it.unimi.dsi.webgraph.labelling
Class FixedWidthIntLabel

java.lang.Object
  extended by it.unimi.dsi.webgraph.labelling.AbstractLabel
      extended by it.unimi.dsi.webgraph.labelling.AbstractIntLabel
          extended by it.unimi.dsi.webgraph.labelling.FixedWidthIntLabel
All Implemented Interfaces:
FlyweightPrototype<Label>, Label

public class FixedWidthIntLabel
extends AbstractIntLabel

An integer represented in fixed width. The provided width must be smaller than 32.


Field Summary
protected  int width
          The bit width used to represent the value of this label.
 
Fields inherited from class it.unimi.dsi.webgraph.labelling.AbstractIntLabel
key, value
 
Constructor Summary
FixedWidthIntLabel(String... arg)
          Creates a new fixed-width integer label using the given key and width with value 0.
FixedWidthIntLabel(String key, int width)
          Creates a new fixed-width int label of value 0.
FixedWidthIntLabel(String key, int width, int value)
          Creates a new fixed-width int label.
 
Method Summary
 Label copy()
          Returns a copy of this label.
 int fixedWidth()
          Returns the width of this label (as provided at construction time).
 int fromBitStream(InputBitStream inputBitStream, int sourceUnused)
          Fills this label with data from the given input bit stream, knowing the source node of the arc.
 int toBitStream(OutputBitStream outputBitStream, int sourceUnused)
          Writes out this label to the given input bit stream, in self-delimiting form, knowing the source node of the arc.
 String toSpec()
          Returns a string representing the specification of this label.
 String toString()
           
 
Methods inherited from class it.unimi.dsi.webgraph.labelling.AbstractIntLabel
attributeKeys, attributeTypes, equals, get, get, getDouble, getDouble, getFloat, getFloat, getInt, getInt, getLong, getLong, hashCode, wellKnownAttributeKey
 
Methods inherited from class it.unimi.dsi.webgraph.labelling.AbstractLabel
getBoolean, getBoolean, getByte, getByte, getChar, getChar, getShort, getShort
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface it.unimi.dsi.webgraph.labelling.Label
getBoolean, getBoolean, getByte, getByte, getChar, getChar, getShort, getShort
 

Field Detail

width

protected final int width
The bit width used to represent the value of this label.

Constructor Detail

FixedWidthIntLabel

public FixedWidthIntLabel(String key,
                          int width,
                          int value)
Creates a new fixed-width int label.

Parameters:
key - the (only) key of this label.
width - the label width (in bits).
value - the value of this label.

FixedWidthIntLabel

public FixedWidthIntLabel(String key,
                          int width)
Creates a new fixed-width int label of value 0.

Parameters:
key - the (only) key of this label.
width - the label width (in bits).

FixedWidthIntLabel

public FixedWidthIntLabel(String... arg)
Creates a new fixed-width integer label using the given key and width with value 0.

Parameters:
arg - two strings containing the key and the width of this label.
Method Detail

copy

public Label copy()
Description copied from interface: Label
Returns a copy of this label.

Returns:
a new label that copies this one.

fromBitStream

public int fromBitStream(InputBitStream inputBitStream,
                         int sourceUnused)
                  throws IOException
Description copied from interface: Label
Fills this label with data from the given input bit stream, knowing the source node of the arc. If Label.fixedWidth() is not negative, the value returned must coincide with Label.fixedWidth(). This method is optional.

Parameters:
inputBitStream - an input bit stream offering a label.
sourceUnused - the source node.
Returns:
the number of bits read to fill this label.
Throws:
IOException

toBitStream

public int toBitStream(OutputBitStream outputBitStream,
                       int sourceUnused)
                throws IOException
Description copied from interface: Label
Writes out this label to the given input bit stream, in self-delimiting form, knowing the source node of the arc. If Label.fixedWidth() is not negative, the value returned must coincide with Label.fixedWidth(). This method is optional.

Parameters:
outputBitStream - an output bit stream where the label will be written.
sourceUnused - the source node.
Returns:
the number of bits written.
Throws:
IOException

fixedWidth

public int fixedWidth()
Returns the width of this label (as provided at construction time).

Returns:
the width of this label.

toString

public String toString()
Overrides:
toString in class AbstractIntLabel

toSpec

public String toSpec()
Description copied from interface: Label
Returns a string representing the specification of this label.

Each label class can be instantiated in several ways (e.g., FixedWidthIntLabel requires a name for the well-known attribute and a number of bits). This method must return a representation that can be used by ObjectParser to instantiate the class, and consequently there must exist a matching constructor whose arguments are strings.

There is an equation that must be always satisfied:

 ObjectParser.fromSpec( x.toSpec() ).toSpec().equals( x.toSpec() )
 

Returns:
a string representing the specification of this label.
See Also:
ObjectParser.fromSpec(String, Class)