java - 未经检查的 Actor 问题

Question

嘿，我正在尝试实现 ShellSort 算法，但现在遇到了问题:

warning: [unchecked] unchecked cast
found : java.util.Vector
required: java.util.Vector<java.lang.Object>
Vector<Object> vcur = (Vector<Object>)currentCols[tcur];
与 vtmp 相同.

不知道问题出在哪里。如果你能帮助我，那就太好了。 :)
这是我的代码:

public static Vector<Object> shellSort(Vector<Object> ul) {
    int lcount = ul.size();
    int colcount = 4; // 2^x
    Vector[] currentCols = { ul };
    for(; colcount > 0; colcount = (colcount / 2)) {
        Vector[] tmpCols = new Vector[colcount];
        for(int t1 = 0; t1 < colcount; t1++) {
            tmpCols[t1] = new Vector<Object>();
        }
        int tcur = 0;
        int tcurlvl = 0;
        int ttmp = 0;
        for(int t2 = 0; t2 < lcount; t2++) {
            Vector<Object> vcur = (Vector<Object>)currentCols[tcur];
            Vector<Object> vtmp = (Vector<Object>)tmpCols[ttmp];
            vtmp.addElement((Object)vcur.elementAt(tcurlvl));

            // step to next place
            tcur++;
            ttmp++;
            if(tcur == currentCols.length) { tcur = 0; tcurlvl++; }
            if(ttmp == tmpCols.length) { ttmp = 0; }
        }
    }
    return ul;
}

Answer 1

我认为这里的问题是类型删除。在运行时，Vector 只是 Vector。例如:

Vector<String> stuff = new Vector<String>()
Vector<Object> objects = (Vector<Object>)stuff

它会编译，但当你尝试将 Int 放入对象时会在运行时失败。