java 在console里面画一棵树的代码，比较有趣

代码出自Java An introduction to Problem solving and Programming 一书.

代码如下：　

package ObjectDesign;

interface ShapeI{
    //set the offset for the shape
    public void setOffset(int newOffset);

    //return the offset for the shape
    public int getOffset();

    //Draws the shape at lineNumber lines
    //down from the current line
    public void drawAt(int lineNumber);

    //Draws the shape at the current line
    public void drawHere();
}

// interface for a rectangle to be drawn on the screen
interface IRectangle extends ShapeI{
    //set the rectangle's dimension
    public void set(int Height,int width);

}

interface ITriangle extends ShapeI{
    //set the triangle's base
    public void set(int newBase);
}

//abstract drawHere with abstract class
// public void drawHere with not abstract class
abstract class ShapeBasis implements ShapeI{
    private int Offset;

    public ShapeBasis(){
        Offset=0;
    }

    public ShapeBasis(int theOffset){
        this.Offset=theOffset;
    }

    public void setOffset(int newOffset){
        this.Offset=newOffset;
    }

    public int getOffset(){
        return Offset;
    }

    public void drawAt(int lineNumber){
        for(int count=0;count<lineNumber;count++){
            System.out.println();
        }
        drawHere();
    }

    public abstract void drawHere();
    /*
    public void drawHere(){
        for(int count=0;count
            System.out.print(" ");
        }
        System.out.println("*");
    }
    */

}

class DrawRectangle extends ShapeBasis implements IRectangle{
    private int height;
    private int width;

    public DrawRectangle(){
        super();
        height=0;
        width=0;
    }

    public DrawRectangle(int Offset,int Height,int width){
        super(Offset);
        this.height=Height;
        this.width = width;
    }

    public void set(int Height, int width){
        this.height=Height;
        this.width=width;
    }

    public void drawHere(){
        drawHorizontalLine();
        drawSides();
        drawHorizontalLine();
    }

    private void drawHorizontalLine(){
        skipSpaces(getOffset());
        for(int count=0;count<width;count++){
            System.out.print("-");
        }System.out.println();
    }

    private static void skipSpaces(int number){
        for(int count=0;count<number;count++){
            System.out.print(" ");
        }
    }

    private void drawSides(){
        for(int count=0;count<(height-2);count++){
            drawOneLineOfSides();
        }
    }

    private void drawOneLineOfSides(){
        skipSpaces(getOffset());
        System.out.print("|");
        skipSpaces(width-2);
        System.out.println("|");
    }
}

class DrawTriangle extends ShapeBasis implements ITriangle{
    private int base;

    public DrawTriangle(){
        super();
        base=0;
    }

    public DrawTriangle(int Offset,int base){
        super(Offset);
        this.base=base;
    }

    //precondition: base is odd
    public void set(int base){
        this.base = base;
    }

    public void drawHere(){
        drawTop();
        drawBase();
    }

    public void drawBase(){
        skipSpaces(getOffset());
        for(int count=0;count<base;count++){
            System.out.print('*');
        }
        System.out.println();
    }

    public void drawTop(){
        int startOfLine = getOffset() + base/2;
        skipSpaces(startOfLine);
        System.out.println('*');
        int lineCount=base/2-1;

        int insideWidth=1;
        for(int count=0;count<lineCount;count++){
            startOfLine--;
            skipSpaces(startOfLine);
            System.out.print('*');
            skipSpaces(insideWidth);
            System.out.println('*');

            //Down one line, so the inside is 2 spaces wider
            insideWidth = insideWidth + 2;
        }
    }

    private static void skipSpaces(int number){
        for(int i=0;i<number;i++){
            System.out.print(" ");
        }
    }
}

public class DrawShapes {
    public static final int INDENT=5;
    public static final int TREE_TOP_WIDTH = 21;
    public static final int TREE_BOTTOM_WIDTH=4;
    public static final int TREE_BOTTOM_HEIGHT=6;

    public static void main(String[] args){
        /*
         *     DrawRectangle dr= new DrawRectangle(5,6,8);
         *    dr.drawHere();
         *    DrawTriangle dT = new DrawTriangle(5,13);
         *    dT.drawHere();
         */
        drawTree(TREE_TOP_WIDTH,TREE_BOTTOM_WIDTH,TREE_BOTTOM_HEIGHT);
    }

    public static void drawTree(int topWidth,int bottomWidth, int bottomHeight){
        System.out.printf("%30s","Plant a Tree on Arbor day");
        DrawTriangle treeTop = new DrawTriangle(INDENT,topWidth);
        drawTop(treeTop);
        DrawRectangle treeTrunk = new DrawRectangle(INDENT+(topWidth/2)-(bottomWidth/2),
            bottomHeight,bottomWidth);
        drawTrunk(treeTrunk);
    }

    public static void drawTop(DrawTriangle treeTop){
        treeTop.drawAt(1);
    }

    public static void drawTrunk(DrawRectangle treeTrunk){
        treeTrunk.drawAt(1);
    }


}

2. 贴个最近看的Eclipse 教程的地址