com.nt.udc.util

Class FileHashtable

java.lang.Object

com.nt.udc.util.FileHashtable

public class FileHashtable
extends java.lang.Object

This class handles the key -> disk based Object mappings, where the disk-based Object is handled with an ObjectStorageFile class. For the most part, use this class as you would a Hashtable class, except note that your Object will be saved to disk immediately. Therefore, it may be slower than an memory-based Hashtable, but the data will be saved.

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	allowCompress
protected java.util.ArrayList	deadPartitionList
protected Factory	keyFactory
protected ObjectStorageFile	objStorage
protected java.util.HashMap	objStorageList
protected java.util.HashMap	offsetTable

Constructor Summary

Constructors

Constructor and Description
FileHashtable(java.util.ArrayList storageFileList, Factory keyFact)
FileHashtable(ObjectStorageFile storage, Factory keyFact) Create a new file-based table.

Method Summary

Modifier and Type	Method and Description
void	addPartition(ObjectStorageFile newStorage, int index)
void	clear() This method is not supported.
void	close() Closes the file table.
void	compressTable() Compresses the ObjectStorageFile's file, and resets the offset table.
boolean	containsKey(java.lang.Object key) Returns whether this table contains the given key.
boolean	containsValue(java.lang.Object value) Returns whether this table contains the given value.
java.util.Set	entrySet() Returns the entries in Map.Entry form.
boolean	equals(java.lang.Object o) Returns whether this table is equal to the given Object.
java.lang.Object	get(java.lang.Object key) Retrieve an Object with the given key.
int	hashCode() Returns the hash code for this table.
boolean	isEmpty() Returns whether the table is empty.
java.util.Enumeration	keys() Returns the keys of the table.
java.util.Set	keySet() Returns the keys of this table as a Set interface.
void	open() Opens the file table.
void	pauseTableCompression() Pause the table compression.
java.lang.Object	put(java.lang.Object key, java.lang.Object value) Puts an Object value in the table using the Object key.
java.lang.Object	put(java.lang.Object key, java.lang.Object value, int index)
void	putAll(java.util.Map t) Puts all of the elements of the given Map into this table.
java.lang.Object	remove(java.lang.Object key) Removes an Object from the table.
protected void	removeDeadPartitions()
java.lang.Object	removeDelayedNARParsing(java.lang.Object key) This method is for exclusive use by MTAggrDispatcher ONLY, because this method must return NAR instead of an arbitrary Object.
void	resumeTableCompression() Compresses the ObjectStorageFile's file, and resets the offset table.
int	size() Returns the number of Objects in the table.
java.lang.String	toString() Returns the table, in displayable format.
java.util.Collection	values() Returns all the values in the table as a Collection interface.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

offsetTable

protected java.util.HashMap offsetTable

objStorage

protected ObjectStorageFile objStorage

objStorageList

protected java.util.HashMap objStorageList

deadPartitionList

protected java.util.ArrayList deadPartitionList

keyFactory

protected Factory keyFactory

allowCompress

protected boolean allowCompress

Constructor Detail

FileHashtable

public FileHashtable(ObjectStorageFile storage,
                     Factory keyFact)
              throws java.io.IOException

Create a new file-based table.

Parameters:

storage - Handles the actual Object storage to disk.

keyFact - Factory class, used to build Object keys when using a previously created table.

Throws:

java.io.IOException

FileHashtable

public FileHashtable(java.util.ArrayList storageFileList,
                     Factory keyFact)
              throws java.io.IOException

Throws:

java.io.IOException

Method Detail

addPartition

public void addPartition(ObjectStorageFile newStorage,
                         int index)
                  throws java.io.IOException

Throws:

java.io.IOException

get

public java.lang.Object get(java.lang.Object key)
                     throws java.io.IOException

Retrieve an Object with the given key.

Parameters:

key - Object key to retrieve the value with.

Returns:

Object value that was stored in the table.

Throws:

java.io.IOException

put

public java.lang.Object put(java.lang.Object key,
                            java.lang.Object value,
                            int index)
                     throws java.io.IOException

Throws:

java.io.IOException

put

public java.lang.Object put(java.lang.Object key,
                            java.lang.Object value)
                     throws java.io.IOException

Puts an Object value in the table using the Object key.

Parameters:

key - Key to index into the table.

value - Value to put in the table.

Returns:

Value that was placed in the table.

