CommandLineOption.java

package rabbitescape.engine.util;

import rabbitescape.engine.err.RabbitEscapeException;

/**
 * Supply a long form option (eg "--start").
 * The short form is generated automatically (eg "-s").
 * Parameters may be supplied as the next arg, or
 * concatenated ( "-s 0", "-s0"). Also with equals is fine
 * (eg --start=0).
 * Limitations;
 * * Options must begin "--".
 * * Different options cannot begin with the same letter
 * * Options may not be repeated on the command line.
 * * parameters cannot start with "=".
 */
public class CommandLineOption
{
    public class UnknownOption extends RabbitEscapeException
    {
        private static final long serialVersionUID = 1L;
        public final String unknownArg;

        public UnknownOption( String arg )
        {
            this.unknownArg = arg;
        }
    }

    public class OptionRequiresParameter extends RabbitEscapeException
    {
        private static final long serialVersionUID = 1L;
        public final String arg;

        public OptionRequiresParameter( String arg )
        {
            this.arg = arg;
        }
    }

    public class OptionDoesNotTakeParameter extends RabbitEscapeException
    {
        private static final long serialVersionUID = 1L;
        public final String arg;

        public OptionDoesNotTakeParameter( String arg )
        {
            this.arg = arg;
        }
    }

    public final String longForm;
    public final String shortForm;
    public final boolean takesParam;
    private String value = null;
    private boolean present = false;

    public CommandLineOption( String longForm, boolean takesParam )
    {
        this.takesParam = takesParam;
        this.longForm = longForm;
        assert( longForm.startsWith( "--" ) );
        this.shortForm = longForm.substring( 1, 3 );
    }

    public void setValue( String value, String parentOption )
    {
        if ( value.length() > 0 && value.startsWith( "-" ) )
        {
            throw new OptionRequiresParameter( parentOption );
        }
        this.value = value;
    }

    public String getValue()
    {
        return value;
    }

    public void setPresent()
    {
        present = true;
    }

    public boolean isPresent()
    {
        return present;
    }

    /**
     * Checks if the command line argument is a match for this one.
     * Also tests for concatenated param.
     */
    public boolean matches( String arg )
    {
        String maybeParam = null;
        if ( arg.startsWith( longForm ) )
        {
            maybeParam = arg.substring( longForm.length() );
        }
        if ( arg.startsWith( shortForm ) )
        {
            maybeParam = arg.substring( shortForm.length() );
        }
        if ( maybeParam == null )
        {
            return false;
        }
        if ( maybeParam.length() > 0 )
        {
            if ( !takesParam )
            {
                throw new OptionDoesNotTakeParameter(shortForm);
            }
            // Handle things like --start=0
            if ( maybeParam.substring( 0, 1 ).equals( "=" ))
            {
                maybeParam = maybeParam.substring( 1 );
            }
            this.setValue( maybeParam, arg );
        }
        return true;
    }

    public OptionRequiresParameter getOptionRequiresParameter( String arg )
    {
        return new OptionRequiresParameter( arg );
    }

    public UnknownOption getUnknownOption( String arg )
    {
        return new UnknownOption( arg );
    }

    public int getInt()
    {
        return Integer.parseInt( value );
    }



}