Automatically handle third-party libraries

[advayDev1]

@ph1lb4 - could you repost your emailed question re: translating dependent jars here?

Please provide the relevant j2objcConfig, the version of the plugin you are using, your dependencies { } block if possible, and any errors.

[ph1lb4]

We have the following dependencies:

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'joda-time:joda-time:2.7'
    compile 'com.google.code.gson:gson:2.3.1'
}

And I included them as stated by you in another post with:

translateClasspaths project.sourceSets.main.compileClasspath.getAsPath()

Everything translates fine, but when it comes to compiling the following problem occurs:

/model/network/JsonResponseHandler.m:7:10: fatal error: 'com/google/gson/JsonElement.h' file not found
#include "com/google/gson/JsonElement.h"
         ^
1 error generated.

Do you know how to fix this? I also read that you are planing on automating this in next versions, which will be really convenient!

The relevant parts:

plugins {
    id 'idea'
    id 'java'
    id 'com.github.j2objccontrib.j2objcgradle' version '0.4.0-alpha'
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'joda-time:joda-time:2.7'
    compile 'com.google.code.gson:gson:2.3.1'
}

j2objcConfig {
    xcodeProjectDir '../ios'  // Xcode workspace directory (suggested directory name)
    xcodeTarget 'IOS-APP'     // iOS app target name (replace with existing app name)

    translateClasspaths './libs/bsh-2.0b4.jar'
    translateClasspaths project.sourceSets.main.compileClasspath.getAsPath()

    translateArgs '--prefixes', 'prefixes.properties'

    finalConfigure()          // Must be last call to configuration
}

[advayDev1]

1. you need the source jars for gson joda and bsh as well; add those with translateSourcepaths
2. then add this line above finalConfigure:
   translateArgs '--build-closure'

that will translate gson joda and bsh as well.

[ph1lb4]

Does that mean it is not possible to use dependencies? Because the best thing about dependencies is that I don't have to worry about the jar files.

[advayDev1]

How dependencies must be provided is a function of j2objc not this plugin. From j2objc's home page:
"Developers must have source code for their Android app, which they either own or are licensed to use." (http://j2objc.org/)

j2objc must have the source code for everything that needs to be translated into objective-c. j2objc happens to provide, for convenience, pre-translated versions of a few libraries like the JRE, junit, guava. But for gson, joda, bsh, etc. you'll need to provide the source.

Or maybe you're asking: if you have and can use the source jars, does setting dependencies { } work automatically with this plugin? Not yet - that's future work. For now you have to set translateSourcepaths.

[advayDev1]

@jjroloff please see this issue and provide any more details you have re: your issue with gson.

[ph1lb4]

Actually I meant if it is possible that your plugin automatically downloads the jar file when a dependency is listed in the build script?

[advayDev1]

On the roadmap #41 but not yet done. The main issue is resolving duplicates across multiple projects (i.e. when gson is loaded by 3 of your j2objc projects, we don't want to translate/compile/etc. it each time).

For now, you'll have to put a -sources jar in a directory, and use translateSourcepaths.

[advayDev1]

@ph1lb4 - I suspect it would be useful for me to add a section to:
https://github.com/j2objc-contrib/j2objc-gradle/blob/master/FAQ.md#how-do-i-setup-dependencies-with-j2objc
for the case of a third-party jar.

We've covered dependencies on prebuilts, native code, and java projects, but not third-party java code in there. I'll send folks a PR (also @jjroloff) and let me know if it is clear.

[ph1lb4]

Ok thank you very much, looking forward to this feature!

In the meantime I am still having troubles even with the jar files. My new build script looks as follows:

buildscript {
    repositories {
        mavenCentral()
    }
}

plugins {
    id 'idea'
    id 'java'
    id 'com.github.j2objccontrib.j2objcgradle' version '0.4.2-alpha'
}

repositories {
    mavenCentral()
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
}

configurations {
    provided
    provided.extendsFrom(compile)
}

sourceSets {
    main { compileClasspath += configurations.provided }
}

j2objcConfig {
    xcodeProjectDir '../ios'  // Xcode workspace directory (suggested directory name)
    xcodeTarget 'IOS-APP'     // iOS app target name (replace with existing app name)

    translateSourcepaths './libs/bsh-2.0b4.jar'
    translateSourcepaths './libs/gson-2.3.1.jar'
    translateSourcepaths './libs/joda-time-2.4.jar'

    translateClasspaths project.sourceSets.main.compileClasspath.getAsPath()

    translateArgs '--prefixes', 'prefixes.properties', '--build-closure'

    finalConfigure()          // Must be last call to configuration
}

However we are still getting the same errors:

.../build/j2objcSrcGen/com/projectr/model/SystemModel.m:7:10: fatal error: 'com/google/gson/JsonObject.h' file not found
#include "com/google/gson/JsonObject.h"
         ^
1 error generated.

