edu.utah.janosvm.kit.util
Class SharedTable

java.lang.Object
  |
  +--edu.utah.janosvm.kit.util.SharedTable

class SharedTable

extends java.lang.Object

The SharedTable class is the core implementation of a hash table that can be shared between multiple teams.

Field Summary

private int	depth The table's position in the stack.
private static int	DEPTH_THRESHOLD The maximum number of SharedTable object's to stack together.
private Association[]	entries The array of references to Associations for this table.
private int	entryCount The number of entries in this table.
private static int	INITIAL_OVERFLOW_SIZE Default overflow array size for a new shared table.
private static int	INITIAL_PRIMARY_SIZE Default primary array size for a new shared table.
private SharedTable	lastGeneration Link to the next table in the stack.
private int[]	overflowLink Array of indexes that link the collision list together.
private int	overflowTableSize The size of the overflow array.
private int	overflowTableUsed The number of slots used in the overflow array.
private int	primaryTableSize The size of the primary hash table.

Constructor Summary

	SharedTable() Construct a SharedTable with the default primary and overflow array sizes.
private	SharedTable(int primarySize, int overflowSize) Construct a SharedTable with the given primary and overflow array sizes.

Method Summary

(package private) java.lang.Object	get(java.lang.Object name) Get an Association from the table using the given identifier object.
int	getEntryCount()
int	getTotalEntryCount()
private int	hashName(java.lang.Object name) Compute the hash for the given identitifer object.
(package private) SharedTable	merge(SharedTable diff, boolean collapse) Merge the current table with the differences introduced by another table.
(package private) void	put(Association assoc) Put an Association into the table.
private void	remove(java.lang.Object name) Remove an Association with the given identifier from the table.
void	walk(SharedTableWriter stw, SharedTableWalker walker)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait, wait0

Field Detail

DEPTH_THRESHOLD

private static final int DEPTH_THRESHOLD

The maximum number of SharedTable object's to stack together.

INITIAL_PRIMARY_SIZE

private static final int INITIAL_PRIMARY_SIZE

Default primary array size for a new shared table.

INITIAL_OVERFLOW_SIZE

private static final int INITIAL_OVERFLOW_SIZE

Default overflow array size for a new shared table.

lastGeneration

private SharedTable lastGeneration

Link to the next table in the stack.

depth

private int depth

The table's position in the stack. The bottom of the stack is 0, positive numbers for the upper elements of the stack.

entries

private Association[] entries

The array of references to Associations for this table.

primaryTableSize

private final int primaryTableSize

The size of the primary hash table.

overflowLink

private int[] overflowLink

Array of indexes that link the collision list together.

overflowTableUsed

private int overflowTableUsed

The number of slots used in the overflow array.

overflowTableSize

private final int overflowTableSize

The size of the overflow array.

entryCount

private int entryCount

The number of entries in this table.

Constructor Detail

SharedTable

public SharedTable()

Construct a SharedTable with the default primary and overflow array sizes.

SharedTable

private SharedTable(int primarySize,
                    int overflowSize)

Construct a SharedTable with the given primary and overflow array sizes.

Parameters:

primarySize - The size of the primary hash table array.

overflowSize - The size of the overflow array for the table.

Method Detail

getEntryCount

public int getEntryCount()

Returns:

The number of entries in this table.

getTotalEntryCount

public int getTotalEntryCount()

Returns:

The number of entries in the stack of tables.

hashName

private int hashName(java.lang.Object name)

Compute the hash for the given identitifer object.

Parameters:

name - The identifier to hash.

Returns:

A hash index that is between zero and this.primaryTableSize, inclusive.

put

void put(Association assoc)
   throws TableFullException

Put an Association into the table.

Parameters:

assoc - The Association object to put in the table.

Throws:

Throws - TableFullException if the overflow array is full and can't accomodate anymore elements.

get

java.lang.Object get(java.lang.Object name)

Get an Association from the table using the given identifier object.

Parameters:

name - The identifier to lookup in the table.

Returns:

The object associated with `name'.

remove

private void remove(java.lang.Object name)

Remove an Association with the given identifier from the table. This is private since it can only be used by merge() on an unshared table.

Parameters:

name - The identifier to lookup and remove from the table.

walk

public void walk(SharedTableWriter stw,
                 SharedTableWalker walker)

merge

SharedTable merge(SharedTable diff,
                  boolean collapse)

Merge the current table with the differences introduced by another table.

Parameters:

diff - A table containing changes to the current table.

collapse - Force the stack of tables to be coalesced into a

collapse - single table.

Returns:

Either the `diff' table thats been connected to the current