FindBugs controversal description
- by Tom Brito
Am I understanding it wrong, or is the description wrong?
Equals checks for noncompatible
operand
(EQ_CHECK_FOR_OPERAND_NOT_COMPATIBLE_WITH_THIS)
This equals method is checking to see
if the argument is some incompatible
type (i.e., a class that is neither a
supertype nor subtype of the class
that defines the equals method). For
example, the Foo class might have an
equals method that looks like:
public boolean equals(Object o) {
if (o instanceof Foo)
return name.equals(((Foo)o).name);
else if (o instanceof String)
return name.equals(o);
else return false;
This is considered bad practice, as it makes it very hard to
implement an equals method that is
symmetric and transitive. Without
those properties, very unexpected
behavoirs are possible.
From: http://findbugs.sourceforge.net/bugDescriptions.html#EQ_CHECK_FOR_OPERAND_NOT_COMPATIBLE_WITH_THIS
The description says that the Foo class might have an aquals method like that, and after it says that "This is considered bad practice". I'm not getting the "right way"..
How should the following method be to be right?
@Override
public boolean equals(Object obj) {
if (obj instanceof DefaultTableModel)
return model.equals((DefaultTableModel)obj);
else
return false;
}
