MediaTracker class is a utility class to track
+ * the status of a number of media objects. Media objects could
+ * include audio clips as well as images, though currently only
+ * images are supported.
+ *
+ * To use a media tracker, create an instance of
+ * MediaTracker and call its addImage
+ * method for each image to be tracked. In addition, each image can
+ * be assigned a unique identifier. This identifier controls the
+ * priority order in which the images are fetched. It can also be used
+ * to identify unique subsets of the images that can be waited on
+ * independently. Images with a lower ID are loaded in preference to
+ * those with a higher ID number.
+ *
+ *
+ *
+ * Tracking an animated image
+ * might not always be useful
+ * due to the multi-part nature of animated image
+ * loading and painting,
+ * but it is supported.
+ * MediaTracker treats an animated image
+ * as completely loaded
+ * when the first frame is completely loaded.
+ * At that point, the MediaTracker
+ * signals any waiters
+ * that the image is completely loaded.
+ * If no ImageObservers are observing the image
+ * when the first frame has finished loading,
+ * the image might flush itself
+ * to conserve resources
+ * (see {@link Image#flush()}).
+ *
+ *
+ * Here is an example of using MediaTracker:
+ *
+ *
+ * import java.applet.Applet;
+ * import java.awt.Color;
+ * import java.awt.Image;
+ * import java.awt.Graphics;
+ * import java.awt.MediaTracker;
+ *
+ * public class ImageBlaster extends Applet implements Runnable {
+ * MediaTracker tracker;
+ * Image bg;
+ * Image anim[] = new Image[5];
+ * int index;
+ * Thread animator;
+ *
+ * // Get the images for the background (id == 0)
+ * // and the animation frames (id == 1)
+ * // and add them to the MediaTracker
+ * public void init() {
+ * tracker = new MediaTracker(this);
+ * bg = getImage(getDocumentBase(),
+ * "images/background.gif");
+ * tracker.addImage(bg, 0);
+ * for (int i = 0; i < 5; i++) {
+ * anim[i] = getImage(getDocumentBase(),
+ * "images/anim"+i+".gif");
+ * tracker.addImage(anim[i], 1);
+ * }
+ * }
+ *
+ * // Start the animation thread.
+ * public void start() {
+ * animator = new Thread(this);
+ * animator.start();
+ * }
+ *
+ * // Stop the animation thread.
+ * public void stop() {
+ * animator = null;
+ * }
+ *
+ * // Run the animation thread.
+ * // First wait for the background image to fully load
+ * // and paint. Then wait for all of the animation
+ * // frames to finish loading. Finally, loop and
+ * // increment the animation frame index.
+ * public void run() {
+ * try {
+ * tracker.waitForID(0);
+ * tracker.waitForID(1);
+ * } catch (InterruptedException e) {
+ * return;
+ * }
+ * Thread me = Thread.currentThread();
+ * while (animator == me) {
+ * try {
+ * Thread.sleep(100);
+ * } catch (InterruptedException e) {
+ * break;
+ * }
+ * synchronized (this) {
+ * index++;
+ * if (index >= anim.length) {
+ * index = 0;
+ * }
+ * }
+ * repaint();
+ * }
+ * }
+ *
+ * // The background image fills the frame so we
+ * // don't need to clear the applet on repaints.
+ * // Just call the paint method.
+ * public void update(Graphics g) {
+ * paint(g);
+ * }
+ *
+ * // Paint a large red rectangle if there are any errors
+ * // loading the images. Otherwise always paint the
+ * // background so that it appears incrementally as it
+ * // is loading. Finally, only paint the current animation
+ * // frame if all of the frames (id == 1) are done loading,
+ * // so that we don't get partial animations.
+ * public void paint(Graphics g) {
+ * if ((tracker.statusAll(false) & MediaTracker.ERRORED) != 0) {
+ * g.setColor(Color.red);
+ * g.fillRect(0, 0, size().width, size().height);
+ * return;
+ * }
+ * g.drawImage(bg, 0, 0, this);
+ * if (tracker.statusID(1, false) == MediaTracker.COMPLETE) {
+ * g.drawImage(anim[index], 10, 10, this);
+ * }
+ * }
+ * }
+ * Component that will be
+ * tracked by a media tracker where the image will
+ * eventually be drawn.
