Package org.apache.bookkeeper.util

Class Shell

  • Direct Known Subclasses:
    Shell.ShellCommandExecutor
    public abstract class Shell
extends java.lang.Object
    A base class for running a Unix command. Shell can be used to run unix commands like du or df. It also offers facilities to gate commands by time-intervals.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static org.apache.commons.logging.Log LOG  
      protected long timeOutInterval  
      static boolean WINDOWS
      Set to true on Windows platforms.

    • Constructor Summary

      Constructors 
      Constructor Description
      Shell()  
      Shell​(long interval)  

    • Method Summary

      All Methods Static Methods Instance Methods Abstract Methods Concrete Methods 
      Modifier and Type Method Description
      static java.lang.String execCommand​(java.lang.String... cmd)
      Static method to execute a shell command.
      static java.lang.String execCommand​(java.util.Map<java.lang.String,​java.lang.String> env, java.lang.String... cmd)
      Static method to execute a shell command.
      static java.lang.String execCommand​(java.util.Map<java.lang.String,​java.lang.String> env, java.lang.String[] cmd, long timeout)
      Static method to execute a shell command.
      protected abstract java.lang.String[] getExecString()
      Return an array containing the command name & its parameters.
      int getExitCode()
      Get the exit code.
      java.lang.Process getProcess()
      Get the current sub-process executing the given command.
      boolean isTimedOut()
      To check if the passed script to shell command executor timed out or not.
      protected abstract void parseExecResult​(java.io.BufferedReader lines)
      Parse the execution result.
      protected void run()
      Check to see if a command needs to be executed and execute if needed.
      protected void setEnvironment​(java.util.Map<java.lang.String,​java.lang.String> env)
      Set the environment for the command.
      protected void setWorkingDirectory​(java.io.File dir)
      Set the working directory.

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • LOG

        public static final org.apache.commons.logging.Log LOG

      • timeOutInterval

        protected long timeOutInterval

      • WINDOWS

        public static final boolean WINDOWS
        Set to true on Windows platforms.

    • Constructor Detail

      • Shell

        public Shell()

      • Shell

        public Shell​(long interval)
        Parameters:
        interval - the minimum duration to wait before re-executing the command.

    • Method Detail

      • setEnvironment

        protected void setEnvironment​(java.util.Map<java.lang.String,​java.lang.String> env)
        Set the environment for the command.
        Parameters:
        env - Mapping of environment variables

      • setWorkingDirectory

        protected void setWorkingDirectory​(java.io.File dir)
        Set the working directory.
        Parameters:
        dir - The directory where the command would be executed

      • run

        protected void run()
            throws java.io.IOException
        Check to see if a command needs to be executed and execute if needed.
        Throws:
        java.io.IOException

      • getExecString

        protected abstract java.lang.String[] getExecString()
        Return an array containing the command name & its parameters.

      • parseExecResult

        protected abstract void parseExecResult​(java.io.BufferedReader lines)
                                 throws java.io.IOException
        Parse the execution result.
        Throws:
        java.io.IOException

      • getProcess

        public java.lang.Process getProcess()
        Get the current sub-process executing the given command.
        Returns:
        process executing the command

      • getExitCode

        public int getExitCode()
        Get the exit code.
        Returns:
        the exit code of the process

      • isTimedOut

        public boolean isTimedOut()
        To check if the passed script to shell command executor timed out or not.
        Returns:
        if the script timed out.

      • execCommand

        public static java.lang.String execCommand​(java.lang.String... cmd)
                                    throws java.io.IOException
        Static method to execute a shell command. Covers most of the simple cases without requiring the user to implement the Shell interface.
        Parameters:
        cmd - shell command to execute.
        Returns:
        the output of the executed command.
        Throws:
        java.io.IOException

      • execCommand

        public static java.lang.String execCommand​(java.util.Map<java.lang.String,​java.lang.String> env,
                                           java.lang.String[] cmd,
                                           long timeout)
                                    throws java.io.IOException
        Static method to execute a shell command. Covers most of the simple cases without requiring the user to implement the Shell interface.
        Parameters:
        env - the map of environment key=value
        cmd - shell command to execute.
        timeout - time in milliseconds after which script should be marked timeout
        Returns:
        the output of the executed command.o
        Throws:
        java.io.IOException

      • execCommand

        public static java.lang.String execCommand​(java.util.Map<java.lang.String,​java.lang.String> env,
                                           java.lang.String... cmd)
                                    throws java.io.IOException
        Static method to execute a shell command. Covers most of the simple cases without requiring the user to implement the Shell interface.
        Parameters:
        env - the map of environment key=value
        cmd - shell command to execute.
        Returns:
        the output of the executed command.
        Throws:
        java.io.IOException