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• C++ simple logging class with UTF-8 output [code example]

  - by Andrew

  Hello everyone, I was working on one of my academic projects and for the first time I needed pure C++ without GUI. After googling for a while, I did not find any simple and easy to use implementation for logging and created my own. This is a simple implementation with iostreams that logs messages to screen and to the file simultaneously. I was thinking of using templates but then I realized that I do not expect any changes and removed that. It is modified std::wostream with two added modifiers: 1. TimeStamp - prints time-stamp 2. LogMode(LogModes) - switches output: file only, screen only, file+screen. *Boost::utf8_codecvt_facet* is used for UTF-8 output. // ############################################################################ // # Name: MyLog.h # // # Purpose: Logging Class Header # // # Author: Andrew Drach # // # Modified by: <somebody> # // # Created: 03/21/10 # // # SVN-ID: $Id$ # // # Copyright: (c) 2010 Andrew Drach # // # Licence: <license> # // ############################################################################ #ifndef INCLUDED_MYLOG_H #define INCLUDED_MYLOG_H // headers -------------------------------------------------------------------- #include <string> #include <iostream> #include <fstream> #include <exception> #include <boost/program_options/detail/utf8_codecvt_facet.hpp> using namespace std; // definitions ---------------------------------------------------------------- // ---------------------------------------------------------------------------- // DblBuf class // Splits up output stream into two // Inspired by http://wordaligned.org/articles/cpp-streambufs // ---------------------------------------------------------------------------- class DblBuf : public wstreambuf { private: // private member declarations DblBuf(); wstreambuf *bf1; wstreambuf *bf2; virtual int_type overflow(int_type ch) { int_type eof = traits_type::eof(); int_type not_eof = !eof; if ( traits_type::eq_int_type(ch,eof) ) return not_eof; else { char_type ch1 = traits_type::to_char_type(ch); int_type r1( bf1on ? bf1->sputc(ch1) : not_eof ); int_type r2( bf2on ? bf2->sputc(ch1) : not_eof ); return (traits_type::eq_int_type(r1,eof) || traits_type::eq_int_type(r2,eof) ) ? eof : ch; } } virtual int sync() { int r1( bf1on ? bf1->pubsync() : NULL ); int r2( bf2on ? bf2->pubsync() : NULL ); return (r1 == 0 && r2 == 0) ? 0 : -1; } public: // public member declarations explicit DblBuf(wstreambuf *bf1, wstreambuf *bf2) : bf1(bf1), bf2(bf2) { if (bf1) bf1on = true; else bf1on = false; if (bf2) bf2on = true; else bf2on = false; } bool bf1on; bool bf2on; }; // ---------------------------------------------------------------------------- // logstream class // Wrapper for a standard wostream with access to modified buffer // ---------------------------------------------------------------------------- class logstream : public wostream { private: // private member declarations logstream(); public: // public member declarations DblBuf *buf; explicit logstream(wstreambuf *StrBuf, bool isStd = false) : wostream(StrBuf, isStd), buf((DblBuf*)StrBuf) {} }; // ---------------------------------------------------------------------------- // Logging mode Class // ---------------------------------------------------------------------------- enum LogModes{LogToFile=1, LogToScreen, LogToBoth}; class LogMode { private: // private member declarations LogMode(); short mode; public: // public member declarations LogMode(short mode1) : mode(mode1) {} logstream& operator()(logstream &stream1) { switch(mode) { case LogToFile: stream1.buf->bf1on = true; stream1.buf->bf2on = false; break; case LogToScreen: stream1.buf->bf1on = false; stream1.buf->bf2on = true; break; case LogToBoth: stream1.buf->bf1on = true; stream1.buf->bf2on = true; } return stream1; } }; logstream& operator<<(logstream &out, LogMode mode) { return mode(out); } wostream& TimeStamp1(wostream &out1) { time_t time1; struct tm timeinfo; wchar_t timestr[512]; // Get current time and convert it to a string time(&time1); localtime_s (&timeinfo, &time1); wcsftime(timestr, 512,L"[%Y-%b-%d %H:%M:%S %p] ",&timeinfo); return out1 << timestr; } // ---------------------------------------------------------------------------- // MyLog class // Logs events to both file and screen // ---------------------------------------------------------------------------- class MyLog { private: // private member declarations MyLog(); auto_ptr<DblBuf> buf; string mErrorMsg1; string mErrorMsg2; string mErrorMsg3; string mErrorMsg4; public: // public member declarations explicit MyLog(string FileName1, wostream *ScrLog1, locale utf8locale1); ~MyLog(); void NewEvent(wstring str1, bool TimeStamp = true); string FileName; wostream *ScrLog; wofstream File; auto_ptr<logstream> Log; locale utf8locale; }; // ---------------------------------------------------------------------------- // MyLog constructor // ---------------------------------------------------------------------------- MyLog::MyLog(string FileName1, wostream *ScrLog1, locale utf8locale1) : // ctors mErrorMsg1("Failed to open file for application logging! []"), mErrorMsg2("Failed to write BOM! []"), mErrorMsg3("Failed to write to file! []"), mErrorMsg4("Failed to close file! []"), FileName(FileName1), ScrLog(ScrLog1), utf8locale(utf8locale1), File(FileName1.c_str()) { // Adjust error strings mErrorMsg1.insert(mErrorMsg1.length()-1,FileName1); mErrorMsg2.insert(mErrorMsg2.length()-1,FileName1); mErrorMsg3.insert(mErrorMsg3.length()-1,FileName1); mErrorMsg4.insert(mErrorMsg4.length()-1,FileName1); // check for file open errors if ( !File ) throw ofstream::failure(mErrorMsg1); // write UTF-8 BOM File << wchar_t(0xEF) << wchar_t(0xBB) << wchar_t(0xBF); // switch locale to UTF-8 File.imbue(utf8locale); // check for write errors if ( File.bad() ) throw ofstream::failure(mErrorMsg2); buf.reset( new DblBuf(File.rdbuf(),ScrLog->rdbuf()) ); Log.reset( new logstream(&*buf) ); } // ---------------------------------------------------------------------------- // MyLog destructor // ---------------------------------------------------------------------------- MyLog::~MyLog() { *Log << TimeStamp1 << "Log finished." << endl; // clean up objects Log.reset(); buf.reset(); File.close(); // check for file close errors if ( File.bad() ) throw ofstream::failure(mErrorMsg4); } //--------------------------------------------------------------------------- #endif // INCLUDED_MYLOG_H Tested on MSVC 2008, boost 1.42. I do not know if this is the right place to share it. Hope it helps anybody. Feel free to make it better.

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• Drupal Ctools Form Wizard in a Block

  - by Iamjon

  Hi everyone I created a custom module that has a Ctools multi step form. It's basically a copy of http://www.nicklewis.org/using-chaos-tools-form-wizard-build-multistep-forms-drupal-6. The form works. I can see it if I got to the url i made for it. For the life of me I can't get the multistep form to show up in a block. Any clues? /** * Implementation of hook_block() * */ function mycrazymodule_block($op='list', $delta=0, $edit=array()) { switch ($op) { case 'list': $blocks[0]['info'] = t('SFT Getting Started'); $blocks[1]['info'] = t('SFT Contact US'); $blocks[2]['info'] = t('SFT News Letter'); return $blocks; case 'view': switch ($delta){ case '0': $block['subject'] = t('SFT Getting Started Subject'); $block['content'] = mycrazymodule_wizard(); break; case '1': $block['subject'] = t('SFT Contact US Subject'); $block['content'] = t('SFT Contact US content'); break; case '2': $block['subject'] = t('SFT News Letter Subject'); $block['content'] = t('SFT News Letter cONTENT'); break; } return $block; } } /** * Implementation of hook_menu(). */ function mycrazymodule_menu() { $items['hellocowboy'] = array( 'title' = 'Two Step Form', 'page callback' = 'mycrazymodule_wizard', 'access arguments' = array('access content') ); return $items; } /** * menu callback for the multistep form * step is whatever arg one is -- and will refer to the keys listed in * $form_info['order'], and $form_info['forms'] arrays */ function mycrazymodule_wizard() { $step = arg(1); // required includes for wizard $form_state = array(); ctools_include('wizard'); ctools_include('object-cache'); // The array that will hold the two forms and their options $form_info = array( 'id' = 'getting_started', 'path' = "hellocowboy/%step", 'show trail' = FALSE, 'show back' = FALSE, 'show cancel' = false, 'show return' =false, 'next text' = 'Submit', 'next callback' = 'getting_started_add_subtask_next', 'finish callback' = 'getting_started_add_subtask_finish', 'return callback' = 'getting_started_add_subtask_finish', 'order' = array( 'basic' = t('Step 1: Basic Info'), 'lecture' = t('Step 2: Choose Lecture'), ), 'forms' = array( 'basic' = array( 'form id' = 'basic_info_form' ), 'lecture' = array( 'form id' = 'choose_lecture_form' ), ), ); $form_state = array( 'cache name' = NULL, ); // no matter the step, you will load your values from the callback page $getstart = getting_started_get_page_cache(NULL); if (!$getstart) { // set form to first step -- we have no data $step = current(array_keys($form_info['order'])); $getstart = new stdClass(); //create cache ctools_object_cache_set('getting_started', $form_state['cache name'], $getstart); //print_r($getstart); } //THIS IS WHERE WILL STORE ALL FORM DATA $form_state['getting_started_obj'] = $getstart; // and this is the witchcraft that makes it work $output = ctools_wizard_multistep_form($form_info, $step, $form_state); return $output; } function basic_info_form(&$form, &$form_state){ $getstart = &$form_state['getting_started_obj']; $form['firstname'] = array( '#weight' = '0', '#type' = 'textfield', '#title' = t('firstname'), '#size' = 60, '#maxlength' = 255, '#required' = TRUE, ); $form['lastname'] = array( '#weight' = '1', '#type' = 'textfield', '#title' = t('lastname'), '#required' = TRUE, '#size' = 60, '#maxlength' = 255, ); $form['phone'] = array( '#weight' = '2', '#type' = 'textfield', '#title' = t('phone'), '#required' = TRUE, '#size' = 60, '#maxlength' = 255, ); $form['email'] = array( '#weight' = '3', '#type' = 'textfield', '#title' = t('email'), '#required' = TRUE, '#size' = 60, '#maxlength' = 255, ); $form['newsletter'] = array( '#weight' = '4', '#type' = 'checkbox', '#title' = t('I would like to receive the newsletter'), '#required' = TRUE, '#return_value' = 1, '#default_value' = 1, ); $form_state['no buttons'] = TRUE; } function basic_info_form_validate(&$form, &$form_state){ $email = $form_state['values']['email']; $phone = $form_state['values']['phone']; if(valid_email_address($email) != TRUE){ form_set_error('Dude you have an error', t('Where is your email?')); } //if (strlen($phone) 0 && !ereg('^[0-9]{1,3}-[0-9]{3}-[0-9]{3,4}-[0-9]{3,4}$', $phone)) { //form_set_error('Dude the phone', t('Phone number must be in format xxx-xxx-nnnn-nnnn.')); //} } function basic_info_form_submit(&$form, &$form_state){ //Grab the variables $firstname =check_plain ($form_state['values']['firstname']); $lastname = check_plain ($form_state['values']['lastname']); $email = check_plain ($form_state['values']['email']); $phone = check_plain ($form_state['values']['phone']); $newsletter = $form_state['values']['newsletter']; //Send the form and Grab the lead id $leadid = send_first_form($lastname, $firstname, $email,$phone, $newsletter); //Put into form $form_state['getting_started_obj']-firstname = $firstname; $form_state['getting_started_obj']-lastname = $lastname; $form_state['getting_started_obj']-email = $email; $form_state['getting_started_obj']-phone = $phone; $form_state['getting_started_obj']-newsletter = $newsletter; $form_state['getting_started_obj']-leadid = $leadid; } function choose_lecture_form(&$form, &$form_state){ $one = 'event 1' $two = 'event 2' $three = 'event 3' $getstart = &$form_state['getting_started_obj']; $form['lecture'] = array( '#weight' = '5', '#default_value' = 'two', '#options' = array( 'one' = $one, 'two' = $two, 'three' = $three, ), '#type' = 'radios', '#title' = t('Select Workshop'), '#required' = TRUE, ); $form['attendees'] = array( '#weight' = '6', '#default_value' = 'one', '#options' = array( 'one' = t('I will be arriving alone'), 'two' =t('I will be arriving with a guest'), ), '#type' = 'radios', '#title' = t('Attendees'), '#required' = TRUE, ); $form_state['no buttons'] = TRUE; } /** * Same idea as previous steps submit * */ function choose_lecture_form_submit(&$form, &$form_state) { $workshop = $form_state['values']['lecture']; $leadid = $form_state['getting_started_obj']-leadid; $attendees = $form_state['values']['attendees']; $form_state['getting_started_obj']-lecture = $workshop; $form_state['getting_started_obj']-attendees = $attendees; send_second_form($workshop, $attendees, $leadid); } /*----PART 3 CTOOLS CALLBACKS -- these usually don't have to be very unique ---------------------- */ /** * Callback generated when the add page process is finished. * this is where you'd normally save. */ function getting_started_add_subtask_finish(&$form_state) { dpm($form_state); $getstart = &$form_state['getting_started_obj']; drupal_set_message('mycrazymodule '.$getstart-name.' successfully deployed' ); //Get id // Clear the cache ctools_object_cache_clear('getting_started', $form_state['cache name']); $form_state['redirect'] = 'hellocowboy'; } /** * Callback for the proceed step * */ function getting_started_add_subtask_next(&$form_state) { dpm($form_state); $getstart = &$form_state['getting_started_obj']; $cache = ctools_object_cache_set('getting_started', $form_state['cache name'], $getstart); } /*----PART 4 CTOOLS FORM STORAGE HANDLERS -- these usually don't have to be very unique ---------------------- */ /** * Remove an item from the object cache. */ function getting_started_clear_page_cache($name) { ctools_object_cache_clear('getting_started', $name); } /** * Get the cached changes to a given task handler. */ function getting_started_get_page_cache($name) { $cache = ctools_object_cache_get('getting_started', $name); return $cache; } //Salesforce Functions function send_first_form($lastname, $firstname,$email,$phone, $newsletter){ $send = array("LastName" = $lastname , "FirstName" = $firstname, "Email" = $email ,"Phone" = $phone , "Newsletter__c" =$newsletter ); $sf = salesforce_api_connect(); $response = $sf-client-create(array($send), 'Lead'); dpm($response); return $response-id; } function send_second_form($workshop, $attendees, $leadid){ $send = array("Id" = $leadid , "Number_Of_Pepole__c" = "2" ); $sf = salesforce_api_connect(); $response = $sf-client-update(array($send), 'Lead'); dpm($response, 'the final response'); return $response-id; }

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• segmentation fault using BaseCode encryption

  - by Natasha Thapa

  i took the code from the links below to encrypt and decrypt a text but i get segmentation fault when trying to run this any ideas?? http://etutorials.org/Programming/secure+programming/Chapter+4.+Symmetric+Cryptography+Fundamentals/4.5+Performing+Base64+Encoding/ http://etutorials.org/Programming/secure+programming/Chapter+4.+Symmetric+Cryptography+Fundamentals/4.6+Performing+Base64+Decoding/ #include <stdlib.h> #include <string.h> #include <stdio.h> static char b64revtb[256] = { -3, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*0-15*/ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*16-31*/ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, /*32-47*/ 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -2, -1, -1, /*48-63*/ -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, /*64-79*/ 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, /*80-95*/ -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, /*96-111*/ 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1, /*112-127*/ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*128-143*/ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*144-159*/ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*160-175*/ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*176-191*/ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*192-207*/ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*208-223*/ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*224-239*/ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 /*240-255*/ }; unsigned char *spc_base64_encode( unsigned char *input , size_t len , int wrap ) ; unsigned char *spc_base64_decode(unsigned char *buf, size_t *len, int strict, int *err); static unsigned int raw_base64_decode(unsigned char *in, unsigned char *out, int strict, int *err); unsigned char *tmbuf = NULL; static char tmpbuffer[] ={0}; int main(void) { memset( tmpbuffer, NULL, sizeof( tmpbuffer ) ); sprintf( tmpbuffer, "%s:%s" , "username", "password" ); tmbuf = spc_base64_encode( (unsigned char *)tmpbuffer , strlen( tmpbuffer ), 0 ); printf(" The text %s has been encrytped to %s \n", tmpbuffer, tmbuf ); unsigned char *decrypt = NULL; int strict; int *err; decrypt = spc_base64_decode( tmbuf , strlen( tmbuf ), 0, err ); printf(" The text %s has been decrytped to %s \n", tmbuf , decrypt); } static char b64table[64] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" "abcdefghijklmnopqrstuvwxyz" "0123456789+/"; /* Accepts a binary buffer with an associated size. * Returns a base64 encoded, NULL-terminated string. */ unsigned char *spc_base64_encode(unsigned char *input, size_t len, int wrap) { unsigned char *output, *p; size_t i = 0, mod = len % 3, toalloc; toalloc = (len / 3) * 4 + (3 - mod) % 3 + 1; if (wrap) { toalloc += len / 57; if (len % 57) toalloc++; } p = output = (unsigned char *)malloc(((len / 3) + (mod ? 1 : 0)) * 4 + 1); if (!p) return 0; while (i < len - mod) { *p++ = b64table[input[i++] >> 2]; *p++ = b64table[((input[i - 1] << 4) | (input[i] >> 4)) & 0x3f]; *p++ = b64table[((input[i] << 2) | (input[i + 1] >> 6)) & 0x3f]; *p++ = b64table[input[i + 1] & 0x3f]; i += 2; if (wrap && !(i % 57)) *p++ = '\n'; } if (!mod) { if (wrap && i % 57) *p++ = '\n'; *p = 0; return output; } else { *p++ = b64table[input[i++] >> 2]; *p++ = b64table[((input[i - 1] << 4) | (input[i] >> 4)) & 0x3f]; if (mod = = 1) { *p++ = '='; *p++ = '='; if (wrap) *p++ = '\n'; *p = 0; return output; } else { *p++ = b64table[(input[i] << 2) & 0x3f]; *p++ = '='; if (wrap) *p++ = '\n'; *p = 0; return output; } } } static unsigned int raw_base64_decode(unsigned char *in, unsigned char *out, int strict, int *err) { unsigned int result = 0, x; unsigned char buf[3], *p = in, pad = 0; *err = 0; while (!pad) { switch ((x = b64revtb[*p++])) { case -3: /* NULL TERMINATOR */ if (((p - 1) - in) % 4) *err = 1; return result; case -2: /* PADDING CHARACTER. INVALID HERE */ if (((p - 1) - in) % 4 < 2) { *err = 1; return result; } else if (((p - 1) - in) % 4 == 2) { /* Make sure there's appropriate padding */ if (*p != '=') { *err = 1; return result; } buf[2] = 0; pad = 2; result++; break; } else { pad = 1; result += 2; break; } case -1: if (strict) { *err = 2; return result; } break; default: switch (((p - 1) - in) % 4) { case 0: buf[0] = x << 2; break; case 1: buf[0] |= (x >> 4); buf[1] = x << 4; break; case 2: buf[1] |= (x >> 2); buf[2] = x << 6; break; case 3: buf[2] |= x; result += 3; for (x = 0; x < 3 - pad; x++) *out++ = buf[x]; break; } break; } } for (x = 0; x < 3 - pad; x++) *out++ = buf[x]; return result; } /* If err is non-zero on exit, then there was an incorrect padding error. We * allocate enough space for all circumstances, but when there is padding, or * there are characters outside the character set in the string (which we are * supposed to ignore), then we end up allocating too much space. You can * realloc() to the correct length if you wish. */ unsigned char *spc_base64_decode(unsigned char *buf, size_t *len, int strict, int *err) { unsigned char *outbuf; outbuf = (unsigned char *)malloc(3 * (strlen(buf) / 4 + 1)); if (!outbuf) { *err = -3; *len = 0; return 0; } *len = raw_base64_decode(buf, outbuf, strict, err); if (*err) { free(outbuf); *len = 0; outbuf = 0; } return outbuf; }

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• Collision problems with drag-n-drop puzzle game.

