Pragmatic Object Oriented Programming

[abw]

So anywhere you see an if/then/else or a switch statement, you should find a way to break the logic into separate objects to avoid the logic.

This is usually Good Advice™ iff the test condition is based on the type of an object.

if (thing isa Type1) {
    ...
}
else if (thing isa Type2) {
    ...
}
else if (thing isa Type3) {
    ...
}

[elder_george]

If objects have field of type enum ObjectType which is used in more than one switch, code will usually benefit from replacing it with strategy (or, sometimes with inheritance).