org.apache.cayenne.exp.parser
Class SimpleNode

java.lang.Object
  org.apache.cayenne.exp.Expression
      org.apache.cayenne.exp.parser.SimpleNode

All Implemented Interfaces:

java.io.Serializable, Node, XMLSerializable

Direct Known Subclasses:

AggregateConditionNode, ASTAdd, ASTDivide, ASTList, ASTMultiply, ASTNegate, ASTPath, ASTScalar, ASTSubtract, ConditionNode

public abstract class SimpleNode
extends Expression
implements Node

Superclass of AST* expressions that implements Node interface defined by JavaCC framework.

Some parts of the parser are based on OGNL parser, copyright (c) 2002, Drew Davidson and Luke Blanshard.

Since:

1.1

See Also:

Serialized Form

Field Summary

protected Node[]	children
protected int	id
protected Node	parent

Fields inherited from class org.apache.cayenne.exp.Expression

ADD, ALL, AND, ANY, AVG, BETWEEN, COUNT, DB_PATH, DIVIDE, EQUAL_TO, EXISTS, GREATER_THAN, GREATER_THAN_EQUAL_TO, IN, LESS_THAN, LESS_THAN_EQUAL_TO, LIKE, LIKE_IGNORE_CASE, LIST, MAX, MIN, MULTIPLY, NEGATIVE, NOT, NOT_BETWEEN, NOT_EQUAL_TO, NOT_IN, NOT_LIKE, NOT_LIKE_IGNORE_CASE, OBJ_PATH, OR, POSITIVE, PRUNED_NODE, RAW_SQL, SOME, SUBQUERY, SUBTRACT, SUM, type

Constructor Summary

protected

SimpleNode(int i)

Method Summary

protected static void	encodeAsEscapedString(java.io.PrintWriter pw, java.lang.String source) Utility method that prints a string to the provided PrintWriter, escaping special characters.
void	encodeAsString(java.io.PrintWriter pw) Stores a String representation of Expression using a provided PrintWriter.
protected static void	encodeScalarAsString(java.io.PrintWriter pw, java.lang.Object scalar) Utility method that encodes an object that is not an expression Node to String.
java.lang.Object	evaluate(java.lang.Object o) Calculates expression value with object as a context for path expressions.
protected java.lang.Object	evaluateChild(int index, java.lang.Object o)
protected abstract java.lang.Object	evaluateNode(java.lang.Object o) Evaluates itself with object, pushing result on the stack.
java.lang.String	expName() Implemented for backwards compatibility with exp package.
protected void	flattenTree() Flattens the tree under this node by eliminating any children that are of the same class as this node and copying their children to this node.
protected abstract java.lang.String	getExpressionOperator(int index)
java.lang.Object	getOperand(int index) Returns a value of operand at index.
int	getOperandCount() Returns a count of operands of this expression.
void	jjtAddChild(Node n, int i) This method tells the node to add its argument to the node's list of children.
void	jjtClose() Called after all the child nodes have been added.
Node	jjtGetChild(int i) This method returns a child node.
int	jjtGetNumChildren() Return the number of children the node has.
Node	jjtGetParent()
void	jjtOpen() Called after the node has been made the current node.
void	jjtSetParent(Node n) This pair of methods are used to inform the node of its parent.
Expression	notExp() Returns a logical NOT of current expression.
protected boolean	pruneNodeForPrunedChild(java.lang.Object prunedChild) Returns true if this node should be pruned from expression tree in the event a child is removed.
void	setOperand(int index, java.lang.Object value) Sets a value of operand at index.
protected java.lang.Object	unwrapChild(Node child)
protected Node	wrapChild(java.lang.Object child)

Methods inherited from class org.apache.cayenne.exp.Expression

andExp, deepCopy, encodeAsXML, equals, expWithParameters, expWithParameters, filter, filterObjects, fromString, getType, joinExp, match, orExp, setType, shallowCopy, toString, transform, transformExpression, traverse, traverse

