Question

I have an enum where the reverse-lookup table I created for it returns null for all values. I added an assert after the lookup table is created, and sure enough, it’s empty. I feel like this is something simple and obvious that I’m overlooking because I use this exact same structure for all my enums and they work fine.

public enum TerrainType {
ROAD(1),
PLAINS(2),
FOREST(3),
MOUNTAINS(4);

private static final Map<Byte,TerrainType> lookup = new HashMap<Byte,TerrainType>();

private final byte terrainId;

static {
    for(TerrainType type : EnumSet.allOf(TerrainType.class)) {
        lookup.put(type.getByte(),type);
    }
    assert lookup.get(1) != null; // <--- THIS ASSERT FIRES, WHY?
} 

TerrainType(int id) {
    assert id > 0 && id < 128: "ID must be from 1 to 127"; 
    this.terrainId = (byte) id;
}

public static TerrainType get(int id) {
    return lookup.get(id);
}

public byte getByte() {
    return this.terrainId;
}
}

Answer 1

The literal 1 is an integer.

This works.

assert lookup.get(Integer.valueOf(1).byteValue()) != null

Alternatively, you could change your terrainId to be of type int