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Hi,
While looking at the PreparedStatement functionality of the
postgresql driver I ran in
AbstractJdbc1Statement.setObject(int parameterIndex, Object x))
into the following snippet of code.
if (x == null)
{
int l_sqlType;
if (x instanceof String)
l_sqlType = Types.VARCHAR;
else if (x instanceof BigDecimal)
l_sqlType = Types.DECIMAL;
else if (x instanceof Short)
l_sqlType = Types.SMALLINT;
else if (x instanceof Integer)
l_sqlType = Types.INTEGER;
else if (x instanceof Long)
l_sqlType = Types.BIGINT;
else if (x instanceof Float)
l_sqlType = Types.FLOAT;
else if (x instanceof Double)
l_sqlType = Types.DOUBLE;
else if (x instanceof byte[])
l_sqlType = Types.BINARY;
else if (x instanceof java.sql.Date)
l_sqlType = Types.DATE;
else if (x instanceof Time)
l_sqlType = Types.TIME;
else if (x instanceof Timestamp)
l_sqlType = Types.TIMESTAMP;
else if (x instanceof Boolean)
l_sqlType = Types.OTHER;
else
l_sqlType = Types.OTHER;
setNull(parameterIndex, l_sqlType);
return ;
}
According to my O'Reilly Java Language Reference, x instanceof
<Type>, where x == null will always return false...am I overlooking
something?
I tested it using the following class:
/**
* test class for 'x instanceof <Class>' where x is null
*/
public class InstanceOf {
public static void main(String[] args) {
Object x = null;
System.out.println("x instanceof Object: "+(x instanceof Object));
System.out.println("x instanceof String: "+(x instanceof String));
System.out.println("x instanceof Integer: "+(x instanceof
Integer));
}
}
With java version "1.4.1_01" I get:
$ java InstanceOf
x instanceof Object: false
x instanceof String: false
x instanceof Integer: false
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