org.apache.jdo.impl.jdoql.tree
Class FieldAccessExpr

java.lang.Object
  antlr.BaseAST
      antlr.CommonAST
          org.apache.jdo.impl.jdoql.jdoqlc.JDOQLAST
              org.apache.jdo.impl.jdoql.tree.NodeImpl
                  org.apache.jdo.impl.jdoql.tree.Expr
                      org.apache.jdo.impl.jdoql.tree.IdentifierExpr
                          org.apache.jdo.impl.jdoql.tree.FieldAccessExpr

All Implemented Interfaces:

antlr.collections.AST, java.lang.Cloneable, Expression, FieldAccessExpression, IdentifierExpression, Node, java.io.Serializable

public final class FieldAccessExpr

extends IdentifierExpr

implements FieldAccessExpression

This node represents a field access expression. Field access expressions have exactly one child, the target expression. This expression can be an arbitrary expression.

Author:

Michael Watzek

See Also:

Serialized Form

Field Summary

(package private) java.lang.reflect.Field	field
(package private) java.lang.String	fieldName
(package private) org.apache.jdo.model.java.JavaField	javaField

Fields inherited from class org.apache.jdo.impl.jdoql.tree.NodeImpl

children, clazz, msg, object, parent

Fields inherited from class org.apache.jdo.impl.jdoql.jdoqlc.JDOQLAST

column, line, typeInfo

Fields inherited from class antlr.CommonAST

Fields inherited from class antlr.BaseAST

down, right

Constructor Summary

	FieldAccessExpr() The noarg constructor is needed for ANTLR support and deserialization.
(package private)	FieldAccessExpr(Expression target, java.lang.String fieldName) This constructor is called by the query tree instance.
(package private)	FieldAccessExpr(int tokenType, java.lang.String name, java.lang.Class clazz) This constructor is called by StaticFieldAccessExpr.
	FieldAccessExpr(antlr.Token token) The noarg constructor is needed for ANTLR support.

Method Summary

void	arrive(NodeVisitor visitor) Delegates to the argument visitor.
private java.lang.reflect.Field	getField()
(package private) org.apache.jdo.model.java.JavaField	getFieldInfo() Returns the model's field object assciated with this instance.
java.lang.Object	getFieldValue(javax.jdo.PersistenceManager pm, java.lang.Object object) Returns the value of the field corresponding with this field access expression for the argument object.
java.lang.String	getName() Returns the name of the accessed field.
Expression	getTarget() Returns the target expression of this field access.
(package private) void	init(Expression target, java.lang.String fieldName) Initializes fields of this.
java.lang.Object	leave(NodeVisitor visitor, java.lang.Object[] results) Delegates to the argument visitor.
void	setName(java.lang.String fieldName) Sets the name of the accessed field.

Methods inherited from class org.apache.jdo.impl.jdoql.tree.IdentifierExpr

getTypeName

Methods inherited from class org.apache.jdo.impl.jdoql.tree.NodeImpl

ASTToChildren, clone, getChildren, getJavaClass, getObject, getParent, getTokenType, setChildren, setObject, setParent, toString, walkNextChild

Methods inherited from class org.apache.jdo.impl.jdoql.jdoqlc.JDOQLAST

getColumn, getLine, getTypeInfo, initialize, initialize, initialize, setColumn, setLine, setTypeInfo, treeToString

Methods inherited from class antlr.CommonAST

getText, getType, initialize, setText, setType

Methods inherited from class antlr.BaseAST

addChild, decode, encode, equals, equalsList, equalsListPartial, equalsTree, equalsTreePartial, findAll, findAllPartial, getFirstChild, getNextSibling, getNumberOfChildren, getTokenNames, removeChildren, setFirstChild, setNextSibling, setVerboseStringConversion, toStringList, toStringTree, xmlSerialize, xmlSerializeNode, xmlSerializeRootClose, xmlSerializeRootOpen

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.jdo.jdoql.tree.IdentifierExpression

getTypeName

Methods inherited from interface org.apache.jdo.jdoql.tree.Node

getChildren, getJavaClass, getObject, getParent, getTokenType, setObject, setParent, walkNextChild

Field Detail

fieldName

java.lang.String fieldName

javaField

transient org.apache.jdo.model.java.JavaField javaField

field

transient java.lang.reflect.Field field

Constructor Detail

FieldAccessExpr

public FieldAccessExpr()

The noarg constructor is needed for ANTLR support and deserialization. The caller must make sure to set the ANTLR tree structure himself or, call setChildren optionally.

FieldAccessExpr

public FieldAccessExpr(antlr.Token token)

The noarg constructor is needed for ANTLR support. The caller must make sure to set the ANTLR tree structure himself or, call setChildren optionally.

FieldAccessExpr

FieldAccessExpr(int tokenType,
                java.lang.String name,
                java.lang.Class clazz)

This constructor is called by StaticFieldAccessExpr. The caller must make sure to set the ANTLR tree structure himself or, call setChildren optionally.

Parameters:

tokenType - the token type

name - the name of this identifier

clazz - the Java type of this identifier

FieldAccessExpr

FieldAccessExpr(Expression target,
                java.lang.String fieldName)

This constructor is called by the query tree instance. It delegates to the super class constructor.

Parameters:

target - the target expression

fieldName - the field name of this field access expression

Method Detail

getName

public java.lang.String getName()

Returns the name of the accessed field. Please note, that this name does not contain any information about the target object of this field access.

Specified by:

getName in interface IdentifierExpression

Overrides:

getName in class IdentifierExpr

Returns:

the field name

setName

public void setName(java.lang.String fieldName)

Sets the name of the accessed field. Please note, that this name must not contain any information about the target object of this field access. This method is used by semantic analysis only.

Parameters:

fieldName - the field name

getTarget

public Expression getTarget()

Returns the target expression of this field access. The target expression can be an instance of ThisExpression or an instance of an arbitrary other Expression, e.g. FieldAccessExpression.

Specified by:

getTarget in interface FieldAccessExpression

Returns:

the target expression

getFieldValue

public java.lang.Object getFieldValue(javax.jdo.PersistenceManager pm,
                                      java.lang.Object object)

Returns the value of the field corresponding with this field access expression for the argument object. Note: If the field value is obtained via reflection and the reflection call throws an IllegalAccessException, then undefined is returned.

Specified by:

getFieldValue in interface FieldAccessExpression

Parameters:

pm - the persistence manager of the query

object - the instance for which to return the field value

Returns:

the field value for object

Throws:

JDOQueryException - if the access to the desired field is denied

arrive

public void arrive(NodeVisitor visitor)

Delegates to the argument visitor.

Specified by:

arrive in interface Node

Overrides:

arrive in class IdentifierExpr

Parameters:

visitor - the node visitor

leave

public java.lang.Object leave(NodeVisitor visitor,
                              java.lang.Object[] results)

Delegates to the argument visitor.

Specified by:

leave in interface Node

Overrides:

leave in class IdentifierExpr

Parameters:

visitor - the node visitor

results - the result array

Returns:

the object returned by the visitor instance

init

void init(Expression target,
          java.lang.String fieldName)

Initializes fields of this.

Parameters:

target - the target expression of this field access

fieldName - the name of the field to access

getFieldInfo

org.apache.jdo.model.java.JavaField getFieldInfo()

Returns the model's field object assciated with this instance. If that field object is null, then it is computed by this method.

Returns:

the model's field object

Throws:

JDOQueryException - if the access to the desired field is denied

getField

private java.lang.reflect.Field getField()