  - by Amplify91

  I am working on an Android game similar to the Rush Hour/Traffic Jam/Blocked puzzle games. The board is a square containing rectangular pieces. Long pieces may only move horizontally, and tall pieces may only move vertically. The object is to free the red piece and move it out of the board. This game is only my second ever programming project in any language, so any tips or best practices would be appreciated along with your answer. I have a class for the game pieces called Pieces that describes how they are sized and drawn to the screen, gives them drag-and-drop functionality, and detects and handles collisions. I then have an activity class called GameView which creates my layout and creates Pieces objects to add to a RelativeLayout called Board. I have considered making Board its own class, but haven't needed to yet. Here's what my work in progress looks like: My Question: Most of this works perfectly fine except for my collision handling. It seems to be detecting collisions well but instead of pushing the pieces outside of each other when there is a collision, it frantically snaps back and forth between (what seems to be) where the piece is being dragged to and where it should be. It looks something like this: Another oddity: when the dragged piece collides with a piece to its left, the collision handling seems to work perfectly. Only piece above, below, and to the right cause problems. Here's the collision code: @Override public boolean onTouchEvent(MotionEvent event){ float eventX = event.getX(); float eventY = event.getY(); switch (event.getAction()) { case MotionEvent.ACTION_DOWN: //check if touch is on piece if (eventX > x && eventX < (x+width) && eventY > y && eventY < (y+height)){ initialX=x; initialY=y; break; }else{ return false; } case MotionEvent.ACTION_MOVE: //determine if piece should move horizontally or vertically if(width>height){ for (Pieces piece : aPieces) { //if object equals itself in array, skip to next object if(piece==this){ continue; } //if next to another piece, //do not allow to move any further towards said piece if(eventX<x&&(x==piece.right+1)){ return false; }else if(eventX>x&&(x==piece.x-width-1)){ return false; } //move normally if no collision //if collision, do not allow to move through other piece if(collides(this,piece)==false){ x = (eventX-(width/2)); }else if(collidesLeft(this,piece)){ x = piece.right+1; break; }else if(collidesRight(this,piece)){ x = piece.x-width-1; break; } } break; }else if(height>width){ for (Pieces piece : aPieces) { if(piece==this){ continue; }else if(collides(this,piece)==false){ y = (eventY-(height/2)); }else if(collidesUp(this,piece)){ y = piece.bottom+1; break; }else if(collidesDown(this,piece)){ y = piece.y-height-1; break; } } } invalidate(); break; case MotionEvent.ACTION_UP: // end move if(this.moves()){ GameView.counter++; } initialX=x; initialY=y; break; } // parse puzzle invalidate(); return true; } This takes place during onDraw: width = sizedBitmap.getWidth(); height = sizedBitmap.getHeight(); right = x+width; bottom = y+height; My collision-test methods look like this with different math for each: private boolean collidesDown(Pieces piece1, Pieces piece2){ float x1 = piece1.x; float y1 = piece1.y; float r1 = piece1.right; float b1 = piece1.bottom; float x2 = piece2.x; float y2 = piece2.y; float r2 = piece2.right; float b2 = piece2.bottom; if((y1<y2)&&(y1<b2)&&(b1>=y2)&&(b1<b2)&&((x1>=x2&&x1<=r2)||(r1>=x2&&x1<=r2))){ return true; }else{ return false; } } private boolean collides(Pieces piece1, Pieces piece2){ if(collidesLeft(piece1,piece2)){ return true; }else if(collidesRight(piece1,piece2)){ return true; }else if(collidesUp(piece1,piece2)){ return true; }else if(collidesDown(piece1,piece2)){ return true; }else{ return false; } } As a second question, should my x,y,right,bottom,width,height variables be ints instead of floats like they are now? Also, any suggestions on how to implement things better would be greatly appreciated, even if not relevant to the question! Thanks in advance for the help and for sitting through such a long question! Update: I have gotten it working almost perfectly with the following code (this doesn't include the code for vertical pieces): @Override public boolean onTouchEvent(MotionEvent event){ float eventX = event.getX(); float eventY = event.getY(); switch (event.getAction()) { case MotionEvent.ACTION_DOWN: //check if touch is on piece if (eventX > x && eventX < (x+width) && eventY > y && eventY < (y+height)){ initialX=x; initialY=y; break; }else{ return false; } case MotionEvent.ACTION_MOVE: //determine if piece should move horizontally or vertically if(width>height){ for (Pieces piece : aPieces) { //if object equals itself in array, skip to next object if(piece==this){ continue; } //check if there the possibility for a horizontal collision if(this.isAllignedHorizontallyWith(piece)){ //check for and handle collisions while moving left if(this.isRightOf(piece)){ if(eventX>piece.right+(width/2)){ x = (int)(eventX-(width/2)); //move normally }else{ x = piece.right+1; } } //check for and handle collisions while moving right if(this.isLeftOf(piece)){ if(eventX<piece.x-(width/2)){ x = (int)(eventX-(width/2)); }else{ x = piece.x-width-1; } } break; }else{ x = (int)(eventX-(width/2)); } The only problem with this code is that it only detects collisions between the moving piece and one other (with preference to one on the left). If there is a piece to collide with on the left and another on the right, it will only detect collisions with the one on the left. I think this is because once it finds a possible collision, it handles it without finishing looping through the array holding all the pieces. How do I get it to check for multiple possible collisions at the same time?

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• Flash AS3 Mysterious Blinking MovieClip

  - by Ben

  This is the strangest problem I've faced in flash so far. I have no idea what's causing it. I can provide a .swf if someone wants to actually see it, but I'll describe it as best I can. I'm creating bullets for a tank object to shoot. The tank is a child of the document class. The way I am creating the bullet is: var bullet:Bullet = new Bullet(); (parent as MovieClip).addChild(bullet); The bullet itself simply moves itself in a direction using code like this.x += 5; The problem is the bullets will trace for their creation and destruction at the correct times, however the bullet is sometimes not visible until half way across the screen, sometimes not at all, and sometimes for the whole traversal. Oddly removing the timer I have on bullet creation seems to solve this. The timer is implemented as such: if(shot_timer == 0) { shoot(); // This contains the aforementioned bullet creation method shot_timer = 10; My enter frame handler for the tank object controls the timer and decrements it every frame if it is greater than zero. Can anyone suggest why this could be happening? EDIT: As requested, full code: Bullet.as package { import flash.display.MovieClip; import flash.events.Event; public class Bullet extends MovieClip { public var facing:int; private var speed:int; public function Bullet():void { trace("created"); speed = 10; addEventListener(Event.ADDED_TO_STAGE,addedHandler); } private function addedHandler(e:Event):void { addEventListener(Event.ENTER_FRAME,enterFrameHandler); removeEventListener(Event.ADDED_TO_STAGE,addedHandler); } private function enterFrameHandler(e:Event):void { //0 - up, 1 - left, 2 - down, 3 - right if(this.x > 720 || this.x < 0 || this.y < 0 || this.y > 480) { removeEventListener(Event.ENTER_FRAME,enterFrameHandler); trace("destroyed"); (parent as MovieClip).removeChild(this); return; } switch(facing) { case 0: this.y -= speed; break; case 1: this.x -= speed; break; case 2: this.y += speed; break; case 3: this.x += speed; break; } } } } Tank.as: package { import flash.display.MovieClip; import flash.events.KeyboardEvent; import flash.events.Event; import flash.ui.Keyboard; public class Tank extends MovieClip { private var right:Boolean = false; private var left:Boolean = false; private var up:Boolean = false; private var down:Boolean = false; private var facing:int = 0; //0 - up, 1 - left, 2 - down, 3 - right private var horAllowed:Boolean = true; private var vertAllowed:Boolean = true; private const GRID_SIZE:int = 100; private var shooting:Boolean = false; private var shot_timer:int = 0; private var speed:int = 2; public function Tank():void { addEventListener(Event.ADDED_TO_STAGE,stageAddHandler); addEventListener(Event.ENTER_FRAME, enterFrameHandler); } private function stageAddHandler(e:Event):void { stage.addEventListener(KeyboardEvent.KEY_DOWN,checkKeys); stage.addEventListener(KeyboardEvent.KEY_UP,keyUps); removeEventListener(Event.ADDED_TO_STAGE,stageAddHandler); } public function checkKeys(event:KeyboardEvent):void { if(event.keyCode == 32) { //trace("Spacebar is down"); shooting = true; } if(event.keyCode == 39) { //trace("Right key is down"); right = true; } if(event.keyCode == 38) { //trace("Up key is down"); // lol up = true; } if(event.keyCode == 37) { //trace("Left key is down"); left = true; } if(event.keyCode == 40) { //trace("Down key is down"); down = true; } } public function keyUps(event:KeyboardEvent):void { if(event.keyCode == 32) { event.keyCode = 0; shooting = false; //trace("Spacebar is not down"); } if(event.keyCode == 39) { event.keyCode = 0; right = false; //trace("Right key is not down"); } if(event.keyCode == 38) { event.keyCode = 0; up = false; //trace("Up key is not down"); } if(event.keyCode == 37) { event.keyCode = 0; left = false; //trace("Left key is not down"); } if(event.keyCode == 40) { event.keyCode = 0; down = false; //trace("Down key is not down") // O.o } } public function checkDirectionPermissions(): void { if(this.y % GRID_SIZE < 5 || GRID_SIZE - this.y % GRID_SIZE < 5) { horAllowed = true; } else { horAllowed = false; } if(this.x % GRID_SIZE < 5 || GRID_SIZE - this.x % GRID_SIZE < 5) { vertAllowed = true; } else { vertAllowed = false; } if(!horAllowed && !vertAllowed) { realign(); } } public function realign():void { if(!horAllowed) { if(this.x % GRID_SIZE < GRID_SIZE / 2) { this.x -= this.x % GRID_SIZE; } else { this.x += (GRID_SIZE - this.x % GRID_SIZE); } } if(!vertAllowed) { if(this.y % GRID_SIZE < GRID_SIZE / 2) { this.y -= this.y % GRID_SIZE; } else { this.y += (GRID_SIZE - this.y % GRID_SIZE); } } } public function enterFrameHandler(Event):void { //trace(shot_timer); if(shot_timer > 0) { shot_timer--; } movement(); firing(); } public function firing():void { if(shooting) { if(shot_timer == 0) { shoot(); shot_timer = 10; } } } public function shoot():void { var bullet = new Bullet(); bullet.facing = facing; //0 - up, 1 - left, 2 - down, 3 - right switch(facing) { case 0: bullet.x = this.x; bullet.y = this.y - this.height / 2; break; case 1: bullet.x = this.x - this.width / 2; bullet.y = this.y; break; case 2: bullet.x = this.x; bullet.y = this.y + this.height / 2; break; case 3: bullet.x = this.x + this.width / 2; bullet.y = this.y; break; } (parent as MovieClip).addChild(bullet); } public function movement():void { //0 - up, 1 - left, 2 - down, 3 - right checkDirectionPermissions(); if(horAllowed) { if(right) { orient(3); realign(); this.x += speed; } if(left) { orient(1); realign(); this.x -= speed; } } if(vertAllowed) { if(up) { orient(0); realign(); this.y -= speed; } if(down) { orient(2); realign(); this.y += speed; } } } public function orient(dest:int):void { //trace("facing: " + facing); //trace("dest: " + dest); var angle = facing - dest; this.rotation += (90 * angle); facing = dest; } } }

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• Android App Crashes On Second Run

  - by user1091286

  My app runs fine on first run. On the Menu I added two choices options and quit. options which set up a new intent who goes to a PreferenceActivity and quit which simply call: "android.os.Process.killProcess(android.os.Process.myPid());" On the second time I run my app (after I quit from inside the emulator) it crashes.. Ideas? the menu is called by the foolowing code: @Override public boolean onCreateOptionsMenu(Menu menu) { getMenuInflater().inflate(R.menu.menu , menu); return true; } - @Override public boolean onOptionsItemSelected(MenuItem item) { // Set up a new intent between the updater service and the main screen Intent options = new Intent(this, OptionsScreenActivity.class); // Switch case on the options switch (item.getItemId()) { case R.id.options: startActivity(options); return true; case R.id.quit: android.os.Process.killProcess(android.os.Process.myPid()); return true; default: return false; } Code for SeekBarPreference: package com.testapp.logic; import com.testapp.R; import android.content.Context; import android.content.res.TypedArray; import android.preference.Preference; import android.util.AttributeSet; import android.util.Log; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.view.ViewParent; import android.widget.RelativeLayout; import android.widget.SeekBar; import android.widget.SeekBar.OnSeekBarChangeListener; import android.widget.TextView; public class SeekBarPreference extends Preference implements OnSeekBarChangeListener { private final String TAG = getClass().getName(); private static final String ANDROIDNS="http://schemas.android.com/apk/res/android"; private static final String PREFS="com.testapp.logic"; private static final int DEFAULT_VALUE = 5; private int mMaxValue = 100; private int mMinValue = 1; private int mInterval = 1; private int mCurrentValue; private String mUnitsLeft = ""; private String mUnitsRight = ""; private SeekBar mSeekBar; private TextView mStatusText; public SeekBarPreference(Context context, AttributeSet attrs) { super(context, attrs); initPreference(context, attrs); } public SeekBarPreference(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); initPreference(context, attrs); } private void initPreference(Context context, AttributeSet attrs) { setValuesFromXml(attrs); mSeekBar = new SeekBar(context, attrs); mSeekBar.setMax(mMaxValue - mMinValue); mSeekBar.setOnSeekBarChangeListener(this); } private void setValuesFromXml(AttributeSet attrs) { mMaxValue = attrs.getAttributeIntValue(ANDROIDNS, "max", 100); mMinValue = attrs.getAttributeIntValue(PREFS, "min", 0); mUnitsLeft = getAttributeStringValue(attrs, PREFS, "unitsLeft", ""); String units = getAttributeStringValue(attrs, PREFS, "units", ""); mUnitsRight = getAttributeStringValue(attrs, PREFS, "unitsRight", units); try { String newInterval = attrs.getAttributeValue(PREFS, "interval"); if(newInterval != null) mInterval = Integer.parseInt(newInterval); } catch(Exception e) { Log.e(TAG, "Invalid interval value", e); } } private String getAttributeStringValue(AttributeSet attrs, String namespace, String name, String defaultValue) { String value = attrs.getAttributeValue(namespace, name); if(value == null) value = defaultValue; return value; } @Override protected View onCreateView(ViewGroup parent){ RelativeLayout layout = null; try { LayoutInflater mInflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE); layout = (RelativeLayout)mInflater.inflate(R.layout.seek_bar_preference, parent, false); } catch(Exception e) { Log.e(TAG, "Error creating seek bar preference", e); } return layout; } @Override public void onBindView(View view) { super.onBindView(view); try { // move our seekbar to the new view we've been given ViewParent oldContainer = mSeekBar.getParent(); ViewGroup newContainer = (ViewGroup) view.findViewById(R.id.seekBarPrefBarContainer); if (oldContainer != newContainer) { // remove the seekbar from the old view if (oldContainer != null) { ((ViewGroup) oldContainer).removeView(mSeekBar); } // remove the existing seekbar (there may not be one) and add ours newContainer.removeAllViews(); newContainer.addView(mSeekBar, ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT); } } catch(Exception ex) { Log.e(TAG, "Error binding view: " + ex.toString()); } updateView(view); } /** * Update a SeekBarPreference view with our current state * @param view */ protected void updateView(View view) { try { RelativeLayout layout = (RelativeLayout)view; mStatusText = (TextView)layout.findViewById(R.id.seekBarPrefValue); mStatusText.setText(String.valueOf(mCurrentValue)); mStatusText.setMinimumWidth(30); mSeekBar.setProgress(mCurrentValue - mMinValue); TextView unitsRight = (TextView)layout.findViewById(R.id.seekBarPrefUnitsRight); unitsRight.setText(mUnitsRight); TextView unitsLeft = (TextView)layout.findViewById(R.id.seekBarPrefUnitsLeft); unitsLeft.setText(mUnitsLeft); } catch(Exception e) { Log.e(TAG, "Error updating seek bar preference", e); } } public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) { int newValue = progress + mMinValue; if(newValue > mMaxValue) newValue = mMaxValue; else if(newValue < mMinValue) newValue = mMinValue; else if(mInterval != 1 && newValue % mInterval != 0) newValue = Math.round(((float)newValue)/mInterval)*mInterval; // change rejected, revert to the previous value if(!callChangeListener(newValue)){ seekBar.setProgress(mCurrentValue - mMinValue); return; } // change accepted, store it mCurrentValue = newValue; mStatusText.setText(String.valueOf(newValue)); persistInt(newValue); } public void onStartTrackingTouch(SeekBar seekBar) {} public void onStopTrackingTouch(SeekBar seekBar) { notifyChanged(); } @Override protected Object onGetDefaultValue(TypedArray ta, int index){ int defaultValue = ta.getInt(index, DEFAULT_VALUE); return defaultValue; } @Override protected void onSetInitialValue(boolean restoreValue, Object defaultValue) { if(restoreValue) { mCurrentValue = getPersistedInt(mCurrentValue); } else { int temp = 0; try { temp = (Integer)defaultValue; } catch(Exception ex) { Log.e(TAG, "Invalid default value: " + defaultValue.toString()); } persistInt(temp); mCurrentValue = temp; } } } Logcat: E/AndroidRuntime( 4525): FATAL EXCEPTION: main E/AndroidRuntime( 4525): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.ui.testapp/com.logic.testapp.SeekBarPreferen ce}: java.lang.InstantiationException: can't instantiate class com.logic.testapp.SeekBarPreference; no empty constructor E/AndroidRuntime( 4525): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1879) E/AndroidRuntime( 4525): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1980) E/AndroidRuntime( 4525): at android.app.ActivityThread.access$600(ActivityThread.java:122) E/AndroidRuntime( 4525): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1146) E/AndroidRuntime( 4525): at android.os.Handler.dispatchMessage(Handler.java:99) E/AndroidRuntime( 4525): at android.os.Looper.loop(Looper.java:137) E/AndroidRuntime( 4525): at android.app.ActivityThread.main(ActivityThread.java:4340) E/AndroidRuntime( 4525): at java.lang.reflect.Method.invokeNative(Native Method) E/AndroidRuntime( 4525): at java.lang.reflect.Method.invoke(Method.java:511) E/AndroidRuntime( 4525): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) E/AndroidRuntime( 4525): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) E/AndroidRuntime( 4525): at dalvik.system.NativeStart.main(Native Method) E/AndroidRuntime( 4525): Caused by: java.lang.InstantiationException: can't instantiate class com.logic.testapp.SeekBarPreference; no empty construc tor E/AndroidRuntime( 4525): at java.lang.Class.newInstanceImpl(Native Method) E/AndroidRuntime( 4525): at java.lang.Class.newInstance(Class.java:1319) E/AndroidRuntime( 4525): at android.app.Instrumentation.newActivity(Instrumentation.java:1023) E/AndroidRuntime( 4525): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1870) E/AndroidRuntime( 4525): ... 11 more W/ActivityManager( 84): Force finishing activity com.ui.testapp/com.logic.testapp.SeekBarPreference W/ActivityManager( 84): Force finishing activity com.ui.testapp/.MainScreen I/WindowManager( 84): createSurface Window{41a90320 paused=false}: DRAW NOW PENDING W/ActivityManager( 84): Activity pause timeout for ActivityRecord{4104a848 com.ui.testapp/com.logic.testapp.SeekBarPreference} W/NetworkManagementSocketTagger( 84): setKernelCountSet(10021, 1) failed with errno -2 I/WindowManager( 84): createSurface Window{412bcc10 com.android.launcher/com.android.launcher2.Launcher paused=false}: DRAW NOW PENDING W/NetworkManagementSocketTagger( 84): setKernelCountSet(10045, 0) failed with errno -2 I/Process ( 4525): Sending signal. PID: 4525 SIG: 9 I/ActivityManager( 84): Process com.ui.testapp (pid 4525) has died. I/WindowManager( 84): WIN DEATH: Window{41a6c9c0 com.ui.testapp/com.ui.testapp.MainScreen paused=true}

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• what "Debug Assertion Failed" mean and how to fix it, c++?

