org.apache.openjpa.jdbc.kernel.exps
Class GetColumn
java.lang.Object
org.apache.openjpa.jdbc.kernel.exps.GetColumn
- All Implemented Interfaces:
- Serializable, JDBCFilterListener, FilterListener
public class GetColumn
- extends Object
- implements JDBCFilterListener
Returns the SQL alias of the named column for use in a query. Note that
to retrieve columns in the table of the candidate object, you must
explicitly qualify the extension with this
, as demonstrated
in the second example below.
Examples:
"company.address.ext:getColumn (\"ID\") == 5"
"this.ext:getColumn (\"CLS\") == \"org.apache.openjpa.example.Person\""
- See Also:
- Serialized Form
Method Summary |
void |
appendTo(SQLBuffer buf,
FilterValue target,
FilterValue[] args,
ClassMapping type,
JDBCStore store)
Append the SQL for this expression or value. |
Object |
evaluate(Object target,
Class targetClass,
Object[] args,
Class[] argClasses,
Object candidate,
StoreContext ctx)
|
boolean |
expectsArguments()
|
boolean |
expectsTarget()
|
String |
getTag()
|
Class |
getType(Class targetClass,
Class[] argClasses)
|
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
TAG
public static final String TAG
- See Also:
- Constant Field Values
GetColumn
public GetColumn()
getTag
public String getTag()
- Specified by:
getTag
in interface FilterListener
expectsArguments
public boolean expectsArguments()
- Specified by:
expectsArguments
in interface FilterListener
expectsTarget
public boolean expectsTarget()
- Specified by:
expectsTarget
in interface FilterListener
evaluate
public Object evaluate(Object target,
Class targetClass,
Object[] args,
Class[] argClasses,
Object candidate,
StoreContext ctx)
- Specified by:
evaluate
in interface FilterListener
appendTo
public void appendTo(SQLBuffer buf,
FilterValue target,
FilterValue[] args,
ClassMapping type,
JDBCStore store)
- Description copied from interface:
JDBCFilterListener
- Append the SQL for this expression or value.
- Specified by:
appendTo
in interface JDBCFilterListener
- Parameters:
buf
- the SQL buffer to append totarget
- the target to act on, or null if the listener
doesn't expect a targetargs
- the values of the arguments given in the filter, or
null if this listener doesn't expect argumentstype
- the class mapping for the query's candidate classstore
- the store that owns the query
getType
public Class getType(Class targetClass,
Class[] argClasses)
- Specified by:
getType
in interface FilterListener
Copyright © 2006-2012 Apache Software Foundation. All Rights Reserved.