /** * A superinterface for functionality common to all Image I/O service * provider interfaces (SPIs). For more information on service * provider classes, see the class comment for the * {@code IIORegistry} class. * * @see IIORegistry * @see javax.imageio.spi.ImageReaderSpi * @see javax.imageio.spi.ImageWriterSpi * @see javax.imageio.spi.ImageTranscoderSpi * @see javax.imageio.spi.ImageInputStreamSpi * @see javax.imageio.spi.ImageOutputStreamSpi */ public abstract class IIOServiceProvider implements RegisterableService { /** * A {@code String} to be returned from * {@code getVendorName}, initially {@code null}. * Constructors should set this to a non-{@code null} value. */ protected String vendorName; /** * A {@code String} to be returned from * {@code getVersion}, initially null. Constructors should * set this to a non-{@code null} value. */ protected String version; /** * Constructs an {@code IIOServiceProvider} with a given * vendor name and version identifier. * * @param vendorName the vendor name. * @param version a version identifier. * * @exception IllegalArgumentException if {@code vendorName} * is {@code null}. * @exception IllegalArgumentException if {@code version} * is {@code null}. */ public IIOServiceProvider(String vendorName, String version) { if (vendorName == null) { throw new IllegalArgumentException("vendorName == null!"); } if (version == null) { throw new IllegalArgumentException("version == null!"); } this.vendorName = vendorName; this.version = version; } /** * Constructs a blank {@code IIOServiceProvider}. It is up * to the subclass to initialize instance variables and/or * override method implementations in order to ensure that the * {@code getVendorName} and {@code getVersion} methods * will return non-{@code null} values. */ public IIOServiceProvider() { } /** * A callback that will be called exactly once after the Spi class * has been instantiated and registered in a * {@code ServiceRegistry}. This may be used to verify that * the environment is suitable for this service, for example that * native libraries can be loaded. If the service cannot function * in the environment where it finds itself, it should deregister * itself from the registry. * * <p> Only the registry should call this method. * * <p> The default implementation does nothing. * * @see ServiceRegistry#registerServiceProvider(Object provider) */ public void onRegistration(ServiceRegistry registry, Class<?> category) { } /** * A callback that will be whenever the Spi class has been * deregistered from a {@code ServiceRegistry}. * * <p> Only the registry should call this method. * * <p> The default implementation does nothing. * * @see ServiceRegistry#deregisterServiceProvider(Object provider) */ public void onDeregistration(ServiceRegistry registry, Class<?> category) { } /** * Returns the name of the vendor responsible for creating this * service provider and its associated implementation. Because * the vendor name may be used to select a service provider, * it is not localized. * * <p> The default implementation returns the value of the * {@code vendorName} instance variable. * * @return a non-{@code null String} containing * the name of the vendor. */ public String getVendorName() { return vendorName; } /** * Returns a string describing the version * number of this service provider and its associated * implementation. Because the version may be used by transcoders * to identify the service providers they understand, this method * is not localized. * * <p> The default implementation returns the value of the * {@code version} instance variable. * * @return a non-{@code null String} containing * the version of this service provider. */ public String getVersion() { return version; } /** * Returns a brief, human-readable description of this service * provider and its associated implementation. The resulting * string should be localized for the supplied * {@code Locale}, if possible. * * @param locale a {@code Locale} for which the return value * should be localized. * * @return a {@code String} containing a description of this * service provider. */ public abstract String getDescription(Locale locale); }