  - by nonon

  hi, why this program gives me a "Debug Assertion Failed" Error Message while running #include "stdafx.h" #include "iostream" #include "fstream" #include "string" using namespace std; int conv_ch(char b) { int f; f=b; b=b+0; switch(b) { case 48: f=0; break; case 49: f=1; break; case 50: f=2; break; case 51: f=3; break; case 52: f=4; break; case 53: f=5; break; case 54: f=6; break; case 55: f=7; break; case 56: f=8; break; case 57: f=9; break; default: f=0; } return f; } class Student { public: string id; size_t id_len; string first_name; size_t first_len; string last_name; size_t last_len; string phone; size_t phone_len; string grade; size_t grade_len; void print(); void clean(); }; void Student::clean() { id.erase (id.begin()+6, id.end()); first_name.erase (first_name.begin()+15, first_name.end()); last_name.erase (last_name.begin()+15, last_name.end()); phone.erase (phone.begin()+10, phone.end()); grade.erase (grade.begin()+2, grade.end()); } void Student::print() { int i; for(i=0;i<6;i++) { cout<<id[i]; } cout<<endl; for(i=0;i<15;i++) { cout<<first_name[i]; } cout<<endl; for(i=0;i<15;i++) { cout<<last_name[i]; } cout<<endl; for(i=0;i<10;i++) { cout<<phone[i]; } cout<<endl; for(i=0;i<2;i++) { cout<<grade[i]; } cout<<endl; } int main() { Student k[80]; char data[1200]; int length,i,recn=0; int rec_length; int counter = 0; fstream myfile; char x1,x2; char y1,y2; char zz; int ad=0; int ser,j; myfile.open ("example.txt",ios::in); int right; int left; int middle; string key; while(!myfile.eof()){ myfile.get(data,1200); char * pch; pch = strtok (data, "#"); printf ("%s\n", pch); j=0; for(i=0;i<6;i++) { k[recn].id[i]=data[j]; j++; } for(i=0;i<15;i++) { k[recn].first_name[i]=data[j]; j++; } for(i=0;i<15;i++) { k[recn].last_name[i]=data[j]; j++; } for(i=0;i<10;i++) { k[recn].phone[i]=data[j]; j++; } for(i=0;i<2;i++) { k[recn].grade[i]=data[j]; j++; } recn++; j=0; } //cout<<recn; string temp1; size_t temp2; int temp3; for(i=0;i<recn-1;i++) { for(j=0;j<recn-1;j++) { if(k[i].id.compare(k[j].id)<0) { temp1 = k[i].first_name; k[i].first_name = k[j].first_name; k[j].first_name = temp1; temp2 = k[i].first_len; k[i].first_len = k[j].first_len; k[j].first_len = temp2; temp1 = k[i].last_name; k[i].last_name = k[j].last_name; k[j].last_name = temp1; temp2 = k[i].last_len; k[i].last_len = k[j].last_len; k[j].last_len = temp2; temp1 = k[i].grade; k[i].grade = k[j].grade; k[j].grade = temp1; temp2 = k[i].grade_len; k[i].grade_len = k[j].grade_len; k[j].grade_len = temp2; temp1 = k[i].id; k[i].id = k[j].id; k[j].id = temp1; temp2 = k[i].id_len; k[i].id_len = k[j].id_len; k[j].id_len = temp2; temp1 = k[i].phone; k[i].phone = k[j].phone; k[j].phone = temp1; temp2 = k[i].phone_len; k[i].phone_len = k[j].phone_len; k[j].phone_len = temp2; } } } for(i=0;i<recn-1;i++) { k[i].clean(); } char z; string id_sear; cout<<"Enter 1 to display , 2 to search , 3 to exit:"; cin>>z; while(1){ switch(z) { case '1': for(i=0;i<recn-1;i++) { k[i].print(); } break; case '2': cin>>key; right=0; left=recn-2; while(right<=left) { middle=((right+left)/2); if(key.compare(k[middle].id)==0){ cout<<"Founded"<<endl; k[middle].print(); break; } else if(key.compare(k[middle].id)<0) { left=middle-1; } else { right=middle+1; } } break; case '3': exit(0); break; } cout<<"Enter 1 to display , 2 to search , 3 to exit:"; cin>>z; } return 0; } the program reads from a file example.txt 313121crewwe matt 0114323111A # 433444cristinaee john 0113344325A+# 324311matte richee 3040554032B # the idea is to read fixed size field structure with a text seprator record strucutre

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• Incorrect output on changing sequence of declarations

  - by max

  Writing C++ code to implement Sutherland-Hodgeman polygon clipping. This order of declaration of these 2 statements gives correct output, reverse does not. int numberOfVertices = 5; Point pointList[] = { {50,50}, {200,300}, {310,110}, {130,90}, {70,40} }; I am passing the polygon vertex set to clippers in order - LEFT, RIGHT, TOP, BOTTOM. The exact error which comes when the declarations are reversed is that the bottom clipper, produces an empty set of vertices so no polygon is displayed after clipping. Correct: Incorrent: Confirmed by outputting the number of vertices produced after each pass: Correct: Incorrect: What is the reason for this error? Code: #include <iostream> #include <GL/glut.h> #define MAXVERTICES 10 #define LEFT 0 #define RIGHT 1 #define TOP 2 #define BOTTOM 3 using namespace std; /* Clipping window */ struct Window { double xmin; double xmax; double ymin; double ymax; }; struct Point { double x; double y; }; /* If I interchange these two lines, the code doesn't work. */ /**************/ int numberOfVertices = 5; Point pointList[] = { {50,50}, {200,300}, {310,110}, {130,90}, {70,40} }; /**************/ const Window w = { 100, 400, 60, 200 }; /* Checks whether a point is inside or outside a window side */ int isInside(Point p, int side) { switch(side) { case LEFT: return p.x >= w.xmin; case RIGHT: return p.x <= w.xmax; case TOP: return p.y <= w.ymax; case BOTTOM: return p.y >= w.ymin; } } /* Calculates intersection of a segment and a window side */ Point intersection(Point p1, Point p2, int side) { Point temp; double slope, intercept; bool infinite; /* Find slope and intercept of segment, taking care of inf slope */ if(p2.x - p1.x != 0) { slope = (p2.y - p1.y) / (p2.x - p1.x); infinite = false; } else { infinite = true; } intercept = p1.y - p1.x * slope; /* Calculate intersections */ switch(side) { case LEFT: temp.x = w.xmin; temp.y = temp.x * slope + intercept; break; case RIGHT: temp.x = w.xmax; temp.y = temp.x * slope + intercept; break; case TOP: temp.y = w.ymax; temp.x = infinite ? p1.x : (temp.y - intercept) / slope; break; case BOTTOM: temp.y = w.ymin; temp.x = infinite ? p1.x : (temp.y - intercept) / slope; break; } return temp; } /* Clips polygon against a side, updating the point list (called once for each side) */ void clipAgainstSide(int sideToClip) { int i, j=0; Point s,p; Point outputList[MAXVERTICES]; /* Main algorithm */ s = pointList[numberOfVertices-1]; for(i=0 ; i<numberOfVertices ; i++) { p = pointList[i]; if(isInside(p, sideToClip)) { /* p inside */ if(!isInside(s, sideToClip)) { /* p inside, s outside */ outputList[j] = intersection(p, s, sideToClip); j++; } outputList[j] = p; j++; } else if(isInside(s, sideToClip)) { /* s inside, p outside */ outputList[j] = intersection(s, p, sideToClip); j++; } s = p; } /* Updating number of points and point list */ numberOfVertices = j; /* ERROR: In last call with BOTTOM argument, numberOfVertices becomes 0 */ /* all earlier 3 calls have correct output */ cout<<numberOfVertices<<endl; for(i=0 ; i<numberOfVertices ; i++) { pointList[i] = outputList[i]; } } void SutherlandHodgemanPolygonClip() { clipAgainstSide(LEFT); clipAgainstSide(RIGHT); clipAgainstSide(TOP); clipAgainstSide(BOTTOM); } void init() { glClearColor(1,1,1,0); glMatrixMode(GL_PROJECTION); gluOrtho2D(0,1000,0,500); } void display() { glClear(GL_COLOR_BUFFER_BIT); /* Displaying ORIGINAL box and polygon */ glColor3f(0,0,1); glBegin(GL_LINE_LOOP); glVertex2i(w.xmin, w.ymin); glVertex2i(w.xmin, w.ymax); glVertex2i(w.xmax, w.ymax); glVertex2i(w.xmax, w.ymin); glEnd(); glColor3f(1,0,0); glBegin(GL_LINE_LOOP); for(int i=0 ; i<numberOfVertices ; i++) { glVertex2i(pointList[i].x, pointList[i].y); } glEnd(); /* Clipping */ SutherlandHodgemanPolygonClip(); /* Displaying CLIPPED box and polygon, 500px right */ glColor3f(0,0,1); glBegin(GL_LINE_LOOP); glVertex2i(w.xmin+500, w.ymin); glVertex2i(w.xmin+500, w.ymax); glVertex2i(w.xmax+500, w.ymax); glVertex2i(w.xmax+500, w.ymin); glEnd(); glColor3f(1,0,0); glBegin(GL_LINE_LOOP); for(int i=0 ; i<numberOfVertices ; i++) { glVertex2i(pointList[i].x+500, pointList[i].y); } glEnd(); glFlush(); } int main(int argc, char** argv) { glutInit(&argc, argv); glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); glutInitWindowSize(1000,500); glutCreateWindow("Sutherland-Hodgeman polygon clipping"); init(); glutDisplayFunc(display); glutMainLoop(); return 0; }

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• Java: Cannot find a method's symbol even though that method is declared later in the class. The remaining code is looking for a class.

  - by Midimistro

  This is an assignment that we use strings in Java to analyze a phone number. The error I am having is anything below tester=invalidCharacters(c); does not compile because every line past tester=invalidCharacters(c); is looking for a symbol or the class. In get invalidResults, all I am trying to do is evaluate a given string for non-alphabetical characters such as *,(,^,&,%,@,#,), and so on. What to answer: Why is it producing an error, what will work, and is there an easier method WITHOUT using regex. Here is the link to the assignment: http://cis.csuohio.edu/~hwang/teaching/cis260/assignments/assignment9.html public class PhoneNumber { private int areacode; private int number; private int ext; /////Constructors///// //Third Constructor (given one string arg) "xxx-xxxxxxx" where first three are numbers and the remaining (7) are numbers or letters public PhoneNumber(String newNumber){ //Note: Set default ext to 0 ext=0; ////Declare Temporary Storage and other variables//// //for the first three numbers String areaCodeString; //for the remaining seven characters String newNumberString; //For use in testing the second half of the string boolean containsLetters; boolean containsInvalid; /////Separate the two parts of string///// //Get the area code part of the string areaCodeString=newNumber.substring(0,2); //Convert the string and set it to the area code areacode=Integer.parseInt(areaCodeString); //Skip the "-" and Get the remaining part of the string newNumberString=newNumber.substring(4); //Create an array of characters from newNumberString to reuse in later methods for int length=newNumberString.length(); char [] myCharacters= new char [length]; int i; for (i=0;i<length;i++){ myCharacters [i]=newNumberString.charAt(i); } //Test if newNumberString contains letters & converting them into numbers String reNewNumber=""; //Test for invalid characters containsInvalid=getInvalidResults(newNumberString,length); if (containsInvalid==false){ containsLetters=getCharResults(newNumberString,length); if (containsLetters==true){ for (i=0;i<length;i++){ myCharacters [i]=(char)convertLetNum((myCharacters [i])); reNewNumber=reNewNumber+myCharacters[i]; } } } if (containsInvalid==false){ number=Integer.parseInt(reNewNumber); } else{ System.out.println("Error!"+"\t"+newNumber+" contains illegal characters. This number will be ignored and skipped."); } } //////Primary Methods/Behaviors/////// //Compare this phone number with the one passed by the caller public boolean equals(PhoneNumber pn){ boolean equal; String concat=(areacode+"-"+number); String pN=pn.toString(); if (concat==pN){ equal=true; } else{ equal=false; } return equal; } //Convert the stored number to a certain string depending on extension public String toString(){ String returned; if(ext==0){ returned=(areacode+"-"+number); } else{ returned=(areacode+"-"+number+" ext "+ext); } return returned; } //////Secondary Methods/////// //Method for testing if the second part of the string contains any letters public static boolean getCharResults(String newNumString,int getLength){ //Recreate a character array int i; char [] myCharacters= new char [getLength]; for (i=0;i<getLength;i++){ myCharacters [i]=newNumString.charAt(i); } boolean doesContainLetter=false; int j; for (j=0;j<getLength;j++){ if ((Character.isDigit(myCharacters[j])==true)){ doesContainLetter=false; } else{ doesContainLetter=true; return doesContainLetter; } } return doesContainLetter; } //Method for testing if the second part of the string contains any letters public static boolean getInvalidResults(String newNumString,int getLength){ boolean doesContainInvalid=false; int i; char c; boolean tester; char [] invalidCharacters= new char [getLength]; for (i=0;i<getLength;i++){ invalidCharacters [i]=newNumString.charAt(i); c=invalidCharacters [i]; tester=invalidCharacters(c); if(tester==true)){ doesContainInvalid=false; } else{ doesContainInvalid=true; return doesContainInvalid; } } return doesContainInvalid; } //Method for evaluating string for invalid characters public boolean invalidCharacters(char letter){ boolean returnNum=false; switch (letter){ case 'A': return returnNum; case 'B': return returnNum; case 'C': return returnNum; case 'D': return returnNum; case 'E': return returnNum; case 'F': return returnNum; case 'G': return returnNum; case 'H': return returnNum; case 'I': return returnNum; case 'J': return returnNum; case 'K': return returnNum; case 'L': return returnNum; case 'M': return returnNum; case 'N': return returnNum; case 'O': return returnNum; case 'P': return returnNum; case 'Q': return returnNum; case 'R': return returnNum; case 'S': return returnNum; case 'T': return returnNum; case 'U': return returnNum; case 'V': return returnNum; case 'W': return returnNum; case 'X': return returnNum; case 'Y': return returnNum; case 'Z': return returnNum; default: return true; } } //Method for converting letters to numbers public int convertLetNum(char letter){ int returnNum; switch (letter){ case 'A': returnNum=2;return returnNum; case 'B': returnNum=2;return returnNum; case 'C': returnNum=2;return returnNum; case 'D': returnNum=3;return returnNum; case 'E': returnNum=3;return returnNum; case 'F': returnNum=3;return returnNum; case 'G': returnNum=4;return returnNum; case 'H': returnNum=4;return returnNum; case 'I': returnNum=4;return returnNum; case 'J': returnNum=5;return returnNum; case 'K': returnNum=5;return returnNum; case 'L': returnNum=5;return returnNum; case 'M': returnNum=6;return returnNum; case 'N': returnNum=6;return returnNum; case 'O': returnNum=6;return returnNum; case 'P': returnNum=7;return returnNum; case 'Q': returnNum=7;return returnNum; case 'R': returnNum=7;return returnNum; case 'S': returnNum=7;return returnNum; case 'T': returnNum=8;return returnNum; case 'U': returnNum=8;return returnNum; case 'V': returnNum=8;return returnNum; case 'W': returnNum=9;return returnNum; case 'X': returnNum=9;return returnNum; case 'Y': returnNum=9;return returnNum; case 'Z': returnNum=9;return returnNum; default: return 0; } } } Note: Please Do not use this program to cheat in your own class. To ensure of this, I will take this question down if it has not been answered by the end of 2013, if I no longer need an explanation for it, or if the term for the class has ended.

