jdk/src/share/classes/javax/imageio/spi/ImageOutputStreamSpi.java
changeset 2 90ce3da70b43
child 5506 202f599c92aa
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/javax/imageio/spi/ImageOutputStreamSpi.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,200 @@
+/*
+ * Copyright 2000-2004 Sun Microsystems, Inc.  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.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package javax.imageio.spi;
+
+import java.io.File;
+import java.io.IOException;
+import javax.imageio.stream.ImageOutputStream;
+
+/**
+ * The service provider interface (SPI) for
+ * <code>ImageOutputStream</code>s.  For more information on service
+ * provider interfaces, see the class comment for the
+ * <code>IIORegistry</code> class.
+ *
+ * <p> This interface allows arbitrary objects to be "wrapped" by
+ * instances of <code>ImageOutputStream</code>.  For example, a
+ * particular <code>ImageOutputStreamSpi</code> might allow a generic
+ * <code>OutputStream</code> to be used as a destination; another
+ * might output to a <code>File</code> or to a device such as a serial
+ * port.
+ *
+ * <p> By treating the creation of <code>ImageOutputStream</code>s as
+ * a pluggable service, it becomes possible to handle future output
+ * destinations without changing the API.  Also, high-performance
+ * implementations of <code>ImageOutputStream</code> (for example,
+ * native implementations for a particular platform) can be installed
+ * and used transparently by applications.
+ *
+ * @see IIORegistry
+ * @see javax.imageio.stream.ImageOutputStream
+ *
+ */
+public abstract class ImageOutputStreamSpi extends IIOServiceProvider {
+
+    /**
+     * A <code>Class</code> object indicating the legal object type
+     * for use by the <code>createInputStreamInstance</code> method.
+     */
+    protected Class<?> outputClass;
+
+    /**
+     * Constructs a blank <code>ImageOutputStreamSpi</code>.  It is up
+     * to the subclass to initialize instance variables and/or
+     * override method implementations in order to provide working
+     * versions of all methods.
+     */
+    protected ImageOutputStreamSpi() {
+    }
+
+    /**
+     * Constructs an <code>ImageOutputStreamSpi</code> with a given
+     * set of values.
+     *
+     * @param vendorName the vendor name.
+     * @param version a version identifier.
+     * @param outputClass a <code>Class</code> object indicating the
+     * legal object type for use by the
+     * <code>createOutputStreamInstance</code> method.
+     *
+     * @exception IllegalArgumentException if <code>vendorName</code>
+     * is <code>null</code>.
+     * @exception IllegalArgumentException if <code>version</code>
+     * is <code>null</code>.
+    */
+    public ImageOutputStreamSpi(String vendorName,
+                                String version,
+                                Class<?> outputClass) {
+        super(vendorName, version);
+        this.outputClass = outputClass;
+    }
+
+    /**
+     * Returns a <code>Class</code> object representing the class or
+     * interface type that must be implemented by an output
+     * destination in order to be "wrapped" in an
+     * <code>ImageOutputStream</code> via the
+     * <code>createOutputStreamInstance</code> method.
+     *
+     * <p> Typical return values might include
+     * <code>OutputStream.class</code> or <code>File.class</code>, but
+     * any class may be used.
+     *
+     * @return a <code>Class</code> variable.
+     *
+     * @see #createOutputStreamInstance(Object, boolean, File)
+     */
+    public Class<?> getOutputClass() {
+        return outputClass;
+    }
+
+    /**
+     * Returns <code>true</code> if the <code>ImageOutputStream</code>
+     * implementation associated with this service provider can
+     * optionally make use of a cache <code>File</code> for improved
+     * performance and/or memory footrprint.  If <code>false</code>,
+     * the value of the <code>cacheFile</code> argument to
+     * <code>createOutputStreamInstance</code> will be ignored.
+     *
+     * <p> The default implementation returns <code>false</code>.
+     *
+     * @return <code>true</code> if a cache file can be used by the
+     * output streams created by this service provider.
+     */
+    public boolean canUseCacheFile() {
+        return false;
+    }
+
+    /**
+     * Returns <code>true</code> if the <code>ImageOutputStream</code>
+     * implementation associated with this service provider requires
+     * the use of a cache <code>File</code>.
+     *
+     * <p> The default implementation returns <code>false</code>.
+     *
+     * @return <code>true</code> if a cache file is needed by the
+     * output streams created by this service provider.
+     */
+    public boolean needsCacheFile() {
+        return false;
+    }
+
+    /**
+     * Returns an instance of the <code>ImageOutputStream</code>
+     * implementation associated with this service provider.  If the
+     * use of a cache file is optional, the <code>useCache</code>
+     * parameter will be consulted.  Where a cache is required, or
+     * not applicable, the value of <code>useCache</code> will be ignored.
+     *
+     * @param output an object of the class type returned by
+     * <code>getOutputClass</code>.
+     * @param useCache a <code>boolean</code> indicating whether a
+     * cache file should be used, in cases where it is optional.
+     * @param cacheDir a <code>File</code> indicating where the
+     * cache file should be created, or <code>null</code> to use the
+     * system directory.
+     *
+     * @return an <code>ImageOutputStream</code> instance.
+     *
+     * @exception IllegalArgumentException if <code>output</code> is
+     * not an instance of the correct class or is <code>null</code>.
+     * @exception IllegalArgumentException if a cache file is needed,
+     * but <code>cacheDir</code> is non-<code>null</code> and is not a
+     * directory.
+     * @exception IOException if a cache file is needed but cannot be
+     * created.
+     *
+     * @see #getOutputClass
+     */
+    public abstract
+        ImageOutputStream createOutputStreamInstance(Object output,
+                                                     boolean useCache,
+                                                     File cacheDir)
+        throws IOException;
+
+    /**
+     * Returns an instance of the <code>ImageOutputStream</code>
+     * implementation associated with this service provider.  A cache
+     * file will be created in the system-dependent default
+     * temporary-file directory, if needed.
+     *
+     * @param output an object of the class type returned by
+     * <code>getOutputClass</code>.
+     *
+     * @return an <code>ImageOutputStream</code> instance.
+     *
+     * @exception IllegalArgumentException if <code>output</code> is
+     * not an instance of the correct class or is <code>null</code>.
+     * @exception IOException if a cache file is needed but cannot be
+     * created.
+     *
+     * @see #getOutputClass()
+     */
+    public ImageOutputStream createOutputStreamInstance(Object output)
+        throws IOException {
+        return createOutputStreamInstance(output, true, null);
+    }
+}