bullet.java

J2ME MIDP_Example_Applications

// Copyright 2003 Nokia Corporation.
//
// THIS SOURCE CODE IS PROVIDED 'AS IS', WITH NO WARRANTIES WHATSOEVER,
// EXPRESS OR IMPLIED, INCLUDING ANY WARRANTY OF MERCHANTABILITY, FITNESS
// FOR ANY PARTICULAR PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE
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// BY THIRD PARTIES
//
// Furthermore, information provided in this source code is preliminary,
// and may be changed substantially prior to final release. Nokia Corporation
// retains the right to make changes to this source code at
// any time, without notice. This source code is provided for informational
// purposes only.
//
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// Corporation.
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// Sun Microsystems, Inc.
// Other product and company names mentioned herein may be trademarks or
// trade names of their respective owners.
//
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// source code. The licensee has the right to market, sell, distribute and
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import javax.microedition.lcdui.*;


// A class that represents a Bullet object. The Base generates bullets.
// Bullets are ListItem's kept in a doubly linked list, so they can
// be easily removed when they become inactive.

class Bullet
    extends ListItem
{
    private final int xMax;
    private final int y;
    private final int dx;
    private final int w;
    private final int h;

    private int x;
    private boolean isActive;


    Bullet(int xMin, int xMax, int y, int w, int h, int dx)
    {
        this.xMax = xMax;
        this.x = xMin;
        this.y = y;
        this.w = w;
        this.h = h;
        this.dx = dx;
        isActive = true;
    }


    void tick()
    {
        if (isActive)
        {
            if ((x + dx) <= xMax)
            {
                x += dx; // move
            }
            else
            {
                 // flew off-screen: false means the bullet is 'dead'
                isActive = false;
            }
        }
    }


    void draw(Graphics g)
    {
        if (isActive)
        {
            g.setColor(Base.COLOR);
            g.fillRect(x, y, w, h);
        }
    }


    void doExplode()
    {
        isActive = false;
    }


    int getX()
    {
        return x;
    }


    int getY()
    {
        return y;
    }


    int getWidth()
    {
        return w;
    }


    int getHeight()
    {
        return h;
    }

    // Active bullets participate in the game, inactive ones do not.
    // Inactive bullets are removed by the game manager.
    boolean isActive()
    {
        return isActive;
    }
}