
Removed the redundant ActivityStateEnum intdef definition and resolved lint warnings in the ActivityState and ApplicationStatus classes. Also updated the c++ enum conversion doc about the new IntDef declaration style that was added in https://crrev.com/14f477472e0e8612c98763b68e9a51bcae954c24 BUG=707186 Review-Url: https://codereview.chromium.org/2877743002 Cr-Commit-Position: refs/heads/master@{#471432}
3.8 KiB
Accessing C++ Enums In Java
[TOC]
Introduction
Accessing C++ enums in Java is implemented via a Python script which analyzes the C++ enum and spits out the corresponding Java class. The enum needs to be annotated in a particular way. By default, the generated class name will be the same as the name of the enum. If all the names of the enum values are prefixed with the MACRO_CASED_ name of the enum those prefixes will be stripped from the Java version.
Features
- Customize the package name of the generated class using the
GENERATED_JAVA_ENUM_PACKAGE
directive (required) - Customize the class name using the
GENERATED_JAVA_CLASS_NAME_OVERRIDE
directive (optional) - Strip enum entry prefixes to make the generated classes less verbose using
the
GENERATED_JAVA_PREFIX_TO_STRIP
directive (optional) - Supports
@IntDef
- Copies comments that directly precede enum entries into the generated Java class
Usage
-
Add directives to your C++ enum
// GENERATED_JAVA_ENUM_PACKAGE: org.chromium.chrome // GENERATED_JAVA_CLASS_NAME_OVERRIDE: FooBar // GENERATED_JAVA_PREFIX_TO_STRIP: BAR_ enum SomeEnum { BAR_A, BAR_B, BAR_C = BAR_B, };
-
Add a new build target
import("//build/config/android/rules.gni") java_cpp_enum("foo_generated_enum") { sources = [ "base/android/native_foo_header.h", ] }
-
Add the new target to the desired android_library targets srcjar_deps:
android_library("base_java") { srcjar_deps = [ ":foo_generated_enum", ] }
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The generated file
org/chromium/chrome/FooBar.java
would contain:package org.chromium.chrome; import android.support.annotation.IntDef; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; @IntDef({ FooBar.A, FooBar.B, FooBar.C }) @Retention(RetentionPolicy.SOURCE) public @interface FooBar { int A = 0; int B = 1; int C = 1; }
Formatting Notes
-
Handling long package names:
// GENERATED_JAVA_ENUM_PACKAGE: ( // org.chromium.chrome.this.package.is.too.long.to.fit.on.a.single.line)
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Enum entries
-
Single line enums should look like this:
// GENERATED_JAVA_ENUM_PACKAGE: org.foo enum NotificationActionType { BUTTON, TEXT };
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Multi-line enums should have one enum entry per line, like this:
// GENERATED_JAVA_ENUM_PACKAGE: org.foo enum NotificationActionType { BUTTON, TEXT };
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Multi-line enum entries are allowed but should be formatted like this:
// GENERATED_JAVA_ENUM_PACKAGE: org.foo enum NotificationActionType { LongKeyNumberOne, LongKeyNumberTwo, ... LongKeyNumberThree = LongKeyNumberOne | LongKeyNumberTwo | ... };
-
-
Preserving comments
// GENERATED_JAVA_ENUM_PACKAGE: org.chromium enum CommentEnum { // This comment will be preserved. ONE, TWO, // This comment will NOT be preserved. THREE }
... public @interface CommentEnum { ... /** * This comment will be preserved. */ int ONE = 0; int TWO = 1; int THREE = 2; }