简化java if语句

Question

Can I simplify this java if construct? It seems too verbose to me, I'd like to have it shorter.

A is persistent Object, which will be null if it's context is accessed first time. Than A is instatniated and given content, and if this fails, some backup content is given to A.

if (A == null) {
    A = staticGetMethod();
    if (A == null) A = new BackupAContent() { ... };
}

Answer 1

Update: Or you could simply remove the nesting as it will still behave the same way.

if (A == null) {
    A = staticGetMethod();
}
if (A == null) {
    new BackupAContent() { ... };
}

---

Should work:

if (A == null && (A = staticGetMethod()) == null) {
    new BackupAContent() { ... };
}

Answer 2

Put your building logic in factory method

if (objA == null) {
    objA = getAInstance();

}

encapsulate the code suggested by Charles into a method to implement Factory_method_pattern

Answer 3

You can use a ternary operator instead of the if statements:

a = a ? a : staticGetMethod();
a = a ? a : new BackupAContent();

That said, I'd stick with what you've got, to be honest -- except that I would add a block for the second conditional rather than putting the statement inline with it.

Answer 4

This is Charles Goodwin's code with a slight change:

if (A == null && (A = staticGetMethod()) == null) {
new BackupAContent() { ... };
}

I used an AND instead of an OR

Answer 5

I think this is the best way to do it:

if(A == null)
{
    if((A = staticGetMethod()) == null) A = new BackupAContent() { ... };
}