+ *
+ * @serial
+ * @see #MediaTracker(Component)
+ */
+ Component target;
+ /**
+ * The head of the list of Images that is being
+ * tracked by the MediaTracker.
+ *
+ * @serial
+ * @see #addImage(Image, int)
+ * @see #removeImage(Image)
+ */
+ MediaEntry head;
+
+ /*
+ * JDK 1.1 serialVersionUID
+ */
+ private static final long serialVersionUID = -483174189758638095L;
+
+ /**
+ * Creates a media tracker to track images for a given component.
+ * @param comp the component on which the images
+ * will eventually be drawn
+ */
+ public MediaTracker(Component comp) {
+ target = comp;
+ }
+
+ /**
+ * Adds an image to the list of images being tracked by this media
+ * tracker. The image will eventually be rendered at its default
+ * (unscaled) size.
+ * @param image the image to be tracked
+ * @param id an identifier used to track this image
+ */
+ public void addImage(Image image, int id) {
+ addImage(image, id, -1, -1);
+ }
+
+ /**
+ * Adds a scaled image to the list of images being tracked
+ * by this media tracker. The image will eventually be
+ * rendered at the indicated width and height.
+ *
+ * @param image the image to be tracked
+ * @param id an identifier that can be used to track this image
+ * @param w the width at which the image is rendered
+ * @param h the height at which the image is rendered
+ */
+ public synchronized void addImage(Image image, int id, int w, int h) {
+ head = MediaEntry.insert(head,
+ new ImageMediaEntry(this, image, id, w, h));
+ }
+
+ /**
+ * Flag indicating that media is currently being loaded.
+ * @see java.awt.MediaTracker#statusAll
+ * @see java.awt.MediaTracker#statusID
+ */
+ public static final int LOADING = 1;
+
+ /**
+ * Flag indicating that the downloading of media was aborted.
+ * @see java.awt.MediaTracker#statusAll
+ * @see java.awt.MediaTracker#statusID
+ */
+ public static final int ABORTED = 2;
+
+ /**
+ * Flag indicating that the downloading of media encountered
+ * an error.
+ * @see java.awt.MediaTracker#statusAll
+ * @see java.awt.MediaTracker#statusID
+ */
+ public static final int ERRORED = 4;
+
+ /**
+ * Flag indicating that the downloading of media was completed
+ * successfully.
+ * @see java.awt.MediaTracker#statusAll
+ * @see java.awt.MediaTracker#statusID
+ */
+ public static final int COMPLETE = 8;
+
+ static final int DONE = (ABORTED | ERRORED | COMPLETE);
+
+ /**
+ * Checks to see if all images being tracked by this media tracker
+ * have finished loading.
+ * + * This method does not start loading the images if they are not + * already loading. + *
+ * If there is an error while loading or scaling an image, then that
+ * image is considered to have finished loading. Use the
+ * isErrorAny or isErrorID methods to
+ * check for errors.
+ * @return true if all images have finished loading,
+ * have been aborted, or have encountered
+ * an error; false otherwise
+ * @see java.awt.MediaTracker#checkAll(boolean)
+ * @see java.awt.MediaTracker#checkID
+ * @see java.awt.MediaTracker#isErrorAny
+ * @see java.awt.MediaTracker#isErrorID
+ */
+ public boolean checkAll() {
+ return checkAll(false, true);
+ }
+
+ /**
+ * Checks to see if all images being tracked by this media tracker
+ * have finished loading.
+ *
+ * If the value of the load flag is true,
+ * then this method starts loading any images that are not yet
+ * being loaded.
+ *
+ * If there is an error while loading or scaling an image, that
+ * image is considered to have finished loading. Use the
+ * isErrorAny and isErrorID methods to
+ * check for errors.
