org.apache.commons.jexl2
Class Interpreter

java.lang.Object
  org.apache.commons.jexl2.Interpreter

All Implemented Interfaces:

ParserVisitor

public class Interpreter
extends Object
implements ParserVisitor

An interpreter of JEXL syntax.

Since:

2.0

Field Summary

protected JexlArithmetic	arithmetic The arithmetic handler.
protected boolean	cache Cache executors.
protected JexlContext	context The context to store/retrieve variables.
protected static Object[]	EMPTY_PARAMS Empty parameters for method matching.
protected Map<String,Object>	functions The map of registered functions.
protected Map<String,Object>	functors The map of registered functions.
protected org.apache.commons.logging.Log	logger The logger.
protected Object[]	registers Registers or arguments.
protected boolean	silent Silent intepreter flag.
protected boolean	strict Strict interpreter flag.
protected Uberspect	uberspect The uberspect.

Constructor Summary

protected	Interpreter(Interpreter base) Copy constructor.
	Interpreter(JexlEngine jexl, JexlContext aContext) Deprecated.
	Interpreter(JexlEngine jexl, JexlContext aContext, boolean strictFlag, boolean silentFlag) Creates an interpreter.

Method Summary

protected JexlNode	findNullOperand(RuntimeException xrt, JexlNode node, Object left, Object right) Finds the node causing a NPE for diadic operators.
Object	getAttribute(Object object, Object attribute) Gets an attribute of an object.
protected Object	getAttribute(Object object, Object attribute, JexlNode node) Gets an attribute of an object.
protected JexlContext	getContext() Gets the context.
protected Uberspect	getUberspect() Gets the uberspect.
Object	interpret(JexlNode node) Interpret the given script/expression.
protected Object	invocationFailed(JexlException xjexl) Triggered when method, function or constructor invocation fails.
protected boolean	isCancelled() Checks whether this interpreter execution was cancelled due to thread interruption.
boolean	isSilent() Checks whether this interpreter throws JexlException when encountering errors.
boolean	isStrict() Checks whether this interpreter considers unknown variables, methods and constructors as errors.
protected Object	resolveNamespace(String prefix, JexlNode node) Resolves a namespace, eventually allocating an instance using context as constructor argument.
void	setAttribute(Object object, Object attribute, Object value) Sets an attribute of an object.
protected void	setAttribute(Object object, Object attribute, Object value, JexlNode node) Sets an attribute of an object.
protected void	setFrame(JexlEngine.Frame frame) Sets this interpreter parameters and arguments.
protected void	setRegisters(Object... theRegisters) Deprecated.
void	setSilent(boolean flag) Deprecated. Do not use; will be removed in a later version
void	setStrict(boolean flag) Deprecated. Do not use; will be removed in a later version
protected Object	unknownVariable(JexlException xjexl) Triggered when variable can not be resolved.
Object	visit(ASTAdditiveNode node, Object data)
Object	visit(ASTAdditiveOperator node, Object data)
Object	visit(ASTAmbiguous node, Object data) Unused, should throw in Parser.
Object	visit(ASTAndNode node, Object data)
Object	visit(ASTArrayAccess node, Object data)
Object	visit(ASTArrayLiteral node, Object data)
Object	visit(ASTAssignment node, Object data)
Object	visit(ASTBitwiseAndNode node, Object data)
Object	visit(ASTBitwiseComplNode node, Object data)
Object	visit(ASTBitwiseOrNode node, Object data)
Object	visit(ASTBitwiseXorNode node, Object data)
Object	visit(ASTBlock node, Object data)
Object	visit(ASTConstructorNode node, Object data)
Object	visit(ASTDivNode node, Object data)
Object	visit(ASTEmptyFunction node, Object data)
Object	visit(ASTEQNode node, Object data)
Object	visit(ASTERNode node, Object data)
Object	visit(ASTFalseNode node, Object data)
Object	visit(ASTFloatLiteral node, Object data) Deprecated. Do not use
Object	visit(ASTForeachStatement node, Object data)
Object	visit(ASTFunctionNode node, Object data)
Object	visit(ASTGENode node, Object data)
Object	visit(ASTGTNode node, Object data)
Object	visit(ASTIdentifier node, Object data)
Object	visit(ASTIfStatement node, Object data)
Object	visit(ASTIntegerLiteral node, Object data) Deprecated. Do not use
Object	visit(ASTJexlScript node, Object data)
Object	visit(ASTLENode node, Object data)
Object	visit(ASTLTNode node, Object data)
Object	visit(ASTMapEntry node, Object data)
Object	visit(ASTMapLiteral node, Object data)
Object	visit(ASTMethodNode node, Object data)
Object	visit(ASTModNode node, Object data)
Object	visit(ASTMulNode node, Object data)
Object	visit(ASTNENode node, Object data)
Object	visit(ASTNotNode node, Object data)
Object	visit(ASTNRNode node, Object data)
Object	visit(ASTNullLiteral node, Object data)
Object	visit(ASTNumberLiteral node, Object data)
Object	visit(ASTOrNode node, Object data)
Object	visit(ASTReferenceExpression node, Object data)
Object	visit(ASTReference node, Object data)
Object	visit(ASTReturnStatement node, Object data)
Object	visit(ASTSizeFunction node, Object data)
Object	visit(ASTSizeMethod node, Object data)
Object	visit(ASTStringLiteral node, Object data)
Object	visit(ASTTernaryNode node, Object data)
Object	visit(ASTTrueNode node, Object data)
Object	visit(ASTUnaryMinusNode node, Object data)
Object	visit(ASTVar node, Object data)
Object	visit(ASTWhileStatement node, Object data)
Object	visit(SimpleNode node, Object data) Unused, satisfy ParserVisitor interface.