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• Using HTML 5 SessionState to save rendered Page Content

  - by Rick Strahl

  HTML 5 SessionState and LocalStorage are very useful and super easy to use to manage client side state. For building rich client side or SPA style applications it's a vital feature to be able to cache user data as well as HTML content in order to swap pages in and out of the browser's DOM. What might not be so obvious is that you can also use the sessionState and localStorage objects even in classic server rendered HTML applications to provide caching features between pages. These APIs have been around for a long time and are supported by most relatively modern browsers and even all the way back to IE8, so you can use them safely in your Web applications. SessionState and LocalStorage are easy The APIs that make up sessionState and localStorage are very simple. Both object feature the same API interface which  is a simple, string based key value store that has getItem, setItem, removeitem, clear and  key methods. The objects are also pseudo array objects and so can be iterated like an array with  a length property and you have array indexers to set and get values with. Basic usage  for storing and retrieval looks like this (using sessionStorage, but the syntax is the same for localStorage - just switch the objects):// set var lastAccess = new Date().getTime(); if (sessionStorage) sessionStorage.setItem("myapp_time", lastAccess.toString()); // retrieve in another page or on a refresh var time = null; if (sessionStorage) time = sessionStorage.getItem("myapp_time"); if (time) time = new Date(time * 1); else time = new Date(); sessionState stores data that is browser session specific and that has a liftetime of the active browser session or window. Shut down the browser or tab and the storage goes away. localStorage uses the same API interface, but the lifetime of the data is permanently stored in the browsers storage area until deleted via code or by clearing out browser cookies (not the cache). Both sessionStorage and localStorage space is limited. The spec is ambiguous about this - supposedly sessionStorage should allow for unlimited size, but it appears that most WebKit browsers support only 2.5mb for either object. This means you have to be careful what you store especially since other applications might be running on the same domain and also use the storage mechanisms. That said 2.5mb worth of character data is quite a bit and would go a long way. The easiest way to get a feel for how sessionState and localStorage work is to look at a simple example. You can go check out the following example online in Plunker: http://plnkr.co/edit/0ICotzkoPjHaWa70GlRZ?p=preview which looks like this: Plunker is an online HTML/JavaScript editor that lets you write and run Javascript code and similar to JsFiddle, but a bit cleaner to work in IMHO (thanks to John Papa for turning me on to it). The sample has two text boxes with counts that update session/local storage every time you click the related button. The counts are 'cached' in Session and Local storage. The point of these examples is that both counters survive full page reloads, and the LocalStorage counter survives a complete browser shutdown and restart. Go ahead and try it out by clicking the Reload button after updating both counters and then shutting down the browser completely and going back to the same URL (with the same browser). What you should see is that reloads leave both counters intact at the counted values, while a browser restart will leave only the local storage counter intact. The code to deal with the SessionStorage (and LocalStorage not shown here) in the example is isolated into a couple of wrapper methods to simplify the code: function getSessionCount() { var count = 0; if (sessionStorage) { var count = sessionStorage.getItem("ss_count"); count = !count ? 0 : count * 1; } $("#txtSession").val(count); return count; } function setSessionCount(count) { if (sessionStorage) sessionStorage.setItem("ss_count", count.toString()); } These two functions essentially load and store a session counter value. The two key methods used here are: sessionStorage.getItem(key); sessionStorage.setItem(key,stringVal); Note that the value given to setItem and return by getItem has to be a string. If you pass another type you get an error. Don't let that limit you though - you can easily enough store JSON data in a variable so it's quite possible to pass complex objects and store them into a single sessionStorage value:var user = { name: "Rick", id="ricks", level=8 } sessionStorage.setItem("app_user",JSON.stringify(user)); to retrieve it:var user = sessionStorage.getItem("app_user"); if (user) user = JSON.parse(user); Simple! If you're using the Chrome Developer Tools (F12) you can also check out the session and local storage state on the Resource tab:   You can also use this tool to refresh or remove entries from storage. What we just looked at is a purely client side implementation where a couple of counters are stored. For rich client centric AJAX applications sessionStorage and localStorage provide a very nice and simple API to store application state while the application is running. But you can also use these storage mechanisms to manage server centric HTML applications when you combine server rendering with some JavaScript to perform client side data caching. You can both store some state information and data on the client (ie. store a JSON object and carry it forth between server rendered HTML requests) or you can use it for good old HTTP based caching where some rendered HTML is saved and then restored later. Let's look at the latter with a real life example. Why do I need Client-side Page Caching for Server Rendered HTML? I don't know about you, but in a lot of my existing server driven applications I have lists that display a fair amount of data. Typically these lists contain links to then drill down into more specific data either for viewing or editing. You can then click on a link and go off to a detail page that provides more concise content. So far so good. But now you're done with the detail page and need to get back to the list, so you click on a 'bread crumbs trail' or an application level 'back to list' button and… …you end up back at the top of the list - the scroll position, the current selection in some cases even filters conditions - all gone with the wind. You've left behind the state of the list and are starting from scratch in your browsing of the list from the top. Not cool! Sound familiar? This a pretty common scenario with server rendered HTML content where it's so common to display lists to drill into, only to lose state in the process of returning back to the original list. Look at just about any traditional forums application, or even StackOverFlow to see what I mean here. Scroll down a bit to look at a post or entry, drill in then use the bread crumbs or tab to go back… In some cases returning to the top of a list is not a big deal. On StackOverFlow that sort of works because content is turning around so quickly you probably want to actually look at the top posts. Not always though - if you're browsing through a list of search topics you're interested in and drill in there's no way back to that position. Essentially anytime you're actively browsing the items in the list, that's when state becomes important and if it's not handled the user experience can be really disrupting. Content Caching If you're building client centric SPA style applications this is a fairly easy to solve problem - you tend to render the list once and then update the page content to overlay the detail content, only hiding the list temporarily until it's used again later. It's relatively easy to accomplish this simply by hiding content on the page and later making it visible again. But if you use server rendered content, hanging on to all the detail like filters, selections and scroll position is not quite as easy. Or is it??? This is where sessionStorage comes in handy. What if we just save the rendered content of a previous page, and then restore it when we return to this page based on a special flag that tells us to use the cached version? Let's see how we can do this. A real World Use Case Recently my local ISP asked me to help out with updating an ancient classifieds application. They had a very busy, local classifieds app that was originally an ASP classic application. The old app was - wait for it: frames based - and even though I lobbied against it, the decision was made to keep the frames based layout to allow rapid browsing of the hundreds of posts that are made on a daily basis. The primary reason they wanted this was precisely for the ability to quickly browse content item by item. While I personally hate working with Frames, I have to admit that the UI actually works well with the frames layout as long as you're running on a large desktop screen. You can check out the frames based desktop site here: http://classifieds.gorge.net/ However when I rebuilt the app I also added a secondary view that doesn't use frames. The main reason for this of course was for mobile displays which work horribly with frames. So there's a somewhat mobile friendly interface to the interface, which ditches the frames and uses some responsive design tweaking for mobile capable operation: http://classifeds.gorge.net/mobile  (or browse the base url with your browser width under 800px)   Here's what the mobile, non-frames view looks like:   As you can see this means that the list of classifieds posts now is a list and there's a separate page for drilling down into the item. And of course… originally we ran into that usability issue I mentioned earlier where the browse, view detail, go back to the list cycle resulted in lost list state. Originally in mobile mode you scrolled through the list, found an item to look at and drilled in to display the item detail. Then you clicked back to the list and BAM - you've lost your place. Because there are so many items added on a daily basis the full list is never fully loaded, but rather there's a "Load Additional Listings"  entry at the button. Not only did we originally lose our place when coming back to the list, but any 'additionally loaded' items are no longer there because the list was now rendering  as if it was the first page hit. The additional listings, and any filters, the selection of an item all were lost. Major Suckage! Using Client SessionStorage to cache Server Rendered Content To work around this problem I decided to cache the rendered page content from the list in SessionStorage. Anytime the list renders or is updated with Load Additional Listings, the page HTML is cached and stored in Session Storage. Any back links from the detail page or the login or write entry forms then point back to the list page with a back=true query string parameter. If the server side sees this parameter it doesn't render the part of the page that is cached. Instead the client side code retrieves the data from the sessionState cache and simply inserts it into the page. It sounds pretty simple, and the overall the process is really easy, but there are a few gotchas that I'll discuss in a minute. But first let's look at the implementation. Let's start with the server side here because that'll give a quick idea of the doc structure. As I mentioned the server renders data from an ASP.NET MVC view. On the list page when returning to the list page from the display page (or a host of other pages) looks like this: https://classifieds.gorge.net/list?back=True The query string value is a flag, that indicates whether the server should render the HTML. Here's what the top level MVC Razor view for the list page looks like:@model MessageListViewModel @{ ViewBag.Title = "Classified Listing"; bool isBack = !string.IsNullOrEmpty(Request.QueryString["back"]); } <form method="post" action="@Url.Action("list")"> <div id="SizingContainer"> @if (!isBack) { @Html.Partial("List_CommandBar_Partial", Model) <div id="PostItemContainer" class="scrollbox" xstyle="-webkit-overflow-scrolling: touch;"> @Html.Partial("List_Items_Partial", Model) @if (Model.RequireLoadEntry) { <div class="postitem loadpostitems" style="padding: 15px;"> <div id="LoadProgress" class="smallprogressright"></div> <div class="control-progress"> Load additional listings... </div> </div> } </div> } </div> </form> As you can see the query string triggers a conditional block that if set is simply not rendered. The content inside of #SizingContainer basically holds  the entire page's HTML sans the headers and scripts, but including the filter options and menu at the top. In this case this makes good sense - in other situations the fact that the menu or filter options might be dynamically updated might make you only cache the list rather than essentially the entire page. In this particular instance all of the content works and produces the proper result as both the list along with any filter conditions in the form inputs are restored. Ok, let's move on to the client. On the client there are two page level functions that deal with saving and restoring state. Like the counter example I showed earlier, I like to wrap the logic to save and restore values from sessionState into a separate function because they are almost always used in several places.page.saveData = function(id) { if (!sessionStorage) return; var data = { id: id, scroll: $("#PostItemContainer").scrollTop(), html: $("#SizingContainer").html() }; sessionStorage.setItem("list_html",JSON.stringify(data)); }; page.restoreData = function() { if (!sessionStorage) return; var data = sessionStorage.getItem("list_html"); if (!data) return null; return JSON.parse(data); }; The data that is saved is an object which contains an ID which is the selected element when the user clicks and a scroll position. These two values are used to reset the scroll position when the data is used from the cache. Finally the html from the #SizingContainer element is stored, which makes for the bulk of the document's HTML. In this application the HTML captured could be a substantial bit of data. If you recall, I mentioned that the server side code renders a small chunk of data initially and then gets more data if the user reads through the first 50 or so items. The rest of the items retrieved can be rather sizable. Other than the JSON deserialization that's Ok. Since I'm using SessionStorage the storage space has no immediate limits. Next is the core logic to handle saving and restoring the page state. At first though this would seem pretty simple, and in some cases it might be, but as the following code demonstrates there are a few gotchas to watch out for. Here's the relevant code I use to save and restore:$( function() { … var isBack = getUrlEncodedKey("back", location.href); if (isBack) { // remove the back key from URL setUrlEncodedKey("back", "", location.href); var data = page.restoreData(); // restore from sessionState if (!data) { // no data - force redisplay of the server side default list window.location = "list"; return; } $("#SizingContainer").html(data.html); var el = $(".postitem[data-id=" + data.id + "]"); $(".postitem").removeClass("highlight"); el.addClass("highlight"); $("#PostItemContainer").scrollTop(data.scroll); setTimeout(function() { el.removeClass("highlight"); }, 2500); } else if (window.noFrames) page.saveData(null); // save when page loads $("#SizingContainer").on("click", ".postitem", function() { var id = $(this).attr("data-id"); if (!id) return true; if (window.noFrames) page.saveData(id); var contentFrame = window.parent.frames["Content"]; if (contentFrame) contentFrame.location.href = "show/" + id; else window.location.href = "show/" + id; return false; }); … The code starts out by checking for the back query string flag which triggers restoring from the client cache. If cached the cached data structure is read from sessionStorage. It's important here to check if data was returned. If the user had back=true on the querystring but there is no cached data, he likely bookmarked this page or otherwise shut down the browser and came back to this URL. In that case the server didn't render any detail and we have no cached data, so all we can do is redirect to the original default list view using window.location. If we continued the page would render no data - so make sure to always check the cache retrieval result. Always! If there is data the it's loaded and the data.html data is restored back into the document by simply injecting the HTML back into the document's #SizingContainer element:$("#SizingContainer").html(data.html); It's that simple and it's quite quick even with a fully loaded list of additional items and on a phone. The actual HTML data is stored to the cache on every page load initially and then again when the user clicks on an element to navigate to a particular listing. The former ensures that the client cache always has something in it, and the latter updates with additional information for the selected element. For the click handling I use a data-id attribute on the list item (.postitem) in the list and retrieve the id from that. That id is then used to navigate to the actual entry as well as storing that Id value in the saved cached data. The id is used to reset the selection by searching for the data-id value in the restored elements. The overall process of this save/restore process is pretty straight forward and it doesn't require a bunch of code, yet it yields a huge improvement in the usability of the site on mobile devices (or anybody who uses the non-frames view). Some things to watch out for As easy as it conceptually seems to simply store and retrieve cached content, you have to be quite aware what type of content you are caching. The code above is all that's specific to cache/restore cycle and it works, but it took a few tweaks to the rest of the script code and server code to make it all work. There were a few gotchas that weren't immediately obvious. Here are a few things to pay attention to: Event Handling Logic Timing of manipulating DOM events Inline Script Code Bookmarking to the Cache Url when no cache exists Do you have inline script code in your HTML? That script code isn't going to run if you restore from cache and simply assign or it may not run at the time you think it would normally in the DOM rendering cycle. JavaScript Event Hookups The biggest issue I ran into with this approach almost immediately is that originally I had various static event handlers hooked up to various UI elements that are now cached. If you have an event handler like:$("#btnSearch").click( function() {…}); that works fine when the page loads with server rendered HTML, but that code breaks when you now load the HTML from cache. Why? Because the elements you're trying to hook those events to may not actually be there - yet. Luckily there's an easy workaround for this by using deferred events. With jQuery you can use the .on() event handler instead:$("#SelectionContainer").on("click","#btnSearch", function() {…}); which monitors a parent element for the events and checks for the inner selector elements to handle events on. This effectively defers to runtime event binding, so as more items are added to the document bindings still work. For any cached content use deferred events. Timing of manipulating DOM Elements Along the same lines make sure that your DOM manipulation code follows the code that loads the cached content into the page so that you don't manipulate DOM elements that don't exist just yet. Ideally you'll want to check for the condition to restore cached content towards the top of your script code, but that can be tricky if you have components or other logic that might not all run in a straight line. Inline Script Code Here's another small problem I ran into: I use a DateTime Picker widget I built a while back that relies on the jQuery date time picker. I also created a helper function that allows keyboard date navigation into it that uses JavaScript logic. Because MVC's limited 'object model' the only way to embed widget content into the page is through inline script. This code broken when I inserted the cached HTML into the page because the script code was not available when the component actually got injected into the page. As the last bullet - it's a matter of timing. There's no good work around for this - in my case I pulled out the jQuery date picker and relied on native <input type="date" /> logic instead - a better choice these days anyway, especially since this view is meant to be primarily to serve mobile devices which actually support date input through the browser (unlike desktop browsers of which only WebKit seems to support it). Bookmarking Cached Urls When you cache HTML content you have to make a decision whether you cache on the client and also not render that same content on the server. In the Classifieds app I didn't render server side content so if the user comes to the page with back=True and there is no cached content I have to a have a Plan B. Typically this happens when somebody ends up bookmarking the back URL. The easiest and safest solution for this scenario is to ALWAYS check the cache result to make sure it exists and if not have a safe URL to go back to - in this case to the plain uncached list URL which amounts to effectively redirecting. This seems really obvious in hindsight, but it's easy to overlook and not see a problem until much later, when it's not obvious at all why the page is not rendering anything. Don't use <body> to replace Content Since we're practically replacing all the HTML in the page it may seem tempting to simply replace the HTML content of the <body> tag. Don't. The body tag usually contains key things that should stay in the page and be there when it loads. Specifically script tags and elements and possibly other embedded content. It's best to create a top level DOM element specifically as a placeholder container for your cached content and wrap just around the actual content you want to replace. In the app above the #SizingContainer is that container. Other Approaches The approach I've used for this application is kind of specific to the existing server rendered application we're running and so it's just one approach you can take with caching. However for server rendered content caching this is a pattern I've used in a few apps to retrofit some client caching into list displays. In this application I took the path of least resistance to the existing server rendering logic. Here are a few other ways that come to mind: Using Partial HTML Rendering via AJAXInstead of rendering the page initially on the server, the page would load empty and the client would render the UI by retrieving the respective HTML and embedding it into the page from a Partial View. This effectively makes the initial rendering and the cached rendering logic identical and removes the server having to decide whether this request needs to be rendered or not (ie. not checking for a back=true switch). All the logic related to caching is made on the client in this case. Using JSON Data and Client RenderingThe hardcore client option is to do the whole UI SPA style and pull data from the server and then use client rendering or databinding to pull the data down and render using templates or client side databinding with knockout/angular et al. As with the Partial Rendering approach the advantage is that there's no difference in the logic between pulling the data from cache or rendering from scratch other than the initial check for the cache request. Of course if the app is a  full on SPA app, then caching may not be required even - the list could just stay in memory and be hidden and reactivated. I'm sure there are a number of other ways this can be handled as well especially using  AJAX. AJAX rendering might simplify the logic, but it also complicates search engine optimization since there's no content loaded initially. So there are always tradeoffs and it's important to look at all angles before deciding on any sort of caching solution in general. State of the Session SessionState and LocalStorage are easy to use in client code and can be integrated even with server centric applications to provide nice caching features of content and data. In this post I've shown a very specific scenario of storing HTML content for the purpose of remembering list view data and state and making the browsing experience for lists a bit more friendly, especially if there's dynamically loaded content involved. If you haven't played with sessionStorage or localStorage I encourage you to give it a try. There's a lot of cool stuff that you can do with this beyond the specific scenario I've covered here… Resources Overview of localStorage (also applies to sessionStorage) Web Storage Compatibility Modernizr Test Suite© Rick Strahl, West Wind Technologies, 2005-2013Posted in JavaScript  HTML5  ASP.NET  MVC   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• value types in the vm