Methods inherited from class java.lang.Object

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

Field Detail

parent

protected Node parent

children

protected Node[] children

id

protected int id

Constructor Detail

SimpleNode

protected SimpleNode(int i)

Method Detail

encodeScalarAsString

protected static void encodeScalarAsString(java.io.PrintWriter pw,
                                           java.lang.Object scalar)

Utility method that encodes an object that is not an expression Node to String.

encodeAsEscapedString

protected static void encodeAsEscapedString(java.io.PrintWriter pw,
                                            java.lang.String source)

Utility method that prints a string to the provided PrintWriter, escaping special characters.

getExpressionOperator

protected abstract java.lang.String getExpressionOperator(int index)

pruneNodeForPrunedChild

protected boolean pruneNodeForPrunedChild(java.lang.Object prunedChild)

Description copied from class: Expression

Returns true if this node should be pruned from expression tree in the event a child is removed.

Specified by:

pruneNodeForPrunedChild in class Expression

expName

public java.lang.String expName()

Implemented for backwards compatibility with exp package.

Overrides:

expName in class Expression

flattenTree

protected void flattenTree()

Flattens the tree under this node by eliminating any children that are of the same class as this node and copying their children to this node.

Specified by:

flattenTree in class Expression

encodeAsString

public void encodeAsString(java.io.PrintWriter pw)

Description copied from class: Expression

Stores a String representation of Expression using a provided PrintWriter.

Specified by:

encodeAsString in class Expression

getOperand

public java.lang.Object getOperand(int index)

Description copied from class: Expression

Returns a value of operand at index. Operand indexing starts at 0.

Specified by:

getOperand in class Expression

wrapChild

protected Node wrapChild(java.lang.Object child)

unwrapChild

protected java.lang.Object unwrapChild(Node child)

getOperandCount

public int getOperandCount()

Description copied from class: Expression

Returns a count of operands of this expression. In real life there are unary (count == 1), binary (count == 2) and ternary (count == 3) expressions.

Specified by:

getOperandCount in class Expression

setOperand

public void setOperand(int index,
                       java.lang.Object value)

Description copied from class: Expression

Sets a value of operand at index. Operand indexing starts at 0.

Specified by:

setOperand in class Expression

jjtOpen

public void jjtOpen()

Description copied from interface: Node

Called after the node has been made the current node. It indicates that child nodes can now be added to it.

Specified by:

jjtOpen in interface Node

jjtClose

public void jjtClose()

Description copied from interface: Node

Called after all the child nodes have been added.

Specified by:

jjtClose in interface Node

jjtSetParent

public void jjtSetParent(Node n)

Description copied from interface: Node

This pair of methods are used to inform the node of its parent.

Specified by:

jjtSetParent in interface Node

jjtGetParent

public Node jjtGetParent()

Specified by:

jjtGetParent in interface Node

jjtAddChild

public void jjtAddChild(Node n,
                        int i)

Description copied from interface: Node

This method tells the node to add its argument to the node's list of children.

Specified by:

jjtAddChild in interface Node

jjtGetChild

public Node jjtGetChild(int i)

Description copied from interface: Node

This method returns a child node. The children are numbered from zero, left to right.

Specified by:

jjtGetChild in interface Node

jjtGetNumChildren

public final int jjtGetNumChildren()

Description copied from interface: Node

Return the number of children the node has.

Specified by:

jjtGetNumChildren in interface Node

evaluateNode

protected abstract java.lang.Object evaluateNode(java.lang.Object o)
                                          throws java.lang.Exception

Evaluates itself with object, pushing result on the stack.

Throws:

java.lang.Exception

evaluateChild

protected java.lang.Object evaluateChild(int index,
                                         java.lang.Object o)
                                  throws java.lang.Exception

Throws:

java.lang.Exception

notExp

public Expression notExp()

Description copied from class: Expression

Returns a logical NOT of current expression.

Specified by:

notExp in class Expression

evaluate

public java.lang.Object evaluate(java.lang.Object o)

Description copied from class: Expression

Calculates expression value with object as a context for path expressions.

Specified by:

evaluate in class Expression