Description Thomas Naskali 2018-10-17 04:55:30 EDT

The following code (requires guava 18.0) shows a compile error "The method closed(C, C) in the type Range is not applicable for the arguments (Entity, Entity)" When upgrading to Photon. This happens in other situations too when mixing raw and generic types.

The code compiles just fine outside of Eclipse via the Java compiler (tried with both IBM and Oracle JDKs) as well as in Eclipse Oxygen.

example #1 (error):

public final class Entity implements Comparable {

	private int index = 1;

	public Entity(int index) {
		this.index = index;
	}

	public int compareTo(Object o) {
		return index;
	}

}

import com.google.common.collect.Range;

public class Test {

	public static void main(String[] args) {
		Entity d1 = new Entity(1);
		Entity d2 = new Entity(2);
		Range<Entity> r = Range.closed(d1, d2);
	}

}


This only happens if you don't specify an argument type for the Comparable generic interface in the Entity class.

example #2 (no error):

public final class Entity implements Comparable<Entity> {

	private int index = 1;

	public Entity(int index) {
		this.index = index;
	}

	public int compareTo(Entity o) {
		return index;
	}

}

import com.google.common.collect.Range;

public class Test {

	public static void main(String[] args) {
		Entity d1 = new Entity(1);
		Entity d2 = new Entity(2);
		Range<Entity> r = Range.closed(d1, d2);
	}

}


Interestingly if you declare the Entity class as a static inner class within the main class where it's used, then the error disappears !

example #3 (no error)

public class Test {

	public static void main(String[] args) {
		Entity d1 = new Entity(1);
		Entity d2 = new Entity(2);
		Range<Entity> r = Range.closed(d1, d2);
	}

	public static final class Entity implements Comparable {

		private int index = 1;

		public Entity(int index) {
			this.index = index;
		}

		public int compareTo(Object o) {
			return index;
		}

	}
	
}