1752204eb6
JIRA: https://jira.spring.io/browse/INT-4058 If you hold the lock, you are the leader. This simple idea gets you a long way if there is no "native" leader initiator. E.g. you can use this with a RDBMS with JdbcLockRegistry. Add some docs on leader election under "endpoints" Make thread name for leader initiator unique In case there are multiple instances in the same context we would like to be able to spot them in the logs. INT-4058: Polishing * Code refactoring in the `LockRegistryLeaderInitiator`: SI use 120 line length * Add `Assert.notNull()` for required properties * Add `this.lock.unlock()` and `Thread.sleep(LockRegistryLeaderInitiator.this.busyWaitMillis)` into the `catch` block to let distributed elections to work. Otherwise there is a big chance that we will acquire the lock and become a leader again just after `yield()` * Change `LockContext.toString()` to use simple `String` concatenation which is optimized by compiler to the `StringBuilder`. That let to have some better micro-performance compared with with extra `Formatter` object in case of `String.format()` * Add `JdbcLockRegistryLeaderInitiatorTests` * Fix `yield()` logic based on the `Future.cancel(true)`. Since one `FutureTask.cancel(true)` makes it as `INTERRUPTED` any subsequent `yield()` does not make any effect, therefore our infinite selector loop isn't interrupted one more time. * Reschedule the `LeaderSelector` in the `yield()` after cancel(true). * Rework `catch` in the selector loop just to the `InterruptedException` and `return null;` to stop looping and let reschedule the selector. * Add one more `onRevoked` logic into the `final` of the selector loop to notify that we have lost leadership during `stop()` * Improve `JdbcLockRegistryLeaderInitiatorTests` to ensure that several `yield()` on the same initiator work well. * Add `What's New` note.
Spring Integration 
Checking out and Building
To check out the project and build from source, do the following:
git clone git://github.com/spring-projects/spring-integration.git
cd spring-integration
./gradlew build
NOTE: While Spring Integration runs with Java SE 6 or higher, a Java 8 compiler is required to build the project.
If you encounter out of memory errors during the build, increase available heap and permgen for Gradle:
GRADLE_OPTS='-XX:MaxPermSize=1024m -Xmx1024m'
To build and install jars into your local Maven cache:
./gradlew install
To build api Javadoc (results will be in build/api):
./gradlew api
To build reference documentation (results will be in build/reference):
./gradlew reference
To build complete distribution including -dist, -docs, and -schema zip files (results will be in build/distributions)
./gradlew dist
Using Eclipse
To generate Eclipse metadata (.classpath and .project files), do the following:
./gradlew eclipse
Once complete, you may then import the projects into Eclipse as usual:
File -> Import -> Existing projects into workspace
Browse to the 'spring-integration' root directory. All projects should import free of errors.
Using IntelliJ IDEA
To generate IDEA metadata (.iml and .ipr files), do the following:
./gradlew idea
Resources
For more information, please visit the Spring Integration website at: http://projects.spring.io/spring-integration