Methods inherited from class java.lang.Object

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

Field Detail

logger

protected final org.apache.commons.logging.Log logger

The logger.

uberspect

protected final Uberspect uberspect

The uberspect.

arithmetic

protected final JexlArithmetic arithmetic

The arithmetic handler.

functions

protected final Map<String,Object> functions

The map of registered functions.

functors

protected Map<String,Object> functors

The map of registered functions.

context

protected final JexlContext context

The context to store/retrieve variables.

strict

protected boolean strict

Strict interpreter flag. Do not modify; will be made final/private in a later version.

silent

protected boolean silent

Silent intepreter flag. Do not modify; will be made final/private in a later version.

cache

protected final boolean cache

Cache executors.

registers

protected Object[] registers

Registers or arguments.

EMPTY_PARAMS

protected static final Object[] EMPTY_PARAMS

Empty parameters for method matching.

Constructor Detail

Interpreter

@Deprecated
public Interpreter(JexlEngine jexl,
                              JexlContext aContext)

Deprecated.

Creates an interpreter.

Parameters:

jexl - the engine creating this interpreter

aContext - the context to evaluate expression

Interpreter

public Interpreter(JexlEngine jexl,
                   JexlContext aContext,
                   boolean strictFlag,
                   boolean silentFlag)

Creates an interpreter.

Parameters:

jexl - the engine creating this interpreter

aContext - the context to evaluate expression

strictFlag - whether this interpreter runs in strict mode

silentFlag - whether this interpreter runs in silent mode

Since:

2.1

Interpreter

protected Interpreter(Interpreter base)

Copy constructor.

Parameters:

base - the base to copy

Since:

2.1

Method Detail

setStrict

@Deprecated
public void setStrict(boolean flag)

Deprecated. Do not use; will be removed in a later version

Sets whether this interpreter considers unknown variables, methods and constructors as errors.

Parameters:

flag - true for strict, false for lenient

Since:

2.1

setSilent

@Deprecated
public void setSilent(boolean flag)

Deprecated. Do not use; will be removed in a later version

Sets whether this interpreter throws JexlException when encountering errors.

Parameters:

flag - true for silent, false for verbose

isStrict

public boolean isStrict()

Checks whether this interpreter considers unknown variables, methods and constructors as errors.

Returns:

true if strict, false otherwise

Since:

2.1

isSilent

public boolean isSilent()

Checks whether this interpreter throws JexlException when encountering errors.

Returns:

true if silent, false otherwise

interpret

public Object interpret(JexlNode node)

Interpret the given script/expression.

If the underlying JEXL engine is silent, errors will be logged through its logger as info.

Parameters:

node - the script or expression to interpret.

Returns:

the result of the interpretation.

Throws:

JexlException - if any error occurs during interpretation.

getContext

protected JexlContext getContext()

Gets the context.

Returns:

the JexlContext used for evaluation.

Since:

2.1

getUberspect

protected Uberspect getUberspect()

Gets the uberspect.

Returns:

an Uberspect

setRegisters

@Deprecated
protected void setRegisters(Object... theRegisters)

Deprecated.

Sets this interpreter registers for bean access/assign expressions.

Use setFrame(...) instead.

Parameters:

theRegisters - the array of registers

setFrame

protected void setFrame(JexlEngine.Frame frame)

Sets this interpreter parameters and arguments.

