public class ProcessWrapper
extends Object

A ProcessWrapper is used by Silver Fabric as a wrapper around the java.lang.Process class, with the purpose of providing convenience methods and additional functionality (sometimes in a platform specific manner), including:

• Custom handling of output streams
• Process shutdown detection
• Forced process killing

There are two contexts in which an enabler developer might use a ProcessWrapper object. The first is in referencing and acting on either ExecContainer's primary process or its shutdown process. These are available via the ExecContainer.getProcess() and ExecContainer.getShutdownProcess() methods, respectively. The basic assumption here is that in the simple case, an enabler will manage a single process and will require one additional process to shutdown the first. The primary ProcessWrapper is created when the enabler startup command is executed, and the shutdown ProcessWrapper is created when enabler shutdown is called.

The second context which might be useful in enabler development is when some "extra" process must be run by the enabler. ProcessWrapper can be used to wrap a short lived task or manage an additional long running process. In either of these cases, one of the factory methods provided by ExecContainer should be used to obtain a ProcessWrapper instance. The recommended form to use is getProcessWrapper(String execString, File targetDir, String pidFilename).

The pidFilename parameter is currently used for forced process killing on windows only. (In the case that the enabler is running on some other platform, the pidFilename parameter is ignored.) On windows, the way that it is used is as follows: a native binary "wrappid.exe" is used to actually execute the process to be run. This binary outputs its own pid to the specified file in the target directory. Then, if a wrapped process fails to stop gracefully on its own, the ProcessWrapper.destroy() method can be called. When this happens, the pid is passed to a second native binary "endprocess.exe", which walks the process tree and kills the process and its children.