java.lang.Object
- org.apache.lucene.util.automaton.BasicOperations

public final class BasicOperations
extends java.lang.Object

Basic automata operations.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static void`	`addEpsilons(Automaton a, java.util.Collection<StatePair> pairs)`	Adds epsilon transitions to the given automaton.
`static Automaton`	`complement(Automaton a)`	Returns a (deterministic) automaton that accepts the complement of the language of the given automaton.
`static Automaton`	`concatenate(java.util.List<Automaton> l)`	Returns an automaton that accepts the concatenation of the languages of the given automata.
`static Automaton`	`concatenate(Automaton a1, Automaton a2)`	Returns an automaton that accepts the concatenation of the languages of the given automata.
`static void`	`determinize(Automaton a)`	Determinizes the given automaton.
`static Automaton`	`intersection(Automaton a1, Automaton a2)`	Returns an automaton that accepts the intersection of the languages of the given automata.
`static boolean`	`isEmpty(Automaton a)`	Returns true if the given automaton accepts no strings.
`static boolean`	`isEmptyString(Automaton a)`	Returns true if the given automaton accepts the empty string and nothing else.
`static boolean`	`isTotal(Automaton a)`	Returns true if the given automaton accepts all strings.
`static Automaton`	`minus(Automaton a1, Automaton a2)`	Returns a (deterministic) automaton that accepts the intersection of the language of `a1` and the complement of the language of `a2`.
`static Automaton`	`optional(Automaton a)`	Returns an automaton that accepts the union of the empty string and the language of the given automaton.
`static Automaton`	`repeat(Automaton a)`	Returns an automaton that accepts the Kleene star (zero or more concatenated repetitions) of the language of the given automaton.
`static Automaton`	`repeat(Automaton a, int min)`	Returns an automaton that accepts `min` or more concatenated repetitions of the language of the given automaton.
`static Automaton`	`repeat(Automaton a, int min, int max)`	Returns an automaton that accepts between `min` and `max` (including both) concatenated repetitions of the language of the given automaton.
`static boolean`	`run(Automaton a, java.lang.String s)`	Returns true if the given string is accepted by the automaton.
`static boolean`	`sameLanguage(Automaton a1, Automaton a2)`	Returns true if these two automata accept exactly the same language.
`static boolean`	`subsetOf(Automaton a1, Automaton a2)`	Returns true if the language of `a1` is a subset of the language of `a2`.
`static Automaton`	`union(java.util.Collection<Automaton> l)`	Returns an automaton that accepts the union of the languages of the given automata.
`static Automaton`	`union(Automaton a1, Automaton a2)`	Returns an automaton that accepts the union of the languages of the given automata.

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

- Method Detail
  - concatenate
```
public static Automaton concatenate(Automaton a1,
                                    Automaton a2)
```
    Returns an automaton that accepts the concatenation of the languages of the given automata.
    Complexity: linear in number of states.
  - concatenate
```
public static Automaton concatenate(java.util.List<Automaton> l)
```
    Returns an automaton that accepts the concatenation of the languages of the given automata.
    Complexity: linear in total number of states.
  - optional
```
public static Automaton optional(Automaton a)
```
    Returns an automaton that accepts the union of the empty string and the language of the given automaton.
    Complexity: linear in number of states.
  - repeat
```
public static Automaton repeat(Automaton a)
```
    Returns an automaton that accepts the Kleene star (zero or more concatenated repetitions) of the language of the given automaton. Never modifies the input automaton language.
    Complexity: linear in number of states.
  - repeat
```
public static Automaton repeat(Automaton a,
                               int min)
```
    Returns an automaton that accepts min or more concatenated repetitions of the language of the given automaton.
    Complexity: linear in number of states and in min.
  - repeat
```
public static Automaton repeat(Automaton a,
                               int min,
                               int max)
```
    Returns an automaton that accepts between min and max (including both) concatenated repetitions of the language of the given automaton.
    Complexity: linear in number of states and in min and max.
  - complement
```
public static Automaton complement(Automaton a)
```
    Returns a (deterministic) automaton that accepts the complement of the language of the given automaton.
    Complexity: linear in number of states (if already deterministic).
  - minus
```
public static Automaton minus(Automaton a1,
                              Automaton a2)
```
    Returns a (deterministic) automaton that accepts the intersection of the language of a1 and the complement of the language of a2. As a side-effect, the automata may be determinized, if not already deterministic.
    Complexity: quadratic in number of states (if already deterministic).
  - intersection
```
public static Automaton intersection(Automaton a1,
                                     Automaton a2)
```
    Returns an automaton that accepts the intersection of the languages of the given automata. Never modifies the input automata languages.
    Complexity: quadratic in number of states.
  - sameLanguage
```
public static boolean sameLanguage(Automaton a1,
                                   Automaton a2)
```
    Returns true if these two automata accept exactly the same language. This is a costly computation! Note also that a1 and a2 will be determinized as a side effect.
  - subsetOf
```
public static boolean subsetOf(Automaton a1,
                               Automaton a2)
```
    Returns true if the language of a1 is a subset of the language of a2. As a side-effect, a2 is determinized if not already marked as deterministic.
    Complexity: quadratic in number of states.
  - union
```
public static Automaton union(Automaton a1,
                              Automaton a2)
```
    Returns an automaton that accepts the union of the languages of the given automata.
    Complexity: linear in number of states.
  - union
```
public static Automaton union(java.util.Collection<Automaton> l)
```
    Returns an automaton that accepts the union of the languages of the given automata.
    Complexity: linear in number of states.
  - determinize
```
public static void determinize(Automaton a)
```
    Determinizes the given automaton.
    Worst case complexity: exponential in number of states.
  - addEpsilons
```
public static void addEpsilons(Automaton a,
                               java.util.Collection<StatePair> pairs)
```
    Adds epsilon transitions to the given automaton. This method adds extra character interval transitions that are equivalent to the given set of epsilon transitions.
    
    Parameters:
    
    pairs - collection of StatePair objects representing pairs of source/destination states where epsilon transitions should be added
  - isEmptyString
```
public static boolean isEmptyString(Automaton a)
```
    Returns true if the given automaton accepts the empty string and nothing else.
  - isEmpty
```
public static boolean isEmpty(Automaton a)
```
    Returns true if the given automaton accepts no strings.
  - isTotal
```
public static boolean isTotal(Automaton a)
```
    Returns true if the given automaton accepts all strings.
  - run
```
public static boolean run(Automaton a,
                          java.lang.String s)
```
    Returns true if the given string is accepted by the automaton.
    Complexity: linear in the length of the string.
    Note: for full performance, use the RunAutomaton class.

Class BasicOperations

Method Summary

Methods inherited from class java.lang.Object

Method Detail

concatenate

concatenate

optional

repeat

repeat

repeat

complement

minus

intersection

sameLanguage

subsetOf

union

union

determinize

addEpsilons

isEmptyString

isEmpty

isTotal

run