org.archive.queue
Class DiskStack

java.lang.Object
  org.archive.queue.DiskStack

All Implemented Interfaces:

java.io.Serializable, Stack

public class DiskStack
extends java.lang.Object
implements Stack, java.io.Serializable

A Stack which serializes objects to disk.

Author:

gojomo

See Also:

Serialized Form

Field Summary

protected long	height total items in stack
(package private) HeaderlessObjectInputStream	popStream stream offering serialization reading from raf
(package private) HeaderlessObjectOutputStream	pushStream stream offering serialization writing into raf
(package private) java.io.RandomAccessFile	raf random-access file into which bojects are serialized
(package private) java.io.DataOutputStream	rawStream stream offering non-serialization writing into raf
protected java.io.File	storage the backing file
protected long	topItemPointer pointer to top prevIndex + topItem in backing file

Constructor Summary

DiskStack(java.io.File storage)

Method Summary

void	close() Close, releasing held resources.
void	discard() Close and delete any disk-based storage
void	disconnect()
long	height() Number of items in the Stack.
boolean	isEmpty()
java.lang.Object	peek()
java.lang.Object	pop() Remove and return item from top of Stack
void	push(java.lang.Object object) Add object to top of Stack
void	release() Release any OS resources, if necessary.

Methods inherited from class java.lang.Object

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

Field Detail

storage

protected java.io.File storage

the backing file

height

protected long height

total items in stack

topItemPointer

protected long topItemPointer

pointer to top prevIndex + topItem in backing file

raf

transient java.io.RandomAccessFile raf

random-access file into which bojects are serialized

rawStream

transient java.io.DataOutputStream rawStream

stream offering non-serialization writing into raf

pushStream

transient HeaderlessObjectOutputStream pushStream

stream offering serialization writing into raf

popStream

transient HeaderlessObjectInputStream popStream

stream offering serialization reading from raf

Constructor Detail

DiskStack

public DiskStack(java.io.File storage)
          throws java.io.IOException

Parameters:

storage -

Throws:

java.io.FileNotFoundException

java.io.IOException

Method Detail

push

public void push(java.lang.Object object)

Description copied from interface: Stack

Add object to top of Stack

Specified by:

push in interface Stack

pop

public java.lang.Object pop()

Description copied from interface: Stack

Remove and return item from top of Stack

Specified by:

pop in interface Stack

Returns:

Item removed from top of Stack

peek

public java.lang.Object peek()

Specified by:

peek in interface Stack

Returns:

Return item from top of Stack without removing it.

height

public long height()

Description copied from interface: Stack

Number of items in the Stack.

Specified by:

height in interface Stack

close

public void close()
           throws java.io.IOException

Close, releasing held resources.

Throws:

java.io.IOException

discard

public void discard()
             throws java.io.IOException

Close and delete any disk-based storage

Throws:

java.io.IOException

disconnect

public void disconnect()

release

public void release()

Description copied from interface: Stack

Release any OS resources, if necessary.

Specified by:

release in interface Stack

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Stack

Returns:

True if empty.