edu.berkeley.cs.db.yfilter.filterinstance
Class Queue

java.lang.Object
  |
  +--edu.berkeley.cs.db.yfilter.filterinstance.Queue

public class Queue

extends java.lang.Object

Implements a circular queue.

Field Summary

protected java.util.Vector	data To store additional data, per element in the Vector.
protected static int	DOC_QUEUE Indicates that the queue contains documents.
protected java.util.Vector	elements Stores the actual elements.
protected EXfilter	filter The filter object, used to handle query additions and deletions.
protected int	idInProcess The current obect being processed.
protected int	index A cumulative index for the elements passing through the queue.
protected int	max_index The max index present in the queue.
protected int	min_index The least index present in the queue.
static java.lang.String	NO_RESULT
static java.lang.String	OBJ_EXPIRED
static java.lang.String	OBJ_NA
protected int	qType This queue is a document queue by default.
protected static int	QUERY_QUEUE Indicates that the queue contains queries.
protected java.util.Hashtable	queryIDMap Handles the map between queue and filter ids for queries, since the filter asynchronously assignes IDs to queries.
static int	WAIT For threads, the wait period for notification.

Constructor Summary

Queue()
Default constructor.

Queue(int capacity)

Queue(int capacity, EXfilter filter)

Method Summary

java.lang.Object	get(int id) Gets an object from the queue.
java.lang.Object	getData(int id) Gets the data associated with the id.
java.util.Hashtable	processNext()
int	set(java.lang.Object o) Adds an object to the queue.
boolean	setData(java.lang.Object o, int id) Adds a data object corresponding to an id.

Methods inherited from class java.lang.Object

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

Field Detail

WAIT

public static int WAIT

For threads, the wait period for notification.

NO_RESULT

public static java.lang.String NO_RESULT

OBJ_EXPIRED

public static java.lang.String OBJ_EXPIRED

OBJ_NA

public static java.lang.String OBJ_NA

DOC_QUEUE

protected static int DOC_QUEUE

Indicates that the queue contains documents.

QUERY_QUEUE

protected static int QUERY_QUEUE

Indicates that the queue contains queries.

qType

protected int qType

This queue is a document queue by default.

min_index

protected int min_index

The least index present in the queue.

max_index

protected int max_index

The max index present in the queue.

index

protected int index

A cumulative index for the elements passing through the queue.

elements

protected java.util.Vector elements

Stores the actual elements. e.g. queries (Query), documents (XMLTree)

data

protected java.util.Vector data

To store additional data, per element in the Vector. e.g. A document can have a Hashtable of matched queries. A query can have matched elements.

idInProcess

protected int idInProcess

The current obect being processed. e.g. the doc ID being processed by the filter.

filter

protected EXfilter filter

The filter object, used to handle query additions and deletions.

queryIDMap

protected java.util.Hashtable queryIDMap

Handles the map between queue and filter ids for queries, since the filter asynchronously assignes IDs to queries.

Constructor Detail

Queue

public Queue(int capacity)

Parameters:

capacity -

Queue

public Queue(int capacity,
             EXfilter filter)

Queue

public Queue()

Default constructor. constructs a document queue of length 100.

Method Detail

set

public int set(java.lang.Object o)

Adds an object to the queue. If the queue is full, pops out the oldest object.

Parameters:

o - The object to be added.

Returns:

int The id of the object in the queue.

get

public java.lang.Object get(int id)

Gets an object from the queue.

Parameters:

id - The object id

Returns:

Object A status string if the object is not in the queue else, the object.

getData

public java.lang.Object getData(int id)

Gets the data associated with the id. e.g. For documents, the data could be matching query elements.

Returns:

Object The data object

setData

public boolean setData(java.lang.Object o,
                       int id)

Adds a data object corresponding to an id. e.g. For a document, this could be the matching query elements.

Parameters:

o - The data object to be added.

id - The id of the corressponding object

Returns:

boolean the status of the action.

processNext

public java.util.Hashtable processNext()