BindVariableExpression (OpenJPA Parent POM 2.4.0 API)

java.lang.Object
- org.apache.openjpa.jdbc.kernel.exps.EmptyExpression
- - org.apache.openjpa.jdbc.kernel.exps.BindVariableExpression

All Implemented Interfaces:

Serializable, Exp, Expression
```
 class BindVariableExpression
extends EmptyExpression
```
Binds a variable to a value. Typically, the initialize(org.apache.openjpa.jdbc.sql.Select, org.apache.openjpa.jdbc.kernel.exps.ExpContext, java.util.Map) and #getJoins methods of this expression are not called. They are only called if the variable being bound is otherwise unused in the filter, in which case we must at least make the joins to the variable because the act of binding a variable should at least guarantee that an instance represting the variable could exist (i.e. the binding collection is not empty).

Author:

Abe White

Constructor Summary

Constructors
Constructor and Description

BindVariableExpression(Variable var, PCPath val, boolean key)
Constructor.

Constructors
Constructor and Description
`BindVariableExpression(Variable var, PCPath val, boolean key)` Constructor.

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`acceptVisit(ExpressionVisitor visitor)` Accept a visit from a tree visitor.
`void`	`appendTo(Select sel, ExpContext ctx, ExpState state, SQLBuffer buf)` Append the SQL for this expression to the given buffer.
`Variable`	`getVariable()`
`ExpState`	`initialize(Select sel, ExpContext ctx, Map contains)` Initialize the expression.
`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
  - BindVariableExpression
```
public BindVariableExpression(Variable var,
                      PCPath val,
                      boolean key)
```
    Constructor. Supply values.
- Method Detail
  - getVariable
```
public Variable getVariable()
```
  - 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
    
    Overrides:
    
    initialize in class EmptyExpression
    
    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
    
    Overrides:
    
    appendTo in class EmptyExpression
  - 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
    
    Overrides:
    
    selectColumns in class EmptyExpression
  - acceptVisit
```
public void acceptVisit(ExpressionVisitor visitor)
```
    Description copied from interface: Expression
    
    Accept a visit from a tree visitor.
    
    Specified by:
    
    acceptVisit in interface Expression
    
    Overrides:
    
    acceptVisit in class EmptyExpression

Class BindVariableExpression

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

BindVariableExpression

Method Detail

getVariable

initialize

appendTo

selectColumns

acceptVisit