tankencoder.java

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

/*
 * MegaMek - Copyright (C) 2003 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 TankEncoder {

    /**
     * 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
    {
        Tank tank = (Tank) entity;
        int value;

        // 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( "<hasNoTurret value=\"" );
        out.write( tank.hasNoTurret() ? "true" : "false" );
        out.write( "\" /><stunnedTurns value=\"" );
        value = tank.getStunnedTurns();
        out.write( String.valueOf(value) );
        out.write( "\" /><jammedTurns value=\"" );
        value = tank.getJammedTurns();
        out.write( String.valueOf(value) );
        out.write( "\" /><moveHit value=\"" );
        out.write( tank.isMovementHit() ? "true" : "false" );
        out.write( "\" /><moveHitPending value=\"" );
        out.write( tank.isMovementHitPending() ? "true" : "false" );

        // Is the turret locked?
        if ( tank.isTurretLocked() ) {
            // Yup.  Record the current facing of the tank and the turret.
            out.write( "\" /><facing value=\"" );
            value = tank.getFacing();
            out.write( String.valueOf(value) );
            out.write( "\" /><turretFacing value=\"" );
            value = tank.getSecondaryFacing();
            out.write( String.valueOf(value) );
            out.write( "\" /><turretLocked value=\"true" );
        }
        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 ) {
        Tank entity = null;
        String attrStr;
        int attrVal;
        int loc;

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

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

        // TODO : perform version checking.

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

        // 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 stunnedTurns node?
            else if ( childName.equals( "stunnedTurns" ) ) {

                // Get the Tank's stunned turns.
                attrStr = child.getAttribute( "value" );
                if ( null == attrStr ) {
                    throw new IllegalStateException
                        ( "Couldn't decode the stunnedTurns for a Tank 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.setStunnedTurns( attrVal );
            }

            // Did we find the jammed turns node?
            else if ( childName.equals( "jammedTurns" ) ) {

                // Get the Tank's jammed turns.
                attrStr = child.getAttribute( "value" );
                if ( null == attrStr ) {
                    throw new IllegalStateException
                        ( "Couldn't decode the jammedTurns for a Tank 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.setJammedTurns( attrVal );
            }

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

                // See if the Tank has a no turret.
                attrStr = child.getAttribute( "value" );
                if ( null == attrStr ) {
                    throw new IllegalStateException
                        ( "Couldn't decode hasNoTurret for a Tank unit." );
                }

                // If the value is "true", the Tank has a no turret.
                if ( attrStr.equals( "true" ) ) {
                    entity.setHasNoTurret( true );
                } else {
                    entity.setHasNoTurret( false );
                }
            }

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

                // See if the Tank has a move hit.
                attrStr = child.getAttribute( "value" );
                if ( null == attrStr ) {
                    throw new IllegalStateException
                        ( "Couldn't decode moveHit for a Tank unit." );
                }

                // If the value is "true", the Tank move a hit pending.
                if ( attrStr.equals( "true" ) ) {
                    entity.immobilize();
                    entity.applyDamage();
                }
            }

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

                // See if the Tank has a move hit pending.
                attrStr = child.getAttribute( "value" );
                if ( null == attrStr ) {
                    throw new IllegalStateException
                        ( "Couldn't decode moveHitPending for a Tank unit." );
                }

                // If the value is "true", the Tank move a hit pending.
                if ( attrStr.equals( "true" ) ) {
                    entity.immobilize();
                }
            }

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

                // Get the Tank's facing.
                attrStr = child.getAttribute( "value" );
                if ( null == attrStr ) {
                    throw new IllegalStateException
                        ( "Couldn't decode the facing for a Tank 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.setFacing( attrVal );
            }

            // Did we find the turret's secondaryFacing node?
            else if ( childName.equals( "turretFacing" ) ) {

                // Get the Tank's turret's facing.
                attrStr = child.getAttribute( "value" );
                if ( null == attrStr ) {
                    throw new IllegalStateException
                        ( "Couldn't decode the turret's secondaryFacing for a Tank 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.setSecondaryFacing( attrVal );
            }

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

                // See if the Tank move a hit pending.
                attrStr = child.getAttribute( "value" );
                if ( null == attrStr ) {
                    throw new IllegalStateException
                        ( "Couldn't decode turretLocked for a Tank unit." );
                }

                // If the value is "true", the Tank move a hit pending.
                if ( attrStr.equals( "true" ) ) {
                    entity.lockTurret();
                }
            }

        } // Handle the next element.

        // Return the entity.
        return entity;

    }

}