Top Description Fields Constructors Methods
com.googlecode.javaewah.datastructure

public Class ImmutableBitSet

extends Object
implements Cloneable, Iterable<Integer>, WordArray
Class Inheritance
All Implemented Interfaces
com.googlecode.javaewah.datastructure.WordArray, java.lang.Iterable, java.lang.Cloneable
Imports
java.nio.LongBuffer, java.util.Iterator, com.googlecode.javaewah.IntIterator
This is an immutable version of the BitSet class in this same package. It is meant to be used with memory-file mapping. 
final FileOutputStream fos = new FileOutputStream(tmpfile);
	BitSet Bitmap = BitSet.bitmapOf(0, 2, 55, 64, 512);
	Bitmap.serialize(new DataOutputStream(fos));
		RandomAccessFile memoryMappedFile = new RandomAccessFile(tmpfile, "r");
		ByteBuffer bb = memoryMappedFile.getChannel().map(
				FileChannel.MapMode.READ_ONLY, 0, totalcount);
		ImmutableBitSet mapped = new ImmutableBitSet(bb.asLongBuffer());

Field Summary

Modifier and TypeField and Description
private LongBuffer
data

Constructor Summary

AccessConstructor and Description
public
ImmutableBitSet(final LongBuffer
the data source
bs)

Construct a ImmutableBitSet from the content of the LongBuffer which should have been initialized with BitSet.serialize (from the BitSet in this same package).

Method Summary

Modifier and TypeMethod and Description
public BitSet

Returns:

a copy
asBitSet()

Get a copy of this ImmutableBitSet as a mutable BitSet.

public int

Returns:

the number of bits
cardinality()

Compute the number of bits set to 1

public ImmutableBitSet
clone()

Overrides java.lang.Object.clone.

Creates and returns a copy of this object.

public boolean

Returns:

true if no set bit is found
empty()

Check whether a bitset contains a set bit.

public boolean
equals(Object
the reference object with which to compare.
o)

Overrides java.lang.Object.equals.

Indicates whether some other object is "equal to" this one.

public boolean

Returns:

value of the bit
get(final int
index
i)

get value of bit i

public int
getNumberOfWords()

Implements com.googlecode.javaewah.datastructure.WordArray.getNumberOfWords.

Get the total number of words contained in this data structure.

public long
getWord(int
the index
index)

Implements com.googlecode.javaewah.datastructure.WordArray.getWord.

Get the word at the given index

public int
hashCode()

Overrides java.lang.Object.hashCode.

Returns a hash code value for this object.

public boolean

Returns:

true if they have a non-empty intersection (result of AND)
intersects(BitSet
other bitset
bs)

Checks whether two bitsets intersect.

public IntIterator

Returns:

an iterator
intIterator()

Iterate over the set bits

public Iterator<Integer>
iterator()

Implements java.lang.Iterable.iterator.

Returns an iterator over elements of type T.

public int

Returns:

next set bit or -1
nextSetBit(final int
current set bit
i)

Usage: for(int i=bs.nextSetBit(0); i>=0; i=bs.nextSetBit(i+1)) { operate on index i here }

public int

Returns:

next unset bit or -1
nextUnsetBit(final int
current unset bit
i)

Usage: for(int i=bs.nextUnsetBit(0); i>=0; i=bs.nextUnsetBit(i+1)) { operate on index i here }

public int

Returns:

the size in bits.
size()

Query the size

public String
toString()

Overrides java.lang.Object.toString.

Returns a string representation of the object.

public IntIterator

Returns:

an iterator
unsetIntIterator()

Iterate over the unset bits

Inherited from java.lang.Object:
finalizegetClassnotifynotifyAllwaitwaitwait

Field Detail

databack to summary
private LongBuffer data

Constructor Detail

ImmutableBitSetback to summary
public ImmutableBitSet(final LongBuffer bs)

Construct a ImmutableBitSet from the content of the LongBuffer which should have been initialized with BitSet.serialize (from the BitSet in this same package). The input is not modified.

Parameters
bs:LongBuffer

the data source

Method Detail

asBitSetback to summary
public BitSet asBitSet()

Get a copy of this ImmutableBitSet as a mutable BitSet.

Returns:BitSet

a copy

cardinalityback to summary
public int cardinality()

Compute the number of bits set to 1

Returns:int

the number of bits

cloneback to summary
public ImmutableBitSet clone()

Overrides java.lang.Object.clone.

Doc from java.lang.Object.clone.

