com.hypirion.io

Class SignalInterceptor

java.lang.Object

com.hypirion.io.SignalInterceptor

public class SignalInterceptor
extends java.lang.Object

The SignalInterceptor class is a static collection of methods used to intercept POSIX signals before they are sent to their original signal handlers. Signal interceptors may be chained: If one attach the handler A to signal X, then attach the handler B to X as well, then all raised signals of type X will first call B, then A, then the original handler.

Signal handlers are Callables, which return booleans. If the signal handler returns true, the call chain will continue. If the signal handler returns false or throws an Exception, the call chain will stop (and no Exception will be thrown). If the signal handler throws an Error, the Error will not be caught.

Since:

com.hypirion.io 0.3.0

Constructor Summary

Constructors

Constructor and Description
SignalInterceptor()

Method Summary

Methods

Modifier and Type	Method and Description
static void	register(java.lang.String signame, java.util.concurrent.Callable fn) Registers the Callable object to the POSIX signal signame.
static boolean	tryRegister(java.lang.String signame, java.util.concurrent.Callable fn) Registers the Callable object to the POSIX signal signame.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SignalInterceptor

public SignalInterceptor()

Method Detail

register

public static void register(java.lang.String signame,
            java.util.concurrent.Callable fn)
                     throws SignalInterceptorException

Registers the Callable object to the POSIX signal signame. The POSIX signal must be in upper case, with the beginning SIG part omitted.

E.g. an interception to SIGINT be converted to the symbol "INT".

Parameters:

signame - the POSIX signal name with SIG omitted.

fn - the Callable to call. The Callable should return either true or false.

Throws:

SignalInterceptorException - if there is no signal with the name signame, or if the JVM doesn't implement the most common JVM signal handling facilities.

tryRegister

public static boolean tryRegister(java.lang.String signame,
                  java.util.concurrent.Callable fn)

Registers the Callable object to the POSIX signal signame. If successful, will return true. If the registering fails, returns false. The POSIX signal must be in upper case, with the beginning SIG part omitted.

E.g. an interception to SIGINT be converted to the symbol "INT".

Parameters:

signame - the POSIX signal name with SIG omitted.

fn - the Callable to call. The Callable should return either true or false.