661 * {@code Image} objects may continue to hold onto images
662 * that are no longer in use for an indefinite period of time,
663 * developers are encouraged to implement their own caching of
664 * images by using the {@link #createImage(java.net.URL) createImage}
665 * variant wherever available.
666 * If the image data stored at the specified URL changes,
667 * the {@code Image} object returned from this method may
668 * still contain stale information which was fetched from the
669 * URL after a prior call.
670 * Previously loaded image data can be manually discarded by
671 * calling the {@link Image#flush flush} method on the
672 * returned {@code Image}.
673 * <p>
674 * This method first checks if there is a security manager installed.
675 * If so, the method calls the security manager's
676 * {@code checkPermission} method with the corresponding
677 * permission to ensure that the access to the image is allowed.
678 * If the connection to the specified URL requires
679 * either {@code URLPermission} or {@code SocketPermission},
680 * then {@code URLPermission} is used for security checks.
681 * For compatibility with pre-1.2 security managers, if the access
682 * is denied with {@code FilePermission} or {@code SocketPermission},
683 * the method throws the {@code SecurityException}
684 * if the corresponding 1.1-style SecurityManager.checkXXX method
685 * also denies permission.
686 * @param url the URL to use in fetching the pixel data.
687 * @return an image which gets its pixel data from
688 * the specified URL.
689 * @throws SecurityException if a security manager exists and its
690 * checkPermission method doesn't allow
691 * the operation.
692 * @see #createImage(java.net.URL)
693 */
694 public abstract Image getImage(URL url);
695
696 /**
697 * Returns an image which gets pixel data from the specified file.
698 * The returned Image is a new object which will not be shared
699 * with any other caller of this method or its getImage variant.
700 * <p>
701 * This method first checks if there is a security manager installed.
702 * If so, the method calls the security manager's
703 * {@code checkRead} method with the specified file to ensure
704 * that the image creation is allowed.
705 * @param filename the name of a file containing pixel data
707 * @return an image which gets its pixel data from
708 * the specified file.
709 * @throws SecurityException if a security manager exists and its
710 * checkRead method doesn't allow the operation.
711 * @see #getImage(java.lang.String)
712 */
713 public abstract Image createImage(String filename);
714
715 /**
716 * Returns an image which gets pixel data from the specified URL.
717 * The returned Image is a new object which will not be shared
718 * with any other caller of this method or its getImage variant.
719 * <p>
720 * This method first checks if there is a security manager installed.
721 * If so, the method calls the security manager's
722 * {@code checkPermission} method with the corresponding
723 * permission to ensure that the image creation is allowed.
724 * If the connection to the specified URL requires
725 * either {@code URLPermission} or {@code SocketPermission},
726 * then {@code URLPermission} is used for security checks.
727 * For compatibility with pre-1.2 security managers, if the access
728 * is denied with {@code FilePermission} or {@code SocketPermission},
729 * the method throws {@code SecurityException}
730 * if the corresponding 1.1-style SecurityManager.checkXXX method
731 * also denies permission.
732 * @param url the URL to use in fetching the pixel data.
733 * @return an image which gets its pixel data from
734 * the specified URL.
735 * @throws SecurityException if a security manager exists and its
736 * checkPermission method doesn't allow
737 * the operation.
738 * @see #getImage(java.net.URL)
739 */
740 public abstract Image createImage(URL url);
741
742 /**
743 * Prepares an image for rendering.
744 * <p>
745 * If the values of the width and height arguments are both
746 * {@code -1}, this method prepares the image for rendering
747 * on the default screen; otherwise, this method prepares an image
748 * for rendering on the default screen at the specified width and height.
749 * <p>
750 * The image data is downloaded asynchronously in another thread,
751 * and an appropriately scaled screen representation of the image is
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661 * {@code Image} objects may continue to hold onto images
662 * that are no longer in use for an indefinite period of time,
663 * developers are encouraged to implement their own caching of
664 * images by using the {@link #createImage(java.net.URL) createImage}
665 * variant wherever available.
666 * If the image data stored at the specified URL changes,
667 * the {@code Image} object returned from this method may
668 * still contain stale information which was fetched from the
669 * URL after a prior call.
670 * Previously loaded image data can be manually discarded by
671 * calling the {@link Image#flush flush} method on the
672 * returned {@code Image}.
673 * <p>
674 * This method first checks if there is a security manager installed.
675 * If so, the method calls the security manager's
676 * {@code checkPermission} method with the corresponding
677 * permission to ensure that the access to the image is allowed.
678 * If the connection to the specified URL requires
679 * either {@code URLPermission} or {@code SocketPermission},
680 * then {@code URLPermission} is used for security checks.
681 * @param url the URL to use in fetching the pixel data.
682 * @return an image which gets its pixel data from
683 * the specified URL.
684 * @throws SecurityException if a security manager exists and its
685 * checkPermission method doesn't allow
686 * the operation.
687 * @see #createImage(java.net.URL)
688 */
689 public abstract Image getImage(URL url);
690
691 /**
692 * Returns an image which gets pixel data from the specified file.
693 * The returned Image is a new object which will not be shared
694 * with any other caller of this method or its getImage variant.
695 * <p>
696 * This method first checks if there is a security manager installed.
697 * If so, the method calls the security manager's
698 * {@code checkRead} method with the specified file to ensure
699 * that the image creation is allowed.
700 * @param filename the name of a file containing pixel data
702 * @return an image which gets its pixel data from
703 * the specified file.
704 * @throws SecurityException if a security manager exists and its
705 * checkRead method doesn't allow the operation.
706 * @see #getImage(java.lang.String)
707 */
708 public abstract Image createImage(String filename);
709
710 /**
711 * Returns an image which gets pixel data from the specified URL.
712 * The returned Image is a new object which will not be shared
713 * with any other caller of this method or its getImage variant.
714 * <p>
715 * This method first checks if there is a security manager installed.
716 * If so, the method calls the security manager's
717 * {@code checkPermission} method with the corresponding
718 * permission to ensure that the image creation is allowed.
719 * If the connection to the specified URL requires
720 * either {@code URLPermission} or {@code SocketPermission},
721 * then {@code URLPermission} is used for security checks.
722 * @param url the URL to use in fetching the pixel data.
723 * @return an image which gets its pixel data from
724 * the specified URL.
725 * @throws SecurityException if a security manager exists and its
726 * checkPermission method doesn't allow
727 * the operation.
728 * @see #getImage(java.net.URL)
729 */
730 public abstract Image createImage(URL url);
731
732 /**
733 * Prepares an image for rendering.
734 * <p>
735 * If the values of the width and height arguments are both
736 * {@code -1}, this method prepares the image for rendering
737 * on the default screen; otherwise, this method prepares an image
738 * for rendering on the default screen at the specified width and height.
739 * <p>
740 * The image data is downloaded asynchronously in another thread,
741 * and an appropriately scaled screen representation of the image is
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