com.plotnix.jex
Class MultilingualInterpreter

java.lang.Object
  |
  +--com.plotnix.jex.Interpreter
        |
        +--com.plotnix.jex.MultilingualInterpreter

public class MultilingualInterpreter

extends Interpreter

A MultilingualInterpreter determines the language for each expression and then interprets it using that language's interpreter.

If the expression string passed to this interpreter starts with "language:", the compiler strips the prefix off and passes the remainder of the expression to the interpreter for the corresponding language.

The prefix is required if the MultilingualInterpreter's default language is null.

If the default language is not null and the expression is missing a prefix, or the prefix does not match an existing compiler, the multilingual interpreter passes the expression unchanged to the default language interpreter.

Version:

$Revision$ $Date$

Author:

Dmitri Plotnikov

Method Summary

void	assign(Context context, java.lang.String expression, java.lang.Object value, java.lang.Object[] arguments) See evaluate
java.lang.Object	evaluate(Context context, java.lang.String expression, java.lang.Object[] arguments) Evaluates the expression using the appropriate Interpreter.
java.lang.Object	evaluate(Context context, java.lang.String expression, java.lang.Object[] arguments, java.lang.Class valueType) Evaluates the expression and casts the result to the supplied type.
static Interpreter	getMultilingualInterpreter(java.lang.String defaultLanguage) Returns a MultilingualInterpreter with the specified default language.
java.util.Iterator	iterate(Context context, java.lang.String expression, java.lang.Object[] arguments) See evaluate
void	validateExpression(java.lang.String expression) Identifies the expression language and validates the expression syntax using the appropriate Interpreter See evaluate
void	validateIterationExpression(java.lang.String expression) Identifies the expression language and validates the iteration expression syntax using the appropriate Interpreter See evaluate
void	validateVariableExpression(java.lang.String expression) Identifies the expression language and validates the variable expression syntax using the appropriate Interpreter See evaluate

Methods inherited from class com.plotnix.jex.Interpreter

getInterpreter, getInterpreterImplementation

Methods inherited from class java.lang.Object

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

Method Detail

getMultilingualInterpreter

public static final Interpreter getMultilingualInterpreter(java.lang.String defaultLanguage)

Returns a MultilingualInterpreter with the specified default language. If the specified default language is not null, an interpreter (or a compiler) for that language should be available.

Parameters:

defaultLanguage - is the default language or null

Returns:

A MultilingualInterpreter

evaluate

public java.lang.Object evaluate(Context context,
                                 java.lang.String expression,
                                 java.lang.Object[] arguments)

Evaluates the expression using the appropriate Interpreter. If the expression has the syntax "lang:expr" and an interpreter is available for the language "lang", it passes the expression to that interpreter. Otherwise, passes the whole unparsed expression to the default language interpreter.

Overrides:

evaluate in class Interpreter

Parameters:

context - is the context in which the expression should be evaluated

expression - is the expression to be evaluated with an optional "lang:" prefix

arguments - is an array of arguments for the expression. Can be null if the expression does not require any arguments.

Returns:

the result of the evaluation

evaluate

public java.lang.Object evaluate(Context context,
                                 java.lang.String expression,
                                 java.lang.Object[] arguments,
                                 java.lang.Class valueType)

Evaluates the expression and casts the result to the supplied type.

Overrides:

evaluate in class Interpreter

See Also:

evaluate(Context, String, Object[])

iterate

public java.util.Iterator iterate(Context context,
                                  java.lang.String expression,
                                  java.lang.Object[] arguments)

See evaluate

Overrides:

iterate in class Interpreter

See Also:

Interpreter.iterate(Context, String, Object[])

assign

public void assign(Context context,
                   java.lang.String expression,
                   java.lang.Object value,
                   java.lang.Object[] arguments)

See evaluate

Overrides:

assign in class Interpreter

See Also:

Interpreter.assign(Context, String, Object, Object[])

validateExpression

public void validateExpression(java.lang.String expression)

Identifies the expression language and validates the expression syntax using the appropriate Interpreter See evaluate

Overrides:

validateExpression in class Interpreter

See Also:

Interpreter.validateExpression(String)

validateIterationExpression

public void validateIterationExpression(java.lang.String expression)

Identifies the expression language and validates the iteration expression syntax using the appropriate Interpreter See evaluate

Overrides:

validateIterationExpression in class Interpreter

See Also:

Interpreter.validateIterationExpression(String)

validateVariableExpression

public void validateVariableExpression(java.lang.String expression)

Identifies the expression language and validates the variable expression syntax using the appropriate Interpreter See evaluate

Overrides:

validateVariableExpression in class Interpreter

See Also:

Interpreter.validateIterationExpression(String)