641 * of the following formats: GIF, JPEG or PNG.
642 * The underlying toolkit attempts to resolve multiple requests
643 * with the same URL to the same returned Image.
644 * <p>
645 * Since the mechanism required to facilitate this sharing of
646 * {@code Image} objects may continue to hold onto images
647 * that are no longer in use for an indefinite period of time,
648 * developers are encouraged to implement their own caching of
649 * images by using the {@link #createImage(java.net.URL) createImage}
650 * variant wherever available.
651 * If the image data stored at the specified URL changes,
652 * the {@code Image} object returned from this method may
653 * still contain stale information which was fetched from the
654 * URL after a prior call.
655 * Previously loaded image data can be manually discarded by
656 * calling the {@link Image#flush flush} method on the
657 * returned {@code Image}.
658 * <p>
659 * This method first checks if there is a security manager installed.
660 * If so, the method calls the security manager's
661 * {@code checkPermission} method with the
662 * url.openConnection().getPermission() permission to ensure
663 * that the access to the image is allowed. For compatibility
664 * with pre-1.2 security managers, if the access is denied with
665 * {@code FilePermission} or {@code SocketPermission},
666 * the method throws the {@code SecurityException}
667 * if the corresponding 1.1-style SecurityManager.checkXXX method
668 * also denies permission.
669 * @param url the URL to use in fetching the pixel data.
670 * @return an image which gets its pixel data from
671 * the specified URL.
672 * @throws SecurityException if a security manager exists and its
673 * checkPermission method doesn't allow
674 * the operation.
675 * @see #createImage(java.net.URL)
676 */
677 public abstract Image getImage(URL url);
678
679 /**
680 * Returns an image which gets pixel data from the specified file.
681 * The returned Image is a new object which will not be shared
682 * with any other caller of this method or its getImage variant.
683 * <p>
684 * This method first checks if there is a security manager installed.
685 * If so, the method calls the security manager's
686 * {@code checkRead} method with the specified file to ensure
687 * that the image creation is allowed.
688 * @param filename the name of a file containing pixel data
689 * in a recognized file format.
690 * @return an image which gets its pixel data from
691 * the specified file.
692 * @throws SecurityException if a security manager exists and its
693 * checkRead method doesn't allow the operation.
694 * @see #getImage(java.lang.String)
695 */
696 public abstract Image createImage(String filename);
697
698 /**
699 * Returns an image which gets pixel data from the specified URL.
700 * The returned Image is a new object which will not be shared
701 * with any other caller of this method or its getImage variant.
702 * <p>
703 * This method first checks if there is a security manager installed.
704 * If so, the method calls the security manager's
705 * {@code checkPermission} method with the
706 * url.openConnection().getPermission() permission to ensure
707 * that the image creation is allowed. For compatibility
708 * with pre-1.2 security managers, if the access is denied with
709 * {@code FilePermission} or {@code SocketPermission},
710 * the method throws {@code SecurityException}
711 * if the corresponding 1.1-style SecurityManager.checkXXX method
712 * also denies permission.
713 * @param url the URL to use in fetching the pixel data.
714 * @return an image which gets its pixel data from
715 * the specified URL.
716 * @throws SecurityException if a security manager exists and its
717 * checkPermission method doesn't allow
718 * the operation.
719 * @see #getImage(java.net.URL)
720 */
721 public abstract Image createImage(URL url);
722
723 /**
724 * Prepares an image for rendering.
725 * <p>
726 * If the values of the width and height arguments are both
727 * {@code -1}, this method prepares the image for rendering
728 * on the default screen; otherwise, this method prepares an image
729 * for rendering on the default screen at the specified width and height.
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641 * of the following formats: GIF, JPEG or PNG.
642 * The underlying toolkit attempts to resolve multiple requests
643 * with the same URL to the same returned Image.
644 * <p>
645 * Since the mechanism required to facilitate this sharing of
646 * {@code Image} objects may continue to hold onto images
647 * that are no longer in use for an indefinite period of time,
648 * developers are encouraged to implement their own caching of
649 * images by using the {@link #createImage(java.net.URL) createImage}
650 * variant wherever available.
651 * If the image data stored at the specified URL changes,
652 * the {@code Image} object returned from this method may
653 * still contain stale information which was fetched from the
654 * URL after a prior call.
655 * Previously loaded image data can be manually discarded by
656 * calling the {@link Image#flush flush} method on the
657 * returned {@code Image}.
658 * <p>
659 * This method first checks if there is a security manager installed.
660 * If so, the method calls the security manager's
661 * {@code checkPermission} method with the corresponding
662 * permission to ensure that the access to the image is allowed.
663 * If the connection to the specified URL requires
664 * either {@code URLPermission} or {@code SocketPermission},
665 * then {@code URLPermission} is used for security checks.
666 * For compatibility with pre-1.2 security managers, if the access
667 * is denied with {@code FilePermission} or {@code SocketPermission},
668 * the method throws the {@code SecurityException}
669 * if the corresponding 1.1-style SecurityManager.checkXXX method
670 * also denies permission.
671 * @param url the URL to use in fetching the pixel data.
672 * @return an image which gets its pixel data from
673 * the specified URL.
674 * @throws SecurityException if a security manager exists and its
675 * checkPermission method doesn't allow
676 * the operation.
677 * @see #createImage(java.net.URL)
678 */
679 public abstract Image getImage(URL url);
680
681 /**
682 * Returns an image which gets pixel data from the specified file.
683 * The returned Image is a new object which will not be shared
684 * with any other caller of this method or its getImage variant.
685 * <p>
686 * This method first checks if there is a security manager installed.
687 * If so, the method calls the security manager's
688 * {@code checkRead} method with the specified file to ensure
689 * that the image creation is allowed.
690 * @param filename the name of a file containing pixel data
691 * in a recognized file format.
692 * @return an image which gets its pixel data from
693 * the specified file.
694 * @throws SecurityException if a security manager exists and its
695 * checkRead method doesn't allow the operation.
696 * @see #getImage(java.lang.String)
697 */
698 public abstract Image createImage(String filename);
699
700 /**
701 * Returns an image which gets pixel data from the specified URL.
702 * The returned Image is a new object which will not be shared
703 * with any other caller of this method or its getImage variant.
704 * <p>
705 * This method first checks if there is a security manager installed.
706 * If so, the method calls the security manager's
707 * {@code checkPermission} method with the corresponding
708 * permission to ensure that the image creation is allowed.
709 * If the connection to the specified URL requires
710 * either {@code URLPermission} or {@code SocketPermission},
711 * then {@code URLPermission} is used for security checks.
712 * For compatibility with pre-1.2 security managers, if the access
713 * is denied with {@code FilePermission} or {@code SocketPermission},
714 * the method throws {@code SecurityException}
715 * if the corresponding 1.1-style SecurityManager.checkXXX method
716 * also denies permission.
717 * @param url the URL to use in fetching the pixel data.
718 * @return an image which gets its pixel data from
719 * the specified URL.
720 * @throws SecurityException if a security manager exists and its
721 * checkPermission method doesn't allow
722 * the operation.
723 * @see #getImage(java.net.URL)
724 */
725 public abstract Image createImage(URL url);
726
727 /**
728 * Prepares an image for rendering.
729 * <p>
730 * If the values of the width and height arguments are both
731 * {@code -1}, this method prepares the image for rendering
732 * on the default screen; otherwise, this method prepares an image
733 * for rendering on the default screen at the specified width and height.
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