FSA (Morfologik FSA v1.8.1 API Documentation)

java.lang.Object
- morfologik.fsa.FSA

All Implemented Interfaces:

java.lang.Iterable<java.nio.ByteBuffer>

Direct Known Subclasses:

CFSA, CFSA2, ConstantArcSizeFSA, FSA5
```
public abstract class FSA
extends java.lang.Object
implements java.lang.Iterable<java.nio.ByteBuffer>
```
This is a top abstract class for handling finite state automata. These automata are arc-based, a design described in Jan Daciuk's Incremental Construction of Finite-State Automata and Transducers, and Their Use in the Natural Language Processing (PhD thesis, Technical University of Gdansk).
Concrete subclasses (implementations) provide varying tradeoffs and features: traversal speed vs. memory size, for example.

See Also:
FSABuilder

Constructor Summary

Constructors
Constructor and Description

FSA()

Constructors
Constructor and Description
`FSA()`

Method Summary

Methods
Modifier and Type	Method and Description
`abstract int`	`getArc(int node, byte label)`
`int`	`getArcCount(int node)` Calculates the number of arcs of a given node.
`abstract byte`	`getArcLabel(int arc)` Return the label associated with a given `arc`.
`abstract int`	`getEndNode(int arc)` Return the end node pointed to by a given `arc`.
`abstract int`	`getFirstArc(int node)`
`abstract java.util.Set<FSAFlags>`	`getFlags()` Returns a set of flags for this FSA instance.
`abstract int`	`getNextArc(int arc)`
`int`	`getRightLanguageCount(int node)`
`abstract int`	`getRootNode()`
`java.lang.Iterable<java.nio.ByteBuffer>`	`getSequences()` An alias of calling `iterator()` directly (`FSA` is also `Iterable`).
`java.lang.Iterable<java.nio.ByteBuffer>`	`getSequences(int node)` Returns an iterator over all binary sequences starting at the given FSA state (node) and ending in final nodes.
`abstract boolean`	`isArcFinal(int arc)` Returns `true` if the destination node at the end of this `arc` corresponds to an input sequence created when building this automaton.
`abstract boolean`	`isArcTerminal(int arc)` Returns `true` if this `arc` does not have a terminating node (@link `getEndNode(int)` will throw an exception).
`java.util.Iterator<java.nio.ByteBuffer>`	`iterator()` Returns an iterator over all binary sequences starting from the initial FSA state (node) and ending in final nodes.
`static FSA`	`read(java.io.File fsa)`
`static <T extends FSA> T`	`read(java.io.InputStream in)` A factory for reading automata in any of the supported versions.
`<T extends StateVisitor> T`	`visitAllStates(T v)` Visit all states.
`<T extends StateVisitor> T`	`visitInPostOrder(T v)` Same as `visitInPostOrder(StateVisitor, int)`, starting from root automaton node.
`<T extends StateVisitor> T`	`visitInPostOrder(T v, int node)` Visits all states reachable from `node` in postorder.
`<T extends StateVisitor> T`	`visitInPreOrder(T v)` Same as `visitInPreOrder(StateVisitor, int)`, starting from root automaton node.
`<T extends StateVisitor> T`	`visitInPreOrder(T v, int node)` Visits all states in preorder.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - FSA
```
public FSA()
```
- Method Detail
  - getRootNode
```
public abstract int getRootNode()
```
    Returns:
    Returns the identifier of the root node of this automaton. Returns 0 if the start node is also the end node (the automaton is empty).
  - getFirstArc
```
public abstract int getFirstArc(int node)
```
    Returns:
    Returns the identifier of the first arc leaving node or 0 if the node has no outgoing arcs.
  - getNextArc
```
public abstract int getNextArc(int arc)
```
    Returns:
    Returns the identifier of the next arc after arc and leaving node. Zero is returned if no more arcs are available for the node.
  - getArc
```
public abstract int getArc(int node,
         byte label)
```
    Returns:
    Returns the identifier of an arc leaving node and labeled with label. An identifier equal to 0 means the node has no outgoing arc labeled label.
  - getArcLabel
```
public abstract byte getArcLabel(int arc)
```
    Return the label associated with a given arc.
  - isArcFinal
```
public abstract boolean isArcFinal(int arc)
```
    Returns true if the destination node at the end of this arc corresponds to an input sequence created when building this automaton.
  - isArcTerminal
```
public abstract boolean isArcTerminal(int arc)
```
    Returns true if this arc does not have a terminating node (@link getEndNode(int) will throw an exception). Implies isArcFinal(int).
  - getEndNode
```
public abstract int getEndNode(int arc)
```
    Return the end node pointed to by a given arc. Terminal arcs (those that point to a terminal state) have no end node representation and throw a runtime exception.
  - getFlags
```
public abstract java.util.Set<FSAFlags> getFlags()
```
    Returns a set of flags for this FSA instance.
  - getArcCount
```
public int getArcCount(int node)
```
    Calculates the number of arcs of a given node. Unless really required, use the following idiom for looping through all arcs:
```
 for (int arc = fsa.getFirstArc(node); arc != 0; arc = fsa.getNextArc(arc)) {
 }
 
