java.awt

Class MediaTracker

java.lang.Object
- java.awt.MediaTracker

Implemented Interfaces:: Serializable

public class MediaTracker

extends Object

implements Serializable

This class is used for keeping track of the status of various media objects. Media objects are tracked by assigning them an ID. It is possible to assign the same ID to mutliple objects, effectivly grouping them together. In this case the status flags (statusID(int,boolean)) and error flag (@link #isErrorID} and getErrorsID(int)) are ORed together. This means that you cannot say exactly which media object has which status, at most you can say that there are certain media objects with some certain status. At the moment only images are supported by this class.

See Also:: Serialized Form

Field Summary
`static int`	`ABORTED` Indicates that the loading operation has been aborted.
`static int`	`COMPLETE` Indicates that the media has been successfully and completely loaded.
`static int`	`ERRORED` Indicates that an error has occured during loading of the media.
`static int`	`LOADING` Indicates that the media is still loading.

Constructor Summary
`MediaTracker(Component c)` Constructs a new MediaTracker for the component `c`.

Method Summary
`void`	`addImage(Image image, int id)` Adds an image to the tracker with the specified `ID`.
`void`	`addImage(Image image, int id, int width, int height)` Adds an image to the tracker with the specified `ID`.
`boolean`	`checkAll()` Checks if all media objects have finished loading, i.e. are `COMPLETE`, `ABORTED` or `ERRORED`.
`boolean`	`checkAll(boolean load)` Checks if all media objects have finished loading, i.e. are `COMPLETE`, `ABORTED` or `ERRORED`.
`boolean`	`checkID(int id)` Checks if the media objects with `ID` have completed loading.
`boolean`	`checkID(int id, boolean load)` Checks if the media objects with `ID` have completed loading.
`Object[]`	`getErrorsAny()` Returns all media objects that have encountered errors during loading.
`Object[]`	`getErrorsID(int id)` Returns all media objects with the specified ID that have encountered an error.
`boolean`	`isErrorAny()` Checks if any of the registered media objects has encountered an error during loading.
`boolean`	`isErrorID(int id)` Returns `true` if any of the media objects with `ID` have encountered errors during loading, false otherwise.
`void`	`removeImage(Image image)` Removes an image from this MediaTracker.
`void`	`removeImage(Image image, int id)` Removes an image with the specified ID from this MediaTracker.
`void`	`removeImage(Image image, int id, int width, int height)` Removes an image with the specified ID and scale from this MediaTracker.
`int`	`statusAll(boolean load)` Returns the status flags of all registered media objects ORed together.
`int`	`statusID(int id, boolean load)` Returns the status flags of the media objects with the specified ID ORed together.
`void`	`waitForAll()` Waits for all media objects to finish loading, either by completing successfully or by aborting or encountering an error.
`boolean`	`waitForAll(long ms)` Waits for all media objects to finish loading, either by completing successfully or by aborting or encountering an error.
`void`	`waitForID(int id)` Waits for all media objects with the specified ID to finish loading, either by completing successfully or by aborting or encountering an error.
`boolean`	`waitForID(int id, long ms)` Waits for all media objects with the specified ID to finish loading, either by completing successfully or by aborting or encountering an error.

Methods inherited from class java.lang.Object
`clone`, `equals`, `extends Object> getClass`, `finalize`, `hashCode`, `notify`, `notifyAll`, `toString`, `wait`, `wait`, `wait`

ABORTED

public static final int ABORTED

Indicates that the loading operation has been aborted.
Field Value:
2

COMPLETE

public static final int COMPLETE

Indicates that the media has been successfully and completely loaded.
Field Value:
8

ERRORED

public static final int ERRORED

Indicates that an error has occured during loading of the media.
Field Value:
4

LOADING

public static final int LOADING

Indicates that the media is still loading.
Field Value:
1

MediaTracker

public MediaTracker(Component c)

Constructs a new MediaTracker for the component c. The component should be the component that uses the media (i.e. draws it).
Parameters:
c - the Component that wants to use the media

addImage

public void addImage(Image image,
                     int id)

Adds an image to the tracker with the specified ID.
Parameters:
image - the image to be added
id - the ID of the tracker list to which the image is added

addImage

public void addImage(Image image,
                     int id,
                     int width,
                     int height)

Adds an image to the tracker with the specified ID. The image is expected to be rendered with the specified width and height.
Parameters:
image - the image to be added
id - the ID of the tracker list to which the image is added
width - the width of the image
height - the height of the image

checkAll

public boolean checkAll()

Checks if all media objects have finished loading, i.e. are COMPLETE, ABORTED or ERRORED. If the media objects are not already loading, a call to this method does not start loading. This is equivalent to a call to checkAll(false).
Returns:
if all media objects have finished loading either by beeing complete, have been aborted or errored.

checkAll

public boolean checkAll(boolean load)

