Module org.eclipse.persistence.core

Package org.eclipse.persistence.internal.expressions

Class ExpressionIterator

java.lang.Object

org.eclipse.persistence.internal.expressions.ExpressionIterator

public abstract class ExpressionIterator
extends Object

Used to itterate an expression tree, through inner subclasses.

Field Summary

Fields

Modifier and Type	Field	Description
protected Object	parameter	Some iterations require a more general parameter.
protected Object	result	Allow the iteration to build a result.
protected SQLSelectStatement	statement	Some iterations require a statement.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	ExpressionIterator()	Block constructor comment.

Method Summary

Modifier and Type	Method	Description
Object	getResult()
SQLSelectStatement	getStatement()
boolean	hasAlreadyVisited(Expression expression)	Answers if this expression has already been visited.
abstract void	iterate(Expression expression)	INTERNAL: This method must be defined by subclasses to implement the logic of the iteratation.
void	iterateOn(Vector expressions)	INTERNAL:
void	iterateOn(Expression expression)	INTERNAL: Return the call.
void	setResult(Object result)
void	setStatement(SQLSelectStatement statement)
boolean	shouldIterateOverSubSelects()	Normally an Iterator will not go into the where clause of an SQLSubSelectExpression.

Methods inherited from class java.lang.Object

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

Field Details

result

protected Object result

Allow the iteration to build a result.

statement

protected SQLSelectStatement statement

Some iterations require a statement.

parameter

protected Object parameter

Some iterations require a more general parameter.

Constructor Details

ExpressionIterator

protected ExpressionIterator()

Block constructor comment.

Method Details

getResult

public Object getResult()

getStatement

public SQLSelectStatement getStatement()

hasAlreadyVisited

public boolean hasAlreadyVisited(Expression expression)

Answers if this expression has already been visited. For a faster iteration override to insure expressions are only visited/processed once.

iterate

public abstract void iterate(Expression expression)

INTERNAL: This method must be defined by subclasses to implement the logic of the iteratation.

iterateOn

public void iterateOn(Vector expressions)

INTERNAL:

iterateOn

public void iterateOn(Expression expression)

INTERNAL: Return the call.

setResult

public void setResult(Object result)

setStatement

public void setStatement(SQLSelectStatement statement)

shouldIterateOverSubSelects

public boolean shouldIterateOverSubSelects()

Normally an Iterator will not go into the where clause of an SQLSubSelectExpression. I.e. when aliasing the parent statement is aliased before the subselects may even be normalized. An iterator to alias the SubSelect must be run later.