```
  - getRightLanguageCount
```
public int getRightLanguageCount(int node)
```
    Returns:
    Returns the number of sequences reachable from the given state if the automaton was compiled with FSAFlags.NUMBERS. The size of the right language of the state, in other words.
    
    Throws:
    
    java.lang.UnsupportedOperationException - If the automaton was not compiled with FSAFlags.NUMBERS. The value can then be computed by manual count of getSequences(int).
  - getSequences
```
public java.lang.Iterable<java.nio.ByteBuffer> getSequences(int node)
```
    Returns an iterator over all binary sequences starting at the given FSA state (node) and ending in final nodes. This corresponds to a set of suffixes of a given prefix from all sequences stored in the automaton.
    The returned iterator is a ByteBuffer whose contents changes on each call to Iterator.next(). The keep the contents between calls to Iterator.next(), one must copy the buffer to some other location.
    
    Important. It is guaranteed that the returned byte buffer is backed by a byte array and that the content of the byte buffer starts at the array's index 0.
    
    See Also:
    Iterable
  - getSequences
```
public final java.lang.Iterable<java.nio.ByteBuffer> getSequences()
```
    An alias of calling iterator() directly (FSA is also Iterable).
  - iterator
```
public final java.util.Iterator<java.nio.ByteBuffer> iterator()
```
    Returns an iterator over all binary sequences starting from the initial FSA state (node) and ending in final nodes. The returned iterator is a ByteBuffer whose contents changes on each call to Iterator.next(). The keep the contents between calls to Iterator.next(), one must copy the buffer to some other location.
    Important. It is guaranteed that the returned byte buffer is backed by a byte array and that the content of the byte buffer starts at the array's index 0.
    
    Specified by:
    
    iterator in interface java.lang.Iterable<java.nio.ByteBuffer>
    
    See Also:
    Iterable
  - visitAllStates
```
public <T extends StateVisitor> T visitAllStates(T v)
```
    Visit all states. The order of visiting is undefined. This method may be faster than traversing the automaton in post or preorder since it can scan states linearly. Returning false from StateVisitor.accept(int) immediately terminates the traversal.
  - visitInPostOrder
```
public <T extends StateVisitor> T visitInPostOrder(T v)
```
    Same as visitInPostOrder(StateVisitor, int), starting from root automaton node.
  - visitInPostOrder
```
public <T extends StateVisitor> T visitInPostOrder(T v,
                                          int node)
```
    Visits all states reachable from node in postorder. Returning false from StateVisitor.accept(int) immediately terminates the traversal.
  - visitInPreOrder
```
public <T extends StateVisitor> T visitInPreOrder(T v)
```
    Same as visitInPreOrder(StateVisitor, int), starting from root automaton node.
  - visitInPreOrder
```
public <T extends StateVisitor> T visitInPreOrder(T v,
                                         int node)
```
    Visits all states in preorder. Returning false from StateVisitor.accept(int) skips traversal of all sub-states of a given state.
  - read
```
public static <T extends FSA> T read(java.io.InputStream in)
                          throws java.io.IOException
```
    A factory for reading automata in any of the supported versions. If possible, explicit constructors should be used.
    
    Throws:
    
    java.io.IOException
    See Also:
    FSA5.FSA5(InputStream)
  - read
```
public static FSA read(java.io.File fsa)
                throws java.io.IOException
```
    Throws:
    
    java.io.IOException

Class FSA

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

FSA

Method Detail

getRootNode

getFirstArc

getNextArc

getArc

getArcLabel

isArcFinal

isArcTerminal

getEndNode

getFlags

getArcCount

getRightLanguageCount

getSequences

getSequences

iterator

visitAllStates

visitInPostOrder

visitInPostOrder

visitInPreOrder

visitInPreOrder

read

read