.../build/j2objcSrcGen/com/projectr/model/calendar/CalendarEvent.m:8:10: fatal error: 'org/joda/time/DateTime.h' file not found
#include "org/joda/time/DateTime.h"
         ^
1 error generated.

.../build/j2objcSrcGen/com/projectr/model/calendar/Calendar.m:10:10: fatal error: 'org/joda/time/DateTime.h' file not found
#include "org/joda/time/DateTime.h"
         ^
1 error generated.

Do you know how to fix this?

[advayDev1]

@ph1lb4

    translateSourcepaths './libs/bsh-2.0b4.jar'
    translateSourcepaths './libs/gson-2.3.1.jar'
    translateSourcepaths './libs/joda-time-2.4.jar'

Are these source jars or classfile jars? If you unzip them do they .java files or .class files?

[ph1lb4]

If unzipped they all contain .class files

[advayDev1]

Yep, you'll need to find source jars for each of those libraries.
If you are using mavenCentral, consider finding them here for example:
http://search.maven.org/#artifactdetails%7Ccom.google.code.gson%7Cgson%7C2.3.1%7Cjar
The links ends with -sources.jar

Put those in a 'srcLibs' directory (to keep them separate from the class jars which you still need), and then change the translateSourcepaths commands to refer to those sources jars.

[ph1lb4]

Oh I see, thank you very much for your patience and help, it builds successfully now!

[advayDev1]

Awesome! Please take a look at #415 and let me know if it is clear enough for newcomers.
I will resolve this issue fixed once that PR is submitted.

[ph1lb4]

Yes, I think the new part in the FAQ makes it much clearer. Should be good for newcomers.

[roisagiv]

This trick worked for me:

shared/build.gradle

plugins {
  id 'java'
  id 'com.github.j2objccontrib.j2objcgradle' version '0.4.2-alpha'
}

configurations {
  j2objc
}

dependencies {
  compile 'com.eclipsesource.minimal-json:minimal-json:0.9.4'
  j2objc 'com.eclipsesource.minimal-json:minimal-json:0.9.4:sources'

  compile 'com.google.guava:guava:18.0'
  compile 'com.google.j2objc:j2objc-annotations:0.9.8'

  // test libraries
  testCompile 'junit:junit:4.11'
  testCompile 'org.mockito:mockito-core:1.9.5'
}

// Plugin settings:
j2objcConfig {
  xcodeProjectDir '../ios'  // Xcode workspace directory (suggested directory name)
  xcodeTarget 'MyTarget'     // iOS app target name (replace with existing app name)

  translateArgs '-use-arc'
  translateArgs '--build-closure'
  extraObjcCompilerArgs '-fobjc-arc'

  translateJ2objcLibs << 'hamcrest-core-1.3.jar'

  configurations.j2objc.each { translateSourcepaths it.absolutePath.toString() }

  finalConfigure()          // Must be last call to configuration
}

[ph1lb4]

What exactly do you mean by trick?
This line:

j2objc 'com.eclipsesource.minimal-json:minimal-json:0.9.4:sources'

[roisagiv]

this line:
j2objc 'com.eclipsesource.minimal-json:minimal-json:0.9.4:sources'
with this line:
configurations.j2objc.each { translateSourcepaths it.absolutePath.toString() }

[ph1lb4]

Ok that is really great! I was just confused because you did not use it for your other dependencies.

[advayDev1]

Yes, that's the first part of the solution: use the sources classifier attribute in the Maven coordinate.
As you pointed out, however, it can't be used for all of the libraries, because some of them are included inside j2objc, and you don't want to use the original source for those, since J2ObjC has custom native code for some of them. We need to solve #180 to have a complete solution - that allows the plugin to decide whether a given Maven coordinate should be downloaded from scratch or used from the j2objc dist.

My current simple plan for #41 is to automatically generate a j2objcSource configuration element on j2objcConfig.finalConfigure() that:

1. For each compile dependency that is a project, use the existing dependsOnJ2objc(proj)
2. For each compile dependency that matches a set of regexes of libs included in J2ObjC, ignore them
3. For every compile dependency specified as a Maven coordinate, attach the 'sources' classifier.
4. Else fail

if any dependencies of type (3) are found, --build-closure is added as well. I should have a PR out later tonight.

If either of you have better ideas, please do tell! Thanks!

[advayDev1]

Proposed solution is #420