Parameters:

frame - the calling frame

Since:

2.1

findNullOperand

protected JexlNode findNullOperand(RuntimeException xrt,
                                   JexlNode node,
                                   Object left,
                                   Object right)

Finds the node causing a NPE for diadic operators.

Parameters:

xrt - the RuntimeException

node - the parent node

left - the left argument

right - the right argument

Returns:

the left, right or parent node

unknownVariable

protected Object unknownVariable(JexlException xjexl)

Triggered when variable can not be resolved.

Parameters:

xjexl - the JexlException ("undefined variable " + variable)

Returns:

throws JexlException if strict, null otherwise

invocationFailed

protected Object invocationFailed(JexlException xjexl)

Triggered when method, function or constructor invocation fails.

Parameters:

xjexl - the JexlException wrapping the original error

Returns:

throws JexlException if strict, null otherwise

isCancelled

protected boolean isCancelled()

Checks whether this interpreter execution was cancelled due to thread interruption.

Returns:

true if cancelled, false otherwise

Since:

2.1

resolveNamespace

protected Object resolveNamespace(String prefix,
                                  JexlNode node)

Resolves a namespace, eventually allocating an instance using context as constructor argument. The lifetime of such instances span the current expression or script evaluation.

Parameters:

prefix - the prefix name (may be null for global namespace)

node - the AST node

Returns:

the namespace instance

visit

public Object visit(ASTAdditiveNode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTAdditiveOperator node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTAndNode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTArrayAccess node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTArrayLiteral node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTAssignment node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTBitwiseAndNode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTBitwiseComplNode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTBitwiseOrNode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTBitwiseXorNode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTBlock node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTDivNode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTEmptyFunction node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTEQNode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTFalseNode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTForeachStatement node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTGENode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTGTNode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTERNode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTIdentifier node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

@Deprecated
public Object visit(ASTFloatLiteral node,
                               Object data)

Deprecated. Do not use

visit

@Deprecated
public Object visit(ASTIntegerLiteral node,
                               Object data)

Deprecated. Do not use

visit

public Object visit(ASTVar node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTIfStatement node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTNumberLiteral node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTJexlScript node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTLENode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTLTNode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTMapEntry node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTMapLiteral node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTMethodNode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTFunctionNode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTConstructorNode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTModNode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTMulNode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTNENode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTNRNode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTNotNode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTNullLiteral node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTOrNode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTReference node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTReferenceExpression node,
                    Object data)

Specified by:

visit in interface ParserVisitor

Since:

2.1

visit

public Object visit(ASTReturnStatement node,
                    Object data)

Specified by:

visit in interface ParserVisitor

Since:

2.1

visit

public Object visit(ASTSizeFunction node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTSizeMethod node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTStringLiteral node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTTernaryNode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTTrueNode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTUnaryMinusNode node,
                    Object data)

Specified by:

visit in interface ParserVisitor

visit

public Object visit(ASTWhileStatement node,
                    Object data)

Specified by:

visit in interface ParserVisitor

getAttribute

public Object getAttribute(Object object,
                           Object attribute)

Gets an attribute of an object.

Parameters:

object - to retrieve value from

attribute - the attribute of the object, e.g. an index (1, 0, 2) or key for a map

Returns:

the attribute value

getAttribute

protected Object getAttribute(Object object,
                              Object attribute,
                              JexlNode node)

Gets an attribute of an object.

Parameters:

object - to retrieve value from

attribute - the attribute of the object, e.g. an index (1, 0, 2) or key for a map

node - the node that evaluated as the object

Returns:

the attribute value

setAttribute

public void setAttribute(Object object,
                         Object attribute,
                         Object value)

Sets an attribute of an object.

Parameters:

object - to set the value to

attribute - the attribute of the object, e.g. an index (1, 0, 2) or key for a map

value - the value to assign to the object's attribute

setAttribute

protected void setAttribute(Object object,
                            Object attribute,
                            Object value,
                            JexlNode node)

Sets an attribute of an object.

Parameters:

object - to set the value to

attribute - the attribute of the object, e.g. an index (1, 0, 2) or key for a map

value - the value to assign to the object's attribute

node - the node that evaluated as the object

visit

public Object visit(SimpleNode node,
                    Object data)

Unused, satisfy ParserVisitor interface.

Specified by:

visit in interface ParserVisitor

Parameters:

node - a node

data - the data

Returns:

does not return

visit

public Object visit(ASTAmbiguous node,
                    Object data)

Unused, should throw in Parser.

Specified by:

visit in interface ParserVisitor

Parameters:

node - a node

data - the data

Returns:

does not return