Hello everybody! Please review my proposal for the CopyOnWriteArrayList.addIfAbsent() method optimization.
http://washi.ru.oracle.com/~igerasim/webrevs/8011215/webrev/index.html Here is the original function body: ------------------------------------------------ Object[] elements = getArray(); int len = elements.length; Object[] newElements = new Object[len + 1]; <-- allocate new array in advance for (int i = 0; i < len; ++i) { if (eq(e, elements[i])) <-- check whether e is null on every iteration return false; // exit, throwing away copy else newElements[i] = elements[i]; <-- copy elements one by one } newElements[len] = e; setArray(newElements); ------------------------------------------------ The proposed change is to reuse CopyOnWriteArrayList.indexOf() function to check if e is already in the array. If the check passed, new array is allocated withArrays.copyOf(). It uses native System.arraycopy(), which is probably faster than copying elements in the loop. Sincerely yours, Ivan
