Creating a osx app bundle in Java registered to a protocol url
Recently we extended our enterprise search engine bleen adding a desktop utility automatically launched clicking on a result link.
To achieve this we created a native applciation ( for windows and osx ) registered to the protocol url bleen://
In this tutorial we will see how to build this utility in Java for Mac OS X.
The base code is a simple java class displaying a Dialog
Application bundle
Creating a OSX application bundle is as easy as creating a directory structure following some simple rules.
Out directory tree will contain :
a jar with out classes
the dependency jars
the info.plist file
a native executable
The following is a ant tast that creates the dir tree.
<target name="application-bundle" depends="jar" description="create mac Os X Application bundle"> <mkdir dir="${dist.appbundle}/Contents/MacOS" /> <mkdir dir="${dist.appbundle}/Contents/Resources/Java" /> <copy file="${auxes.dir}/JavaApplicationStub" todir="${dist.appbundle}/Contents/MacOS" /> <exec executable="chmod"> <arg value="755" /> <arg value="${dist.appbundle}/Contents/MacOS/JavaApplicationStub" /> </exec> <copy file="${auxes.dir}/Info.plist" todir="${dist.appbundle}/Contents" /> <copy file="${auxes.dir}/icon.icns" todir="${dist.appbundle}/Contents/Resources" /> <copy file="${dist.dir}/application.jar" todir="${dist.appbundle}/Contents/Resources/Java" /> <copy file="lib/libreria1.jar" todir="${dist.appbundle}/Contents/Resources/Java"/> </target>
The result is a directory tree viewed ad a application document by OSX.
URL protocol
The application runtime information are stored in info.plist file.
We edited this file inserting a couple of new keys. These keys link out app to the protocol demo://
URL Types
URL Identifier
URL Schemes
Now, the system will launch our utility every time the user clicks on a link starting with demo://
To allow osx to know out utility exist we must :
copy the app to /Application directory
or manually launch it at least once
OpenURL
Now we reached our target but we don’t use the clicked url in our code, yet.
To use it, we must relay on a system event osx raises to ask applications to manage urls. We use an extension library provided by Apple, registering a handler to the OpenURI event.
public static void main(final String[] args) { Application.getApplication().setOpenURIHandler( new OpenURIHandler() { @Override public void openURI(final OpenURIEvent pEvent) { JOptionPane.showMessageDialog ( null, pEvent.getURI().toString(), “demo”, JOptionPane.ERROR_MESSAGE); } }); }
Dependencies
Note that our dependencies jar must be located in Contents/Resources/Java and every jar must be declared in Info.plist under the keys Java/Classpath
Download
You can find a demo project download on our public space in Assembla - link
References
Handling URL shemes in Cocoa
JavaApplicationStub
AppleJavaExtensions
MRJAdapter - java library to enhance osx integration
Apple doc - References to the java info.plist keys
Apple doc - References to application bundles creations
Apple javadoc - Javadoc for Apple Java extensions