This class is a subclass of java.io.FilterInputStream ; it allows a stream to be read and a checksum computed on its contents at the same time. This is useful when you want to check the integrity of a stream of data against a published checksum value. To create a CheckedInputStream , you must specify both the stream it should read and a Checksum object, such as CRC32 , that implements the particular checksum algorithm you desire . The read( ) and skip( ) methods are the same as those of other input streams. As bytes are read, they are incorporated into the checksum that is being computed. The getChecksum( ) method does not return the checksum value itself, but rather the Checksum object. You must call the getValue( ) method of this object to obtain the checksum value. Figure 16-135. java.util.zip.CheckedInputStreampublic class CheckedInputStream extends java.io.FilterInputStream { // Public Constructors public CheckedInputStream (java.io.InputStream in , Checksum cksum ); // Public Instance Methods public Checksum getChecksum ( ); // Public Methods Overriding FilterInputStream public int read ( ) throws java.io.IOException; public int read (byte[ ] buf , int off , int len ) throws java.io.IOException; public long skip (long n ) throws java.io.IOException; } |