stream.statistics

Class History<T>

java.lang.Object

stream.statistics.History<T>

Type Parameters:

T - The type of objects associated with each timepoint/timestamp.

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

StatisticsHistory

public class History<T>
extends Object
implements Serializable

This is a generic implementation of a history. Basically a history associates items of type T with timestamps, which are grouped to discrete timestamps, e.g. every full hour, every 5 minutes, etc.

The type T is usually a data structure, which allows aggregation of multiple values of nearby time points.

Author:

Christian Bockermann <chris@jwall.org>

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static long	DAY
(package private) long	historyLength
static long	HOUR
(package private) long	last
(package private) LinkedHashMap<Long,T>	map
static long	MILLISECOND
static long	MINUTE
static long	MONTH
static long	SECOND
private static long	serialVersionUID The unique class ID
(package private) long	stepSize
static long	WEEK
static long	YEAR

Constructor Summary

Constructors

Constructor and Description
History(long stepSize, long historyLength)

Method Summary

Methods

Modifier and Type	Method and Description
void	add(Long timestamp, T data)
protected Long	adjust(Long timestamp) This method maps the given timestamp to the last official timestamp, as induced by the stepSize.
void	clear()
void	forget() This method removes any data that is associated with a timestamp older than historyLength milliseconds.
T	get(int i)
T	get(Long timestamp)
List<T>	getData()
Long	getLength()
int	getPosition(Long timestamp)
int	getSteps()
long	getStepSize() Returns the step size for this history.
Long	getTimestamp(int i)
protected long	last() Returns the last official timestamp for this history.
Long	map(int i) Returns the timestamp for the ith element of this history.
Long	mapTimestamp(Long timestamp)

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

private static final long serialVersionUID

The unique class ID

See Also:

Constant Field Values

MILLISECOND

public static final long MILLISECOND

See Also:

Constant Field Values

SECOND

public static final long SECOND

See Also:

Constant Field Values

MINUTE

public static final long MINUTE

See Also:

Constant Field Values

HOUR

public static final long HOUR

See Also:

Constant Field Values

DAY

public static final long DAY

See Also:

Constant Field Values

WEEK

public static final long WEEK

See Also:

Constant Field Values

MONTH

public static final long MONTH

See Also:

Constant Field Values

YEAR

public static final long YEAR

See Also:

Constant Field Values

stepSize

long stepSize

historyLength

long historyLength

map

LinkedHashMap<Long,T> map

last

long last

Constructor Detail

History

public History(long stepSize,
       long historyLength)

Method Detail

getStepSize

public long getStepSize()

Returns the step size for this history.

Returns:

getLength

public Long getLength()

See Also:

org.jwall.web.audit.console.statistics.History#getLength()

get

public T get(int i)

See Also:

org.jwall.web.audit.console.statistics.History#get(int)

getPosition

public int getPosition(Long timestamp)

See Also:

org.jwall.web.audit.console.statistics.History#getPosition(java.lang.Long)

getSteps

public int getSteps()

See Also:

org.jwall.web.audit.console.statistics.History#getSteps()

getTimestamp

public Long getTimestamp(int i)

See Also:

org.jwall.web.audit.console.statistics.History#getTimestamp(int)

get

public T get(Long timestamp)

See Also:

org.jwall.web.audit.console.statistics.History#get(java.lang.Long)

add

public void add(Long timestamp,
       T data)

See Also:

org.jwall.web.audit.console.statistics.History#add(java.lang.Long, java.lang.Object)

adjust

protected Long adjust(Long timestamp)

This method maps the given timestamp to the last official timestamp, as induced by the stepSize.

Parameters:

timestamp -

Returns:

mapTimestamp

public Long mapTimestamp(Long timestamp)

forget

public void forget()

This method removes any data that is associated with a timestamp older than historyLength milliseconds. Items will only be removed if older than historyLength AND there are more than getSteps() items contained in this history.

last

protected long last()

Returns the last official timestamp for this history. This is either the timestamp of the last element added to the history or the adjusted current timestamp.

Returns:

map

public Long map(int i)

Returns the timestamp for the ith element of this history.

Parameters:

i -

Returns:

getData

public List<T> getData()

clear

public void clear()