Creates and returns a copy of this object. The precise meaning of "copy" may depend on the class of the object. The general intent is that, for any object x, the expression: 

x.clone() != x
will be true, and that the expression: 
x.clone().getClass() == x.getClass()
will be true, but these are not absolute requirements. While it is typically the case that: 
x.clone().equals(x)
will be true, this is not an absolute requirement.

By convention, the returned object should be obtained by calling super.clone. If a class and all of its superclasses (except Object) obey this convention, it will be the case that x.clone().getClass() == x.getClass().

By convention, the object returned by this method should be independent of this object (which is being cloned). To achieve this independence, it may be necessary to modify one or more fields of the object returned by super.clone before returning it. Typically, this means copying any mutable objects that comprise the internal "deep structure" of the object being cloned and replacing the references to these objects with references to the copies. If a class contains only primitive fields or references to immutable objects, then it is usually the case that no fields in the object returned by super.clone need to be modified.

Returns:ImmutableBitSet

a clone of this instance.

Annotations
@Override
emptyback to summary
public boolean empty()

Check whether a bitset contains a set bit.

Returns:boolean

true if no set bit is found

equalsback to summary
public boolean equals(Object o)

Overrides java.lang.Object.equals.

Doc from java.lang.Object.equals.

Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

  • It is reflexive: for any non-null reference value x, x.equals(x) should return true.
  • It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
  • It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
  • It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
  • For any non-null reference value x, x.equals(null) should return false.

An equivalence relation partitions the elements it operates on into equivalence classes; all the members of an equivalence class are equal to each other. Members of an equivalence class are substitutable for each other, at least for some purposes.

Parameters
o:Object

the reference object with which to compare.

Returns:boolean

true if this object is the same as the obj argument; false otherwise.

Annotations
@Override
getback to summary
public boolean get(final int i)

get value of bit i

Parameters
i:int

index

Returns:boolean

value of the bit

getNumberOfWordsback to summary
public int getNumberOfWords()

Implements com.googlecode.javaewah.datastructure.WordArray.getNumberOfWords.

Doc from com.googlecode.javaewah.datastructure.WordArray.getNumberOfWords.

Get the total number of words contained in this data structure.

Returns:int

the number

Annotations
@Override
getWordback to summary
public long getWord(int index)

Implements com.googlecode.javaewah.datastructure.WordArray.getWord.

Doc from com.googlecode.javaewah.datastructure.WordArray.getWord.

Get the word at the given index

Parameters
index:int

the index

Returns:long

the word

Annotations
@Override
hashCodeback to summary
public int hashCode()

Overrides java.lang.Object.hashCode.

Doc from java.lang.Object.hashCode.

Returns a hash code value for this object. This method is supported for the benefit of hash tables such as those provided by java.util.HashMap.

The general contract of hashCode is:

  • Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
  • If two objects are equal according to the equals method, then calling the hashCode method on each of the two objects must produce the same integer result.
  • It is not required that if two objects are unequal according to the equals method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.
Returns:int

a hash code value for this object

Annotations
@Override
intersectsback to summary
public boolean intersects(BitSet bs)

Checks whether two bitsets intersect.

Parameters
bs:BitSet

other bitset

Returns:boolean

true if they have a non-empty intersection (result of AND)

intIteratorback to summary
public IntIterator intIterator()

Iterate over the set bits

Returns:IntIterator

an iterator

iteratorback to summary
public Iterator<Integer> iterator()

Implements java.lang.Iterable.iterator.

Doc from java.lang.Iterable.iterator.

Returns an iterator over elements of type T.

Returns:Iterator<Integer>

an Iterator.

Annotations
@Override
nextSetBitback to summary
public int nextSetBit(final int i)

Usage: for(int i=bs.nextSetBit(0); i>=0; i=bs.nextSetBit(i+1)) { operate on index i here }

Parameters
i:int

current set bit

Returns:int

next set bit or -1

nextUnsetBitback to summary
public int nextUnsetBit(final int i)

Usage: for(int i=bs.nextUnsetBit(0); i>=0; i=bs.nextUnsetBit(i+1)) { operate on index i here }

Parameters
i:int

current unset bit

Returns:int

next unset bit or -1

sizeback to summary
public int size()

Query the size

Returns:int

the size in bits.

toStringback to summary
public String toString()

Overrides java.lang.Object.toString.

Doc from java.lang.Object.toString.

Returns a string representation of the object. Satisfying this method's contract implies a non-null result must be returned.

Returns:String

a string representation of the object

Annotations
@Override
unsetIntIteratorback to summary
public IntIterator unsetIntIterator()

Iterate over the unset bits

Returns:IntIterator

an iterator