VisualVM OQL：查找具有（间接）的对象到达/引用两个对象ID？

Question

我的问题相当短，紧凑：

如果我找到一个带有VISUALVM的两个对象，我可以执行什么样的OQL查询以查找具有（间接）到达或引用这两个对象的所有对象？

jb：

编辑代码后，我提出以下内容：

//QUERY SCRIPT: find object that (indirectly) references to all target objects
    //list all objects that the objects we search for should (indirectly) refer to
    var targetObjects =     [   heap.findObject("811819664"), //eg. obj that contains a player's health
                    heap.findObject("811820024") //eg. obj that contains the same player's name
                ];

    //list all objects here that every or most objects have as an indirect referer (eg. base class loaders)
    var ignoreReferers =    []; //eg. [heap.findObject("ignId1")];

    //set array with all elements that refer to each target object
    var targetObjectsReferers = [];
    for (var tarObjIndex in targetObjects) {
        var targetObjRefElements = [];

        //get the live path of this target object
        var livePaths = heap.livepaths(targetObjects[tarObjIndex]);

        //cleanup every live path
        for (var livePathsIndex in livePaths) {
            var curLivePath = livePaths[livePathsIndex];
            if ((curLivePath == null) || (curLivePath == "undefined")) continue;

            //remove last element from live path as it is the actual object
            curLivePath.pop();

            //remove elements that equal an ignore referer object
            for (var pathElementIndex in curLivePath) {
            if ((curLivePath[pathElementIndex] == null) || (curLivePath[pathElementIndex] == "undefined")) continue;

                for (var ignoreIndex in ignoreReferers) {
                    if (identical(curLivePath[pathElementIndex], ignoreReferers[ignoreIndex])) curLivePath.splice(pathElementIndex, 1); //FIXME: this might fail if index is not updated
                }
            }       
        }

        //merge remaining life paths elements into targetObjRefElements
        for (var livePathsIndex in livePaths) {
            var curLivePath = livePaths[livePathsIndex];

            for (var curLivePathIndex in curLivePath) {
                targetObjRefElements.push(curLivePath[curLivePathIndex]);
            }
        }

        //remove duplicate referers
        targetObjRefElements = unique(targetObjRefElements, 'objectid(it)');

        //add to target objects referers
        targetObjectsReferers.push(targetObjRefElements);
    }

    //filter and return
    filter(targetObjectsReferers[0], function(it1) {
        var rslt = contains(targetObjectsReferers[1], function(it2) { //FIXME: this limits it to 2 objects!
            return identical(it1, it2);
        });
        return rslt;
    });

.

返回一个流行音乐未定时一段时间内未定义，我正在尝试解决。如果我设法解决我可以看到它是否提供了预期的结果。

Answer 1

It sounds like you are trying to get all reference chains keeping your objects alive. You can use heap.livepaths(object) function to obtain them. You can take some hints from the following code

var paths1 = heap.livepaths(heap.findObject("1684177040")) // use the objectid of the first instance
var paths2 = heap.livepaths(heap.findObject("1684177160")) // use the objectid of the second instance

var pathArr1 = unique(rcs2array(paths1), 'objectid(it)') // flatten all the livepaths to a single array of instances
var pathArr2 = unique(rcs2array(paths2), 'objectid(it)') // the same for the second instance

// calculate the arrays' intersection - the result is the set of object keeping both of your instances alive
filter(pathArr1, function(it1) { 
  var rslt = contains(pathArr2, function(it2) {
     return (objectid(it1) == objectid(it2))
  })
  return rslt
})

// helper function to convert an array of reference chains to a flat array of objects
function rcs2array(rcs) {
  var arr = new Array()

  for(var i=0;i<rcs.length;i++) {
    var rc = rcs[i];
    for(var j=0;j<rc.length;j++) {
        arr.push(rc[j])
    }
  }
  return arr
}

Please, bear in mind that this works only in VisualVM and jhat