org.foray.graphic.factory
Class PNGFactory

java.lang.Object
  org.foray.graphic.factory.GraphicFactory
      org.foray.graphic.factory.PNGFactory

public class PNGFactory
extends GraphicFactory

ImageReader object for PNG image type.

Author:

Pankaj Narula

Field Summary

protected static byte[]

PNG_HEADER The header bytes at the beginning of a PNG file.

Constructor Summary

PNGFactory(GraphicServer4a server)
Constructor.

Method Summary

PNGGraphic

attemptCreate(URL url, BufferedInputStream bis) Subclasses implement this method to try to create an appropriate Graphic instance.

Methods inherited from class org.foray.graphic.factory.GraphicFactory

getLogger, getServer, makeGraphic, maxBytesToVerify

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

PNG_HEADER

protected static final byte[] PNG_HEADER

The header bytes at the beginning of a PNG file.

Constructor Detail

PNGFactory

public PNGFactory(GraphicServer4a server)

Constructor.

Parameters:

server - The parent graphic server.

Method Detail

attemptCreate

public PNGGraphic attemptCreate(URL url,
                                BufferedInputStream bis)
                         throws IOException

Description copied from class: GraphicFactory

Subclasses implement this method to try to create an appropriate Graphic instance. Note that this superclass handles the task of marking and resetting the input stream, so all the subclass needs to do is read the stream.

Specified by:

attemptCreate in class GraphicFactory

Parameters:

url - The URL which contains the graphic content.

bis - The reusable input stream containing the bytes from url.

Returns:

The newly-created Graphic instance, or null if this factory was unable to create such an instance.

Throws:

IOException - For IO errors.