protomechencoder.java

MegaMek is a networked Java clone of BattleTech, a turn-based sci-fi boardgame for 2+ players. Fight

/*
 * MegaMek - Copyright (C) 2003, 2004 Ben Mazur ([e-mail])
 * 
 *  This program is free software; you can redistribute it and/or modify it 
 *  under the terms of the GNU General Public License as published by the Free 
 *  Software Foundation; either version 2 of the License, or (at your option) 
 *  any later version.
 * 
 *  This program is distributed in the hope that it will be useful, but 
 *  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
 *  or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 
 *  for more details.
 */

package megamek.common.xml;

import java.io.Writer;
import java.io.IOException;
import java.util.Enumeration;
import gd.xml.tiny.ParsedXML;
import megamek.common.*;

/**
 * Objects of this class can encode a <code>Entity</code> object as XML
 * into an output writer and decode one from a parsed XML node.  It is used
 * when saving games into a version- neutral format.
 *
 * @author      James Damour <[e-mail]>
 */
public class ProtomechEncoder {

    /**
     * Encode a <code>Entity</code> object to an output writer.
     *
     * @param   entity - the <code>Entity</code> to be encoded.
     *          This value must not be <code>null</code>.
     * @param   out - the <code>Writer</code> that will receive the XML.
     *          This value must not be <code>null</code>.
     * @throws  <code>IllegalArgumentException</code> if the entity is
     *          <code>null</code>.
     * @throws  <code>IOException</code> if there's any error on write.
     */
    public static void encode( Entity entity, Writer out )
        throws IOException
    {
        Enumeration iter; // used when marching through a list of sub-elements
        int value;
        Protomech proto = (Protomech) entity;

        // First, validate our input.
        if ( null == entity ) {
            throw new IllegalArgumentException( "The entity is null." );
        }
        if ( null == out ) {
            throw new IllegalArgumentException( "The writer is null." );
        }

        // Our EntityEncoder already gave us our root element.
        out.write( "<bv value=\"");
        value = (int) ( proto.calculateBattleValue() /
                        proto.getCrew().getBVSkillMultiplier() );
        out.write( value );
        out.write( "\" /><hasMainGun value=\"" );
        out.write( proto.hasMainGun() ? "true" : "false" );
        for ( int loc = 0; loc < proto.locations(); loc++ ) {
            out.write( "\" /><pilotDamageTaken loc=\"" );
            out.write( loc );
            out.write( "\" value=\"" );
            value = proto.getPilotDamageTaken( loc );
            out.write( value );
        } // Handle the next location
        out.write( "\" />" );

    }

    /**
     * Decode a <code>Entity</code> object from the passed node.
     *
     * @param   node - the <code>ParsedXML</code> node for this object.
     *          This value must not be <code>null</code>.
     * @param   game - the <code>IGame</code> the decoded object belongs to.
     * @return  the <code>Entity</code> object based on the node.
     * @throws  <code>IllegalArgumentException</code> if the node is
     *          <code>null</code>.
     * @throws  <code>IllegalStateException</code> if the node does not
     *          contain a valid <code>Entity</code>.
     */
    public static Entity decode( ParsedXML node, IGame game ) {
        Protomech entity = null;
        String attrStr;
        int attrVal;
        int loc;

        // Did we get a null node?
        if ( null == node ) {
            throw new IllegalArgumentException( "The Protomech node is null." );
        }

        // Make sure that the node is for an Protomech unit.
        attrStr = node.getAttribute( "name" );
        if ( !node.getName().equals( "class" ) ||
             null == attrStr || !attrStr.equals( "Protomech" ) ) {
            throw new IllegalStateException( "Not passed an Protomech node." );
        }

        // TODO : perform version checking.

        // Create the entity.
        entity = new Protomech();

        // Walk the board node's children.
        Enumeration children = node.elements();
        while ( children.hasMoreElements() ) {
            ParsedXML child = (ParsedXML) children.nextElement();
            String childName = child.getName();

            // Handle null child names.
            if ( null == childName ) {

                // No-op.
            }

            // Did we find the BV node?
            else if ( childName.equals( "bv" ) ) {

                // Get the Proto's BV.
                attrStr = child.getAttribute( "value" );
                if ( null == attrStr ) {
                    throw new IllegalStateException
                        ( "Couldn't decode the BV for a Protomech unit." );
                }

                // Try to pull the number from the attribute string
                try {
                    attrVal = Integer.parseInt( attrStr );
                }
                catch ( NumberFormatException exp ) {
                    throw new IllegalStateException
                        ( "Couldn't get an integer from " + attrStr );
                }
                entity.setBattleValue( attrVal );
            }

            // Did we find the main gun node?
            else if ( childName.equals( "hasMainGun" ) ) {

                // See if the Proto has a main gun.
                attrStr = child.getAttribute( "value" );
                if ( null == attrStr ) {
                    throw new IllegalStateException
                        ( "Couldn't decode hasMainGun for a Protomech unit." );
                }

                // If the value is "true", the Proto has a main gun.
                if ( attrStr.equals( "true" ) ) {
                    entity.setHasMainGun( true );
                } else {
                    entity.setHasMainGun( false );
                }
            }

            // Did we find the location-specific pilot damage node?
            else if ( childName.equals( "pilotDamageTaken" ) ) {

                // Get the damage taken by the pilot in this location.
                attrStr = child.getAttribute( "value" );
                if ( null == attrStr ) {
                    throw new IllegalStateException
                        ( "Couldn't decode the damage for a Protomech unit." );
                }

                // Try to pull the number from the attribute string
                try {
                    attrVal = Integer.parseInt( attrStr );
                }
                catch ( NumberFormatException exp ) {
                    throw new IllegalStateException
                        ( "Couldn't get an integer from " + attrStr );
                }

                // Get this location.
                attrStr = child.getAttribute( "loc" );
                if ( null == attrStr ) {
                    throw new IllegalStateException
                        ( "Couldn't decode the location for a Protomech unit." );
                }

                // Try to pull the number from the attribute string
                try {
                    loc = Integer.parseInt( attrStr );
                }
                catch ( NumberFormatException exp ) {
                    throw new IllegalStateException
                        ( "Couldn't get an integer from " + attrStr );
                }
                entity.setPilotDamageTaken( loc, attrVal );
            }

        } // Handle the next element.

        // Return the entity.
        return entity;
    }

}