freemarker.template.expression
Class DynamicKeyName

java.lang.Object
  freemarker.template.expression.DynamicKeyName

All Implemented Interfaces:

Expression, Operator, Unary, Variable, java.io.Serializable

public final class DynamicKeyName
extends java.lang.Object
implements Unary, Variable, java.io.Serializable

A unary operator that uses the string value of an expression as a hash key. It associates with other Variable expressions to its left.

Version:

$Id: DynamicKeyName.java 1153 2013-04-15 10:59:37Z run2000 $

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface freemarker.template.expression.Unary

Unary.Association

Constructor Summary

DynamicKeyName(Expression key)
Constructor that takes an Expression used to evaluate the key name at run time.

Method Summary

boolean	equals(java.lang.Object o) Determines whether this object is equal to the given object.
Unary.Association	getAssociationType() Retrieve the operator association for this operator.
TemplateModel	getAsTemplateModel(TemplateWriteableHashModel modelRoot) Sets the target of this DynamicKeyName operator.
java.lang.String	getName(TemplateWriteableHashModel modelRoot) Retrieve the name of this portion of the variable.
ExpressionBuilder.Precedence	getPrecedence() Return the precedence for this operator to the caller.
java.util.Set<ExpressionUtils.ExpressionType>	getType() Determine the type of result that can be calculated by this expression.
int	hashCode() Returns the hash code for this operator.
boolean	isComplete() Are both the key name and target specified?
boolean	isConstant() Determine whether result calculated by this expression is a constant value.
Expression	resolveExpression() Resolves the current expression, possibly into a different expression object.
void	setTarget(Expression target) Sets the target of the dynamic key.
void	setTemplateModel(TemplateWriteableHashModel modelRoot, TemplateModel value) Implements a write of the given value to a writeable hash model or writeable list model.
java.lang.String	toString() Returns a string representation of the object.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

DynamicKeyName

public DynamicKeyName(Expression key)

Constructor that takes an Expression used to evaluate the key name at run time.

Parameters:

key - the expression to be used to evaluate the key name

Throws:

java.lang.NullPointerException - the key expression was null

java.lang.IllegalArgumentException - the key could not be evaluated as a number or a String

Method Detail

setTarget

public void setTarget(Expression target)

Sets the target of the dynamic key.

Specified by:

setTarget in interface Unary

Parameters:

target - the target of the dynamic key

Throws:

java.lang.IllegalArgumentException - the expression was not suitable for a dynamic key name evaluation

isComplete

public boolean isComplete()

Are both the key name and target specified?

Specified by:

isComplete in interface Expression

Returns:

true if both target and key name are specified, otherwise false

getType

public java.util.Set<ExpressionUtils.ExpressionType> getType()

Determine the type of result that can be calculated by this expression. This is in the form of an integer constant ored together from values in the ExpressionUtils class.

Specified by:

getType in interface Expression

isConstant

public boolean isConstant()

Determine whether result calculated by this expression is a constant value.

Specified by:

isConstant in interface Expression

getAssociationType

public Unary.Association getAssociationType()

Retrieve the operator association for this operator.

Specified by:

getAssociationType in interface Unary

Returns:

POSTFIX.

getAsTemplateModel

public TemplateModel getAsTemplateModel(TemplateWriteableHashModel modelRoot)
                                 throws TemplateException

Sets the target of this DynamicKeyName operator.

Specified by:

getAsTemplateModel in interface Expression

Parameters:

modelRoot - the template model that will be evaluated by the expression

Throws:

TemplateException - the target is of the wrong type for this operator.

setTemplateModel

public void setTemplateModel(TemplateWriteableHashModel modelRoot,
                             TemplateModel value)
                      throws TemplateException

Implements a write of the given value to a writeable hash model or writeable list model.

Specified by:

setTemplateModel in interface Variable

Parameters:

modelRoot - the root model, for determining context

value - the value to be assigned

Throws:

TemplateException - there was a problem performing the assignment

getName

public java.lang.String getName(TemplateWriteableHashModel modelRoot)
                         throws TemplateException

Retrieve the name of this portion of the variable.

Specified by:

getName in interface Variable

Parameters:

modelRoot - the model to be used in cases where the variable is the result of an Expression.

Throws:

TemplateException - the name could not be determined

getPrecedence

public ExpressionBuilder.Precedence getPrecedence()

Return the precedence for this operator to the caller. Used for associating operators according to precedence.

Specified by:

getPrecedence in interface Operator

Returns:

an enumeration indicating the precedence of this operator

toString

public java.lang.String toString()

Returns a string representation of the object.

Overrides:

toString in class java.lang.Object

Returns:

a String representation of this expression

equals

public boolean equals(java.lang.Object o)

Determines whether this object is equal to the given object.

Overrides:

equals in class java.lang.Object

Parameters:

o - the object to be compared with

Returns:

true if the objects are equal, otherwise false

hashCode

public int hashCode()

Returns the hash code for this operator.

Overrides:

hashCode in class java.lang.Object

Returns:

the hash code of this object

resolveExpression

public Expression resolveExpression()

Resolves the current expression, possibly into a different expression object. This is loosely equivalent to the serialization protocol's readResolve method. Situations where this may be used are:

• Caching frequently-used expression objects
• Evaluating constant expressions, and returning a constant reference

Specified by:

resolveExpression in interface Expression