org.apache.openjpa.jdbc.kernel.exps
Class CompareEqualExpression

java.lang.Object
  org.apache.openjpa.jdbc.kernel.exps.CompareEqualExpression

All Implemented Interfaces:

Serializable, Exp, Expression

Direct Known Subclasses:

EqualExpression, EqualTypeExpression, NotEqualExpression, NotEqualTypeExpression

abstract class CompareEqualExpression
extends Object
implements Exp

Compares two values for equality.

Author:

Abe White

Constructor Summary

CompareEqualExpression(Val val1, Val val2)
Constructor.

Method Summary

void	acceptVisit(ExpressionVisitor visitor) Accept a visit from a tree visitor.
protected abstract void	appendTo(Select sel, ExpContext ctx, BinaryOpExpState state, SQLBuffer buf, boolean val1Null, boolean val2Null) Append the SQL for the comparison.
void	appendTo(Select sel, ExpContext ctx, ExpState state, SQLBuffer buf) Append the SQL for this expression to the given buffer.
Val	getValue1()
Val	getValue2()
ExpState	initialize(Select sel, ExpContext ctx, Map contains) Initialize the expression.
protected boolean	isDirectComparison() Subclasses can override this method if, when they compare to another, value, the comparison is indirect.
void	selectColumns(Select sel, ExpContext ctx, ExpState state, boolean pks) Select just the columns for this expression.

Methods inherited from class java.lang.Object

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

Constructor Detail

CompareEqualExpression

public CompareEqualExpression(Val val1,
                              Val val2)

Constructor. Supply values to compare.

Method Detail

getValue1

public Val getValue1()

getValue2

public Val getValue2()

initialize

public ExpState initialize(Select sel,
                           ExpContext ctx,
                           Map contains)

Description copied from interface: Exp

Initialize the expression. This method should recursively initialize any sub-expressions or values.

Specified by:

initialize in interface Exp

contains - map of relation paths to the number of times the paths appear in a contains() expression; used to ensure paths used for contains() within the same AND expression used different aliases

appendTo

public void appendTo(Select sel,
                     ExpContext ctx,
                     ExpState state,
                     SQLBuffer buf)

Description copied from interface: Exp

Append the SQL for this expression to the given buffer. The SQL should optionally include any joins this expression needs.

Specified by:

appendTo in interface Exp

selectColumns

public void selectColumns(Select sel,
                          ExpContext ctx,
                          ExpState state,
                          boolean pks)

Description copied from interface: Exp

Select just the columns for this expression.

Specified by:

selectColumns in interface Exp

appendTo

protected abstract void appendTo(Select sel,
                                 ExpContext ctx,
                                 BinaryOpExpState state,
                                 SQLBuffer buf,
                                 boolean val1Null,
                                 boolean val2Null)

Append the SQL for the comparison.

isDirectComparison

protected boolean isDirectComparison()

Subclasses can override this method if, when they compare to another, value, the comparison is indirect. For example, field.contains (x) should compare element values to null, not the field itself.

acceptVisit

public void acceptVisit(ExpressionVisitor visitor)

Description copied from interface: Expression

Accept a visit from a tree visitor.

Specified by:

acceptVisit in interface Expression