Checks if all media objects have finished loading, i.e. are COMPLETE, ABORTED or ERRORED. If the media objects are not already loading, and load is true then a call to this method starts loading the media objects.
Parameters:
load - if true this method starts loading objects that are not already loading
Returns:
if all media objects have finished loading either by beeing complete, have been aborted or errored.

checkID

public boolean checkID(int id)

Checks if the media objects with ID have completed loading.
Parameters:
id - the ID of the media objects to check
Returns:
true if all media objects with ID have successfully finished

checkID

public boolean checkID(int id,
                       boolean load)

Checks if the media objects with ID have completed loading. If load is true then media objects that are not already loading will be started to load.
Parameters:
id - the ID of the media objects to check
load - if set to true then media objects that are not already loading are started
Returns:
true if all media objects with ID have successfully finished

getErrorsAny

public Object[] getErrorsAny()

Returns all media objects that have encountered errors during loading.
Returns:
an array of all media objects that have encountered errors or null if there were no errors at all

getErrorsID

public Object[] getErrorsID(int id)

Returns all media objects with the specified ID that have encountered an error.
Parameters:
id - the ID of the media objects to check
Returns:
an array of all media objects with the specified ID that have encountered an error

isErrorAny

public boolean isErrorAny()

Checks if any of the registered media objects has encountered an error during loading.
Returns:
true if at least one media object has encountered an error during loading, false otherwise

isErrorID

public boolean isErrorID(int id)

Returns true if any of the media objects with ID have encountered errors during loading, false otherwise.
Parameters:
id - the ID of the media objects to check
Returns:
true if any of the media objects with ID have encountered errors during loading, false otherwise

removeImage

public void removeImage(Image image)

Removes an image from this MediaTracker.
Parameters:
image - the image to be removed

removeImage

public void removeImage(Image image,
                        int id)

Removes an image with the specified ID from this MediaTracker.
Parameters:
image - the image to be removed

removeImage

public void removeImage(Image image,
                        int id,
                        int width,
                        int height)

Removes an image with the specified ID and scale from this MediaTracker.
Parameters:
image - the image to be removed

statusAll

public int statusAll(boolean load)

Returns the status flags of all registered media objects ORed together. If load is true then media objects that are not already loading will be started to load.
Parameters:
load - if set to true then media objects that are not already loading are started
Returns:
the status flags of all tracked media objects ORed together

statusID

public int statusID(int id,
                    boolean load)

Returns the status flags of the media objects with the specified ID ORed together. If load is true then media objects that are not already loading will be started to load.
Parameters:
load - if set to true then media objects that are not already loading are started
Returns:
the status flags of all tracked media objects ORed together

waitForAll

public void waitForAll()
            throws InterruptedException

Waits for all media objects to finish loading, either by completing successfully or by aborting or encountering an error.
Throws:
InterruptedException - if another thread interrupted the current thread while waiting

waitForAll

public boolean waitForAll(long ms)
            throws InterruptedException

Waits for all media objects to finish loading, either by completing successfully or by aborting or encountering an error. This method waits at most ms milliseconds. If the media objects have not completed loading within this timeframe, this method returns false, otherwise true.
Parameters:
ms - timeframe in milliseconds to wait for the media objects to finish
Returns:
true if all media objects have successfully loaded within the timeframe, false otherwise
Throws:
InterruptedException - if another thread interrupted the current thread while waiting

waitForID

public void waitForID(int id)
            throws InterruptedException

Waits for all media objects with the specified ID to finish loading, either by completing successfully or by aborting or encountering an error.
Parameters:
id - the ID of the media objects to wait for
Throws:
InterruptedException - if another thread interrupted the current thread while waiting

waitForID

public boolean waitForID(int id,
                         long ms)
            throws InterruptedException

Waits for all media objects with the specified ID to finish loading, either by completing successfully or by aborting or encountering an error. This method waits at most ms milliseconds. If the media objects have not completed loading within this timeframe, this method returns false, otherwise true.
Parameters:
id - the ID of the media objects to wait for
ms - timeframe in milliseconds to wait for the media objects to finish
Returns:
true if all media objects have successfully loaded within the timeframe, false otherwise
Throws:
InterruptedException - if another thread interrupted the current thread while waiting

MediaTracker.java -- Class used for keeping track of images Copyright (C) 1999, 2002, 2004, 2005 Free Software Foundation, Inc. This file is part of GNU Classpath. GNU Classpath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GNU Classpath 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 for more details. You should have received a copy of the GNU General Public License along with GNU Classpath; see the file COPYING. If not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. Linking this library statically or dynamically with other modules is making a combined work based on this library. Thus, the terms and conditions of the GNU General Public License cover the whole combination. As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version.

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java.awt

Class MediaTracker

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Details

ABORTED

COMPLETE

ERRORED

LOADING

Constructor Details

MediaTracker

Method Details

addImage

addImage

checkAll

checkAll

checkID

checkID

getErrorsAny

getErrorsID

isErrorAny

isErrorID

removeImage

removeImage

removeImage

statusAll

statusID

waitForAll

waitForAll

waitForID

waitForID