  - by john.rose

  value types in the vm p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times} p.p2 {margin: 0.0px 0.0px 14.0px 0.0px; font: 14.0px Times} p.p3 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times} p.p4 {margin: 0.0px 0.0px 15.0px 0.0px; font: 14.0px Times} p.p5 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Courier} p.p6 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Courier; min-height: 17.0px} p.p7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times; min-height: 18.0px} p.p8 {margin: 0.0px 0.0px 0.0px 36.0px; text-indent: -36.0px; font: 14.0px Times; min-height: 18.0px} p.p9 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times; min-height: 18.0px} p.p10 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times; color: #000000} li.li1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times} li.li7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times; min-height: 18.0px} span.s1 {font: 14.0px Courier} span.s2 {color: #000000} span.s3 {font: 14.0px Courier; color: #000000} ol.ol1 {list-style-type: decimal} Or, enduring values for a changing world. Introduction A value type is a data type which, generally speaking, is designed for being passed by value in and out of methods, and stored by value in data structures. The only value types which the Java language directly supports are the eight primitive types. Java indirectly and approximately supports value types, if they are implemented in terms of classes. For example, both Integer and String may be viewed as value types, especially if their usage is restricted to avoid operations appropriate to Object. In this note, we propose a definition of value types in terms of a design pattern for Java classes, accompanied by a set of usage restrictions. We also sketch the relation of such value types to tuple types (which are a JVM-level notion), and point out JVM optimizations that can apply to value types. This note is a thought experiment to extend the JVM’s performance model in support of value types. The demonstration has two phases.  Initially the extension can simply use design patterns, within the current bytecode architecture, and in today’s Java language. But if the performance model is to be realized in practice, it will probably require new JVM bytecode features, changes to the Java language, or both.  We will look at a few possibilities for these new features. An Axiom of Value In the context of the JVM, a value type is a data type equipped with construction, assignment, and equality operations, and a set of typed components, such that, whenever two variables of the value type produce equal corresponding values for their components, the values of the two variables cannot be distinguished by any JVM operation. Here are some corollaries: A value type is immutable, since otherwise a copy could be constructed and the original could be modified in one of its components, allowing the copies to be distinguished. Changing the component of a value type requires construction of a new value. The equals and hashCode operations are strictly component-wise. If a value type is represented by a JVM reference, that reference cannot be successfully synchronized on, and cannot be usefully compared for reference equality. A value type can be viewed in terms of what it doesn’t do. We can say that a value type omits all value-unsafe operations, which could violate the constraints on value types.  These operations, which are ordinarily allowed for Java object types, are pointer equality comparison (the acmp instruction), synchronization (the monitor instructions), all the wait and notify methods of class Object, and non-trivial finalize methods. The clone method is also value-unsafe, although for value types it could be treated as the identity function. Finally, and most importantly, any side effect on an object (however visible) also counts as an value-unsafe operation. A value type may have methods, but such methods must not change the components of the value. It is reasonable and useful to define methods like toString, equals, and hashCode on value types, and also methods which are specifically valuable to users of the value type. Representations of Value Value types have two natural representations in the JVM, unboxed and boxed. An unboxed value consists of the components, as simple variables. For example, the complex number x=(1+2i), in rectangular coordinate form, may be represented in unboxed form by the following pair of variables: /*Complex x = Complex.valueOf(1.0, 2.0):*/ double x_re = 1.0, x_im = 2.0; These variables might be locals, parameters, or fields. Their association as components of a single value is not defined to the JVM. Here is a sample computation which computes the norm of the difference between two complex numbers: double distance(/*Complex x:*/ double x_re, double x_im,         /*Complex y:*/ double y_re, double y_im) {     /*Complex z = x.minus(y):*/     double z_re = x_re - y_re, z_im = x_im - y_im;     /*return z.abs():*/     return Math.sqrt(z_re*z_re + z_im*z_im); } A boxed representation groups component values under a single object reference. The reference is to a ‘wrapper class’ that carries the component values in its fields. (A primitive type can naturally be equated with a trivial value type with just one component of that type. In that view, the wrapper class Integer can serve as a boxed representation of value type int.) The unboxed representation of complex numbers is practical for many uses, but it fails to cover several major use cases: return values, array elements, and generic APIs. The two components of a complex number cannot be directly returned from a Java function, since Java does not support multiple return values. The same story applies to array elements: Java has no ’array of structs’ feature. (Double-length arrays are a possible workaround for complex numbers, but not for value types with heterogeneous components.) By generic APIs I mean both those which use generic types, like Arrays.asList and those which have special case support for primitive types, like String.valueOf and PrintStream.println. Those APIs do not support unboxed values, and offer some problems to boxed values. Any ’real’ JVM type should have a story for returns, arrays, and API interoperability. The basic problem here is that value types fall between primitive types and object types. Value types are clearly more complex than primitive types, and object types are slightly too complicated. Objects are a little bit dangerous to use as value carriers, since object references can be compared for pointer equality, and can be synchronized on. Also, as many Java programmers have observed, there is often a performance cost to using wrapper objects, even on modern JVMs. Even so, wrapper classes are a good starting point for talking about value types. If there were a set of structural rules and restrictions which would prevent value-unsafe operations on value types, wrapper classes would provide a good notation for defining value types. This note attempts to define such rules and restrictions. Let’s Start Coding Now it is time to look at some real code. Here is a definition, written in Java, of a complex number value type. @ValueSafe public final class Complex implements java.io.Serializable {     // immutable component structure:     public final double re, im;     private Complex(double re, double im) {         this.re = re; this.im = im;     }     // interoperability methods:     public String toString() { return "Complex("+re+","+im+")"; }     public List<Double> asList() { return Arrays.asList(re, im); }     public boolean equals(Complex c) {         return re == c.re && im == c.im;     }     public boolean equals(@ValueSafe Object x) {         return x instanceof Complex && equals((Complex) x);     }     public int hashCode() {         return 31*Double.valueOf(re).hashCode()                 + Double.valueOf(im).hashCode();     }     // factory methods:     public static Complex valueOf(double re, double im) {         return new Complex(re, im);     }     public Complex changeRe(double re2) { return valueOf(re2, im); }     public Complex changeIm(double im2) { return valueOf(re, im2); }     public static Complex cast(@ValueSafe Object x) {         return x == null ? ZERO : (Complex) x;     }     // utility methods and constants:     public Complex plus(Complex c)  { return new Complex(re+c.re, im+c.im); }     public Complex minus(Complex c) { return new Complex(re-c.re, im-c.im); }     public double abs() { return Math.sqrt(re*re + im*im); }     public static final Complex PI = valueOf(Math.PI, 0.0);     public static final Complex ZERO = valueOf(0.0, 0.0); } This is not a minimal definition, because it includes some utility methods and other optional parts.  The essential elements are as follows: The class is marked as a value type with an annotation. The class is final, because it does not make sense to create subclasses of value types. The fields of the class are all non-private and final.  (I.e., the type is immutable and structurally transparent.) From the supertype Object, all public non-final methods are overridden. The constructor is private. Beyond these bare essentials, we can observe the following features in this example, which are likely to be typical of all value types: One or more factory methods are responsible for value creation, including a component-wise valueOf method. There are utility methods for complex arithmetic and instance creation, such as plus and changeIm. There are static utility constants, such as PI. The type is serializable, using the default mechanisms. There are methods for converting to and from dynamically typed references, such as asList and cast. The Rules In order to use value types properly, the programmer must avoid value-unsafe operations.  A helpful Java compiler should issue errors (or at least warnings) for code which provably applies value-unsafe operations, and should issue warnings for code which might be correct but does not provably avoid value-unsafe operations.  No such compilers exist today, but to simplify our account here, we will pretend that they do exist. A value-safe type is any class, interface, or type parameter marked with the @ValueSafe annotation, or any subtype of a value-safe type.  If a value-safe class is marked final, it is in fact a value type.  All other value-safe classes must be abstract.  The non-static fields of a value class must be non-public and final, and all its constructors must be private. Under the above rules, a standard interface could be helpful to define value types like Complex.  Here is an example: @ValueSafe public interface ValueType extends java.io.Serializable {     // All methods listed here must get redefined.     // Definitions must be value-safe, which means     // they may depend on component values only.     List<? extends Object> asList();     int hashCode();     boolean equals(@ValueSafe Object c);     String toString(); } //@ValueSafe inherited from supertype: public final class Complex implements ValueType { … The main advantage of such a conventional interface is that (unlike an annotation) it is reified in the runtime type system.  It could appear as an element type or parameter bound, for facilities which are designed to work on value types only.  More broadly, it might assist the JVM to perform dynamic enforcement of the rules for value types. Besides types, the annotation @ValueSafe can mark fields, parameters, local variables, and methods.  (This is redundant when the type is also value-safe, but may be useful when the type is Object or another supertype of a value type.)  Working forward from these annotations, an expression E is defined as value-safe if it satisfies one or more of the following: The type of E is a value-safe type. E names a field, parameter, or local variable whose declaration is marked @ValueSafe. E is a call to a method whose declaration is marked @ValueSafe. E is an assignment to a value-safe variable, field reference, or array reference. E is a cast to a value-safe type from a value-safe expression. E is a conditional expression E0 ? E1 : E2, and both E1 and E2 are value-safe. Assignments to value-safe expressions and initializations of value-safe names must take their values from value-safe expressions. A value-safe expression may not be the subject of a value-unsafe operation.  In particular, it cannot be synchronized on, nor can it be compared with the “==” operator, not even with a null or with another value-safe type. In a program where all of these rules are followed, no value-type value will be subject to a value-unsafe operation.  Thus, the prime axiom of value types will be satisfied, that no two value type will be distinguishable as long as their component values are equal. More Code To illustrate these rules, here are some usage examples for Complex: Complex pi = Complex.valueOf(Math.PI, 0); Complex zero = pi.changeRe(0);  //zero = pi; zero.re = 0; ValueType vtype = pi; @SuppressWarnings("value-unsafe")   Object obj = pi; @ValueSafe Object obj2 = pi; obj2 = new Object();  // ok List<Complex> clist = new ArrayList<Complex>(); clist.add(pi);  // (ok assuming List.add param is @ValueSafe) List<ValueType> vlist = new ArrayList<ValueType>(); vlist.add(pi);  // (ok) List<Object> olist = new ArrayList<Object>(); olist.add(pi);  // warning: "value-unsafe" boolean z = pi.equals(zero); boolean z1 = (pi == zero);  // error: reference comparison on value type boolean z2 = (pi == null);  // error: reference comparison on value type boolean z3 = (pi == obj2);  // error: reference comparison on value type synchronized (pi) { }  // error: synch of value, unpredictable result synchronized (obj2) { }  // unpredictable result Complex qq = pi; qq = null;  // possible NPE; warning: “null-unsafe" qq = (Complex) obj;  // warning: “null-unsafe" qq = Complex.cast(obj);  // OK @SuppressWarnings("null-unsafe")   Complex empty = null;  // possible NPE qq = empty;  // possible NPE (null pollution) The Payoffs It follows from this that either the JVM or the java compiler can replace boxed value-type values with unboxed ones, without affecting normal computations.  Fields and variables of value types can be split into their unboxed components.  Non-static methods on value types can be transformed into static methods which take the components as value parameters. Some common questions arise around this point in any discussion of value types. Why burden the programmer with all these extra rules?  Why not detect programs automagically and perform unboxing transparently?  The answer is that it is easy to break the rules accidently unless they are agreed to by the programmer and enforced.  Automatic unboxing optimizations are tantalizing but (so far) unreachable ideal.  In the current state of the art, it is possible exhibit benchmarks in which automatic unboxing provides the desired effects, but it is not possible to provide a JVM with a performance model that assures the programmer when unboxing will occur.  This is why I’m writing this note, to enlist help from, and provide assurances to, the programmer.  Basically, I’m shooting for a good set of user-supplied “pragmas” to frame the desired optimization. Again, the important thing is that the unboxing must be done reliably, or else programmers will have no reason to work with the extra complexity of the value-safety rules.  There must be a reasonably stable performance model, wherein using a value type has approximately the same performance characteristics as writing the unboxed components as separate Java variables. There are some rough corners to the present scheme.  Since Java fields and array elements are initialized to null, value-type computations which incorporate uninitialized variables can produce null pointer exceptions.  One workaround for this is to require such variables to be null-tested, and the result replaced with a suitable all-zero value of the value type.  That is what the “cast” method does above. Generically typed APIs like List<T> will continue to manipulate boxed values always, at least until we figure out how to do reification of generic type instances.  Use of such APIs will elicit warnings until their type parameters (and/or relevant members) are annotated or typed as value-safe.  Retrofitting List<T> is likely to expose flaws in the present scheme, which we will need to engineer around.  Here are a couple of first approaches: public interface java.util.List<@ValueSafe T> extends Collection<T> { … public interface java.util.List<T extends Object|ValueType> extends Collection<T> { … (The second approach would require disjunctive types, in which value-safety is “contagious” from the constituent types.) With more transformations, the return value types of methods can also be unboxed.  This may require significant bytecode-level transformations, and would work best in the presence of a bytecode representation for multiple value groups, which I have proposed elsewhere under the title “Tuples in the VM”. But for starters, the JVM can apply this transformation under the covers, to internally compiled methods.  This would give a way to express multiple return values and structured return values, which is a significant pain-point for Java programmers, especially those who work with low-level structure types favored by modern vector and graphics processors.  The lack of multiple return values has a strong distorting effect on many Java APIs. Even if the JVM fails to unbox a value, there is still potential benefit to the value type.  Clustered computing systems something have copy operations (serialization or something similar) which apply implicitly to command operands.  When copying JVM objects, it is extremely helpful to know when an object’s identity is important or not.  If an object reference is a copied operand, the system may have to create a proxy handle which points back to the original object, so that side effects are visible.  Proxies must be managed carefully, and this can be expensive.  On the other hand, value types are exactly those types which a JVM can “copy and forget” with no downside. Array types are crucial to bulk data interfaces.  (As data sizes and rates increase, bulk data becomes more important than scalar data, so arrays are definitely accompanying us into the future of computing.)  Value types are very helpful for adding structure to bulk data, so a successful value type mechanism will make it easier for us to express richer forms of bulk data. Unboxing arrays (i.e., arrays containing unboxed values) will provide better cache and memory density, and more direct data movement within clustered or heterogeneous computing systems.  They require the deepest transformations, relative to today’s JVM.  There is an impedance mismatch between value-type arrays and Java’s covariant array typing, so compromises will need to be struck with existing Java semantics.  It is probably worth the effort, since arrays of unboxed value types are inherently more memory-efficient than standard Java arrays, which rely on dependent pointer chains. It may be sufficient to extend the “value-safe” concept to array declarations, and allow low-level transformations to change value-safe array declarations from the standard boxed form into an unboxed tuple-based form.  Such value-safe arrays would not be convertible to Object[] arrays.  Certain connection points, such as Arrays.copyOf and System.arraycopy might need additional input/output combinations, to allow smooth conversion between arrays with boxed and unboxed elements. Alternatively, the correct solution may have to wait until we have enough reification of generic types, and enough operator overloading, to enable an overhaul of Java arrays. Implicit Method Definitions The example of class Complex above may be unattractively complex.  I believe most or all of the elements of the example class are required by the logic of value types. If this is true, a programmer who writes a value type will have to write lots of error-prone boilerplate code.  On the other hand, I think nearly all of the code (except for the domain-specific parts like plus and minus) can be implicitly generated. Java has a rule for implicitly defining a class’s constructor, if no it defines no constructors explicitly.  Likewise, there are rules for providing default access modifiers for interface members.  Because of the highly regular structure of value types, it might be reasonable to perform similar implicit transformations on value types.  Here’s an example of a “highly implicit” definition of a complex number type: public class Complex implements ValueType {  // implicitly final     public double re, im;  // implicitly public final     //implicit methods are defined elementwise from te fields:     //  toString, asList, equals(2), hashCode, valueOf, cast     //optionally, explicit methods (plus, abs, etc.) would go here } In other words, with the right defaults, a simple value type definition can be a one-liner.  The observant reader will have noticed the similarities (and suitable differences) between the explicit methods above and the corresponding methods for List<T>. Another way to abbreviate such a class would be to make an annotation the primary trigger of the functionality, and to add the interface(s) implicitly: public @ValueType class Complex { … // implicitly final, implements ValueType (But to me it seems better to communicate the “magic” via an interface, even if it is rooted in an annotation.) Implicitly Defined Value Types So far we have been working with nominal value types, which is to say that the sequence of typed components is associated with a name and additional methods that convey the intention of the programmer.  A simple ordered pair of floating point numbers can be variously interpreted as (to name a few possibilities) a rectangular or polar complex number or Cartesian point.  The name and the methods convey the intended meaning. But what if we need a truly simple ordered pair of floating point numbers, without any further conceptual baggage?  Perhaps we are writing a method (like “divideAndRemainder”) which naturally returns a pair of numbers instead of a single number.  Wrapping the pair of numbers in a nominal type (like “QuotientAndRemainder”) makes as little sense as wrapping a single return value in a nominal type (like “Quotient”).  What we need here are structural value types commonly known as tuples. For the present discussion, let us assign a conventional, JVM-friendly name to tuples, roughly as follows: public class java.lang.tuple.$DD extends java.lang.tuple.Tuple {      double $1, $2; } Here the component names are fixed and all the required methods are defined implicitly.  The supertype is an abstract class which has suitable shared declarations.  The name itself mentions a JVM-style method parameter descriptor, which may be “cracked” to determine the number and types of the component fields. The odd thing about such a tuple type (and structural types in general) is it must be instantiated lazily, in response to linkage requests from one or more classes that need it.  The JVM and/or its class loaders must be prepared to spin a tuple type on demand, given a simple name reference, $xyz, where the xyz is cracked into a series of component types.  (Specifics of naming and name mangling need some tasteful engineering.) Tuples also seem to demand, even more than nominal types, some support from the language.  (This is probably because notations for non-nominal types work best as combinations of punctuation and type names, rather than named constructors like Function3 or Tuple2.)  At a minimum, languages with tuples usually (I think) have some sort of simple bracket notation for creating tuples, and a corresponding pattern-matching syntax (or “destructuring bind”) for taking tuples apart, at least when they are parameter lists.  Designing such a syntax is no simple thing, because it ought to play well with nominal value types, and also with pre-existing Java features, such as method parameter lists, implicit conversions, generic types, and reflection.  That is a task for another day. Other Use Cases Besides complex numbers and simple tuples there are many use cases for value types.  Many tuple-like types have natural value-type representations. These include rational numbers, point locations and pixel colors, and various kinds of dates and addresses. Other types have a variable-length ‘tail’ of internal values. The most common example of this is String, which is (mathematically) a sequence of UTF-16 character values. Similarly, bit vectors, multiple-precision numbers, and polynomials are composed of sequences of values. Such types include, in their representation, a reference to a variable-sized data structure (often an array) which (somehow) represents the sequence of values. The value type may also include ’header’ information. Variable-sized values often have a length distribution which favors short lengths. In that case, the design of the value type can make the first few values in the sequence be direct ’header’ fields of the value type. In the common case where the header is enough to represent the whole value, the tail can be a shared null value, or even just a null reference. Note that the tail need not be an immutable object, as long as the header type encapsulates it well enough. This is the case with String, where the tail is a mutable (but never mutated) character array. Field types and their order must be a globally visible part of the API.  The structure of the value type must be transparent enough to have a globally consistent unboxed representation, so that all callers and callees agree about the type and order of components  that appear as parameters, return types, and array elements.  This is a trade-off between efficiency and encapsulation, which is forced on us when we remove an indirection enjoyed by boxed representations.  A JVM-only transformation would not care about such visibility, but a bytecode transformation would need to take care that (say) the components of complex numbers would not get swapped after a redefinition of Complex and a partial recompile.  Perhaps constant pool references to value types need to declare the field order as assumed by each API user. This brings up the delicate status of private fields in a value type.  It must always be possible to load, store, and copy value types as coordinated groups, and the JVM performs those movements by moving individual scalar values between locals and stack.  If a component field is not public, what is to prevent hostile code from plucking it out of the tuple using a rogue aload or astore instruction?  Nothing but the verifier, so we may need to give it more smarts, so that it treats value types as inseparable groups of stack slots or locals (something like long or double). My initial thought was to make the fields always public, which would make the security problem moot.  But public is not always the right answer; consider the case of String, where the underlying mutable character array must be encapsulated to prevent security holes.  I believe we can win back both sides of the tradeoff, by training the verifier never to split up the components in an unboxed value.  Just as the verifier encapsulates the two halves of a 64-bit primitive, it can encapsulate the the header and body of an unboxed String, so that no code other than that of class String itself can take apart the values. Similar to String, we could build an efficient multi-precision decimal type along these lines: public final class DecimalValue extends ValueType {     protected final long header;     protected private final BigInteger digits;     public DecimalValue valueOf(int value, int scale) {         assert(scale >= 0);         return new DecimalValue(((long)value << 32) + scale, null);     }     public DecimalValue valueOf(long value, int scale) {         if (value == (int) value)             return valueOf((int)value, scale);         return new DecimalValue(-scale, new BigInteger(value));     } } Values of this type would be passed between methods as two machine words. Small values (those with a significand which fits into 32 bits) would be represented without any heap data at all, unless the DecimalValue itself were boxed. (Note the tension between encapsulation and unboxing in this case.  It would be better if the header and digits fields were private, but depending on where the unboxing information must “leak”, it is probably safer to make a public revelation of the internal structure.) Note that, although an array of Complex can be faked with a double-length array of double, there is no easy way to fake an array of unboxed DecimalValues.  (Either an array of boxed values or a transposed pair of homogeneous arrays would be reasonable fallbacks, in a current JVM.)  Getting the full benefit of unboxing and arrays will require some new JVM magic. Although the JVM emphasizes portability, system dependent code will benefit from using machine-level types larger than 64 bits.  For example, the back end of a linear algebra package might benefit from value types like Float4 which map to stock vector types.  This is probably only worthwhile if the unboxing arrays can be packed with such values. More Daydreams A more finely-divided design for dynamic enforcement of value safety could feature separate marker interfaces for each invariant.  An empty marker interface Unsynchronizable could cause suitable exceptions for monitor instructions on objects in marked classes.  More radically, a Interchangeable marker interface could cause JVM primitives that are sensitive to object identity to raise exceptions; the strangest result would be that the acmp instruction would have to be specified as raising an exception. @ValueSafe public interface ValueType extends java.io.Serializable,         Unsynchronizable, Interchangeable { … public class Complex implements ValueType {     // inherits Serializable, Unsynchronizable, Interchangeable, @ValueSafe     … It seems possible that Integer and the other wrapper types could be retro-fitted as value-safe types.  This is a major change, since wrapper objects would be unsynchronizable and their references interchangeable.  It is likely that code which violates value-safety for wrapper types exists but is uncommon.  It is less plausible to retro-fit String, since the prominent operation String.intern is often used with value-unsafe code. We should also reconsider the distinction between boxed and unboxed values in code.  The design presented above obscures that distinction.  As another thought experiment, we could imagine making a first class distinction in the type system between boxed and unboxed representations.  Since only primitive types are named with a lower-case initial letter, we could define that the capitalized version of a value type name always refers to the boxed representation, while the initial lower-case variant always refers to boxed.  For example: complex pi = complex.valueOf(Math.PI, 0); Complex boxPi = pi;  // convert to boxed myList.add(boxPi); complex z = myList.get(0);  // unbox Such a convention could perhaps absorb the current difference between int and Integer, double and Double. It might also allow the programmer to express a helpful distinction among array types. As said above, array types are crucial to bulk data interfaces, but are limited in the JVM.  Extending arrays beyond the present limitations is worth thinking about; for example, the Maxine JVM implementation has a hybrid object/array type.  Something like this which can also accommodate value type components seems worthwhile.  On the other hand, does it make sense for value types to contain short arrays?  And why should random-access arrays be the end of our design process, when bulk data is often sequentially accessed, and it might make sense to have heterogeneous streams of data as the natural “jumbo” data structure.  These considerations must wait for another day and another note. More Work It seems to me that a good sequence for introducing such value types would be as follows: Add the value-safety restrictions to an experimental version of javac. Code some sample applications with value types, including Complex and DecimalValue. Create an experimental JVM which internally unboxes value types but does not require new bytecodes to do so.  Ensure the feasibility of the performance model for the sample applications. Add tuple-like bytecodes (with or without generic type reification) to a major revision of the JVM, and teach the Java compiler to switch in the new bytecodes without code changes. A staggered roll-out like this would decouple language changes from bytecode changes, which is always a convenient thing. A similar investigation should be applied (concurrently) to array types.  In this case, it seems to me that the starting point is in the JVM: Add an experimental unboxing array data structure to a production JVM, perhaps along the lines of Maxine hybrids.  No bytecode or language support is required at first; everything can be done with encapsulated unsafe operations and/or method handles. Create an experimental JVM which internally unboxes value types but does not require new bytecodes to do so.  Ensure the feasibility of the performance model for the sample applications. Add tuple-like bytecodes (with or without generic type reification) to a major revision of the JVM, and teach the Java compiler to switch in the new bytecodes without code changes. That’s enough musing me for now.  Back to work!

