如何从哈希图值获取对象数组的数组？

Question

Please forgive for not elaborating the question well. I am sure the example below will tell you what i mean. I need to get all values of anObject from a hashmap. As u can see from the example below, the key would be anObject and the value would be an array of anObject.

HashMap<anObject,anObject[]> testMap = new HashMap<anObject,anObject[]>(); //Define map

anObject someObject1 = new anObject("one");
anObject someObject2 = new anObject("two")

anObject[] manyObjects1 = new anObject[3];
manyObjects1[0] = new anObject(0);
manyObjects1[1] = new anObject(1);
manyObjects1[2] = new anObject(2);
anObject[] manyObjects2 = new anObject[3];
manyObjects2[0] = new anObject(0);
manyObjects2[1] = new anObject(1);
manyObjects2[2] = new anObject(2);

testMap.put(someObject1,manyObjects1);
testMap.put(someObject2,manyObjects2);

//Get anObject from all the values put into testMap
anObject[] getAllValues1 = (anObject[])testMap.values().toArray; //is this correct or
anObject[][] getAllValues2 = (anObject[][])testMap.values().toArray; //is this correct 

Answer 1

You'd want to use toArray(T[]) :

Collection values = testMap.values();
anObject[][] getAllValues2 = (anObject[][])values.toArray(new anObject[values.size()][]);

Because you're getting back an array of the values in the map, and the values in the map are arrays, you need to indicate you're getting back an array of arrays, so [][] .