Projog (projog-core 0.10.0 API)

java.lang.Object
- org.projog.api.Projog

```
public final class Projog
extends Object
```
Provides an entry point for other Java code to interact with Projog.
Contains a single instance of KnowledgeBase.

Constructor Summary

Constructors
Constructor and Description
`Projog(ProjogListener... listeners)` Constructs a new `Projog` object using `ProjogDefaultProperties` and the specified `ProjogListener`s.
`Projog(ProjogProperties projogProperties, ProjogListener... listeners)` Constructs a new `Projog` object with the specified `ProjogProperties` and `ProjogListener`s.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`addArithmeticOperator(PredicateKey key, ArithmeticOperator operator)` Associates a `ArithmeticOperator` with this `KnowledgeBase` of this `Projog`.
`void`	`addListener(ProjogListener listener)` Registers an `ProjogListener` to receive notifications of events generated during the evaluation of Prolog goals.
`void`	`addPredicateFactory(PredicateKey key, PredicateFactory predicateFactory)` Associates a `PredicateFactory` with the `KnowledgeBase` of this `Projog`.
`void`	`consultFile(File prologScript)` Populates this objects `KnowledgeBase` with clauses read from the specified file.
`void`	`consultReader(Reader reader)` Populates this objects `KnowledgeBase` with clauses read from the specified `Reader`.
`void`	`consultResource(String resourceName)` Populates this objects `KnowledgeBase` with clauses read from the specified resource.
`QueryPlan`	`createPlan(String prologQuery)` Creates a `QueryPlan` for querying the Projog environment.
`QueryStatement`	`createStatement(String prologQuery)` Creates a `QueryStatement` for querying the Projog environment.
`void`	`executeOnce(String prologQuery)` Evaluate once the given query.
`QueryResult`	`executeQuery(String prologQuery)` Creates a `QueryResult` for querying the Projog environment.
`String`	`formatTerm(Term t)` Returns a string representation of the specified `Term`.
`KnowledgeBase`	`getKnowledgeBase()` Returns the `KnowledgeBase` associated with this object.
`ProjogStackTraceElement[]`	`getStackTrace(Throwable exception)` Provides programmatic access to the stack trace information printed by `printProjogStackTrace(Throwable)`.
`void`	`printProjogStackTrace(Throwable exception)` Prints the all clauses contained in the specified throwable's stack trace to the standard error stream.
`void`	`printProjogStackTrace(Throwable exception, PrintStream out)` Prints the all clauses contained in the specified throwable's stack trace to the specified print stream.
`void`	`setUserInput(InputStream is)` Reassigns the "standard" input stream.
`void`	`setUserOutput(PrintStream ps)` Reassigns the "standard" output stream.

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

- Constructor Detail
  - Projog
```
public Projog(ProjogListener... listeners)
```
    Constructs a new Projog object using ProjogDefaultProperties and the specified ProjogListeners.
  - Projog
```
public Projog(ProjogProperties projogProperties,
              ProjogListener... listeners)
```
    Constructs a new Projog object with the specified ProjogProperties and ProjogListeners.
- Method Detail
  - consultFile
```
public void consultFile(File prologScript)
```
    Populates this objects KnowledgeBase with clauses read from the specified file.
    
    Parameters:
    
    prologScript - source of the prolog syntax defining the clauses to add
    
    Throws:
    
    ProjogException - if there is any problem parsing the syntax or adding the new clauses
  - consultReader
```
public void consultReader(Reader reader)
```
    Populates this objects KnowledgeBase with clauses read from the specified Reader.
    
    Parameters:
    
    reader - source of the prolog syntax defining the clauses to add
    
    Throws:
    
    ProjogException - if there is any problem parsing the syntax or adding the new clauses
  - consultResource
```
public void consultResource(String resourceName)
```
    Populates this objects KnowledgeBase with clauses read from the specified resource.
    If prologSourceResourceName refers to an existing file on the file system then that file is used as the source of the prolog syntax else prologSourceResourceName is read from the classpath.
    
    Parameters:
    
    resourceName - source of the prolog syntax defining clauses to add to the KnowledgeBase
    
    Throws:
    
    ProjogException - if there is any problem parsing the syntax or adding the new clauses to the KnowledgeBase
  - setUserInput
```
public void setUserInput(InputStream is)
```
    Reassigns the "standard" input stream.
    By default the "standard" input stream will be System.in.
  - setUserOutput
```
public void setUserOutput(PrintStream ps)
```
    Reassigns the "standard" output stream.
    By default the "standard" output stream will be System.out.
  - addPredicateFactory
```
public void addPredicateFactory(PredicateKey key,
                                PredicateFactory predicateFactory)
```
    Associates a PredicateFactory with the KnowledgeBase of this Projog.
    This method provides a mechanism for "plugging in" or "injecting" implementations of PredicateFactory at runtime. This mechanism provides an easy way to configure and extend the functionality of Projog - including adding functionality not possible to define in pure Prolog syntax.
    
    Parameters:
    
    key - The name and arity to associate the PredicateFactory with.
    
    predicateFactory - The PredicateFactory to be added.
    