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• PHP script keeps doing mmap/munmap

  - by Aurélien Momow

  Hello, My PHP script contains a loop, which does nothing much more than echoing and dereferencing pointers (like in $tab[$othertab[$i]]- stuff). It was working great until yesterday, when this script starting being VERY slow (like 50 times slower than before). After using strace, i figured out that 90% of the time, the script does mmap/munmap. Here is a random portion of the strace log : mmap(NULL, 266240, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fac0156c000 munmap(0x7fac0156c000, 266240) = 0 mmap(NULL, 266240, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fac0156c000 munmap(0x7fac0156c000, 266240) = 0 mmap(NULL, 266240, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fac0156c000 munmap(0x7fac0156c000, 266240) = 0 mmap(NULL, 266240, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fac0156c000 munmap(0x7fac0156c000, 266240) = 0 mmap(NULL, 266240, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fac0156c000 munmap(0x7fac0156c000, 266240) = 0 mmap(NULL, 266240, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fac0156c000 munmap(0x7fac0156c000, 266240) = 0 mmap(NULL, 266240, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fac0156c000 munmap(0x7fac0156c000, 266240) = 0 mmap(NULL, 266240, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fac0156c000 munmap(0x7fac0156c000, 266240) = 0 mmap(NULL, 266240, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fac0156c000 munmap(0x7fac0156c000, 266240) = 0 mmap(NULL, 266240, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fac0156c000 munmap(0x7fac0156c000, 266240) = 0 mmap(NULL, 266240, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fac0156c000 munmap(0x7fac0156c000, 266240) = 0 mmap(NULL, 266240, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fac0156c000 munmap(0x7fac0156c000, 266240) = 0 mmap(NULL, 266240, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fac0156c000 munmap(0x7fac0156c000, 266240) = 0 mmap(NULL, 266240, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fac0156c000 mmap(NULL, 266240, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fac0152b000 mmap(NULL, 266240, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fac014ea000 Here is the result of the strace -c command : % time seconds usecs/call calls errors syscall ------ ----------- ----------- --------- --------- ---------------- 82.77 0.004092 0 13542 mmap 9.69 0.000479 0 3642 write 7.54 0.000373 0 13541 munmap 0.00 0.000000 0 100 read 0.00 0.000000 0 88 poll 0.00 0.000000 0 25 4 access ------ ----------- ----------- --------- --------- ---------------- 100.00 0.004944 30938 4 total Here is the php script : function affAnnonce($tabAnnonces, $isDoublon = 0) { GLOBAL $db, $base, $tabDomaine, $doublon, $traduction, $tab_contrat, $tab_emploi, $tab_categ, $tab_metier, $tab_region, $tab_departement, $tab_secteur, $tab_experience, $calc_all, $tabLangues, $tabLanguesNiveau, $tabNoAffAnnonce, $tabHisto; foreach($tabAnnonces AS $tmp) { if (in_array($tmp['id'], $tabNoAffAnnonce) === true) { continue; } $value->host = "../"; foreach($tabDomaine AS $domaine => $valeur) { if ($domaine == $tmp['domaine']) { $value->host = $valeur->host; break; } } // Ordre // secteur;metier;contrat;emploi;region;langues;domaine $tabPushModif = array(); if ($tmp['push_preview'] != '') { $tabPushModif = explode(';', $tmp['push_preview']); $tabPushModif['secteur'] = $tabPushModif[0]; $tabPushModif['metier'] = $tabPushModif[1]; $tabPushModif['contrat'] = $tabPushModif[2]; $tabPushModif['id_emploi'] = $tabPushModif[3]; $tabPushModif['regions'] = $tabPushModif[4]; $tabPushModif['langues'] = $tabPushModif[5]; $tabPushModif['domaine'] = $tabPushModif[6]; } $infoSoc = get_nom_societe($tmp['id_societe']); $number = ($tmp['nb_preview_push'] != '' ? $tmp['nb_preview_push'] : '&nbsp;'); $secteurs = explode ("/", $tmp[secteur]); $sector = ""; $count_sect = count($secteurs); for ($k = 0; $k < $count_sect; $k++) { if ($secteurs[$k] != '') { $sector .= $tab_secteur[$secteurs[$k]].'/'; } } $tmp['poste'] = apresinsertion($tmp['poste']); $tmp['metier'] = $tab_metier[$tmp['metier']]; $tmp['region'] = $tab_region[$tmp['region']]; $tmp['departement'] = $tab_departement[$tmp['departement']]; $tmp['secteur'] = $sector; $tmp['id_contrat'] = $tmp['contrat']; $tmp['contrat'] = $tab_contrat[$tmp['contrat']]; $tmp['emploi'] = $tab_emploi[$tmp['id_emploi']]; $tmp['categorie'] = $tab_categ[$tmp['categorie']]; echo '<tr id="'.($isDoublon ? 'dbl_' : '').$tmp['id'].'"><td align="center" class="tdFirst nowrap dbl_'.$tmp['id'].'" id="aff_'.$tmp['id'].'"'; switch($tmp['affiche']) { case '0': echo ' bgcolor=#DBB7FF'; break; default : ; } echo '><a href=?op=annonces&search4='.$tmp[id].' target=_new>'.$tmp[id].'</a><br />'; echo '<a href="'.$value->host.'" target="blank">'.strtoupper($tmp['domaine']).'<br /><img src="../images/flags/'.$tmp['domaine'].'.png" border=0 align=middle></a>'; echo '</TD><TD align=center class=tdNext'; if ($tmp['filtre'] == 1) echo ' bgcolor=#FF0000'; echo '>'; if ($isDoublon) echo '<a id="'.$tmp['id'].'" class="doublon" href="#">DOUBLON</a> - '; if (($tmp[id_reponse] == 1) || ($tmp[id_reponse] == 2) || ($tmp[id_reponse] == 4) || ($tmp[id_reponse] == 5)) echo '<a href="javascript:voir_annonce(\''.$tmp['id'].'\', \''.$value->host.'\')" onMouseOver="showPreview('.$tmp['id'].');" onMouseOut="hidePreview('.$tmp['id'].');">'.$tmp['poste'].'</a>'; if ($tmp[id_reponse] == 3) echo '<a href="javascript:voir_annonce3(\''.$tmp['url_reponse'].'\')" onMouseOver="showPreview('.$tmp['id'].');" onMouseOut="hidePreview('.$tmp['id'].');">'.$tmp['poste'].'</a>'; if ($tmp['urgent'] == 1) print " - <font class=r_bold>urgent</font>"; if ($tmp['gold'] == 1) print " - <font class=g_bold>gold</font>"; if ($tmp['cvtheque'] == 1) print " - CVthèque"; if ($tmp['url_reponse'] != '' && $tmp['id_reponse'] != 3) { echo '<br /><br />URL - '; $len = strlen($tmp['url_reponse']); if ($len > 50) { $link = substr($tmp['url_reponse'], 0, 47).'...'; } else { $link = $tmp['url_reponse']; } echo '<a href="'.$tmp['url_reponse'].'" style="color: #666;" target="_blank">'.$link.'</a>'; } // Début du div ou sera placé l'annonce echo '<br /><div id="preview_'.$tmp['id'].'" name="preview_'.$tmp['id'].'" class="tdStyle1" style="z-index: 1000; display: none; position: fixed; left: 0px; top: 0px; padding: 4px; border: 1px solid #666; background: #fff; text-align: left; width: 777px;" onMouseOver="showPreview('.$tmp['id'].');" onMouseOut="hidePreview('.$tmp['id'].');">'; $tmp["url"] = substr($tmp["url"], 7); $id_modele = getIdModeleByAnnonce($tmp['id_societe'], $tmp["id"], $tmp['domaine']); $tmp["poste"] = mb_strtoupper($tmp["poste"]); $isFnh = isFnhAnnonce($tmp['id']); $logo = ""; if ($isFnh) { $logo_jpg = getFnhLogo(); $logo = "<img align='center' border='0' src='".$logo_jpg."' />"; } else { if ($id_modele > 0) { if ($tmp['id_reponse'] == 1) { $logo_gif = "../fichiers/societes/".$tmp['id_societe']."/".$id_modele.".gif"; if (file_exists($logo_gif)) { $logo = "<img align=center border=0 src=".$logo_gif.">"; } } else { $rep = "../fichiers/societes/".$tmp['id_societe']."/".$id_modele; $logo_jpg = $rep.".jpg"; $logo_swf = $rep.".swf"; $logo_gif = $rep.".gif"; if (file_exists($logo_jpg)) { $logo = "<img align=center border=0 src=".$logo_jpg.">"; } elseif (file_exists($logo_swf)) $logo = '<object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=7,0,0,0" width="120" height="600"> <param name=movie value="'.$logo_swf.'"> <param name=quality value=high> <embed src="'.$logo_swf.'" quality=high pluginspage="http://www.macromedia.com/shockwave/download/index.cgi?P1_Prod_Version=ShockwaveFlash" type="application/x-shockwave-flash" width="120" height="600"></embed> </object>'; elseif (file_exists($logo_gif)) { $logo = "<img align=center border=0 src=".$logo_gif.">"; } } } } if (strlen($logo) > 0 && strlen($tmp['url']) > 0) $logo = "<a href=http://".$tmp['url']." target=_blank>".$logo."</a>"; if (strlen($tmp['url_reponse']) <= 0) { $tmp['url_reponse'] = "../jobs/repondre_annonce.php?id=".$tmp['id']."\" onClick=\""; if ($tmp['contact_email'] == "") $tmp['url_reponse'] .= "alert('".$traduction->aff_word("repondre_courrier", $tabTrad['only_word']).'\n'.$tmp['societe'].'\n'.str_replace("<br />", '\n', ereg_replace("[\r\n\t]", "", $tmp['adresse']))."');"; else $tmp['url_reponse'] .= "popUp(this.href, 'scroll', 540, 400);"; $tmp['url_reponse'] .= "return false;"; } ?> <table width="775" cellspacing="0" cellpadding="0" border=0> <? if ($tmp['id_reponse'] != "2") { ?> <tr> <td width="575" align=center valign=top> <table width="535" border=0 cellspacing=0 cellpadding=2> <tr> <td colspan="2" class="nom_societe"><?=$tmp['societe']?></td> </tr> <tr> <td colspan="2"><hr size=1 color=#000000></td> </tr> <tr> <td colspan="2" align="right"><?=date_2fr($tmp["date_affichage"], 1)?></td> </tr> <tr> <td align="right" class=bold><?=$traduction->aff_word("pays")?>&nbsp;:</td> <td align="left"><?=$tmp['pays0']?></td> </tr> <? if ($tmp['region']) { ?> <tr> <td align="right" class=bold><?=$traduction->aff_word("region")?>&nbsp;:</td> <td align="left"><?=$tmp['region']?></td> </tr> <? } if ($tmp['departement']) { ?> <tr> <td align="right" class=bold><?=$traduction->aff_word("departement")?>&nbsp;:</td> <td align="left"><?=$tmp['departement']?></td> </tr> <? } if ($tmp['ville']) { ?> <tr> <td align="right" class=bold><?=$traduction->aff_word("ville")?>&nbsp;:</td> <td align="left"><?=$tmp['ville']?></td> </tr> <? } if ($tmp['debut']) { ?> <tr> <td align="right" class=bold><?=$traduction->aff_word("debut_travail")?>&nbsp;:</td> <td align="left"><?=$tmp['debut']?></td> </tr> <? } ?> <tr> <td align="right" class=bold><?=$traduction->aff_word("type_contrat")?>&nbsp;:</td> <td align="left"><?=$tmp['contrat']?></td> </tr> <? if ($tmp['emploi']) { ?> <tr> <td align="right" class=bold><?=$traduction->aff_word("type_emploi")?>&nbsp;:</td> <td align="left"><?=$tmp['emploi']?></td> </tr> <? } if ($tmp['salaire']) { ?> <tr> <td align="right" class=bold><?=$traduction->aff_word("salaire")?>&nbsp;:</td> <td align="left"><?=$tmp['salaire']?></td> </tr> <? } if ($tmp['experience']) { ?> <tr> <td align="right" class=bold><?=$traduction->aff_word("experience_metier")?>&nbsp;:</td> <td align="left"><?=$tab_experience[$tmp['experience']]?></td> </tr> <? } if ($tmp['reference']) { ?> <tr> <td align="right" class=bold><?=$traduction->aff_word("reference")?>&nbsp;:</td> <td align="left"><?=$tmp['reference']?></td> </tr> <? } ?> <tr> <td>&nbsp;</td> <td><hr size=1 color=#000000 width=405></td> </tr> <? if ($tmp['presentation']) { ?> <tr> <td valign=top align="right" class=bold><?=$traduction->aff_word("presentation")?>&nbsp;:</td> <td style="text-align: justify;"><?=$tmp['presentation']?></td> </tr> <tr> <td>&nbsp;</td> <td><hr size=1 color=#000000 width=405></td> </tr> <? } ?> <tr> <td valign="top" class=bold align="right"><?=$traduction->aff_word("poste")?>&nbsp;:</td> <td valign="top" class=titre_poste align=center><?=$tmp['poste']?></td> </tr> <tr> <td colspan=2>&nbsp;</td> </tr> <tr> <td valign="top" class=bold align="right"><?=$traduction->aff_word("description")?>&nbsp;:</td> <td style="text-align: justify;"><?=$tmp['description']?></td> </tr> <tr> <td width=100%>&nbsp;</td> <td width=405><hr size=1 color=#000000 width=405></td> </tr> <? if ($tmp['profil']) { ?> <tr> <td valign="top" align="right" class=bold><?=$traduction->aff_word("profil")?>&nbsp;:</td> <td valign="top" style="text-align: justify;"><?=$tmp['profil']?></td> </tr> <tr> <td>&nbsp;</td> <td><hr size=1 color=#000000 width=405></td> </tr> <? } if ($tmp['recommandation']) { ?> <tr> <td valign="top" align="left"></td> <td valign="top" style="text-align: justify;"><?=$tmp['recommandation']?></td> </tr> <tr> <td>&nbsp;</td> <td><hr size=1 color=#000000 width=405></td> </tr> <? } if ($tmp['contact_nom'] || $tmp['contact_prenom']) { ?> <tr> <td valign="top" align="right" class=bold><?=$traduction->aff_word("contact")?>&nbsp;:</td> <td valign="top" align="left"><?=$tmp['contact_prenom']?>&nbsp;<?=$tmp['contact_nom']?></td> </tr> <tr> <td>&nbsp;</td> <td><hr size=1 color=#000000 width=405></td> </tr> <? } ?> <? } elseif ($tmp['domaine'] != 'de') { ?> <tr> <td colspan=2><table width="755" align=right valign=top><tr><td><?=$tmp['presentation']?></td></tr></table></td> </tr> <? } ?> <tr> <td rowspan=6>&nbsp;</td> <td><a href="<?=$tmp['url_reponse']?>" target="_blank">&gt;&gt;&nbsp;<?=$traduction->aff_word("repondre_en_ligne")?></a></td> </tr> <tr> <td><a href="../jobs/affiche_imprime_annonce.php?id=<?=$tmp['id']?>" onClick="popUp(this.href, 'scroll', 540, 400);return false;" target="_blank">&gt;&gt;&nbsp;<?=$traduction->aff_word("version_imprimer")?></a></td> </tr> <tr> <td><a href="../jobs/send_friend_annonce.php?id=<?=$tmp['id']?>" onClick="popUp(this.href, 'clean', 400, 300);return false;" target="_blank">&gt;&gt;&nbsp;<?=$traduction->aff_word("envoi_ami")?></a></td> </tr> <tr> <td><a href="./affiche_liste.php?soc=<?=$tmp['societe_clean']?>">&gt;&gt;&nbsp;<?=$traduction->aff_word("toutes_offres")?> <?=$tmp['societe']?></a></td> </tr> <tr> <td><a href="../jobs/index.php">&gt;&gt;&nbsp;<?=$traduction->aff_word("nouvelle_recherche")?></a></td> </tr> <tr> <td><a href="../jobs/index.php" onClick="javascript:retour(); return false;">&lt;&lt;&nbsp;<?=$traduction->aff_word("retour")?></a></td> </tr> <? if ($tmp['id_reponse'] != "2") { ?> </table> </td> <td width="200" align=center class=black_bord valign=top> <table width="190" cellspacing=0 cellpadding=0 border=0> <tr> <td colspan="2" align="center" valign="top" class=bold><? if ($tmp['id_reponse'] != "5") { ?><br><? } ?><?=$logo?><br><br><?=$tmp['societe']?></td> </tr> <? if ($tmp['adresse']) { ?> <tr> <td align="center" colspan=2><?=$tmp['adresse']?></td> </tr> <tr> <td colspan=2>&nbsp;</td> </tr> <? } if ($tmp['contact_tel']) { ?> <tr> <td class=bold align=right><?=$traduction->aff_word("tel")?> :</td> <td align=center><?=$tmp['contact_tel']?></td> </tr> <? } if ($tmp['contact_fax']) { ?> <tr> <td class=bold align=right><?=$traduction->aff_word("fax")?> :</td> <td align=center><?=$tmp['contact_fax']?></td> </tr> <? } if ($tmp['url']) { ?> <tr> <td colspan=2 align=center><a href="http://<?=$tmp['url']?>" target="_blank"><?=$tmp['url']?></a></td> </tr> <? } ?> </table> </td> </tr> <? } ?> </table> <? echo '</div>'; // Fin du div ou sera placé l'annonce echo "</TD><TD align=center class=tdNext><b>".date_2fr($tmp['date_creation'], 1)."</b><br>".date_2fr($tmp['date_affichage'], 1); echo "</TD><TD align=center class=tdNext>".$tmp[societe]."<br>(<i><a href=".$value->host."login/login.php?login=".$infoSoc->email."&pass=".$infoSoc->password." target=_blank>".$infoSoc->nom."</a></i>)<br><a href=index.php?op=entreprise&ac=tableau_bord&id_societe=".$tmp['id_societe'].">compte</a></TD>"; $color = ''; switch($tmp[push_mail]) { case "0": $color = " bgcolor=#DBB7FF"; break; case "2": $color = " bgcolor=#CCCCCC"; break; default : ; } $type_rep = ""; switch ($tmp[id_reponse]) { case 1: $type_rep = "Standard"; break; case 2: $type_rep = "Chartée"; break; case 3: $type_rep = "Metamoteur"; break; case 4: $type_rep = "Reponse sur site"; break; case 5: $type_rep = "Semi-chartée"; break; } print " <td align=center class=tdNext> <table width=100% border=0 cellspacing=0 cellpadding=0> <tr> <td align=center class=cadreBas>".$tmp['contrat']." - ".$tmp['emploi']."</td> <td $color align=center rowspan=4 width=40%> <a onclick=\"javascript:colorannonce(this, '#CFFFCF');\" href=?op=agentalertes&action=modify_push&amp;id_annonce=".$tmp[id]." target=_blank>Modifier push</a><br><br> <a onclick=\"sendPush(this, ".$tmp['id']."); return false;\" href=\"#\">Envoyer Push</a> </td> </tr> <tr> <td align=center class=cadreBas>".(strlen($tmp['metier']) > 0 ? $tmp['metier'] : '<font class=gris_i>'.$tmp['categorie'].'</font>')."</td> </tr> <tr> <td align=center class=cadreBas>".$tmp[secteur]."</td> </tr> <tr> <td align=center>".($number < 500 ? '<font color="red">' : ($number > 1500 ? '<font color="orange">' : '<font color="green">')).$number."</font></td> </tr> </table> </td> <td align=center class=tdNext> <table width=100% border=0 cellspacing=0 cellpadding=0> <tr> <td align=center class=cadreBas>"; if (strlen($tabPushModif['regions']) > 0) { $tab = explode('/', $tabPushModif['regions']); foreach($tab AS $elem) { if (strlen($elem) <= 0) continue; if (strpos($elem, 'dep-') !== false) { echo $tab_departement[substr($elem, 4)]; $query_tmp = 'SELECT region FROM ref_departement WHERE id = "'.substr($elem, 4).'"'; $obj = $db->getObj($query_tmp); if ($obj) { echo ' - '.$tab_region[$obj->region]; $query_tmp = 'SELECT rp.code_pays FROM ref_pays rp INNER JOIN ref_region rr ON rr.pays = rp.id WHERE rr.id = "'.$obj->region.'"'; $obj = $db->getObj($query_tmp); if ($obj) echo ' ('.$obj->code_pays.')'; } } elseif (is_numeric($elem) === false) { echo '<font class=gris_i>'.$tmp['departement'].' - '.$tmp['region'].'</font> ('.$elem.')'; } else { echo '<font class=gris_i>'.$tmp['departement'].'</font> - '.$tab_region[$elem]; $query_tmp = 'SELECT rp.code_pays FROM ref_pays rp INNER JOIN ref_region rr ON rr.pays = rp.id WHERE rr.id = "'.$obj->region.'"'; $obj = $db->getObj($query_tmp); if ($obj) echo ' ('.$obj->code_pays.')'; } } } else echo $tmp['departement']." - ".$tmp['region']." (".$tmp['code_pays'].")"; echo "</td> </tr> <tr> <td align=center class=cadreBas>".$tmp[ville]."</td> </tr> <tr> <td align=center class=cadreBas>"; if (strlen($tabPushModif['metier']) > 0) { $tmpExp = array(); $tab = explode('/', $tabPushModif['metier']); foreach($tab AS $elem) { if (strlen($elem) <= 0) continue; $tmpMetier = explode('-', $elem); if (isset($tmpMetier[1])) { if (in_array($tmpMetier[1], $tmpExp) === true) continue; $tmpExp[] = $tmpMetier[1]; if ($tmpMetier[1] == $tmp['experience']) echo '<b>'.$tab_experience[$tmpMetier[1]].'</b>/'; else echo $tab_experience[$tmpMetier[1]].'/'; } } if (count($tmpExp) <= 0) echo '<font class=gris_i>'.$tab_experience[$tmp['experience']].'</font>'; } else echo $tab_experience[$tmp['experience']]; echo "</td> </tr> <tr> <td align=center>".$tabLangues[$tmp['id_langue']]->langue." - ".$tabLanguesNiveau[$tmp['id_langue_niveau']]->langue_niveau."</td> </tr> </table> </td> <td align=center class=tdNext> <table width=100% cellspacing=0 cellpadding=0 border=0> <tr> <td align=center class=cadreBas>$type_rep</td> </tr> <tr> <td align=center>".$tmp[compteur_vu]."&nbsp;/&nbsp;<a href=?op=gcand&ac=liste&id_annonce=".$tmp[id]."&statut=all target=_new>".$tmp[compteur_repondu]."</a></td> </tr> </table> </td> <td align=center class=tdNext> <table width=100% cellspacing=0 cellpadding=0 border=0> <tr> <td align=center class=cadreBas><a href=?op=annonces&ac=modifier&id_annonce=".$tmp['id']." target=_new>Modifier</a></td> </tr> <tr> <td align=center class=cadreBas><a href='' onClick=\"valid_delete('".$tmp['id']."'); return false;\">Supprimer</a></td> </tr> <tr> <td align=center><a href='' onClick='changeAff(".$tmp['id']."); return false;' id='changeAff_".$tmp['id']."'>".($tmp['affiche'] == 1 ? 'Mettre hors ligne' : 'Mettre en ligne')."</a></td> </tr> </table> </td> <td align=center class='tdNext gris'> <p style=\"color:#444;\"> &nbsp;".nl2br($tmp['push_res']).'</p>'; if (is_array($tabHisto[$tmp['id']])) { echo '<p style="color:#888; padding-top:5px;">'; foreach($tabHisto[$tmp['id']] as $histo) { echo $histo['type_modif'].' '.HumanDateTime($histo['date']).' par '.$histo['user']; if ($histo['new_annonce']) { echo ' [New ID : <a href="index.php?op=annonces&search4='.$histo['new_annonce'].'">'.$histo['new_annonce'].'</a>]'; } echo '<br />'; } echo '</p>'; } echo " </td> <td align=center>&nbsp;".$tmp['source']; if (!empty($tmp['source_ref'])) { echo '<br /><a href="redirect.php?site='.$tmp['source_ref'].'" target="_blank">Voir original</a>'; } echo '</td></tr>'; if (isset($doublon) && !$isDoublon) { $query2 = " SELECT a.*, rp.pays0, rp.code_pays FROM annonces a INNER JOIN ref_pays rp ON rp.id = a.pays WHERE a.id_societe = '".$tmp['id_societe']."' AND a.contrat = '".$tmp['id_contrat']."' AND a.domaine = '".$tmp['domaine']."' AND a.id != '".$tmp['id']."' AND ADDDATE(a.date_creation, INTERVAL 2 MONTH) > '".$tmp['date_creation']."' AND a.poste = \"".addslashes($tmp['poste'])."\" AND a.ville = \"".addslashes($tmp['ville'])."\" AND a.societe = \"".addslashes($tmp['societe'])."\" AND (a.id_societe != 1 OR (a.id_societe = 1 AND a.contact_email = \"".$tab_annonce['contact_email']."\")) ORDER BY a.id DESC"; $tabAnnonces2 = $db->getTab($query2); if (count($tabAnnonces2) > 0) { $tabId = array(); foreach($tabAnnonces2 as $annonc) { $tabId[] = $annonc['id']; } $tmpListAnnonceTab = annoncelist::getHistorique($tabId); $tmpTabHisto = createTabHisto($tmpListAnnonceTab); $tabHisto += $tmpTabHisto; //Additionne les 2 tableaux, contrairement à array_merge il garde les clés !! affAnnonce($tabAnnonces2, 1); foreach($tabAnnonces2 AS $tmpAnn) $tabNoAffAnnonce[] = $tmpAnn['id']; } } } } ?> Only this script is slow, all the others on the same server/domain/directory work great. On an other server, the same script works fine. The script takes up to 90% of CPU when running. Any ideas?