+ * @param load if true, start loading any
+ * images that are not yet being loaded
+ * @return true if all images have finished loading,
+ * have been aborted, or have encountered
+ * an error; false otherwise
+ * @see java.awt.MediaTracker#checkID
+ * @see java.awt.MediaTracker#checkAll()
+ * @see java.awt.MediaTracker#isErrorAny()
+ * @see java.awt.MediaTracker#isErrorID(int)
+ */
+ public boolean checkAll(boolean load) {
+ return checkAll(load, true);
+ }
+
+ private synchronized boolean checkAll(boolean load, boolean verify) {
+ MediaEntry cur = head;
+ boolean done = true;
+ while (cur != null) {
+ if ((cur.getStatus(load, verify) & DONE) == 0) {
+ done = false;
+ }
+ cur = cur.next;
+ }
+ return done;
+ }
+
+ /**
+ * Checks the error status of all of the images.
+ * @return true if any of the images tracked
+ * by this media tracker had an error during
+ * loading; false otherwise
+ * @see java.awt.MediaTracker#isErrorID
+ * @see java.awt.MediaTracker#getErrorsAny
+ */
+ public synchronized boolean isErrorAny() {
+ MediaEntry cur = head;
+ while (cur != null) {
+ if ((cur.getStatus(false, true) & ERRORED) != 0) {
+ return true;
+ }
+ cur = cur.next;
+ }
+ return false;
+ }
+
+ /**
+ * Returns a list of all media that have encountered an error.
+ * @return an array of media objects tracked by this
+ * media tracker that have encountered
+ * an error, or null if
+ * there are none with errors
+ * @see java.awt.MediaTracker#isErrorAny
+ * @see java.awt.MediaTracker#getErrorsID
+ */
+ public synchronized Object[] getErrorsAny() {
+ MediaEntry cur = head;
+ int numerrors = 0;
+ while (cur != null) {
+ if ((cur.getStatus(false, true) & ERRORED) != 0) {
+ numerrors++;
+ }
+ cur = cur.next;
+ }
+ if (numerrors == 0) {
+ return null;
+ }
+ Object errors[] = new Object[numerrors];
+ cur = head;
+ numerrors = 0;
+ while (cur != null) {
+ if ((cur.getStatus(false, false) & ERRORED) != 0) {
+ errors[numerrors++] = cur.getMedia();
+ }
+ cur = cur.next;
+ }
+ return errors;
+ }
+
+ /**
+ * Starts loading all images tracked by this media tracker. This
+ * method waits until all the images being tracked have finished
+ * loading.
+ *
+ * If there is an error while loading or scaling an image, then that
+ * image is considered to have finished loading. Use the
+ * isErrorAny or isErrorID methods to
+ * check for errors.
+ * @see java.awt.MediaTracker#waitForID(int)
+ * @see java.awt.MediaTracker#waitForAll(long)
+ * @see java.awt.MediaTracker#isErrorAny
+ * @see java.awt.MediaTracker#isErrorID
+ * @exception InterruptedException if any thread has
+ * interrupted this thread
+ */
+ public void waitForAll() throws InterruptedException {
+ waitForAll(0);
+ }
+
+ /**
+ * Starts loading all images tracked by this media tracker. This
+ * method waits until all the images being tracked have finished
+ * loading, or until the length of time specified in milliseconds
+ * by the ms argument has passed.
+ *
+ * If there is an error while loading or scaling an image, then
+ * that image is considered to have finished loading. Use the
+ * isErrorAny or isErrorID methods to
+ * check for errors.
+ * @param ms the number of milliseconds to wait
+ * for the loading to complete
+ * @return true if all images were successfully
+ * loaded; false otherwise
+ * @see java.awt.MediaTracker#waitForID(int)
+ * @see java.awt.MediaTracker#waitForAll(long)
+ * @see java.awt.MediaTracker#isErrorAny
+ * @see java.awt.MediaTracker#isErrorID
+ * @exception InterruptedException if any thread has
+ * interrupted this thread.
