Spring Framework

org.springframework.expression.spel.ast
Class SpelNodeImpl

java.lang.Object
  extended by org.springframework.expression.spel.ast.SpelNodeImpl
All Implemented Interfaces:
SpelNode
Direct Known Subclasses:
Assign, BeanReference, CompoundExpression, ConstructorReference, Elvis, FunctionReference, Identifier, Indexer, InlineList, Literal, MethodReference, Operator, OperatorNot, Projection, PropertyOrFieldReference, QualifiedIdentifier, Selection, Ternary, TypeReference, VariableReference

public abstract class SpelNodeImpl
extends java.lang.Object
implements SpelNode

The common supertype of all AST nodes in a parsed Spring Expression Language format expression.

Since:
3.0
Author:
Andy Clement

Field Summary
protected  SpelNodeImpl[] children
           
protected  int pos
           
 
Constructor Summary
SpelNodeImpl(int pos, SpelNodeImpl... operands)
           
 
Method Summary
 SpelNode getChild(int index)
          Helper method that returns a SpelNode rather than an Antlr Tree node.
 int getChildCount()
           
 int getEndPosition()
           
 java.lang.Class<?> getObjectClass(java.lang.Object obj)
          Determine the class of the object passed in, unless it is already a class object.
protected  SpelNodeImpl getPreviousChild()
           
 int getStartPosition()
           
 TypedValue getTypedValue(ExpressionState expressionState)
          Evaluate the expression node in the context of the supplied expression state and return the typed value.
 java.lang.Object getValue(ExpressionState expressionState)
          Evaluate the expression node in the context of the supplied expression state and return the value.
protected
<T> T
getValue(ExpressionState state, java.lang.Class<T> desiredReturnType)
           
abstract  TypedValue getValueInternal(ExpressionState expressionState)
           
 boolean isWritable(ExpressionState expressionState)
          Determine if this expression node will support a setValue() call.
protected  boolean nextChildIs(java.lang.Class... clazzes)
           
 void setValue(ExpressionState expressionState, java.lang.Object newValue)
          Evaluate the expression to a node and then set the new value on that node.
abstract  java.lang.String toStringAST()
           
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

pos

protected int pos

children

protected SpelNodeImpl[] children
Constructor Detail

SpelNodeImpl

public SpelNodeImpl(int pos,
                    SpelNodeImpl... operands)
Method Detail

getPreviousChild

protected SpelNodeImpl getPreviousChild()

nextChildIs

protected boolean nextChildIs(java.lang.Class... clazzes)
Returns:
true if the next child is one of the specified classes

getValue

public final java.lang.Object getValue(ExpressionState expressionState)
                                throws EvaluationException
Description copied from interface: SpelNode
Evaluate the expression node in the context of the supplied expression state and return the value.

Specified by:
getValue in interface SpelNode
Parameters:
expressionState - the current expression state (includes the context)
Returns:
the value of this node evaluated against the specified state
Throws:
EvaluationException

getTypedValue

public final TypedValue getTypedValue(ExpressionState expressionState)
                               throws EvaluationException
Description copied from interface: SpelNode
Evaluate the expression node in the context of the supplied expression state and return the typed value.

Specified by:
getTypedValue in interface SpelNode
Parameters:
expressionState - the current expression state (includes the context)
Returns:
the type value of this node evaluated against the specified state
Throws:
EvaluationException

isWritable

public boolean isWritable(ExpressionState expressionState)
                   throws EvaluationException
Description copied from interface: SpelNode
Determine if this expression node will support a setValue() call.

Specified by:
isWritable in interface SpelNode
Parameters:
expressionState - the current expression state (includes the context)
Returns:
true if the expression node will allow setValue()
Throws:
EvaluationException - if something went wrong trying to determine if the node supports writing

setValue

public void setValue(ExpressionState expressionState,
                     java.lang.Object newValue)
              throws EvaluationException
Description copied from interface: SpelNode
Evaluate the expression to a node and then set the new value on that node. For example, if the expression evaluates to a property reference then the property will be set to the new value.

Specified by:
setValue in interface SpelNode
Parameters:
expressionState - the current expression state (includes the context)
newValue - the new value
Throws:
EvaluationException - if any problem occurs evaluating the expression or setting the new value

getChild

public SpelNode getChild(int index)
Description copied from interface: SpelNode
Helper method that returns a SpelNode rather than an Antlr Tree node.

Specified by:
getChild in interface SpelNode
Returns:
the child node cast to a SpelNode

getChildCount

public int getChildCount()
Specified by:
getChildCount in interface SpelNode
Returns:
the number of children under this node

getObjectClass

public java.lang.Class<?> getObjectClass(java.lang.Object obj)
Description copied from interface: SpelNode
Determine the class of the object passed in, unless it is already a class object.

Specified by:
getObjectClass in interface SpelNode
Parameters:
obj - the object that the caller wants the class of
Returns:
the class of the object if it is not already a class object, or null if the object is null

getValue

protected final <T> T getValue(ExpressionState state,
                               java.lang.Class<T> desiredReturnType)
                    throws EvaluationException
Throws:
EvaluationException

getValueInternal

public abstract TypedValue getValueInternal(ExpressionState expressionState)
                                     throws EvaluationException
Throws:
EvaluationException

toStringAST

public abstract java.lang.String toStringAST()
Specified by:
toStringAST in interface SpelNode
Returns:
the string form of this AST node

getStartPosition

public int getStartPosition()
Specified by:
getStartPosition in interface SpelNode
Returns:
the start position of this Ast node in the expression string

getEndPosition

public int getEndPosition()
Specified by:
getEndPosition in interface SpelNode
Returns:
the end position of this Ast node in the expression string

Spring Framework