com.bea.adapter.util
Class CommandRunner

java.lang.Object
  java.lang.Thread
      com.bea.adapter.util.CommandRunner

All Implemented Interfaces:

Runnable

public class CommandRunner

extends Thread

Helper class for executing a command via a Process obtained by the Runtime object in a thread. The main value-add of this class is to allow for setting a maximum time to wait for the process to return and if the max is exceeded, handle the error reporting gracefully. Here's how to use the CommandRunner to compile a Java file using "javac":

 CommandRunner runner = new CommandRunner("javac HelloWorld.java");
 runner.start();
 if (!CommandRunner.SUCCESS.equals(runner.getExitValue())) {
   throw new IllegalStateException(runner.getErrorMessage());
 }
 

Field Summary

static long	DEFAULT_MAX_WAIT The default max wait period for waiting for a process to complete.
static String	EXCEPTION Possible return value from getExitValue; indicates that an exception was encountered while executing the command, such as the executable was not in the user's path.
static String	SUCCESS Possible return value from getExitValue; indicates that the external process returned 0 as an exit value.
static String	TIMEOUT Possible return value from getExitValue; indicates the process did NOT return an exit value in the maximum allowable time period, perhaps the external process is hung.

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

CommandRunner(String strCommand)
Constructs an instance to execute a command and wait a maximum of 10 seconds for it to finish.

CommandRunner(String strCommand, long lMaxWait)
Constructs an instance to execute a command and wait a maximum of lMaxWait milliseconds for it to finish.

Method Summary

String	getCommand()
String	getErrorMessage()
String	getExitValue() Returns the exit value from executing the command: CommandRunner.TIMEOUT indicates that the process timed-out, CommandRunner.SUCCESS indicates the process returned 0, CommandRunner.EXCEPTION indicates an exception was encountered while executing the command.
void	run() Executes the command established in the constructor.

Methods inherited from class java.lang.Thread

activeCount, checkAccess, countStackFrames, currentThread, destroy, dumpStack, enumerate, getContextClassLoader, getName, getPriority, getThreadGroup, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setName, setPriority, sleep, sleep, start, stop, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

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

Field Detail

EXCEPTION

public static final String EXCEPTION

Possible return value from getExitValue; indicates that an exception was encountered while executing the command, such as the executable was not in the user's path.

See Also:

Constant Field Values

TIMEOUT

public static final String TIMEOUT

Possible return value from getExitValue; indicates the process did NOT return an exit value in the maximum allowable time period, perhaps the external process is hung.

See Also:

Constant Field Values

SUCCESS

public static final String SUCCESS

Possible return value from getExitValue; indicates that the external process returned 0 as an exit value.

See Also:

Constant Field Values

DEFAULT_MAX_WAIT

public static final long DEFAULT_MAX_WAIT

The default max wait period for waiting for a process to complete.

See Also:

Constant Field Values

Constructor Detail

CommandRunner

public CommandRunner(String strCommand)

Constructs an instance to execute a command and wait a maximum of 10 seconds for it to finish.

Parameters:

strCommand - - command to execute

CommandRunner

public CommandRunner(String strCommand,
                     long lMaxWait)

Constructs an instance to execute a command and wait a maximum of lMaxWait milliseconds for it to finish.

Parameters:

strCommand - - command to execute

lMaxWait - - maximum number of milliseconds to wait until the command returns a value.

Method Detail

getExitValue

public String getExitValue()

Returns the exit value from executing the command: CommandRunner.TIMEOUT indicates that the process timed-out, CommandRunner.SUCCESS indicates the process returned 0, CommandRunner.EXCEPTION indicates an exception was encountered while executing the command.

Returns:

a String indicating the outcome of the command.

getCommand

public String getCommand()

Returns:

the command that this instance executes.

getErrorMessage

public String getErrorMessage()

Returns:

a String of information read from the process' error stream.

run

public void run()

Executes the command established in the constructor.