Practical exercise unit 7 Topic : MapReduce program in Java Work purpose : Display function, convolution function and the assignment perform the code study

FSDataInputStream
FileSystem object's open() method standard java class instead of . io FSDataInputStream of the class object returns _ This class is a specialization of java . io.DataInputStream of flow desired from the part information reading enable giver random access help with :
File from the length bigger seek( ) instead to call IOException the of the Java class from the skip( ) method different as if io.InputStream , the stream current from the position outside to the point take goes to the seek( ) method in the file optional absolute to the position transition enable gives _
Listing 3.3 of Listing 3.2 extension and the file standard to exit two times sends and the first times of the file At the beginning of located _
Seekable interface location to determine provides and file from the beginning current the offset get method own into gets ( getPos ( )):
File from the length bigger seek( ) instead to call IOException the of the Java class from the skip( ) method different as if io.InputStream , the stream current from the position outside to the point take goes , the seek ( ) method in the file optional absolute to the position transition enable gives _
Listing 3.3 of Listing 3.2 extension and the file standard to exit two times sends and the first times of the file At the beginning of located _

Read( ) method up to length reads bytes given file from the position offset in the offset to the position in the clipboard buffer.Return value in reality read bytes the number own into takes _ call while doing , you acceptance done the value your check is necessary because it is long less to be can _ readFully () methods is read into buffer.length byte ( or buffer . length buffer byte array acceptance doer version for ) ; if this of the file to the end if , EOFException is sent .
This of methods all of them current file offset keeps and thread- safe. They are of the file main content reading during of the file another refer to parts ( for example , metadata ) . to do for comfortable mechanism provides .
Finally , that's it in mind hold seek() call relatively expensive and caution with use need _ In the application to information access model one how many location determination operations not but _ flowing information again to work based on to be needed ( for example , using MapReduce ) .