Re: Warning unchecked call
Nigel Wade wrote:
On Fri, 22 Jan 2010 02:31:43 -0800, jc_usernet wrote:
Hello.
I am adding a simple method to a class for db access. It is to copy a
column of data from a ResultSet class to a Vector class object. It
works but I get a compile warning which I wish I knew how to remove. The
message is;
------------------------------------------------------------
ResultSetTableModel.java:175: warning: [unchecked] unchecked call to
add(E) as a member of the raw type java.util.Vector
v.add( resultSet.getInt(colName) );
------------------------------------------------------------
The compiler is warning you that it cannot check that what you are adding
to the Vector is of the correct class. Presumably you have declared the
Vector without specifying what class it should contain.
and the method I have added is
------------------------------------------------------------ // new
method by JC
// obtain a column into a vector for a string column public Vector
getVectorFrmStringColumn( String colName )
throws IllegalStateException
{
Vector v = new Vector();
You have declared an untyped Vector. This Vector can contain anything,
the compiler is unable to verify that what you add to it is of the
correct type. So, the compiler will warn you every time you add something
to it that its type is unchecked.
// ensure database connection is available if ( !connectedToDatabase
)
throw new IllegalStateException( "Not Connected to
Database" );
// obtain a string column specified by colName try {
//System.out.println(" Before vector"); resultSet.beforeFirst();
while ( resultSet.next() ) {
v.add( resultSet.getString(colName) ); // this is line
175
}
}
catch( SQLException sqlException ) {
System.out.println( "sqlException occurred.");
sqlException.printStackTrace();
}
catch(Exception xception ) {
System.out.println(" The unknown exception ");
System.out.println( xception.toString() );
}
return v;
}
------------------------------------------------------------
How do I get rid of this warning ?
Learn about generics:
<http://java.sun.com/docs/books/effective/generics.pdf>
Don't use Vector. It's an old class that was superseded in 1998 by ArrayList.
--
Lew
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