+ */
+ public synchronized boolean waitForAll(long ms)
+ throws InterruptedException
+ {
+ long end = System.currentTimeMillis() + ms;
+ boolean first = true;
+ while (true) {
+ int status = statusAll(first, first);
+ if ((status & LOADING) == 0) {
+ return (status == COMPLETE);
+ }
+ first = false;
+ long timeout;
+ if (ms == 0) {
+ timeout = 0;
+ } else {
+ timeout = end - System.currentTimeMillis();
+ if (timeout <= 0) {
+ return false;
+ }
+ }
+ wait(timeout);
+ }
+ }
+
+ /**
+ * Calculates and returns the bitwise inclusive OR of the
+ * status of all media that are tracked by this media tracker.
+ *
+ * Possible flags defined by the
+ * MediaTracker class are LOADING,
+ * ABORTED, ERRORED, and
+ * COMPLETE. An image that hasn't started
+ * loading has zero as its status.
+ *
+ * If the value of load is true, then
+ * this method starts loading any images that are not yet being loaded.
+ *
+ * @param load if true, start loading
+ * any images that are not yet being loaded
+ * @return the bitwise inclusive OR of the status of
+ * all of the media being tracked
+ * @see java.awt.MediaTracker#statusID(int, boolean)
+ * @see java.awt.MediaTracker#LOADING
+ * @see java.awt.MediaTracker#ABORTED
+ * @see java.awt.MediaTracker#ERRORED
+ * @see java.awt.MediaTracker#COMPLETE
+ */
+ public int statusAll(boolean load) {
+ return statusAll(load, true);
+ }
+
+ private synchronized int statusAll(boolean load, boolean verify) {
+ MediaEntry cur = head;
+ int status = 0;
+ while (cur != null) {
+ status = status | cur.getStatus(load, verify);
+ cur = cur.next;
+ }
+ return status;
+ }
+
+ /**
+ * Checks to see if all images tracked by this media tracker that
+ * are tagged with the specified identifier have finished loading.
+ *
+ * This method does not start loading the images if they are not + * already loading. + *
+ * If there is an error while loading or scaling an image, then that
+ * image is considered to have finished loading. Use the
+ * isErrorAny or isErrorID methods to
+ * check for errors.
+ * @param id the identifier of the images to check
+ * @return true if all images have finished loading,
+ * have been aborted, or have encountered
+ * an error; false otherwise
+ * @see java.awt.MediaTracker#checkID(int, boolean)
+ * @see java.awt.MediaTracker#checkAll()
+ * @see java.awt.MediaTracker#isErrorAny()
+ * @see java.awt.MediaTracker#isErrorID(int)
+ */
+ public boolean checkID(int id) {
+ return checkID(id, false, true);
+ }
+
+ /**
+ * Checks to see if all images tracked by this media tracker that
+ * are tagged with the specified identifier have finished loading.
+ *
+ * If the value of the load flag is true,
+ * then this method starts loading any images that are not yet
+ * being loaded.
+ *
+ * If there is an error while loading or scaling an image, then that
+ * image is considered to have finished loading. Use the
+ * isErrorAny or isErrorID methods to
+ * check for errors.
+ * @param id the identifier of the images to check
+ * @param load if true, start loading any
+ * images that are not yet being loaded
+ * @return true if all images have finished loading,
+ * have been aborted, or have encountered
+ * an error; false otherwise
+ * @see java.awt.MediaTracker#checkID(int, boolean)
+ * @see java.awt.MediaTracker#checkAll()
+ * @see java.awt.MediaTracker#isErrorAny()
+ * @see java.awt.MediaTracker#isErrorID(int)
+ */
+ public boolean checkID(int id, boolean load) {
+ return checkID(id, load, true);
+ }
+
+ private synchronized boolean checkID(int id, boolean load, boolean verify)
+ {
+ MediaEntry cur = head;
+ boolean done = true;
+ while (cur != null) {
+ if (cur.getID() == id
+ && (cur.getStatus(load, verify) & DONE) == 0)
+ {
+ done = false;
+ }
+ cur = cur.next;
+ }
+ return done;
+ }
+
+ /**
+ * Checks the error status of all of the images tracked by this
+ * media tracker with the specified identifier.
