dk.rode.thesis.interpreter
Class Interpreter<T>

java.lang.Object
  dk.rode.thesis.interpreter.Interpreter<T>

Type Parameters:

T - The type of value the evaluated expressions evaluate to.

public class Interpreter<T>
extends Object

An interpreter can interpret expressions.

Only expressions evaluating to values of a given type can be used. The type is supplied at construction time.

An interpreter supports break expressions storing typed expressions with a matching (sub-) type.

Author:

Gunni Rode / rode.dk

See Also:

Context

Field Summary

private Class<T>

type The super-type of expression values handled by this interpreter.

Constructor Summary

Interpreter(Class<T> type)
Constructor.

Interpreter(TypeLiteral<T> type)
Constructor.

Method Summary

<E extends T> T	interpret(Context context, Expression<E> expression) Interpret the expression syntax tree having the root supplied as expression, and returns the result.
<E extends T> E	interpret(Context context, Expression<E> expression, Class<? super E> type) Interpret the expression syntax tree having the root supplied as expression, and returns the result.
String	toString() Returns the string representation of this interpreter.
Class<T>	type() Return the super-type of expression values handled by this interpreter.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

type

private final Class<T> type

The super-type of expression values handled by this interpreter.

Never null.

Constructor Detail

Interpreter

public Interpreter(Class<T> type)

Constructor.

Parameters:

type - The super-type of expression values handled by this interpreter.

Throws:

NullPointerException - If type is null.

Interpreter

public Interpreter(TypeLiteral<T> type)

Constructor.

Parameters:

type - The super-type of expression values handled by this interpreter.

Throws:

NullPointerException - If type is null.

Method Detail

interpret

public <E extends T> T interpret(Context context,
                                 Expression<E> expression)
            throws ExpressionException

Interpret the expression syntax tree having the root supplied as expression, and returns the result.

The is no guarantee that the evaluation will ever complete!

Type Parameters:

E - The type of value the evaluation of expression produces.

Parameters:

context - The variable context to use; cannot be null.

expression - The root expression; cannot be null.

Returns:

The result of the evaluation, or null if the evaluation was exited prematurely.

Throws:

NullPointerException - If either argument is null.

ExpressionException - If the evaluation fails.

interpret

public <E extends T> E interpret(Context context,
                                 Expression<E> expression,
                                 Class<? super E> type)
                      throws ExpressionException

Interpret the expression syntax tree having the root supplied as expression, and returns the result.

The is no guarantee that the evaluation will ever complete!

Type Parameters:

E - The type of value the evaluation of expression produces.

Parameters:

context - The variable context to use; cannot be null.

expression - The root expression; cannot be null.

type - The type of value the evaluation of expression produces; cannot be null.

Returns:

The result of the evaluation, or null if the evaluation was exited prematurely.

Throws:

NullPointerException - If either argument is null.

ExpressionException - If the evaluation fails.

toString

public String toString()

Returns the string representation of this interpreter.

Overrides:

toString in class Object

Returns:

The string representation; never null.

type

public Class<T> type()

Return the super-type of expression values handled by this interpreter.

Returns:

The type; never null.

See Also:

TypedExpression.type()