KeyChain

java.lang.Object
- org.qbroker.common.KeyChain

All Implemented Interfaces:

java.util.Comparator

Direct Known Subclasses:

DoubleKeyChain, FloatKeyChain, IntKeyChain, LongKeyChain, StringKeyChain
```
public abstract class KeyChain
extends java.lang.Object
implements java.util.Comparator
```
KeyChain 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 sequnce key can be one of the data types of string, int, long, float or double number. KeyChain has also the support for the meataData as an option so that the extra information can be stored to a separate array together with each object. The metadata is an int array. KeyChain has a public method of sort(). It can be used to sort 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.

Key Type
Key Type Data Type

KEY_STRING String

KEY_INT int

KEY_LONG long

KEY_FLOAT float

KEY_DOUBLE double

KEY_TIME time

KEY_SEQUENCE sequence number

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

Author:

yannanlu@yahoo.com

Key Type
Key Type	Data Type
KEY_STRING	String
KEY_INT	int
KEY_LONG	long
KEY_FLOAT	float
KEY_DOUBLE	double
KEY_TIME	time
KEY_SEQUENCE	sequence number

Field Summary

Fields
Modifier and Type	Field and Description
`protected long`	`ctime`
`protected java.util.ArrayList<java.lang.Object>`	`elements`
`protected boolean`	`isSorted`
`static int`	`KEY_DOUBLE`
`static int`	`KEY_FLOAT`
`static int`	`KEY_INT`
`static int`	`KEY_LONG`
`static int`	`KEY_SEQUENCE`
`static int`	`KEY_STRING`
`static int`	`KEY_TIME`
`protected java.util.ArrayList<int[]>`	`metadata`
`protected long`	`mtime`
`protected int`	`size`
`protected long[]`	`ts`

Constructor Summary

Constructors
Constructor and Description

KeyChain(java.lang.String name, int type, int capacity)

Constructors
Constructor and Description
`KeyChain(java.lang.String name, int type, int capacity)`

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`abstract int`	`add(java.lang.Object key, long mtime, 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.
`void`	`clear()` It cleans up the chain.
`abstract int`	`compare(java.lang.Object a, java.lang.Object b)` It compares thekeys of a and b in the ascending order
`boolean`	`equals(java.lang.Object o)`
`protected void`	`finalize()`
`abstract int`	`find(java.lang.Object key)` It looks for the given key in a sorted instance of KeyChain.
`abstract 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.
`int`	`getCapacity()` returns capacity of the cache
`long`	`getCTime()` It returns the ctime of the chain
`abstract 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`	`getKeyType()`
`abstract 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`	`getMTime()` It returns the mtime of the chain
`java.lang.String`	`getName()`
`abstract long`	`getTimestamp(int i)` It returns the timestamp for the object at the given index or -1 if the index is out of bound.
`abstract int`	`insert(java.lang.Object key, long mtime, int[] meta, java.lang.Object obj)` It inserts the key and the object to the sorted chain and keeps the sorted order.
`abstract int`	`locate(long currentTime, int bakeTime)` It assumes the key chain has been sorted in ascending order.
`int`	`removable()` returns number of the objects whose keys have been removed
`abstract 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`	`size()` returns total number of the objects
`abstract int`	`sort()` It sorts the array of keys in ascending order.
`abstract 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 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

- Field Detail
  - size
```
protected int size
```
  - ctime
```
protected long ctime
```
  - mtime
```
protected long mtime
```
  - isSorted
```
protected boolean isSorted
```
  - ts
```
protected long[] ts
```
  - elements
```
protected java.util.ArrayList<java.lang.Object> elements
```
  - metadata
```
protected java.util.ArrayList<int[]> metadata
```
  - KEY_STRING
```
public static final int KEY_STRING
```
    See Also:
    
    Constant Field Values
  - KEY_INT
```
public static final int KEY_INT
```
    See Also:
    
    Constant Field Values
  - KEY_LONG
```
public static final int KEY_LONG
```
    See Also:
    
    Constant Field Values
  - KEY_FLOAT
```
public static final int KEY_FLOAT
```
    See Also:
    
    Constant Field Values
  - KEY_DOUBLE
```
public static final int KEY_DOUBLE
```
    See Also:
    
    Constant Field Values
  - KEY_TIME
```
public static final int KEY_TIME
```
    See Also:
    
    Constant Field Values
  - KEY_SEQUENCE
```
public static final int KEY_SEQUENCE
```
    See Also:
    
    Constant Field Values
- Constructor Detail
  - KeyChain
```
public KeyChain(java.lang.String name,
                int type,
                int capacity)
```
- Method Detail
  - getCapacity
```
public int getCapacity()
```
    returns capacity of the cache
  - size
```
public int size()
```
    returns total number of the objects
  - removable
```
public int removable()
```
    returns number of the objects whose keys have been removed
  - getName
```
public java.lang.String getName()
```
  - getKeyType
```
public int getKeyType()
```
  - getCTime
```
public long getCTime()
```
    It returns the ctime of the chain
  - getMTime
```
public long getMTime()
```
    It returns the mtime of the chain
  - add
```
public abstract int add(java.lang.Object key,
                        long mtime,
                        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 abstract int insert(java.lang.Object key,
                           long mtime,
                           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.
  - remove
```
public abstract 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.
  - get
```
public abstract 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.
  - getTimestamp
```
public abstract long getTimestamp(int i)
```
    It returns the timestamp for the object at the given index or -1 if the index is out of bound.
  - getMetaData
```
public abstract int[] getMetaData(int i)
```
    It returns the metaData of the key at the given index or null if the index is out of bound.
  - getKey
```
public abstract 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.
  - find
```
public abstract 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.
  - sort
```
public abstract int sort()
```
    It sorts the array of keys in ascending order.
  - locate
```
public abstract 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.
  - truncate
```
public abstract 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.
  - clear
```
public void clear()
```
    It cleans up the chain.
  - finalize
```
protected void finalize()
```
    Overrides:
    
    finalize in class java.lang.Object
  - compare
```
public abstract int compare(java.lang.Object a,
                            java.lang.Object b)
```
    It compares thekeys of a and b in the ascending order
    
    Specified by:
    
    compare in interface java.util.Comparator
  - equals
```
public boolean equals(java.lang.Object o)
```
    Specified by:
    
    equals in interface java.util.Comparator
    
    Overrides:
    
    equals in class java.lang.Object

Class KeyChain

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.Comparator

Field Detail

size

ctime

mtime

isSorted

ts

elements

metadata

KEY_STRING

KEY_INT

KEY_LONG

KEY_FLOAT

KEY_DOUBLE

KEY_TIME

KEY_SEQUENCE

Constructor Detail

KeyChain

Method Detail

getCapacity

size

removable

getName

getKeyType

getCTime

getMTime

add

insert

remove

get

getTimestamp

getMetaData

getKey

find

sort

locate

truncate

clear

finalize

compare

equals