org.qbroker.common

Class DoubleKeyChain

java.lang.Object

org.qbroker.common.KeyChain

org.qbroker.common.DoubleKeyChain

All Implemented Interfaces:

java.util.Comparator

public class DoubleKeyChain
extends KeyChain

DoubleKeyChain contains an array of the sequence keys, timestamp, metadata and objects. The sequence key is stored in an array with the internal index to the object and the timestamp. The data type of the sequence key is Double. DoubleKeyChain has also the support for metadata as an option so that extra information can be stored to a separate array together with each object. The metadata is an int array. DoubleKeyChain has a public method of sort(). It sorts the objects in the ascending order according to their sequence keys. The index of the keys may not be same as their internal index to the object.

This is NOT MT-Safe. Therefore please use it with care.

Author:

yannanlu@yahoo.com

Field Summary

Fields inherited from class org.qbroker.common.KeyChain

ctime, elements, isSorted, KEY_DOUBLE, KEY_FLOAT, KEY_INT, KEY_LONG, KEY_SEQUENCE, KEY_STRING, KEY_TIME, metadata, mtime, size, ts

Constructor Summary

Constructors

Constructor and Description
DoubleKeyChain(java.lang.String name, int capacity)

Method Summary

Modifier and Type	Method and Description
int	add(double key, long currentTime, int[] meta, java.lang.Object obj) It adds the key and the object to the chain, and returns total number of keys in the chain.
int	add(java.lang.Object key, long currentTime, int[] meta, java.lang.Object obj) It adds the key and the object to the chain, and returns total number of keys in the chain.
int	compare(java.lang.Object a, java.lang.Object b) It compares a and b in the ascending order
int	find(java.lang.Object key) It looks for the given key in a sorted instance of KeyChain.
java.lang.Object	get(int i) It returns the object of the key at the given index or null if the index is out of bound.
java.lang.Object	getKey(int i) It returns the key in its data type at the given index or null if the index is out of bound.
int[]	getMetaData(int i) It returns the metadata of the key at the given index or null if the index is out of bound.
long	getTimestamp(int i) It returns the timestamp of the key at the given index or -1 if the index is out of bound.
int	insert(java.lang.Object key, long currentTime, int[] meta, java.lang.Object obj) It inserts the key and the object to the sorted chain and keeps the sorted order.
int	locate(long currentTime, int bakeTime) It assumes the key chain has been sorted in ascending order.
java.lang.Object	remove(int i) It removes the key at the given index from the chain and disables its metadata and the object so that they will not be available any more.
int	sort() It sorts the array of keys in ascending order.
int	truncate(int k) It truncates the chain by deleting the first given number of keys permanently and returns the number of keys deleted.

Methods inherited from class org.qbroker.common.KeyChain

clear, equals, finalize, getCapacity, getCTime, getKeyType, getMTime, getName, removable, size

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Comparator

comparing, comparing, comparingDouble, comparingInt, comparingLong, naturalOrder, nullsFirst, nullsLast, reversed, reverseOrder, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Constructor Detail

DoubleKeyChain

public DoubleKeyChain(java.lang.String name,
                      int capacity)

Method Detail

add

public int add(java.lang.Object key,
               long currentTime,
               int[] meta,
               java.lang.Object obj)

It adds the key and the object to the chain, and returns total number of keys in the chain. If the chain is in the sorted order, it will break the order of keys.

Specified by:

add in class KeyChain

add

public int add(double key,
               long currentTime,
               int[] meta,
               java.lang.Object obj)

It adds the key and the object to the chain, and returns total number of keys in the chain. If the chain is in the sorted order, it will break the order of keys.

insert

public int insert(java.lang.Object key,
                  long currentTime,
                  int[] meta,
                  java.lang.Object obj)

It inserts the key and the object to the sorted chain and keeps the sorted order. It returns total number of keys in the chain.

Specified by:

insert in class KeyChain

remove

public java.lang.Object remove(int i)

It removes the key at the given index from the chain and disables its metadata and the object so that they will not be available any more. However, they still take space in the chain. To delete it permanently, the method of truncate() must be called. It returns the object upon success or null otherwise.

Specified by:

remove in class KeyChain

get

public java.lang.Object get(int i)

It returns the object of the key at the given index or null if the index is out of bound.

Specified by:

get in class KeyChain

getMetaData

public int[] getMetaData(int i)

It returns the metadata of the key at the given index or null if the index is out of bound.

Specified by:

getMetaData in class KeyChain

getTimestamp

public long getTimestamp(int i)

It returns the timestamp of the key at the given index or -1 if the index is out of bound.

Specified by:

getTimestamp in class KeyChain

getKey

public java.lang.Object getKey(int i)

It returns the key in its data type at the given index or null if the index is out of bound.

Specified by:

getKey in class KeyChain

find

public int find(java.lang.Object key)

It looks for the given key in a sorted instance of KeyChain. If the key is found, the last index of the key will be returned. Otherwise, it returns a negative number. For a negative return value of r, the index of -(r+1) specifies the index at which the specified key can be inserted to maintain the sorted order.

Specified by:

find in class KeyChain

sort

public int sort()

It sorts the array of keys in ascending order.

Specified by:

sort in class KeyChain

locate

public int locate(long currentTime,
                  int bakeTime)

It assumes the key chain has been sorted in ascending order. Then it looks for the last fully baked key. Upon found the key, it returns the number of keys with lower values or same value as compared to the last fully baked key. Otherwise, it returns 0.

Specified by:

locate in class KeyChain

truncate

public int truncate(int k)

It truncates the chain by deleting the first given number of keys permanently and returns the number of keys deleted. It assumes all keys have already been sorted. If there are active keys left, it will also reset the ctime to that of the most baked key. If k is less than or equal to 0, it will delete all removed keys.

Specified by:

truncate in class KeyChain

compare

public int compare(java.lang.Object a,
                   java.lang.Object b)

It compares a and b in the ascending order

Specified by:

compare in interface java.util.Comparator

Specified by:

compare in class KeyChain