MapIsEmptyMethod (DataNucleus RDBMS plugin 6.0.1-SNAPSHOT API)

java.lang.Object
- org.datanucleus.store.rdbms.sql.method.MapIsEmptyMethod

All Implemented Interfaces:

SQLMethod
```
public class MapIsEmptyMethod
extends Object
implements SQLMethod
```
Method for evaluating {mapExpr}.isEmpty(). Returns a BooleanExpression, utilising the size() expression. So the SQL will be something like
```
 (SELECT COUNT(*) FROM MAPTABLE A0_SUB WHERE A0_SUB.OWNER_ID_OID = A0.OWNER_ID) = 0
 
```

Constructor Summary

Constructors
Constructor Description

MapIsEmptyMethod()

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`SQLExpression`	`getExpression(SQLStatement stmt, SQLExpression expr, List<SQLExpression> args)`	Return the expression for this SQL function.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - MapIsEmptyMethod
```
public MapIsEmptyMethod()
```
- Method Detail
  - getExpression
```
public SQLExpression getExpression(SQLStatement stmt,
                                   SQLExpression expr,
                                   List<SQLExpression> args)
```
    Description copied from interface: SQLMethod
    
    Return the expression for this SQL function.
    
    Specified by:
    
    getExpression in interface SQLMethod
    
    Parameters:
    
    stmt - SQLStatement that this expression is for
    
    expr - The expression that it is invoked on
    
    args - Arguments passed in
    
    Returns:
    
    The SQL expression using the SQL function