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javaif-statementpojocode-cleanup

Concat all nonNull properties of a POJO

I have a POJO which has 10-15 fields(can be primitive,Custom Object or String). I want to concat all the NonNull fields in a String.

Is there any clean way to do without using 10-15 if statements.

Solution

  • You could use Reflection:

    Foo foo = new Foo(3, 89, null);

Field[] fields = foo.getClass().getDeclaredFields();

for(Field field: fields) {
    Object fieldValue = field.get(foo);
    if(fieldValue != null) {
        // Do your actual logic here
        System.out.println(fieldValue);
    }
}

    with a Foo class like this:

        static class Foo {
        int bar;
        int barre;
        String barString;

        public Foo(int bar, int barre, String barString) {
            this.bar = bar;
            this.barre = barre;
            this.barString = barString;
        }
    }

    note: this is assuming that you can access the fields in Foo, if they are private then you have to use getters instead.