com.google.gwt.dev.jjs.impl

Class EqualityNormalizer

java.lang.Object

com.google.gwt.dev.jjs.impl.EqualityNormalizer

public class EqualityNormalizer
extends Object

Rewrite Java == so that it will execute correctly in JavaScript. After this pass, Java's == is considered equivalent to JavaScript's ===.

Whenever possible, a Java == is replaced by a JavaScript ==. This is shorter than ===, and it avoids any complication due to GWT treating both null and undefined as a valid translation of a Java null.

However, whenever something that may be an unboxed type is compared to something that may not be a unboxed type, use ===. A Java object compared to a string should always yield false, but that's not true when comparing in JavaScript using ==. The cases where === must be used are:

• One or both sides have unknown unboxed type status.
• One side is definitely an unboxed type and one side is definitely ! unboxed type.
  TODO: This case could be optimized as (a == null) & (b == null).

Since null !== undefined, it is also necessary to normalize null vs. undefined if it's possible for one side to be null and the other to be undefined.

An "unboxed type" is a String, Boolean, or Double that is represented as a naked raw JS type.

Method Summary

Modifier and Type	Method and Description
static void	exec(JProgram program)

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, toString

Method Detail

exec

public static void exec(JProgram program)