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Interface ActiveList


public interface ActiveList

An active list is maintained as a sorted list Note that all scores are represented in LogMath logbase


Field Summary
static java.lang.String PROP_ABSOLUTE_BEAM_WIDTH
          property that sets the desired (or target) size for this active list.
static int PROP_ABSOLUTE_BEAM_WIDTH_DEFAULT
          The default value for the PROP_ABSOLUTE_BEAM_WIDTH property
static java.lang.String PROP_RELATIVE_BEAM_WIDTH
          Property that sets the minimum score relative to the maximum score in the list for pruning.
static double PROP_RELATIVE_BEAM_WIDTH_DEFAULT
          The default value for the PROP_RELATIVE_BEAM_WIDTH property
static java.lang.String PROP_STRICT_PRUNING
          Property that indicates whether or not the active list will implement 'strict pruning'.
static boolean PROP_STRICT_PRUNING_DEFAULT
          The default for the PROP_STRICT_PRUNING property
 
Method Summary
 void add(Token token)
          Adds the given token to the list, keeping track of the lowest scoring token
 float getBeamThreshold()
          gets the beam threshold best upon the best scoring token
 float getBestScore()
          gets the best score in the list
 Token getBestToken()
          Gets the best scoring token for this active list
 java.util.List getTokens()
          Gets the list of all tokens
 java.util.Iterator iterator()
          Returns an iterator over the elements in this active list
 ActiveList newInstance()
          Creates a new empty version of this active list with the same general properties.
 ActiveList purge()
          Purges the active list of excess members returning a (potentially new) active list
 void replace(Token oldToken, Token newToken)
          Replaces an old token with a new token
 void setBestToken(Token token)
          Sets the best scoring token for this active list
 int size()
          Returns the size of this list
 

Field Detail

PROP_ABSOLUTE_BEAM_WIDTH

public static final java.lang.String PROP_ABSOLUTE_BEAM_WIDTH
property that sets the desired (or target) size for this active list. This is sometimes referred to as the beam size

See Also:
Constant Field Values

PROP_ABSOLUTE_BEAM_WIDTH_DEFAULT

public static final int PROP_ABSOLUTE_BEAM_WIDTH_DEFAULT
The default value for the PROP_ABSOLUTE_BEAM_WIDTH property

See Also:
Constant Field Values

PROP_RELATIVE_BEAM_WIDTH

public static final java.lang.String PROP_RELATIVE_BEAM_WIDTH
Property that sets the minimum score relative to the maximum score in the list for pruning. Tokens with a score less than relativeBeamWidth * maximumScore will be pruned from the list

See Also:
Constant Field Values

PROP_RELATIVE_BEAM_WIDTH_DEFAULT

public static final double PROP_RELATIVE_BEAM_WIDTH_DEFAULT
The default value for the PROP_RELATIVE_BEAM_WIDTH property

See Also:
Constant Field Values

PROP_STRICT_PRUNING

public static final java.lang.String PROP_STRICT_PRUNING
Property that indicates whether or not the active list will implement 'strict pruning'. When strict pruning is enabled, the active list will not remove tokens from the active list until they have been completely scored. If strict pruning is not enabled, tokens can be removed from the active list based upon their entry scores. The default setting is false (disabled).

See Also:
Constant Field Values

PROP_STRICT_PRUNING_DEFAULT

public static final boolean PROP_STRICT_PRUNING_DEFAULT
The default for the PROP_STRICT_PRUNING property

See Also:
Constant Field Values
Method Detail

add

public void add(Token token)
Adds the given token to the list, keeping track of the lowest scoring token

Parameters:
token - the token to add

replace

public void replace(Token oldToken,
                    Token newToken)
Replaces an old token with a new token

Parameters:
oldToken - the token to replace (or null in which case, replace works like add).
newToken - the new token to be placed in the list.

purge

public ActiveList purge()
Purges the active list of excess members returning a (potentially new) active list

Returns:
a purged active list

iterator

public java.util.Iterator iterator()
Returns an iterator over the elements in this active list

Returns:
an iterator

size

public int size()
Returns the size of this list

Returns:
the size

getTokens

public java.util.List getTokens()
Gets the list of all tokens

Returns:
the set of tokens

getBeamThreshold

public float getBeamThreshold()
gets the beam threshold best upon the best scoring token

Returns:
the beam threshold

getBestScore

public float getBestScore()
gets the best score in the list

Returns:
the best score

setBestToken

public void setBestToken(Token token)
Sets the best scoring token for this active list

Parameters:
token - the best scoring token

getBestToken

public Token getBestToken()
Gets the best scoring token for this active list

Returns:
the best scoring token

newInstance

public ActiveList newInstance()
Creates a new empty version of this active list with the same general properties.

Returns:
a new active list.