java - Guava's ComparisonChain conversion to JavaScript -


i'm converting code javascript java, , i've come across code:

static final comparator<point> comparexcoord = new comparator<point>() {     @override     public int compare(point o1, point o2) {         return comparisonchain.start().                 compare(o1.x, o2.x).                 compare(o1.y, o2.y).                 result();     } };  static final comparator<point> compareycoord = new comparator<point>() {     @override     public int compare(point o1, point o2) {         return comparisonchain.start().                 compare(o1.y, o2.y).                 compare(o1.x, o2.x).result();     } };  ...  arrays.binarysearch(ypoints, point.make(double.negative_infinity, ymin),             compareycoord);

seems fair enough, it'll return resultant object of matching comparison chain.

but don't understand both methods seem naive eyes exact same thing: return if either x or y properties match. difference first checks x property first, i.e., order of checks different.

also, if that's true, arrays.binarysearch method return ypoints elements equal x properties. don't feel function intended do.

so, javascript translation be:

function comparexcoord(p1, p2) {   return (p1.x === p2.x) ? p1 :           (p1.y === p2.y) ? p1 : undefined; }  function compareycoord(p1, p2) {   return (p1.y === p2.y) ? p1 :           (p1.x === p2.x) ? p1 : undefined; }

but both of these simplified return (p1.y === p2.y || p1.x === p2.x) ? p1 : undefined;.

i feel i'm misunderstanding how comparisonchain works. order of chain important? bonus points directions how translate javascript.

you need bear in mind java comparator return value three-valued (i.e. higher, lower, or equal). order in compare coordinates important - sorting x first not same sorting y first.


Comments

Post a Comment

Popular posts from this blog

c# - Update a combobox from a presenter (MVP) -

i using mvp in project, new in mvp. have 2 comboboxes. when select option in combobox, combobox should filled new data. this action in presenter. view 'view1' in presenter, , introduced combobox1 , combobox2 properties in 'view1', because need 'datasource', 'displaymember', 'valuemember' , 'refresh()' in method below. but, when using pattern, enough send property like public string combobox2 { { return combobox1.selectedvalue.tosstring(); } } into presenter not whole combobox. how can solve problem? public void onselectedindexchangedcombobox1() { if (view1.combobox1.selectedindex == -1) { return; } datatable dt = tools.getdatatable("a path"); var query = (from o in dt.asenumerable() o.field<string>("afield") == farmerview.combobox1.selectedvalue.tostring() orderby o.field<string>("anotherfield") select...
Read more

How to understand 2 main() functions after using uftrace to profile the C++ program? -

i trying uftrace profile following simple c++ program: #include <iostream> class { public: a() {std::cout << "a created" << std::endl;} ~a() {std::cout << "a destroyed" << std::endl;} }; int main() { a; return 0; } the profile result this: # uftrace a.out created destroyed # duration tid function 2.026 [ 4828] | __cxa_atexit(); [ 4828] | main() { [ 4828] | __static_initialization_and_destruction_0() { 89.397 [ 4828] | std::ios_base::init::init(); 0.768 [ 4828] | __cxa_atexit(); 93.029 [ 4828] | } /* __static_initialization_and_destruction_0 */ 94.425 [ 4828] | } /* main */ [ 4828] | main() { [ 4828] | a::a() { 11.104 [ 4828] | std::operator <<(); 10.825 [ 4828] | std::basic_ostream::operator <<(); 24.514 [ 4828] | } /* a::a */ [ 4828] | a::~a() { 0.978 [ 4828] | ...
Read more

How to put a lock and transaction on table using spring 4 or above using jdbcTemplate and annotations like @Transactional? -

i trying put lock on table while writing on table , if happened in between roll-back . trying convert below code lock table test_g1 read; lock table test_g write; -- begin; start transaction; insert test_g1 values(143); insert test_g values(145); select * test_g1; select * test_g; rollback; select * test_g; unlock tables; how convert above code @transactional spring jdbctemplate code? @transactional(rollbackfor={dataaccessexception.class}) public void test(){ jdbctemplate.execute("insert test1 (id, nam) values (4, 'a')"); throw new dataaccessexception("error") { }; } here trying throw error, insert statement should rollback it's not happening . thanks edit-1 attaching code , doing in jdbcdaoimpl.java , mentioned problem comment above test() . app.java package com.cgiri.javabrains.spring4; import org.springframework.beans.factory.annotation.autowired; import org.springframework.context.applic...
Read more