#include <dbbi.h>
Inheritance diagram for DictionaryBasedBreakIterator::
Public Methods | |
virtual | ~DictionaryBasedBreakIterator () |
Destructor. More... | |
DictionaryBasedBreakIterator () | |
Default constructor. More... | |
DictionaryBasedBreakIterator (const DictionaryBasedBreakIterator &other) | |
Copy constructor. More... | |
DictionaryBasedBreakIterator & | operator= (const DictionaryBasedBreakIterator &that) |
Assignment operator. More... | |
virtual BreakIterator * | clone (void) const |
Returns a newly-constructed RuleBasedBreakIterator with the same behavior, and iterating over the same text, as this one. More... | |
virtual int32_t | previous (void) |
Advances the iterator backwards, to the last boundary preceding this one. More... | |
virtual int32_t | following (int32_t offset) |
Sets the iterator to refer to the first boundary position following the specified position. More... | |
virtual int32_t | preceding (int32_t offset) |
Sets the iterator to refer to the last boundary position before the specified position. More... | |
virtual UClassID | getDynamicClassID (void) const |
Returns a unique class ID POLYMORPHICALLY. More... | |
Static Public Methods | |
UClassID | getStaticClassID (void) |
Returns the class ID for this class. More... | |
Protected Methods | |
virtual int32_t | handleNext (void) |
This method is the actual implementation of the next() method. More... | |
virtual void | reset (void) |
removes the cache of break positions (usually in response to a change in position of some sort). More... | |
void | init () |
init Initialize a dbbi. More... | |
virtual BreakIterator * | createBufferClone (void *stackBuffer, int32_t &BufferSize, UErrorCode &status) |
Private Methods | |
DictionaryBasedBreakIterator (UDataMemory *tablesImage, const char *dictionaryFilename, UErrorCode &status) | |
======================================================================= Create a dictionary based break boundary detection iterator. More... | |
void | divideUpDictionaryRange (int32_t startPos, int32_t endPos, UErrorCode &status) |
This is the function that actually implements the dictionary-based algorithm. More... | |
Private Attributes | |
int32_t * | cachedBreakPositions |
when a range of characters is divided up using the dictionary, the break positions that are discovered are stored here, preventing us from having to use either the dictionary or the state table again until the iterator leaves this range of text. More... | |
int32_t | numCachedBreakPositions |
The number of elements in cachedBreakPositions. More... | |
int32_t | positionInCache |
if cachedBreakPositions is not null, this indicates which item in the cache the current iteration position refers to. More... | |
DictionaryBasedBreakIteratorTables * | fTables |
Friends | |
class | DictionaryBasedBreakIteratorTables |
class | BreakIterator |
This is necessary, for example, to handle word and line breaking in Thai, which doesn't use spaces between words. The state-table-based algorithm used by RuleBasedBreakIterator is used to divide up text as far as possible, and then contiguous ranges of letters are repeatedly compared against a list of known words (i.e., the dictionary) to divide them up into words.
Applications do not normally need to include this header.
This class will probably be deprecated in a future release of ICU, and replaced with a more flexible and capable dictionary based break iterator. This change should be invisible to applications, because creation and use of instances of DictionaryBasedBreakIterator is through the factories and abstract API on class BreakIterator, which will remain stable.
This class is not intended to be subclassed.
DictionaryBasedBreakIterator uses the same rule language as RuleBasedBreakIterator, but adds one more special substitution name: <dictionary>. This substitution name is used to identify characters in words in the dictionary. The idea is that if the iterator passes over a chunk of text that includes two or more characters in a row that are included in <dictionary>, it goes back through that range and derives additional break positions (if possible) using the dictionary.
DictionaryBasedBreakIterator is also constructed with the filename of a dictionary file. It follows a prescribed search path to locate the dictionary (right now, it looks for it in /com/ibm/text/resources in each directory in the classpath, and won't find it in JAR files, but this location is likely to change). The dictionary file is in a serialized binary format. We have a very primitive (and slow) BuildDictionaryFile utility for creating dictionary files, but aren't currently making it public. Contact us for help.
NOTE The DictionaryBasedIterator class is still under development. The APIs are not in stable condition yet.
Definition at line 62 of file dbbi.h.
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======================================================================= Create a dictionary based break boundary detection iterator.
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Destructor.
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Default constructor. Creates an "empty" break iterator. Such an iterator can subsequently be assigned to.
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Copy constructor.
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Returns a newly-constructed RuleBasedBreakIterator with the same behavior, and iterating over the same text, as this one.
Reimplemented from RuleBasedBreakIterator. |
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This is the function that actually implements the dictionary-based algorithm. Given the endpoints of a range of text, it uses the dictionary to determine the positions of any boundaries in this range. It stores all the boundary positions it discovers in cachedBreakPositions so that we only have to do this work once for each time we enter the range.
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Sets the iterator to refer to the first boundary position following the specified position. @offset The position from which to begin searching for a break position.
Reimplemented from RuleBasedBreakIterator. |
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Returns a unique class ID POLYMORPHICALLY. Pure virtual override. This method is to implement a simple version of RTTI, since not all C++ compilers support genuine RTTI. Polymorphic operator==() and clone() methods call this method.
Reimplemented from RuleBasedBreakIterator. |
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Returns the class ID for this class. This is useful only for comparing to a return value from getDynamicClassID(). For example: Base* polymorphic_pointer = createPolymorphicObject(); if (polymorphic_pointer->getDynamicClassID() == Derived::getStaticClassID()) ...
Reimplemented from RuleBasedBreakIterator. |
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This method is the actual implementation of the next() method. All iteration vectors through here. This method initializes the state machine to state 1 and advances through the text character by character until we reach the end of the text or the state machine transitions to state 0. We update our return value every time the state machine passes through a possible end state.
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init Initialize a dbbi. Common routine for use by constructors.
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Assignment operator.
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Sets the iterator to refer to the last boundary position before the specified position. @offset The position to begin searching for a break from.
Reimplemented from RuleBasedBreakIterator. |
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Advances the iterator backwards, to the last boundary preceding this one.
Reimplemented from RuleBasedBreakIterator. |
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removes the cache of break positions (usually in response to a change in position of some sort).
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when a range of characters is divided up using the dictionary, the break positions that are discovered are stored here, preventing us from having to use either the dictionary or the state table again until the iterator leaves this range of text.
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The number of elements in cachedBreakPositions.
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if cachedBreakPositions is not null, this indicates which item in the cache the current iteration position refers to.
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