Package org.apache.commons.jexl3.internal

Class TemplateEngine.TemplateExpression

java.lang.Object

org.apache.commons.jexl3.internal.TemplateEngine.TemplateExpression

All Implemented Interfaces:

JxltEngine.Expression

Direct Known Subclasses:

TemplateEngine.CompositeExpression, TemplateEngine.ConstantExpression, TemplateEngine.JexlBasedExpression

Enclosing class:

TemplateEngine

abstract class TemplateEngine.TemplateExpression
extends java.lang.Object
implements JxltEngine.Expression

The abstract base class for all unified expressions, immediate '${...}' and deferred '#{...}'.

Field Summary

Fields

Modifier and Type	Field	Description
protected TemplateEngine.TemplateExpression	source	The source of this template expression(see prepare(org.apache.commons.jexl3.internal.Interpreter)).

Constructor Summary

Constructors

Constructor	Description
TemplateExpression(TemplateEngine.TemplateExpression src)	Creates an TemplateExpression.

Method Summary

Modifier and Type	Method	Description
java.lang.String	asString()	Generates this expression's string representation.
protected abstract java.lang.Object	evaluate(Interpreter interpreter)	Interprets a sub-expression.
java.lang.Object	evaluate(JexlContext context)	Evaluates this expression.
protected java.lang.Object	evaluate(JexlContext context, Frame frame, JexlOptions options)	Evaluates this expression.
(package private) JexlInfo	getInfo()
TemplateEngine.TemplateExpression	getSource()	Gets this expression's source expression.
(package private) abstract TemplateEngine.ExpressionType	getType()	Gets this TemplateExpression type.
java.util.Set<java.util.List<java.lang.String>>	getVariables()	Gets the list of variables accessed by this expression.
protected void	getVariables(Engine.VarCollector collector)	Fills up the list of variables accessed by this unified expression.
boolean	isDeferred()	Checks whether this expression is deferred.
boolean	isImmediate()	Checks whether this expression is immediate.
protected JexlOptions	options(JexlContext context)	The options to use during evaluation.
protected TemplateEngine.TemplateExpression	prepare(Interpreter interpreter)	Prepares a sub-expression for interpretation.
TemplateEngine.TemplateExpression	prepare(JexlContext context)	Evaluates the immediate sub-expressions.
protected TemplateEngine.TemplateExpression	prepare(JexlContext context, Frame frame, JexlOptions options)	Prepares this expression.
java.lang.String	toString()	Formats this expression, adding its source string representation in comments if available: 'expression /*= source *\/'' .

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.commons.jexl3.JxltEngine.Expression

asString

Field Detail

source

protected final TemplateEngine.TemplateExpression source

The source of this template expression(see prepare(org.apache.commons.jexl3.internal.Interpreter)).

Constructor Detail

TemplateExpression

TemplateExpression(TemplateEngine.TemplateExpression src)

Creates an TemplateExpression.

Parameters:

src - the source TemplateExpression if any

Method Detail

asString

public java.lang.String asString()

Description copied from interface: JxltEngine.Expression

Generates this expression's string representation.

Specified by:

asString in interface JxltEngine.Expression

Returns:

the string representation

evaluate

protected abstract java.lang.Object evaluate(Interpreter interpreter)

Interprets a sub-expression.

Parameters:

interpreter - a JEXL interpreter

Returns:

the result of interpretation

Throws:

JexlException - (only for nested and composite)

evaluate

public final java.lang.Object evaluate(JexlContext context)

Description copied from interface: JxltEngine.Expression

Evaluates this expression.

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

Specified by:

evaluate in interface JxltEngine.Expression

Parameters:

context - the variable context

Returns:

the result of this expression evaluation or null if an error occurs and the JexlEngine is running in silent mode

evaluate

protected final java.lang.Object evaluate(JexlContext context,
                                          Frame frame,
                                          JexlOptions options)

Evaluates this expression.

Parameters:

frame - the frame storing parameters and local variables

context - the context storing global variables

options - flags and properties that can alter the evaluation behavior.

Returns:

the expression value

Throws:

JexlException - if expression evaluation fails

getInfo

JexlInfo getInfo()

Returns:

the info

getSource

public final TemplateEngine.TemplateExpression getSource()

Description copied from interface: JxltEngine.Expression

Gets this expression's source expression.

If this expression was prepared, this allows to retrieve the original expression that lead to it.

Other expressions return themselves.

Specified by:

getSource in interface JxltEngine.Expression

Returns:

the source expression

getType

abstract TemplateEngine.ExpressionType getType()

Gets this TemplateExpression type.

Returns:

its type

getVariables

public java.util.Set<java.util.List<java.lang.String>> getVariables()

Description copied from interface: JxltEngine.Expression

Gets the list of variables accessed by this expression.

This method will visit all nodes of the sub-expressions and extract all variables whether they are written in 'dot' or 'bracketed' notation. (a.b is equivalent to a['b']).

Specified by:

getVariables in interface JxltEngine.Expression

Returns:

the set of variables, each as a list of strings (ant-ish variables use more than 1 string) or the empty set if no variables are used

getVariables

protected void getVariables(Engine.VarCollector collector)

Fills up the list of variables accessed by this unified expression.

Parameters:

collector - the variable collector

isDeferred

public final boolean isDeferred()

Description copied from interface: JxltEngine.Expression

Checks whether this expression is deferred.

Specified by:

isDeferred in interface JxltEngine.Expression

Returns:

true if deferred, false otherwise

isImmediate

public boolean isImmediate()

Description copied from interface: JxltEngine.Expression

Checks whether this expression is immediate.

Specified by:

isImmediate in interface JxltEngine.Expression

Returns:

true if immediate, false otherwise

options

protected JexlOptions options(JexlContext context)

The options to use during evaluation.

Parameters:

context - the context

Returns:

the options

prepare

protected TemplateEngine.TemplateExpression prepare(Interpreter interpreter)

Prepares a sub-expression for interpretation.

Parameters:

interpreter - a JEXL interpreter

Returns:

a prepared unified expression

Throws:

JexlException - (only for nested and composite)

prepare

public final TemplateEngine.TemplateExpression prepare(JexlContext context)

Description copied from interface: JxltEngine.Expression

Evaluates the immediate sub-expressions.

When the expression is dependant upon immediate and deferred sub-expressions, evaluates the immediate sub-expressions with the context passed as parameter and returns this expression deferred form.

In effect, this binds the result of the immediate sub-expressions evaluation in the context, allowing to differ evaluation of the remaining (deferred) expression within another context. This only has an effect to nested and composite expressions that contain differed and immediate sub-expressions.

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

Specified by:

prepare in interface JxltEngine.Expression

Parameters:

context - the context to use for immediate expression evaluations

Returns:

an JxltEngine.Expression or null if an error occurs and the JexlEngine is running in silent mode

prepare

protected final TemplateEngine.TemplateExpression prepare(JexlContext context,
                                                          Frame frame,
                                                          JexlOptions options)

Prepares this expression.

Parameters:

frame - the frame storing parameters and local variables

context - the context storing global variables

options - flags and properties that can alter the evaluation behavior.

Returns:

the expression value

Throws:

JexlException - if expression preparation fails

toString

public final java.lang.String toString()

Description copied from interface: JxltEngine.Expression

Formats this expression, adding its source string representation in comments if available: 'expression /*= source *\/'' .

Specified by:

toString in interface JxltEngine.Expression

Overrides:

toString in class java.lang.Object

Returns:

the formatted expression string