Processing the command line : Console « Development Class « Java
Processing the command line
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* ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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*
* Copyright 1999 (C) Exoffice Technologies Inc. All Rights Reserved.
*
* $Id: CommandLine.java,v 1.1 2004/11/26 01:51:02 tanderson Exp $
*
* Date Author Changes
* 1/6/2000 jima Created
* 1/9/2000 jima changed package name from com.comware to org.exolab
* 7/1/2000 jima removed the CW prefix from the class name
* 1/8/2001 jima Removed it from jtf library and imported it into
* the openjms library
*/
import java.util.Hashtable;
import java.util.Vector;
/**
* This core class is responsible for processing the command line and
* storing away the list of options and parameters specified. The
* difference between an option and a command line is that an option
* is a boolean value (true if it is specified and false otherwise)
* and a parameter always has an associated value.
*
* @version $version$
* @author jima
**/
public class CommandLine {
/**
* A list of option of switches on the command line. A switch
* is either set or not
*/
private Vector _switches = new Vector();
/**
* A dictionary of all the options and their associated values
*/
private Hashtable _options = new Hashtable();
/**
* Construct an instance of this class with the specified string
* array.
*
* @param args command line argument
*/
public CommandLine(String[] args) {
processCommandLine(args);
}
/**
* Default constructor which simply initialised the class
*/
public CommandLine() {
}
/**
* Check if the following option or command has been specified
*
* @param name name of option or command
* @return boolean true if it has been specified
*/
public boolean exists(String name) {
return _switches.contains(name) || _options.containsKey(name);
}
/**
* Check if the following option has been specified.
*
* @param name name of the option
* @return boolean true if it has been specified
*/
public boolean isSwitch(String name) {
return _switches.contains(name);
}
/**
* Check if the following parameter has been specified.
*
* @param name name of the parameter
* @return boolean true if it has been specified
*/
public boolean isParameter(String name) {
return _options.containsKey(name);
}
/**
* Return the value of the parameter or option. If the string nominates
* an option then return null
*
* @param name name of option or parameter
* @return String value of parameter or null
*/
public String value(String name) {
String result = null;
if (_options.containsKey(name)) {
result = (String) _options.get(name);
}
return result;
}
/**
* Return the value of the parameter or option, returning a default
* value if none is specified
*
* @param name name of option or parameter
* @param defaultValue the default value
* @return String value of parameter
*/
public String value(String name, String defaultValue) {
String result = value(name);
return (result != null) ? result : defaultValue;
}
/**
* Add the following option or parameter to the list. An option will
* have a null value, whereas a parameter will have a non-null value.
* <p>
* This will automatically overwrite the previous value, if one has been
* specified.
*
* @param name name of option or parameter
* @param value value of name
* @return boolean true if it was successfully added
*/
public boolean add(String name, String value) {
return add(name, value, true);
}
/**
* Add the following option or parameter to the list. An option will
* have a null value, whereas a parameter will have a non-null value.
* <p>
* If the overwrite flag is true then this value will overwrite the
* previous value. If the overwrite flag is false and the name already
* exists then it will not overwrite it and the function will return
* false. In all other circumstances it will return true.
*
* @param name name of option or parameter
* @param value value of name
* @param overwrite true to overwrite previous value
* @return boolean true if it was successfully added
*/
public boolean add(String name, String value, boolean overwrite) {
boolean result = false;
if (value == null) {
// it is an option
if ((_switches.contains(name)) &&
(overwrite)) {
_switches.addElement(name);
result = true;
} else if (!_switches.contains(name)) {
_switches.addElement(name);
result = true;
}
} else {
// parameter
if ((_options.containsKey(name)) &&
(overwrite)) {
_options.put(name, value);
result = true;
} else if (!_options.containsKey(name)) {
_options.put(name, value);
result = true;
}
}
return result;
}
/**
* This method processes the command line and extracts the list of
* options and command lines. It doesn't intepret the meaning of the
* entities, which is left to the application.
*
* @param args command line as a collection of tokens
*/
private void processCommandLine(String[] args) {
boolean prev_was_hyphen = false;
String prev_key = null;
for (int index = 0; index < args.length; index++) {
if (args[index].startsWith("-")) {
// if the previous string started with a hyphen then
// it was an option store store it, without the hyphen
// in the _switches vector. Otherwise if the previous was
// not a hyphen then store key and value in the _options
// hashtable
if (prev_was_hyphen) {
add(prev_key, null);
}
prev_key = args[index].substring(1);
prev_was_hyphen = true;
// check to see whether it is the last element in the
// arg list. If it is then assume it is an option and
// break the processing
if (index == args.length - 1) {
add(prev_key, null);
break;
}
} else {
// it does not start with a hyphen. If the prev_key is
// not null then set the value to the prev_value.
if (prev_key != null) {
add(prev_key, args[index]);
prev_key = null;
}
prev_was_hyphen = false;
}
}
}
}
