multithreading - Should implementations of java.util.Comparator.compare(T o1, T o2) be thread safe? -

-

or should care when used in parallel implementations java.util.arrays.parallelsort(t[] a, comparator<? super t> cmp) ?

the comparison method nature pure function evaluated against objects may considered immutable @ least during sorting operation. mutating objects during sorting break essential assumption of sorting algorithm, order imposed comparator stable throughout operation.

the above implies that, although comparator must thread-safe when used in parallel sort, given no special effort. on flip side, need make sure doesn't contain thread-unsafe code 1 reason or another, such using thread-unsafe collaborator instance shared across invocations of compare().


Comments

Post a Comment

Popular posts from this blog

php - Hide output during test execution -

-
i have var_dumps in php code (i understand there must none in end, still), , while tests running outputs non necessary information console, there method ignore code execution? i've tried /** * @codecoverageignore */ and // @codecoverageignorestart print '*'; // @codecoverageignoreend but ignores coverage, , still executes code. you can set setoutputcallback nothing function. effect suppress output printed in test or in tested class. as example: namespace acme\demobundle\tests; class nooutputtest extends \phpunit_framework_testcase { public function testsuppressedoutput() { // suppress output console $this->setoutputcallback(function() {}); print '*'; $this->assertfalse(false, "don't see *"); } } you can find reference in doc hope help
Read more

javascript - Migrate custom AngularJS filter from 1.2.28 to 1.4.x -

-
i have complex json response iterated on using ng-repeat. relatively small subset of attributes within result set displayed on screen, filtering of results should restricted values user can see, otherwise filtering behavior confusing end-user. since 1 of attributes wish filter on nested array, custom filter needed since built-in angularjs filterfilter not iterate on array elements best of knowledge. i able working time in angularjs v1.2.28, unfortunately appears break during migration v1.4.3. have not spent time isolate in release cadence functionality broke however. i have not found helpful information in migration guides indicate has changed. know actual/expected parameters filter receive different values in latest major version of angularjs, leads failure. ng-repeat filter expression: <li ng-repeat="user in users | list_filter:{establishment: {id: filtertext, names: [{name: filtertext}], locations: [{streetaddress1: filtertext, streetaddress2: filtertext, city:...
Read more

Update Magento products with multiple images -

-
Image
i'm developing magento store , imported products, in these products there more 1 image , when imported products 1 came with, need update products images left, knows how in quick mode? thanks! step 1: export products before begin, make sure changes product data have been saved. on admin menu, select system > import/export > dataflow - profiles. in list of profiles, select export products. in panel on left, click run profile. to begin process, click run profile in popup button. wait few moments profile begin execution. length of time takes complete process depends on size of database. not close window. when process complete,you can find exported csv file in following location on server: [magento-install-dir]/var/export/export_all_products.csv the csv data appears in spreadsheet rows of product records organized columns of attributes, attribute code in header of each column. step 2: copy product images server the csv file contains path each prod...
Read more