UriMatcher类的addURI()方法

  今天看到Uri的匹配器用于匹配Uri,addURI()方法的源码如下：

 public void addURI(String authority, String path, int code){  
  
        if (code < 0) {  
            throw new IllegalArgumentException("code " + code  
                    + " is invalid: it must be positive");  
  
        }  
        //以"/"分隔path  
        String[] tokens = path != null ? PATH_SPLIT_PATTERN.split(path) : null;  
        //判断分隔后的数组长度.并取其值  
        int numTokens = tokens != null ? tokens.length : 0;  
        //当前对象  
        UriMatcher node = this;  
          
        for (int i = -1; i < numTokens; i++) {  
            //当前循环变量小于0就取authority,否则就获取分隔后的数组的字符,并赋值给token  
            String token = i < 0 ? authority : tokens[i];  
            //把当前对象的集合赋值给children  
            ArrayList<UriMatcher> children = node.mChildren;  
            //获取其长度  
            int numChildren = children.size();    
                 UriMatcher child;  
            int j;    
            for (j = 0; j < numChildren; j++) {  
                //获取children对象的孩子  
                child = children.get(j);  
                //判断当前的token和child对象中的mText是否相等  
                if (token.equals(child.mText)) {  
                    //把child 赋值给 node;  
                    node = child;  
                    break;  
                }  
            }  
            //获取循环变量j并判断是否等于children对应的大小.也就是判断是否是最后一个  
            if (j == numChildren) {  
                // Child not found, create it  
                //没有发现孩子,并创建  
                child = new UriMatcher();  
                ///判断当前的token是否等于"#"  
                if (token.equals("#")) {  
                    //mWhich=1  
                    child.mWhich = NUMBER;  
                } else if (token.equals("*")) {  
                    //mWhich=2  
                    child.mWhich = TEXT;  
                } else {  
                    //mWhich=0  
                    child.mWhich = EXACT;  
                }  
                //mText=当前的token  
                child.mText = token;  
                //添加到mChildren集合中  
                node.mChildren.add(child);  
                //node = child;  
                node = child;  
            }  
        }  
        //node.mCode = code;  
        node.mCode = code;  
    }  
  
    static final Pattern PATH_SPLIT_PATTERN = Pattern.compile("/");