+ * @param id the identifier of the images to check
+ * @return true if any of the images with the
+ * specified identifier had an error during
+ * loading; false otherwise
+ * @see java.awt.MediaTracker#isErrorAny
+ * @see java.awt.MediaTracker#getErrorsID
+ */
+ public synchronized boolean isErrorID(int id) {
+ MediaEntry cur = head;
+ while (cur != null) {
+ if (cur.getID() == id
+ && (cur.getStatus(false, true) & ERRORED) != 0)
+ {
+ return true;
+ }
+ cur = cur.next;
+ }
+ return false;
+ }
+
+ /**
+ * Returns a list of media with the specified ID that
+ * have encountered an error.
+ * @param id the identifier of the images to check
+ * @return an array of media objects tracked by this media
+ * tracker with the specified identifier
+ * that have encountered an error, or
+ * null if there are none with errors
+ * @see java.awt.MediaTracker#isErrorID
+ * @see java.awt.MediaTracker#isErrorAny
+ * @see java.awt.MediaTracker#getErrorsAny
+ */
+ public synchronized Object[] getErrorsID(int id) {
+ MediaEntry cur = head;
+ int numerrors = 0;
+ while (cur != null) {
+ if (cur.getID() == id
+ && (cur.getStatus(false, true) & ERRORED) != 0)
+ {
+ numerrors++;
+ }
+ cur = cur.next;
+ }
+ if (numerrors == 0) {
+ return null;
+ }
+ Object errors[] = new Object[numerrors];
+ cur = head;
+ numerrors = 0;
+ while (cur != null) {
+ if (cur.getID() == id
+ && (cur.getStatus(false, false) & ERRORED) != 0)
+ {
+ errors[numerrors++] = cur.getMedia();
+ }
+ cur = cur.next;
+ }
+ return errors;
+ }
+
+ /**
+ * Starts loading all images tracked by this media tracker with the
+ * specified identifier. This method waits until all the images with
+ * the specified identifier have finished loading.
+ *
+ * If there is an error while loading or scaling an image, then that
+ * image is considered to have finished loading. Use the
+ * isErrorAny and isErrorID methods to
+ * check for errors.
+ * @param id the identifier of the images to check
+ * @see java.awt.MediaTracker#waitForAll
+ * @see java.awt.MediaTracker#isErrorAny()
+ * @see java.awt.MediaTracker#isErrorID(int)
+ * @exception InterruptedException if any thread has
+ * interrupted this thread.
+ */
+ public void waitForID(int id) throws InterruptedException {
+ waitForID(id, 0);
+ }
+
+ /**
+ * Starts loading all images tracked by this media tracker with the
+ * specified identifier. This method waits until all the images with
+ * the specified identifier have finished loading, or until the
+ * length of time specified in milliseconds by the ms
+ * argument has passed.
+ *
+ * If there is an error while loading or scaling an image, then that
+ * image is considered to have finished loading. Use the
+ * statusID, isErrorID, and
+ * isErrorAny methods to check for errors.
+ * @param id the identifier of the images to check
+ * @param ms the length of time, in milliseconds, to wait
+ * for the loading to complete
+ * @see java.awt.MediaTracker#waitForAll
+ * @see java.awt.MediaTracker#waitForID(int)
+ * @see java.awt.MediaTracker#statusID
+ * @see java.awt.MediaTracker#isErrorAny()
+ * @see java.awt.MediaTracker#isErrorID(int)
+ * @exception InterruptedException if any thread has
+ * interrupted this thread.
+ */
+ public synchronized boolean waitForID(int id, long ms)
+ throws InterruptedException
+ {
+ long end = System.currentTimeMillis() + ms;
+ boolean first = true;
+ while (true) {
+ int status = statusID(id, first, first);
+ if ((status & LOADING) == 0) {
+ return (status == COMPLETE);
+ }
+ first = false;
+ long timeout;
+ if (ms == 0) {
+ timeout = 0;
+ } else {
+ timeout = end - System.currentTimeMillis();
+ if (timeout <= 0) {
+ return false;
+ }
+ }
+ wait(timeout);
+ }
+ }
+
+ /**
+ * Calculates and returns the bitwise inclusive OR of the
+ * status of all media with the specified identifier that are
+ * tracked by this media tracker.
