org.mycore.frontend.cli
Class MCRCommand

java.lang.Object
  org.mycore.frontend.cli.MCRCommand

public class MCRCommand
extends Object

Represents a command understood by the command line interface. A command has an external input syntax that the user uses to invoke the command and points to a method in a class that implements the command.

Version:

$Revision: 13085 $ $Date: 2008-02-06 18:27:24 +0100 (Mi, 06 Feb 2008) $

Author:

Frank Lützenkirchen, Jens Kupferschmidt

See Also:

MCRCommandLineInterface

Field Summary

protected String	className The class providing the implementation method
protected String	help The help text String
protected MessageFormat	messageFormat The input format used for invoking this command
protected Method	method The java method that implements this command
protected String	methodName The method implementing this command
protected int	numParameters The number of invocation parameters
protected Class[]	parameterTypes The types of the invocation parameters
protected String	suffix The beginning of the message format up to the first parameter

Constructor Summary

MCRCommand(String format, String methodSignature, String helpText)
Creates a new MCRCommand.

Method Summary

protected Object[]	buildInvocationParameters(Object[] commandParameters) Transforms the parameters found by the MessageFormat parse method into such that can be used to invoke the method implementing this command
protected String	getHelpText() The method return the helpt text of this command.
protected Method	getMethod(ClassLoader classLoader) Returns the method implementing the command behavior.
List<String>	invoke(String input) Tries to invoke the method that implements the behavior of this command given the user input from the command line.
List<String>	invoke(String input, ClassLoader classLoader)
protected Object[]	parseCommandLine(String commandLine) Parses an input string and tries to match it with the message format used to invoke this command.
String	showSyntax() Returns the input syntax to be used for invoking this command from the command prompt.

Methods inherited from class java.lang.Object

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

Field Detail

messageFormat

protected MessageFormat messageFormat

The input format used for invoking this command

method

protected Method method

The java method that implements this command

parameterTypes

protected Class[] parameterTypes

The types of the invocation parameters

numParameters

protected int numParameters

The number of invocation parameters

className

protected String className

The class providing the implementation method

methodName

protected String methodName

The method implementing this command

suffix

protected String suffix

The beginning of the message format up to the first parameter

help

protected String help

The help text String

Constructor Detail

MCRCommand

public MCRCommand(String format,
                  String methodSignature,
                  String helpText)

Creates a new MCRCommand.

Parameters:

format - the command syntax, e.g. "save document {0} to directory {1}"

methodSignature - the method to invoke, e.g. "miless.commandline.DocumentCommands.saveDoc int String"

helpText - the helpt text for this command

Method Detail

getMethod

protected Method getMethod(ClassLoader classLoader)
                    throws ClassNotFoundException,
                           NoSuchMethodException

Returns the method implementing the command behavior.

Returns:

The method to be invoked for executing the command

Throws:

ClassNotFoundException - when the class that implements the method was not found

NoSuchMethodException - When the method specified in the constructor was not found

getHelpText

protected String getHelpText()

The method return the helpt text of this command.

Returns:

the help text as String

parseCommandLine

protected Object[] parseCommandLine(String commandLine)

Parses an input string and tries to match it with the message format used to invoke this command.

Parameters:

commandLine - The input from the command line

Returns:

null, if the input does not match the message format; otherwise an array holding the parameter values from the command line

buildInvocationParameters

protected Object[] buildInvocationParameters(Object[] commandParameters)

Transforms the parameters found by the MessageFormat parse method into such that can be used to invoke the method implementing this command

Parameters:

commandParameters - The parameters as returned by the parseCommandLine method

Returns:

The parameters that can be used to invoke the implementing method

invoke

public List<String> invoke(String input)
                    throws IllegalAccessException,
                           InvocationTargetException,
                           ClassNotFoundException,
                           NoSuchMethodException

Tries to invoke the method that implements the behavior of this command given the user input from the command line. This is only done when the command line syntax matches the syntax used by this command.

Parameters:

input - The command entered by the user at the command prompt

Returns:

null, if the command syntax did not match and the command was not invoked, otherwise a List of commands is returned which may be empty or otherwise contains commands that should be processed next

Throws:

IllegalAccessException - when the method can not be invoked

InvocationTargetException - when an exception is thrown by the invoked method

ClassNotFoundException - when the class providing the method could not be found

NoSuchMethodException - when the method specified does not exist

invoke

public List<String> invoke(String input,
                           ClassLoader classLoader)
                    throws IllegalAccessException,
                           InvocationTargetException,
                           ClassNotFoundException,
                           NoSuchMethodException

Throws:

IllegalAccessException

InvocationTargetException

ClassNotFoundException

NoSuchMethodException

showSyntax

public final String showSyntax()

Returns the input syntax to be used for invoking this command from the command prompt.

Returns:

the input syntax for this command