MyObfHelper.java

public class MyObfHelper<Owner, Type> extends ObfHelper<Owner, Type> {
    
    public static final ObfHelper<Entity, Double> LAST_PORTAL_POS = new ObfHelper<>(Entity.class, "field_181016_an");
    public static final ObfHelper<Entity, Double> LAST_PORTAL_VEC = new ObfHelper<>(Entity.class, "field_181017_ao");
    public static final ObfHelper<Entity, Double> TELEPORT_DIRECTION = new ObfHelper<>(Entity.class, "field_181018_ap");
    
    protected ObfHelper(Class<Owner> owner, String srgname) {
        super(owner, srgname);
    }
}

ObfHelper.java

public abstract class ObfHelper<Owner, Type> {
    
    private Class<Owner> owner;
    private String name;
    
    private Field field;
    private Method method;
    
    protected ObfHelper(Class<Owner> owner, String srgname) {
        this.owner = owner;
        this.name = remap(owner, srgname);
    }
    
    public Class<Owner> getOwner() {
        return owner;
    }
    
    public String getName() {
        return name;
    }
    
    public Field getField() {
        if (field == null) {
            field = owner.getField(name);
            field.setAccessible(true);
        }
        return field;
    }
    
    public Method getMethod(Class<?>... args) {
        if (method == null) {
            method = owner.getMethod(name, args);
            method.setAccessible(true);
        }
        return method;
    }
    
    public Type getFieldValue(Owner instance) {
        return (Type) getField().getValue(instance);
    }
    
    public void setFieldValue(Owner instance, Type value) {
        getField().setValue(instance, value);
    }
    
    public Type invoke(Owner instance, Object... args) {
        return getMethod().invoke(instance, args);
    }
}