+ *
+ * Possible flags defined by the
+ * MediaTracker class are LOADING,
+ * ABORTED, ERRORED, and
+ * COMPLETE. An image that hasn't started
+ * loading has zero as its status.
+ *
+ * If the value of load is true, then
+ * this method starts loading any images that are not yet being loaded.
+ * @param id the identifier of the images to check
+ * @param load if true, start loading
+ * any images that are not yet being loaded
+ * @return the bitwise inclusive OR of the status of
+ * all of the media with the specified
+ * identifier that are being tracked
+ * @see java.awt.MediaTracker#statusAll(boolean)
+ * @see java.awt.MediaTracker#LOADING
+ * @see java.awt.MediaTracker#ABORTED
+ * @see java.awt.MediaTracker#ERRORED
+ * @see java.awt.MediaTracker#COMPLETE
+ */
+ public int statusID(int id, boolean load) {
+ return statusID(id, load, true);
+ }
+
+ private synchronized int statusID(int id, boolean load, boolean verify) {
+ MediaEntry cur = head;
+ int status = 0;
+ while (cur != null) {
+ if (cur.getID() == id) {
+ status = status | cur.getStatus(load, verify);
+ }
+ cur = cur.next;
+ }
+ return status;
+ }
+
+ /**
+ * Removes the specified image from this media tracker.
+ * All instances of the specified image are removed,
+ * regardless of scale or ID.
+ * @param image the image to be removed
+ * @see java.awt.MediaTracker#removeImage(java.awt.Image, int)
+ * @see java.awt.MediaTracker#removeImage(java.awt.Image, int, int, int)
+ * @since JDK1.1
+ */
+ public synchronized void removeImage(Image image) {
+ MediaEntry cur = head;
+ MediaEntry prev = null;
+ while (cur != null) {
+ MediaEntry next = cur.next;
+ if (cur.getMedia() == image) {
+ if (prev == null) {
+ head = next;
+ } else {
+ prev.next = next;
+ }
+ cur.cancel();
+ } else {
+ prev = cur;
+ }
+ cur = next;
+ }
+ notifyAll(); // Notify in case remaining images are "done".
+ }
+
+ /**
+ * Removes the specified image from the specified tracking
+ * ID of this media tracker.
+ * All instances of Image being tracked
+ * under the specified ID are removed regardless of scale.
+ * @param image the image to be removed
+ * @param id the tracking ID frrom which to remove the image
+ * @see java.awt.MediaTracker#removeImage(java.awt.Image)
+ * @see java.awt.MediaTracker#removeImage(java.awt.Image, int, int, int)
+ * @since JDK1.1
+ */
+ public synchronized void removeImage(Image image, int id) {
+ MediaEntry cur = head;
+ MediaEntry prev = null;
+ while (cur != null) {
+ MediaEntry next = cur.next;
+ if (cur.getID() == id && cur.getMedia() == image) {
+ if (prev == null) {
+ head = next;
+ } else {
+ prev.next = next;
+ }
+ cur.cancel();
+ } else {
+ prev = cur;
+ }
+ cur = next;
+ }
+ notifyAll(); // Notify in case remaining images are "done".
+ }
+
+ /**
+ * Removes the specified image with the specified
+ * width, height, and ID from this media tracker.
+ * Only the specified instance (with any duplicates) is removed.
+ * @param image the image to be removed
+ * @param id the tracking ID from which to remove the image
+ * @param width the width to remove (-1 for unscaled)
+ * @param height the height to remove (-1 for unscaled)
+ * @see java.awt.MediaTracker#removeImage(java.awt.Image)
+ * @see java.awt.MediaTracker#removeImage(java.awt.Image, int)
+ * @since JDK1.1
+ */
+ public synchronized void removeImage(Image image, int id,
+ int width, int height) {
+ MediaEntry cur = head;
+ MediaEntry prev = null;
+ while (cur != null) {
+ MediaEntry next = cur.next;
+ if (cur.getID() == id && cur instanceof ImageMediaEntry
+ && ((ImageMediaEntry) cur).matches(image, width, height))
+ {
+ if (prev == null) {
+ head = next;
+ } else {
+ prev.next = next;
+ }
+ cur.cancel();
+ } else {
+ prev = cur;
+ }
+ cur = next;
+ }
+ notifyAll(); // Notify in case remaining images are "done".