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• Using R to Analyze G1GC Log Files

  - by user12620111

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  Using R to Analyze G1GC Log Files   Using R to Analyze G1GC Log Files Introduction Working in Oracle Platform Integration gives an engineer opportunities to work on a wide array of technologies. My team’s goal is to make Oracle applications run best on the Solaris/SPARC platform. When looking for bottlenecks in a modern applications, one needs to be aware of not only how the CPUs and operating system are executing, but also network, storage, and in some cases, the Java Virtual Machine. I was recently presented with about 1.5 GB of Java Garbage First Garbage Collector log file data. If you’re not familiar with the subject, you might want to review Garbage First Garbage Collector Tuning by Monica Beckwith. The customer had been running Java HotSpot 1.6.0_31 to host a web application server. I was told that the Solaris/SPARC server was running a Java process launched using a commmand line that included the following flags: -d64 -Xms9g -Xmx9g -XX:+UseG1GC -XX:MaxGCPauseMillis=200 -XX:InitiatingHeapOccupancyPercent=80 -XX:PermSize=256m -XX:MaxPermSize=256m -XX:+PrintGC -XX:+PrintGCTimeStamps -XX:+PrintHeapAtGC -XX:+PrintGCDateStamps -XX:+PrintFlagsFinal -XX:+DisableExplicitGC -XX:+UnlockExperimentalVMOptions -XX:ParallelGCThreads=8 Several sources on the internet indicate that if I were to print out the 1.5 GB of log files, it would require enough paper to fill the bed of a pick up truck. Of course, it would be fruitless to try to scan the log files by hand. Tools will be required to summarize the contents of the log files. Others have encountered large Java garbage collection log files. There are existing tools to analyze the log files: IBM’s GC toolkit The chewiebug GCViewer gchisto HPjmeter Instead of using one of the other tools listed, I decide to parse the log files with standard Unix tools, and analyze the data with R. Data Cleansing The log files arrived in two different formats. I guess that the difference is that one set of log files was generated using a more verbose option, maybe -XX:+PrintHeapAtGC, and the other set of log files was generated without that option. Format 1 In some of the log files, the log files with the less verbose format, a single trace, i.e. the report of a singe garbage collection event, looks like this: {Heap before GC invocations=12280 (full 61): garbage-first heap total 9437184K, used 7499918K [0xfffffffd00000000, 0xffffffff40000000, 0xffffffff40000000) region size 4096K, 1 young (4096K), 0 survivors (0K) compacting perm gen total 262144K, used 144077K [0xffffffff40000000, 0xffffffff50000000, 0xffffffff50000000) the space 262144K, 54% used [0xffffffff40000000, 0xffffffff48cb3758, 0xffffffff48cb3800, 0xffffffff50000000) No shared spaces configured. 2014-05-14T07:24:00.988-0700: 60586.353: [GC pause (young) 7324M->7320M(9216M), 0.1567265 secs] Heap after GC invocations=12281 (full 61): garbage-first heap total 9437184K, used 7496533K [0xfffffffd00000000, 0xffffffff40000000, 0xffffffff40000000) region size 4096K, 0 young (0K), 0 survivors (0K) compacting perm gen total 262144K, used 144077K [0xffffffff40000000, 0xffffffff50000000, 0xffffffff50000000) the space 262144K, 54% used [0xffffffff40000000, 0xffffffff48cb3758, 0xffffffff48cb3800, 0xffffffff50000000) No shared spaces configured. } A simple grep can be used to extract a summary: $ grep "\[ GC pause (young" g1gc.log 2014-05-13T13:24:35.091-0700: 3.109: [GC pause (young) 20M->5029K(9216M), 0.0146328 secs] 2014-05-13T13:24:35.440-0700: 3.459: [GC pause (young) 9125K->6077K(9216M), 0.0086723 secs] 2014-05-13T13:24:37.581-0700: 5.599: [GC pause (young) 25M->8470K(9216M), 0.0203820 secs] 2014-05-13T13:24:42.686-0700: 10.704: [GC pause (young) 44M->15M(9216M), 0.0288848 secs] 2014-05-13T13:24:48.941-0700: 16.958: [GC pause (young) 51M->20M(9216M), 0.0491244 secs] 2014-05-13T13:24:56.049-0700: 24.066: [GC pause (young) 92M->26M(9216M), 0.0525368 secs] 2014-05-13T13:25:34.368-0700: 62.383: [GC pause (young) 602M->68M(9216M), 0.1721173 secs] But that format wasn't easily read into R, so I needed to be a bit more tricky. I used the following Unix command to create a summary file that was easy for R to read. $ echo "SecondsSinceLaunch BeforeSize AfterSize TotalSize RealTime" $ grep "\[GC pause (young" g1gc.log | grep -v mark | sed -e 's/[A-SU-z\(\),]/ /g' -e 's/->/ /' -e 's/: / /g' | more SecondsSinceLaunch BeforeSize AfterSize TotalSize RealTime 2014-05-13T13:24:35.091-0700 3.109 20 5029 9216 0.0146328 2014-05-13T13:24:35.440-0700 3.459 9125 6077 9216 0.0086723 2014-05-13T13:24:37.581-0700 5.599 25 8470 9216 0.0203820 2014-05-13T13:24:42.686-0700 10.704 44 15 9216 0.0288848 2014-05-13T13:24:48.941-0700 16.958 51 20 9216 0.0491244 2014-05-13T13:24:56.049-0700 24.066 92 26 9216 0.0525368 2014-05-13T13:25:34.368-0700 62.383 602 68 9216 0.1721173 Format 2 In some of the log files, the log files with the more verbose format, a single trace, i.e. the report of a singe garbage collection event, was more complicated than Format 1. Here is a text file with an example of a single G1GC trace in the second format. As you can see, it is quite complicated. It is nice that there is so much information available, but the level of detail can be overwhelming. I wrote this awk script (download) to summarize each trace on a single line. #!/usr/bin/env awk -f BEGIN { printf("SecondsSinceLaunch IncrementalCount FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize\n") } ###################### # Save count data from lines that are at the start of each G1GC trace. # Each trace starts out like this: # {Heap before GC invocations=14 (full 0): # garbage-first heap total 9437184K, used 325496K [0xfffffffd00000000, 0xffffffff40000000, 0xffffffff40000000) ###################### /{Heap.*full/{ gsub ( "\\)" , "" ); nf=split($0,a,"="); split(a[2],b," "); getline; if ( match($0, "first") ) { G1GC=1; IncrementalCount=b[1]; FullCount=substr( b[3], 1, length(b[3])-1 ); } else { G1GC=0; } } ###################### # Pull out time stamps that are in lines with this format: # 2014-05-12T14:02:06.025-0700: 94.312: [GC pause (young), 0.08870154 secs] ###################### /GC pause/ { DateTime=$1; SecondsSinceLaunch=substr($2, 1, length($2)-1); } ###################### # Heap sizes are in lines that look like this: # [ 4842M->4838M(9216M)] ###################### /\[ .*]$/ { gsub ( "\\[" , "" ); gsub ( "\ \]" , "" ); gsub ( "->" , " " ); gsub ( "\\( " , " " ); gsub ( "\ \)" , " " ); split($0,a," "); if ( split(a[1],b,"M") > 1 ) {BeforeSize=b[1]*1024;} if ( split(a[1],b,"K") > 1 ) {BeforeSize=b[1];} if ( split(a[2],b,"M") > 1 ) {AfterSize=b[1]*1024;} if ( split(a[2],b,"K") > 1 ) {AfterSize=b[1];} if ( split(a[3],b,"M") > 1 ) {TotalSize=b[1]*1024;} if ( split(a[3],b,"K") > 1 ) {TotalSize=b[1];} } ###################### # Emit an output line when you find input that looks like this: # [Times: user=1.41 sys=0.08, real=0.24 secs] ###################### /\[Times/ { if (G1GC==1) { gsub ( "," , "" ); split($2,a,"="); UserTime=a[2]; split($3,a,"="); SysTime=a[2]; split($4,a,"="); RealTime=a[2]; print DateTime,SecondsSinceLaunch,IncrementalCount,FullCount,UserTime,SysTime,RealTime,BeforeSize,AfterSize,TotalSize; G1GC=0; } } The resulting summary is about 25X smaller that the original file, but still difficult for a human to digest. SecondsSinceLaunch IncrementalCount FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize ... 2014-05-12T18:36:34.669-0700: 3985.744 561 0 0.57 0.06 0.16 1724416 1720320 9437184 2014-05-12T18:36:34.839-0700: 3985.914 562 0 0.51 0.06 0.19 1724416 1720320 9437184 2014-05-12T18:36:35.069-0700: 3986.144 563 0 0.60 0.04 0.27 1724416 1721344 9437184 2014-05-12T18:36:35.354-0700: 3986.429 564 0 0.33 0.04 0.09 1725440 1722368 9437184 2014-05-12T18:36:35.545-0700: 3986.620 565 0 0.58 0.04 0.17 1726464 1722368 9437184 2014-05-12T18:36:35.726-0700: 3986.801 566 0 0.43 0.05 0.12 1726464 1722368 9437184 2014-05-12T18:36:35.856-0700: 3986.930 567 0 0.30 0.04 0.07 1726464 1723392 9437184 2014-05-12T18:36:35.947-0700: 3987.023 568 0 0.61 0.04 0.26 1727488 1723392 9437184 2014-05-12T18:36:36.228-0700: 3987.302 569 0 0.46 0.04 0.16 1731584 1724416 9437184 Reading the Data into R Once the GC log data had been cleansed, either by processing the first format with the shell script, or by processing the second format with the awk script, it was easy to read the data into R. g1gc.df = read.csv("summary.txt", row.names = NULL, stringsAsFactors=FALSE,sep="") str(g1gc.df) ## 'data.frame': 8307 obs. of 10 variables: ## $ row.names : chr "2014-05-12T14:00:32.868-0700:" "2014-05-12T14:00:33.179-0700:" "2014-05-12T14:00:33.677-0700:" "2014-05-12T14:00:35.538-0700:" ... ## $ SecondsSinceLaunch: num 1.16 1.47 1.97 3.83 6.1 ... ## $ IncrementalCount : int 0 1 2 3 4 5 6 7 8 9 ... ## $ FullCount : int 0 0 0 0 0 0 0 0 0 0 ... ## $ UserTime : num 0.11 0.05 0.04 0.21 0.08 0.26 0.31 0.33 0.34 0.56 ... ## $ SysTime : num 0.04 0.01 0.01 0.05 0.01 0.06 0.07 0.06 0.07 0.09 ... ## $ RealTime : num 0.02 0.02 0.01 0.04 0.02 0.04 0.05 0.04 0.04 0.06 ... ## $ BeforeSize : int 8192 5496 5768 22528 24576 43008 34816 53248 55296 93184 ... ## $ AfterSize : int 1400 1672 2557 4907 7072 14336 16384 18432 19456 21504 ... ## $ TotalSize : int 9437184 9437184 9437184 9437184 9437184 9437184 9437184 9437184 9437184 9437184 ... head(g1gc.df) ## row.names SecondsSinceLaunch IncrementalCount ## 1 2014-05-12T14:00:32.868-0700: 1.161 0 ## 2 2014-05-12T14:00:33.179-0700: 1.472 1 ## 3 2014-05-12T14:00:33.677-0700: 1.969 2 ## 4 2014-05-12T14:00:35.538-0700: 3.830 3 ## 5 2014-05-12T14:00:37.811-0700: 6.103 4 ## 6 2014-05-12T14:00:41.428-0700: 9.720 5 ## FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize ## 1 0 0.11 0.04 0.02 8192 1400 9437184 ## 2 0 0.05 0.01 0.02 5496 1672 9437184 ## 3 0 0.04 0.01 0.01 5768 2557 9437184 ## 4 0 0.21 0.05 0.04 22528 4907 9437184 ## 5 0 0.08 0.01 0.02 24576 7072 9437184 ## 6 0 0.26 0.06 0.04 43008 14336 9437184 Basic Statistics Once the data has been read into R, simple statistics are very easy to generate. All of the numbers from high school statistics are available via simple commands. For example, generate a summary of every column: summary(g1gc.df) ## row.names SecondsSinceLaunch IncrementalCount FullCount ## Length:8307 Min. : 1 Min. : 0 Min. : 0.0 ## Class :character 1st Qu.: 9977 1st Qu.:2048 1st Qu.: 0.0 ## Mode :character Median :12855 Median :4136 Median : 12.0 ## Mean :12527 Mean :4156 Mean : 31.6 ## 3rd Qu.:15758 3rd Qu.:6262 3rd Qu.: 61.0 ## Max. :55484 Max. :8391 Max. :113.0 ## UserTime SysTime RealTime BeforeSize ## Min. :0.040 Min. :0.0000 Min. : 0.0 Min. : 5476 ## 1st Qu.:0.470 1st Qu.:0.0300 1st Qu.: 0.1 1st Qu.:5137920 ## Median :0.620 Median :0.0300 Median : 0.1 Median :6574080 ## Mean :0.751 Mean :0.0355 Mean : 0.3 Mean :5841855 ## 3rd Qu.:0.920 3rd Qu.:0.0400 3rd Qu.: 0.2 3rd Qu.:7084032 ## Max. :3.370 Max. :1.5600 Max. :488.1 Max. :8696832 ## AfterSize TotalSize ## Min. : 1380 Min. :9437184 ## 1st Qu.:5002752 1st Qu.:9437184 ## Median :6559744 Median :9437184 ## Mean :5785454 Mean :9437184 ## 3rd Qu.:7054336 3rd Qu.:9437184 ## Max. :8482816 Max. :9437184 Q: What is the total amount of User CPU time spent in garbage collection? sum(g1gc.df$UserTime) ## [1] 6236 As you can see, less than two hours of CPU time was spent in garbage collection. Is that too much? To find the percentage of time spent in garbage collection, divide the number above by total_elapsed_time*CPU_count. In this case, there are a lot of CPU’s and it turns out the the overall amount of CPU time spent in garbage collection isn’t a problem when viewed in isolation. When calculating rates, i.e. events per unit time, you need to ask yourself if the rate is homogenous across the time period in the log file. Does the log file include spikes of high activity that should be separately analyzed? Averaging in data from nights and weekends with data from business hours may alias problems. If you have a reason to suspect that the garbage collection rates include peaks and valleys that need independent analysis, see the “Time Series” section, below. Q: How much garbage is collected on each pass? The amount of heap space that is recovered per GC pass is surprisingly low: At least one collection didn’t recover any data. (“Min.=0”) 25% of the passes recovered 3MB or less. (“1st Qu.=3072”) Half of the GC passes recovered 4MB or less. (“Median=4096”) The average amount recovered was 56MB. (“Mean=56390”) 75% of the passes recovered 36MB or less. (“3rd Qu.=36860”) At least one pass recovered 2GB. (“Max.