java_jvm代码的一些规范

阅读了一些jvm代码，仔细斟酌了一些大神的命名习惯和注释规范，有人可能觉得我太蛋疼了，当我觉得有规范比自己乱来一同要好的多

我在这里记录一下，只是习惯问题，并不影响阅读，大家可以自己取舍的学习一下

这里还有一篇好文，偶然看到的，一语就道中了java与c++程序员风格上的差别

http://www.ibm.com/developerworks/java/library/j-noaccent/index.html

1.java文件的内容顺序一般为

/* * Copyright (c) 1997, 2007, Oracle and/or its affiliates. All rights reserved. * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. */package java.awt;import java.awt.image.Raster;class GradientPaintContext implements PaintContext {}

版权声明，包，依赖类，类

2.过长的话，要换行，比上一行多一个缩进,从=开始

    static ColorModel xrgbmodel =        new DirectColorModel(24, 0x00ff0000, 0x0000ff00, 0x000000ff);

还有一种是参数过长，要把参数对齐，最后用“，”结尾

    public GradientPaintContext(ColorModel cm,                                Point2D p1, Point2D p2, AffineTransform xform,                                Color c1, Color c2, boolean cyclic)

3.关键字前后要有空格

        if (ulenSq <= Double.MIN_VALUE) {            dx = 0;            dy = 0;        } else {

4.参数时，”，“后要加空格，运算符前后加空格

    static synchronized void putCachedRaster(ColorModel cm, Raster ras) {        if (cached != null) {

5.方法内一般为行注释，其他供javadoc一般是块注释，注意行注释//后要追加一个空格

            } else {                // We are acyclic                if (dx < 0) {                    // If we are using the acyclic form below, we need                    // dx to be non-negative for simplicity of scanning                    // across the scan lines for the transition points.                    // To ensure that constraint, we negate the dx/dy                    // values and swap the points and colors.                    Point2D p = p1; p1 = p2; p2 = p;

6.类型转换括号也要加空格

                Raster ras = (Raster) cached.get();

7.当局部变量太多是，为了让类属性更加突出，不会混淆，加个this

                    Point2D p = p1; p1 = p2; p2 = p;                    Color c = c1; c1 = c2; c2 = c;                    dx = -dx;                    dy = -dy;                }            }        }        Point2D dp1 = xform.transform(p1, null);        this.x1 = dp1.getX();        this.y1 = dp1.getY();        this.cyclic = cyclic;

8.逻辑链接时，为了让逻辑显得更清楚，可以换行

                if (ras != null &&                    ras.getWidth() >= w &&                    ras.getHeight() >= h)

9.参数传递时，复杂对象可以用缩写，用最少的字表达最多的意思，简单对象（int,double,string,char）一般为全名

    public GradientPaintContext(ColorModel cm,                                Point2D p1, Point2D p2, AffineTransform xform,                                Color c1, Color c2, boolean cyclic)

10.尽可能的在需要使用是才声明，把使用和定义放到一个语句里面 int a = 123;

            double colrel = rowrel;            int j = w;            if (colrel <= 0.0) {                int rgb = interp[0];                do {                    pixels[off++] = rgb;                    colrel += dx;                } while (--j > 0 && colrel <= 0.0);            }            while (colrel < 1.0 && --j >= 0) {                pixels[off++] = interp[(int) (colrel * 256)];                colrel += dx;            }