+ }
+
+ synchronized void setDone() {
+ notifyAll();
+ }
+}
+
+abstract class MediaEntry {
+ MediaTracker tracker;
+ int ID;
+ MediaEntry next;
+
+ int status;
+ boolean cancelled;
+
+ MediaEntry(MediaTracker mt, int id) {
+ tracker = mt;
+ ID = id;
+ }
+
+ abstract Object getMedia();
+
+ static MediaEntry insert(MediaEntry head, MediaEntry me) {
+ MediaEntry cur = head;
+ MediaEntry prev = null;
+ while (cur != null) {
+ if (cur.ID > me.ID) {
+ break;
+ }
+ prev = cur;
+ cur = cur.next;
+ }
+ me.next = cur;
+ if (prev == null) {
+ head = me;
+ } else {
+ prev.next = me;
+ }
+ return head;
+ }
+
+ int getID() {
+ return ID;
+ }
+
+ abstract void startLoad();
+
+ void cancel() {
+ cancelled = true;
+ }
+
+ static final int LOADING = MediaTracker.LOADING;
+ static final int ABORTED = MediaTracker.ABORTED;
+ static final int ERRORED = MediaTracker.ERRORED;
+ static final int COMPLETE = MediaTracker.COMPLETE;
+
+ static final int LOADSTARTED = (LOADING | ERRORED | COMPLETE);
+ static final int DONE = (ABORTED | ERRORED | COMPLETE);
+
+ synchronized int getStatus(boolean doLoad, boolean doVerify) {
+ if (doLoad && ((status & LOADSTARTED) == 0)) {
+ status = (status & ~ABORTED) | LOADING;
+ startLoad();
+ }
+ return status;
+ }
+
+ void setStatus(int flag) {
+ synchronized (this) {
+ status = flag;
+ }
+ tracker.setDone();
+ }
+}
+
+class ImageMediaEntry extends MediaEntry implements ImageObserver,
+java.io.Serializable {
+ Image image;
+ int width;
+ int height;
+
+ /*
+ * JDK 1.1 serialVersionUID
+ */
+ private static final long serialVersionUID = 4739377000350280650L;
+
+ ImageMediaEntry(MediaTracker mt, Image img, int c, int w, int h) {
+ super(mt, c);
+ image = img;
+ width = w;
+ height = h;
+ }
+
+ boolean matches(Image img, int w, int h) {
+ return (image == img && width == w && height == h);
+ }
+
+ Object getMedia() {
+ return image;
+ }
+
+ synchronized int getStatus(boolean doLoad, boolean doVerify) {
+ if (doVerify) {
+ int flags = tracker.target.checkImage(image, width, height, null);
+ int s = parseflags(flags);
+ if (s == 0) {
+ if ((status & (ERRORED | COMPLETE)) != 0) {
+ setStatus(ABORTED);
+ }
+ } else if (s != status) {
+ setStatus(s);
+ }
+ }
+ return super.getStatus(doLoad, doVerify);
+ }
+
+ void startLoad() {
+ if (tracker.target.prepareImage(image, width, height, this)) {
+ setStatus(COMPLETE);
+ }
+ }
+
+ int parseflags(int infoflags) {
+ if ((infoflags & ERROR) != 0) {
+ return ERRORED;
+ } else if ((infoflags & ABORT) != 0) {
+ return ABORTED;
+ } else if ((infoflags & (ALLBITS | FRAMEBITS)) != 0) {
+ return COMPLETE;
+ }
+ return 0;
+ }
+
+ public boolean imageUpdate(Image img, int infoflags,
+ int x, int y, int w, int h) {
+ if (cancelled) {
+ return false;
+ }
+ int s = parseflags(infoflags);
+ if (s != 0 && s != status) {
+ setStatus(s);
+ }
+ return ((status & LOADING) != 0);
+ }
+}