ImageIO.java 文件源码

/**
 * Returns an <code>Iterator</code> containing all currently
 * registered <code>ImageWriter</code>s that claim to be able to
 * encode the named format.
 *
 * @param formatName a <code>String</code> containing the informal
 * name of a format (<i>e.g.</i>, "jpeg" or "tiff".
 *
 * @return an <code>Iterator</code> containing
 * <code>ImageWriter</code>s.
 *
 * @exception IllegalArgumentException if <code>formatName</code> is
 * <code>null</code>.
 *
 * @see javax.imageio.spi.ImageWriterSpi#getFormatNames
 */
public static Iterator<ImageWriter>
    getImageWritersByFormatName(String formatName)
{
    if (formatName == null) {
        throw new IllegalArgumentException("formatName == null!");
    }
    Iterator iter;
    // Ensure category is present
    try {
        iter = theRegistry.getServiceProviders(ImageWriterSpi.class,
                                new ContainsFilter(writerFormatNamesMethod,
                                                   formatName),
                                        true);
    } catch (IllegalArgumentException e) {
        return Collections.emptyIterator();
    }
    return new ImageWriterIterator(iter);
}