org.entityfs.support.io
Class AbstractCommands

java.lang.Object
  org.entityfs.support.io.AbstractCommands

public abstract class AbstractCommands
extends Object

This is an abstract class that command class implementations can inherit. It contains methods for running external commands.

Since:

1.0

Author:

Karl Gustafsson

Constructor Summary

protected

AbstractCommands(LogAdapterHolder lah) Constructor.

Method Summary

protected Process	execAndWait(String cmd) Execute an external command, such as ls and wait for it to complete.
protected String	getErrorMessage(Process p, String cmd) Create an error message from the error message from a process.
protected LogAdapter	getLogAdapter() Get the file system's current log adapter.
protected String	getOutput(InputStream is) Get the output from a stream, for instance from the output of a process.

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractCommands

protected AbstractCommands(LogAdapterHolder lah)

Constructor.

Parameters:

lah - The file system's log adapter holder.

Method Detail

getLogAdapter

protected LogAdapter getLogAdapter()

Get the file system's current log adapter.

Returns:

The file system's current log adapter.

execAndWait

protected Process execAndWait(String cmd)
                       throws InterruptedException

Execute an external command, such as ls and wait for it to complete.

This does not work if the command generates a lot of output because the process' output buffers are limited in size. In that case the running process' output must be regularly read to keep it from stalling. See Process.

Parameters:

cmd - The command to run

Returns:

The Process object for the completed process.

Throws:

InterruptedException - If the command was interrupted.

getOutput

protected String getOutput(InputStream is)

Get the output from a stream, for instance from the output of a process.

Parameters:

is - The stream to read from. The stream is closed by this method.

Returns:

The output contained in the stream.

getErrorMessage

protected String getErrorMessage(Process p,
                                 String cmd)

Create an error message from the error message from a process. Call this to get an error message if the process exited with an exit code other than 0.

Parameters:

p - The process that generated an error.

cmd - The command that failed.

Returns:

An error message.