    Throws:
    
    ProjogException - if there is already a PredicateFactory associated with the PredicateKey
  - addArithmeticOperator
```
public void addArithmeticOperator(PredicateKey key,
                                  ArithmeticOperator operator)
```
    Associates a ArithmeticOperator with this KnowledgeBase of this Projog.
    This method provides a mechanism for "plugging in" or "injecting" implementations of ArithmeticOperator at runtime. This mechanism provides an easy way to configure and extend the functionality of Projog - including adding functionality not possible to define in pure Prolog syntax.
    
    Parameters:
    
    key - The name and arity to associate the ArithmeticOperator with.
    
    operator - The instance of ArithmeticOperator to be associated with key.
    
    Throws:
    
    ProjogException - if there is already a ArithmeticOperator associated with the PredicateKey
  - createPlan
```
public QueryPlan createPlan(String prologQuery)
```
    Creates a QueryPlan for querying the Projog environment.
    The newly created object represents the query parsed from the specified syntax. A single QueryPlan can be used to create multiple QueryStatement objects.
    
    Parameters:
    
    prologQuery - prolog syntax representing a query
    
    Returns:
    
    representation of the query parsed from the specified syntax
    
    Throws:
    
    ProjogException - if an error occurs parsing prologQuery
    
    See Also:
    
    createStatement(String), executeQuery(String), executeOnce(String)
  - createStatement
```
public QueryStatement createStatement(String prologQuery)
```
    Creates a QueryStatement for querying the Projog environment.
    The newly created object represents the query parsed from the specified syntax. Before the query is executed, values can be assigned to variables in the query by using QueryStatement.setTerm(String, Term). The query can be executed by calling QueryStatement.executeQuery(). The resulting QueryResult can be used to access the result.
    Note: If you do not intend to assign terms to variables then executeQuery(String) can be called instead.
    
    Parameters:
    
    prologQuery - prolog syntax representing a query
    
    Returns:
    
    representation of the query parsed from the specified syntax
    
    Throws:
    
    ProjogException - if an error occurs parsing prologQuery
    
    See Also:
    
    createPlan(String), executeQuery(String), executeOnce(String)
  - executeQuery
```
public QueryResult executeQuery(String prologQuery)
```
    Creates a QueryResult for querying the Projog environment.
    The newly created object represents the query parsed from the specified syntax. The QueryResult.next() and QueryResult.getTerm(String) methods can be used to evaluate the query and access values unified to the variables of the query.
    
    Parameters:
    
    prologQuery - prolog syntax representing a query
    
    Returns:
    
    representation of the query parsed from the specified syntax
    
    Throws:
    
    ProjogException - if an error occurs parsing prologQuery
    
    See Also:
    
    createPlan(String), createStatement(String), executeOnce(String)
  - executeOnce
```
public void executeOnce(String prologQuery)
```
    Evaluate once the given query.
    The query will only be evaluated once, even if further solutions could of been found on backtracking.
    
    Parameters:
    
    prologQuery - prolog syntax representing a query
    
    Throws:
    
    ProjogException - if an error occurs parsing prologQuery or no solution can be found for it
    
    See Also:
    
    createPlan(String), createStatement(String), executeQuery(String)
  - addListener
```
public void addListener(ProjogListener listener)
```
    Registers an ProjogListener to receive notifications of events generated during the evaluation of Prolog goals.
    
    Parameters:
    
    listener - an listener to be added
  - formatTerm
```
public String formatTerm(Term t)
```
    Returns a string representation of the specified Term.
    
    Parameters:
    
    t - the Term to represent as a string
    
    Returns:
    
    a string representation of the specified Term
    
    See Also:
    
    TermFormatter.formatTerm(Term)
  - getKnowledgeBase
```
public KnowledgeBase getKnowledgeBase()
```
    Returns the KnowledgeBase associated with this object.
    Each Projog object is associated with its own KnowledgeBase. In normal usage it should not be necessary to call this method - as the other methods of Projog provide a more convenient mechanism for updating and querying the "core" inference engine.
    
    Returns:
    
    the KnowledgeBase associated with this object.
    
    See Also:
    
    KnowledgeBaseUtils
  - printProjogStackTrace
```
public void printProjogStackTrace(Throwable exception)
```
    Prints the all clauses contained in the specified throwable's stack trace to the standard error stream.
  - printProjogStackTrace
```
public void printProjogStackTrace(Throwable exception,
                                  PrintStream out)
```
    Prints the all clauses contained in the specified throwable's stack trace to the specified print stream.
  - getStackTrace
```
public ProjogStackTraceElement[] getStackTrace(Throwable exception)
```
    Provides programmatic access to the stack trace information printed by printProjogStackTrace(Throwable).

Class Projog

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Projog

Projog

Method Detail

consultFile

consultReader

consultResource

setUserInput

setUserOutput

addPredicateFactory

addArithmeticOperator

createPlan

createStatement

executeQuery

executeOnce

addListener

formatTerm

getKnowledgeBase

printProjogStackTrace

printProjogStackTrace

getStackTrace