Throws:

java.io.IOException

pauseTableCompression

public void pauseTableCompression()

Pause the table compression.

remove

public java.lang.Object remove(java.lang.Object key)
                        throws java.io.IOException

Removes an Object from the table.

Parameters:

key - Object key, used to find the Object in the table.

Returns:

Object value at the key.

Throws:

java.io.IOException

removeDelayedNARParsing

public java.lang.Object removeDelayedNARParsing(java.lang.Object key)
                                         throws java.io.IOException

This method is for exclusive use by MTAggrDispatcher ONLY, because this method must return NAR instead of an arbitrary Object. A clone of remove(), but this one calls ObjectStorageFile.getDelayedParsing() instead. and manually

Parameters:

key -

Returns:

THE TYPE IS IMPORTANT!!! It's either type com.nt.common.util.ByteArray (which then needs parsing from ObjectStorageFile.objectFromBytes()), or type whatever it was originally. (There's gotta be a better way, but I can't figure out how to bypass the "useMemHash" thing.

Throws:

java.io.IOException

removeDeadPartitions

protected void removeDeadPartitions()
                             throws java.io.IOException

Throws:

java.io.IOException

resumeTableCompression

public void resumeTableCompression()
                            throws java.io.IOException

Compresses the ObjectStorageFile's file, and resets the offset table.

Throws:

java.io.IOException

compressTable

public void compressTable()
                   throws java.lang.NullPointerException,
                          java.io.IOException

Compresses the ObjectStorageFile's file, and resets the offset table.

Throws:

java.lang.NullPointerException

java.io.IOException

close

public void close()
           throws java.io.IOException

Closes the file table.

Throws:

java.io.IOException

open

public void open()
          throws java.io.IOException

Opens the file table.

Throws:

java.io.IOException

clear

public void clear()
           throws java.lang.UnsupportedOperationException

This method is not supported.

Throws:

java.lang.UnsupportedOperationException

containsKey

public boolean containsKey(java.lang.Object key)

Returns whether this table contains the given key.

Parameters:

key - Key to find.

Returns:

true, if this table contains the key

containsValue

public boolean containsValue(java.lang.Object value)
                      throws java.io.IOException

Returns whether this table contains the given value.

Parameters:

value - Value to find.

Returns:

true, if this table contains the value

Throws:

java.io.IOException

keySet

public java.util.Set keySet()
                     throws java.lang.UnsupportedOperationException

Returns the keys of this table as a Set interface. !! Currently UNSUPPORTED !!

Returns:

Keys of the table, as a Set interface.

Throws:

java.lang.UnsupportedOperationException

size

public int size()

Returns the number of Objects in the table.

Returns:

Number of Objects in the table.

isEmpty

public boolean isEmpty()

Returns whether the table is empty.

Returns:

true, if the table is empty

toString

public java.lang.String toString()

Returns the table, in displayable format.

Overrides:

toString in class java.lang.Object

Returns:

Table, in String format.

entrySet

public java.util.Set entrySet()
                       throws java.lang.UnsupportedOperationException

Returns the entries in Map.Entry form. !! Currently UNSUPPORTED !!

Returns:

set of Map.Entry objects

Throws:

java.lang.UnsupportedOperationException

equals

public boolean equals(java.lang.Object o)

Returns whether this table is equal to the given Object.

Overrides:

equals in class java.lang.Object

Parameters:

o - Object to test for equality

Returns:

true, if this table is equal to the given Object

hashCode

public int hashCode()
             throws java.lang.UnsupportedOperationException

Returns the hash code for this table. !! Currently UNSUPPORTED !!

Overrides:

hashCode in class java.lang.Object

Returns:

hash code value for this table

Throws:

java.lang.UnsupportedOperationException

putAll

public void putAll(java.util.Map t)
            throws java.lang.UnsupportedOperationException

Puts all of the elements of the given Map into this table. !! Currently UNSUPPORTED !!

Parameters:

t - holds elements to enter into this table

Throws:

java.lang.UnsupportedOperationException

values

public java.util.Collection values()
                            throws java.lang.UnsupportedOperationException

Returns all the values in the table as a Collection interface. !! Currently UNSUPPORTED !!

Returns:

Values, in a Collection interface.

Throws:

java.lang.UnsupportedOperationException

keys

public java.util.Enumeration keys()

Returns the keys of the table.

Returns:

keys, as an Enumeration