Package org.apache.commons.exec

Interface Executor

  • All Known Implementing Classes:
    DaemonExecutor, DefaultExecutor
    public interface Executor
    The main abstraction to start an external process. The interface allows to:
    • set a current working directory for the subprocess
    • provide a set of environment variables passed to the subprocess
    • capture the subprocess output of stdout and stderr using an ExecuteStreamHandler
    • kill long-running processes using an ExecuteWatchdog
    • define a set of expected exit values
    • terminate any started processes when the main process is terminating using a ProcessDestroyer

    The following example shows the basic usage: 

     Executor exec = DefaultExecutor.builder().get();
 CommandLine cl = new CommandLine("ls -l");
 int exitValue = exec.execute(cl);

    • Method Detail

      • execute

        int execute​(CommandLine command)
     throws ExecuteException,
            java.io.IOException
        Executes a command synchronously. The child process inherits all environment variables of the parent process.
        Parameters:
        command - the command to execute.
        Returns:
        process exit value.
        Throws:
        ExecuteException - execution of subprocess failed or the subprocess returned an exit value indicating a failure setExitValue(int).
        java.io.IOException - If an I/O error occurs.

      • execute

        void execute​(CommandLine command,
             ExecuteResultHandler handler)
      throws ExecuteException,
             java.io.IOException
        Executes a command asynchronously. The child process inherits all environment variables of the parent process. Result provided to callback handler.
        Parameters:
        command - the command to execute.
        handler - capture process termination and exit code.
        Throws:
        ExecuteException - execution of subprocess failed.
        java.io.IOException - If an I/O error occurs.

      • execute

        int execute​(CommandLine command,
            java.util.Map<java.lang.String,​java.lang.String> environment)
     throws ExecuteException,
            java.io.IOException
        Executes a command synchronously.
        Parameters:
        command - the command to execute.
        environment - The environment for the new process. If null, the environment of the current process is used.
        Returns:
        process exit value.
        Throws:
        ExecuteException - execution of subprocess failed or the subprocess returned an exit value indicating a failure setExitValue(int).
        java.io.IOException - If an I/O error occurs.

      • execute

        void execute​(CommandLine command,
             java.util.Map<java.lang.String,​java.lang.String> environment,
             ExecuteResultHandler handler)
      throws ExecuteException,
             java.io.IOException
        Executes a command asynchronously. The child process inherits all environment variables of the parent process. Result provided to callback handler.
        Parameters:
        command - the command to execute.
        environment - The environment for the new process. If null, the environment of the current process is used.
        handler - capture process termination and exit code.
        Throws:
        ExecuteException - execution of subprocess failed.
        java.io.IOException - If an I/O error occurs.

      • getProcessDestroyer

        ProcessDestroyer getProcessDestroyer()
        Sets the handler for cleanup of started processes if the main process is going to terminate.
        Returns:
        the ProcessDestroyer.

      • getWatchdog

        ExecuteWatchdog getWatchdog()
        Gets the watchdog used to kill of processes running, typically, too long time.
        Returns:
        the watchdog.

      • getWorkingDirectory

        java.io.File getWorkingDirectory()
        Gets the working directory of the created process.
        Returns:
        the working directory.

      • getWorkingDirectoryPath

        default java.nio.file.Path getWorkingDirectoryPath()
        Gets the working directory of the created process.
        Returns:
        the working directory.
        Since:
        1.5.0

      • isFailure

        boolean isFailure​(int exitValue)
        Tests whether exitValue signals a failure. If no exit values are set than the default conventions of the OS is used. e.g. most OS regard an exit code of '0' as successful execution and everything else as failure.
        Parameters:
        exitValue - the exit value (return code) to be checked.
        Returns:
        true if exitValue signals a failure.

      • setExitValue

        void setExitValue​(int value)
        Sets the exitValue of the process to be considered successful. If a different exit value is returned by the process then execute(CommandLine) will throw an ExecuteException.
        Parameters:
        value - the exit code representing successful execution.

      • setExitValues

        void setExitValues​(int[] values)
        Sets a list of exitValue of the process to be considered successful. The caller can pass one of the following values.
        • an array of exit values to be considered successful
        • an empty array for auto-detect of successful exit codes relying on isFailure(int)
        • null to indicate to skip checking of exit codes
        If an undefined exit value is returned by the process then execute(CommandLine) will throw an ExecuteException.
        Parameters:
        values - a list of the exit codes.

      • setProcessDestroyer

        void setProcessDestroyer​(ProcessDestroyer processDestroyer)
        Sets the handler for cleanup of started processes if the main process is going to terminate.
        Parameters:
        processDestroyer - the ProcessDestroyer.

      • setStreamHandler

        void setStreamHandler​(ExecuteStreamHandler streamHandler)
        Sets a custom the StreamHandler used for providing input and retrieving the output. If you don't provide a proper stream handler the executed process might block when writing to stdout and/or stderr (see Process).
        Parameters:
        streamHandler - the stream handler.

      • setWatchdog

        void setWatchdog​(ExecuteWatchdog watchDog)
        Sets the watchdog used to kill of processes running, typically, too long time.
        Parameters:
        watchDog - the watchdog.

      • setWorkingDirectory

        void setWorkingDirectory​(java.io.File dir)
        Sets the working directory of the created process. The working directory must exist when you start the process.
        Parameters:
        dir - the working directory.