Java tutorial
/* * Copyright (c) 2000, 2013, 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.event; import java.util.EventListener; import javax.imageio.ImageReader; /** * An interface used by {@code ImageReader} implementations to * notify callers of their image and thumbnail reading methods of * progress. * * <p> This interface receives general indications of decoding * progress (via the {@code imageProgress} and * {@code thumbnailProgress} methods), and events indicating when * an entire image has been updated (via the * {@code imageStarted}, {@code imageComplete}, * {@code thumbnailStarted} and {@code thumbnailComplete} * methods). Applications that wish to be informed of pixel updates * as they happen (for example, during progressive decoding), should * provide an {@code IIOReadUpdateListener}. * * @see IIOReadUpdateListener * @see javax.imageio.ImageReader#addIIOReadProgressListener * @see javax.imageio.ImageReader#removeIIOReadProgressListener * */ public interface IIOReadProgressListener extends EventListener { /** * Reports that a sequence of read operations is beginning. * {@code ImageReader} implementations are required to call * this method exactly once from their * {@code readAll(Iterator)} method. * * @param source the {@code ImageReader} object calling this method. * @param minIndex the index of the first image to be read. */ void sequenceStarted(ImageReader source, int minIndex); /** * Reports that a sequence of read operations has completed. * {@code ImageReader} implementations are required to call * this method exactly once from their * {@code readAll(Iterator)} method. * * @param source the {@code ImageReader} object calling this method. */ void sequenceComplete(ImageReader source); /** * Reports that an image read operation is beginning. All * {@code ImageReader} implementations are required to call * this method exactly once when beginning an image read * operation. * * @param source the {@code ImageReader} object calling this method. * @param imageIndex the index of the image being read within its * containing input file or stream. */ void imageStarted(ImageReader source, int imageIndex); /** * Reports the approximate degree of completion of the current * {@code read} call of the associated * {@code ImageReader}. * * <p> The degree of completion is expressed as a percentage * varying from {@code 0.0F} to {@code 100.0F}. The * percentage should ideally be calculated in terms of the * remaining time to completion, but it is usually more practical * to use a more well-defined metric such as pixels decoded or * portion of input stream consumed. In any case, a sequence of * calls to this method during a given read operation should * supply a monotonically increasing sequence of percentage * values. It is not necessary to supply the exact values * {@code 0} and {@code 100}, as these may be inferred * by the callee from other methods. * * <p> Each particular {@code ImageReader} implementation may * call this method at whatever frequency it desires. A rule of * thumb is to call it around each 5 percent mark. * * @param source the {@code ImageReader} object calling this method. * @param percentageDone the approximate percentage of decoding that * has been completed. */ void imageProgress(ImageReader source, float percentageDone); /** * Reports that the current image read operation has completed. * All {@code ImageReader} implementations are required to * call this method exactly once upon completion of each image * read operation. * * @param source the {@code ImageReader} object calling this * method. */ void imageComplete(ImageReader source); /** * Reports that a thumbnail read operation is beginning. All * {@code ImageReader} implementations are required to call * this method exactly once when beginning a thumbnail read * operation. * * @param source the {@code ImageReader} object calling this method. * @param imageIndex the index of the image being read within its * containing input file or stream. * @param thumbnailIndex the index of the thumbnail being read. */ void thumbnailStarted(ImageReader source, int imageIndex, int thumbnailIndex); /** * Reports the approximate degree of completion of the current * {@code getThumbnail} call within the associated * {@code ImageReader}. The semantics are identical to those * of {@code imageProgress}. * * @param source the {@code ImageReader} object calling this method. * @param percentageDone the approximate percentage of decoding that * has been completed. */ void thumbnailProgress(ImageReader source, float percentageDone); /** * Reports that a thumbnail read operation has completed. All * {@code ImageReader} implementations are required to call * this method exactly once upon completion of each thumbnail read * operation. * * @param source the {@code ImageReader} object calling this * method. */ void thumbnailComplete(ImageReader source); /** * Reports that a read has been aborted via the reader's * {@code abort} method. No further notifications will be * given. * * @param source the {@code ImageReader} object calling this * method. */ void readAborted(ImageReader source); }