=2121000”) g1gc.df$Delta = g1gc.df$BeforeSize - g1gc.df$AfterSize summary(g1gc.df$Delta) ## Min. 1st Qu. Median Mean 3rd Qu. Max. ## 0 3070 4100 56400 36900 2120000 Q: What is the maximum User CPU time for a single collection? The worst garbage collection (“Max.”) is many standard deviations away from the mean. The data appears to be right skewed. summary(g1gc.df$UserTime) ## Min. 1st Qu. Median Mean 3rd Qu. Max. ## 0.040 0.470 0.620 0.751 0.920 3.370 sd(g1gc.df$UserTime) ## [1] 0.3966 Basic Graphics Once the data is in R, it is trivial to plot the data with formats including dot plots, line charts, bar charts (simple, stacked, grouped), pie charts, boxplots, scatter plots histograms, and kernel density plots. Histogram of User CPU Time per Collection I don't think that this graph requires any explanation. hist(g1gc.df$UserTime, main="User CPU Time per Collection", xlab="Seconds", ylab="Frequency") Box plot to identify outliers When the initial data is viewed with a box plot, you can see the one crazy outlier in the real time per GC. Save this data point for future analysis and drop the outlier so that it’s not throwing off our statistics. Now the box plot shows many outliers, which will be examined later, using times series analysis. Notice that the scale of the x-axis changes drastically once the crazy outlier is removed. par(mfrow=c(2,1)) boxplot(g1gc.df$UserTime,g1gc.df$SysTime,g1gc.df$RealTime, main="Box Plot of Time per GC\n(dominated by a crazy outlier)", names=c("usr","sys","elapsed"), xlab="Seconds per GC", ylab="Time (Seconds)", horizontal = TRUE, outcol="red") crazy.outlier.df=g1gc.df[g1gc.df$RealTime > 400,] g1gc.df=g1gc.df[g1gc.df$RealTime < 400,] boxplot(g1gc.df$UserTime,g1gc.df$SysTime,g1gc.df$RealTime, main="Box Plot of Time per GC\n(crazy outlier excluded)", names=c("usr","sys","elapsed"), xlab="Seconds per GC", ylab="Time (Seconds)", horizontal = TRUE, outcol="red") box(which = "outer", lty = "solid") Here is the crazy outlier for future analysis: crazy.outlier.df ## row.names SecondsSinceLaunch IncrementalCount ## 8233 2014-05-12T23:15:43.903-0700: 20741 8316 ## FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize ## 8233 112 0.55 0.42 488.1 8381440 8235008 9437184 ## Delta ## 8233 146432 R Time Series Data To analyze the garbage collection as a time series, I’ll use Z’s Ordered Observations (zoo). “zoo is the creator for an S3 class of indexed totally ordered observations which includes irregular time series.” require(zoo) ## Loading required package: zoo ## ## Attaching package: 'zoo' ## ## The following objects are masked from 'package:base': ## ## as.Date, as.Date.numeric head(g1gc.df[,1]) ## [1] "2014-05-12T14:00:32.868-0700:" "2014-05-12T14:00:33.179-0700:" ## [3] "2014-05-12T14:00:33.677-0700:" "2014-05-12T14:00:35.538-0700:" ## [5] "2014-05-12T14:00:37.811-0700:" "2014-05-12T14:00:41.428-0700:" options("digits.secs"=3) times=as.POSIXct( g1gc.df[,1], format="%Y-%m-%dT%H:%M:%OS%z:") g1gc.z = zoo(g1gc.df[,-c(1)], order.by=times) head(g1gc.z) ## SecondsSinceLaunch IncrementalCount FullCount ## 2014-05-12 17:00:32.868 1.161 0 0 ## 2014-05-12 17:00:33.178 1.472 1 0 ## 2014-05-12 17:00:33.677 1.969 2 0 ## 2014-05-12 17:00:35.538 3.830 3 0 ## 2014-05-12 17:00:37.811 6.103 4 0 ## 2014-05-12 17:00:41.427 9.720 5 0 ## UserTime SysTime RealTime BeforeSize AfterSize ## 2014-05-12 17:00:32.868 0.11 0.04 0.02 8192 1400 ## 2014-05-12 17:00:33.178 0.05 0.01 0.02 5496 1672 ## 2014-05-12 17:00:33.677 0.04 0.01 0.01 5768 2557 ## 2014-05-12 17:00:35.538 0.21 0.05 0.04 22528 4907 ## 2014-05-12 17:00:37.811 0.08 0.01 0.02 24576 7072 ## 2014-05-12 17:00:41.427 0.26 0.06 0.04 43008 14336 ## TotalSize Delta ## 2014-05-12 17:00:32.868 9437184 6792 ## 2014-05-12 17:00:33.178 9437184 3824 ## 2014-05-12 17:00:33.677 9437184 3211 ## 2014-05-12 17:00:35.538 9437184 17621 ## 2014-05-12 17:00:37.811 9437184 17504 ## 2014-05-12 17:00:41.427 9437184 28672 Example of Two Benchmark Runs in One Log File The data in the following graph is from a different log file, not the one of primary interest to this article. I’m including this image because it is an example of idle periods followed by busy periods. It would be uninteresting to average the rate of garbage collection over the entire log file period. More interesting would be the rate of garbage collect in the two busy periods. Are they the same or different? Your production data may be similar, for example, bursts when employees return from lunch and idle times on weekend evenings, etc. Once the data is in an R Time Series, you can analyze isolated time windows. Clipping the Time Series data Flashing back to our test case… Viewing the data as a time series is interesting. You can see that the work intensive time period is between 9:00 PM and 3:00 AM. Lets clip the data to the interesting period:     par(mfrow=c(2,1)) plot(g1gc.z$UserTime, type="h", main="User Time per GC\nTime: Complete Log File", xlab="Time of Day", ylab="CPU Seconds per GC", col="#1b9e77") clipped.g1gc.z=window(g1gc.z, start=as.POSIXct("2014-05-12 21:00:00"), end=as.POSIXct("2014-05-13 03:00:00")) plot(clipped.g1gc.z$UserTime, type="h", main="User Time per GC\nTime: Limited to Benchmark Execution", xlab="Time of Day", ylab="CPU Seconds per GC", col="#1b9e77") box(which = "outer", lty = "solid") Cumulative Incremental and Full GC count Here is the cumulative incremental and full GC count. When the line is very steep, it indicates that the GCs are repeating very quickly. Notice that the scale on the Y axis is different for full vs. incremental. plot(clipped.g1gc.z[,c(2:3)], main="Cumulative Incremental and Full GC count", xlab="Time of Day", col="#1b9e77") GC Analysis of Benchmark Execution using Time Series data In the following series of 3 graphs: The “After Size” show the amount of heap space in use after each garbage collection. Many Java objects are still referenced, i.e. alive, during each garbage collection. This may indicate that the application has a memory leak, or may indicate that the application has a very large memory footprint. Typically, an application's memory footprint plateau's in the early stage of execution. One would expect this graph to have a flat top. The steep decline in the heap space may indicate that the application crashed after 2:00. The second graph shows that the outliers in real execution time, discussed above, occur near 2:00. when the Java heap seems to be quite full. The third graph shows that Full GCs are infrequent during the first few hours of execution. The rate of Full GC's, (the slope of the cummulative Full GC line), changes near midnight.   plot(clipped.g1gc.z[,c("AfterSize","RealTime","FullCount")], xlab="Time of Day", col=c("#1b9e77","red","#1b9e77")) GC Analysis of heap recovered Each GC trace includes the amount of heap space in use before and after the individual GC event. During garbage coolection, unreferenced objects are identified, the space holding the unreferenced objects is freed, and thus, the difference in before and after usage indicates how much space has been freed. The following box plot and bar chart both demonstrate the same point - the amount of heap space freed per garbage colloection is surprisingly low. par(mfrow=c(2,1)) boxplot(as.vector(clipped.g1gc.z$Delta), main="Amount of Heap Recovered per GC Pass", xlab="Size in KB", horizontal = TRUE, col="red") hist(as.vector(clipped.g1gc.z$Delta), main="Amount of Heap Recovered per GC Pass", xlab="Size in KB", breaks=100, col="red") box(which = "outer", lty = "solid") This graph is the most interesting. The dark blue area shows how much heap is occupied by referenced Java objects. This represents memory that holds live data. The red fringe at the top shows how much data was recovered after each garbage collection. barplot(clipped.g1gc.z[,c("AfterSize","Delta")], col=c("#7570b3","#e7298a"), xlab="Time of Day", border=NA) legend("topleft", c("Live Objects","Heap Recovered on GC"), fill=c("#7570b3","#e7298a")) box(which = "outer", lty = "solid") When I discuss the data in the log files with the customer, I will ask for an explaination for the large amount of referenced data resident in the Java heap. There are two are posibilities: There is a memory leak and the amount of space required to hold referenced objects will continue to grow, limited only by the maximum heap size. After the maximum heap size is reached, the JVM will throw an “Out of Memory” exception every time that the application tries to allocate a new object. If this is the case, the aplication needs to be debugged to identify why old objects are referenced when they are no longer needed. The application has a legitimate requirement to keep a large amount of data in memory. The customer may want to further increase the maximum heap size. Another possible solution would be to partition the application across multiple cluster nodes, where each node has responsibility for managing a unique subset of the data. Conclusion In conclusion, R is a very powerful tool for the analysis of Java garbage collection log files. The primary difficulty is data cleansing so that information can be read into an R data frame. Once the data has been read into R, a rich set of tools may be used for thorough evaluation.

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• Android 1.6: "android.view.WindowManager$BadTokenException: Unable to add window -- token null is no

  - by Dan Monego

  I'm trying to open a dialog window, but every time I try to open it it throws this exception: E/AndroidRuntime( 206): Uncaught handler: thread main exiting due to uncaught exception E/AndroidRuntime( 206): android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application E/AndroidRuntime( 206): at android.view.ViewRoot.setView(ViewRoot.java:460) E/AndroidRuntime( 206): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:177) E/AndroidRuntime( 206): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91) E/AndroidRuntime( 206): at android.app.Dialog.show(Dialog.java:238) E/AndroidRuntime( 206): at android.app.Activity.showDialog(Activity.java:2413) I'm creating it by calling showDialog with the display's id. The onCreateDialog handler logs fine and I can step through it without an issue, but I've attached since it seems like I'm missing something in it: @Override public Dialog onCreateDialog(int id) { Dialog dialog; Context appContext = this.getApplicationContext(); switch(id) { case RENAME_DIALOG_ID: Log.i("Edit", "Creating rename dialog..."); dialog = new Dialog(appContext); dialog.setContentView(R.layout.rename); dialog.setTitle("Rename " + noteName); break; default: dialog = null; break; } return dialog; } Is there something missing from this? Some questions have talked about having this problem when creating a dialog from onCreate, which happen because the activity isn't created yet, but this is coming from a call from a menu object, and the appContext variable seems like it is correctly populated in the debugger.

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• FragmentStatePagerAdapter IllegalStateException: <MyFragment> is not currently in the FragmentManager

  - by Ixx

  I'm getting this on some cases, when going back to the activity, which uses a FragmentStatePagerAdapter, using back button of the devices. Not always. Not reproducible. I'm using support package v4, last revision (8). Already searched with google, no success finding a useful answer. Looking in the source, it's thrown here: FragmentManager.java @Override public void putFragment(Bundle bundle, String key, Fragment fragment) { if (fragment.mIndex < 0) { throw new IllegalStateException("Fragment " + fragment + " is not currently in the FragmentManager"); } bundle.putInt(key, fragment.mIndex); } But why is the index of fragment < 0 there? The code instantiating the fragments: @Override public Fragment getItem(int position) { Fragment fragment = null; switch(position) { case 0: fragment = Fragment1.newInstance(param1); break; case 1: fragment = MyFragment2.newInstance(param2, param3); break; } return fragment; } @Override public int getCount() { return 2; } I also can't debug through the source since the support package doesn't let me attach the source, for some reason... but that's a different question...

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• Using WPF and SlimDx (DirectX 10/11)

  - by slurmomatic

  I am using SlimDX with WinForms for a while now, but want to make the switch to WPF now. However, I can't figure out how to get DX10/11 working with WPF. The February release of SlimDX provides a WPF example, which only works with DX 9 though. I found the following solution: http://jmorrill.hjtcentral.com/Home/tabid/428/EntryId/437/Direct3D-10-11-Direct2D-in-WPF.aspx but can't get it to work with SlimDX. My main problem is the shared resource handle as I don't know how to retrieve the shared handle from a SlimDX texture. I can't find any information to this topic. In C++ the code looks like this: HRESULT D3DImageEx::GetSharedHandle(IUnknown *pUnknown, HANDLE * pHandle) { HRESULT hr = S_OK; *pHandle = NULL; IDXGIResource* pSurface; if (FAILED(hr = pUnknown->QueryInterface(__uuidof(IDXGIResource), (void**)&pSurface))) return hr; hr = pSurface->GetSharedHandle(pHandle); pSurface->Release(); return hr; } Basically, what I want to do (because I think that this is the solution), is to share a texture between a Direct3d9DeviceEx (for rendering the WPF D3DImage) and a Direct3d10Device (a texture render target for my scene). Any pointers in the right direction are greatly appreciated.

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• WPF / C#: Transforming coordinates from an image control to the image source

  - by Gabriel

  I'm trying to learn WPF, so here's a simple question, I hope: I have a window that contains an Image element bound to a separate data object with user-configurable Stretch property <Image Name="imageCtrl" Source="{Binding MyImage}" Stretch="{Binding ImageStretch}" /> When the user moves the mouse over the image, I would like to determine the coordinates of the mouse with respect to the original image (before stretching/cropping that occurs when it is displayed in the control), and then do something with those coordinates (update the image). I know I can add an event-handler to the MouseMove event over the Image control, but I'm not sure how best to transform the coordinates: void imageCtrl_MouseMove(object sender, MouseEventArgs e) { Point locationInControl = e.GetPosition(imageCtrl); Point locationInImage = ??? updateImage(locationInImage); } Now I know I could compare the size of Source to the ActualSize of the control, and then switch on imageCtrl.Stretch to compute the scalars and offsets on X and Y, and do the transform myself. But WPF has all the information already, and this seems like functionality that might be built-in to the WPF libraries somewhere. So I'm wondering: is there a short and sweet solution? Or do I need to write this myself? EDIT I'm appending my current, not-so-short-and-sweet solution. Its not that bad, but I'd be somewhat suprised if WPF didn't provide this functionality automatically: Point ImgControlCoordsToPixelCoords(Point locInCtrl, double imgCtrlActualWidth, double imgCtrlActualHeight) { if (ImageStretch == Stretch.None) return locInCtrl; Size renderSize = new Size(imgCtrlActualWidth, imgCtrlActualHeight); Size sourceSize = bitmap.Size; double xZoom = renderSize.Width / sourceSize.Width; double yZoom = renderSize.Height / sourceSize.Height; if (ImageStretch == Stretch.Fill) return new Point(locInCtrl.X / xZoom, locInCtrl.Y / yZoom); double zoom; if (ImageStretch == Stretch.Uniform) zoom = Math.Min(xZoom, yZoom); else // (imageCtrl.Stretch == Stretch.UniformToFill) zoom = Math.Max(xZoom, yZoom); return new Point(locInCtrl.X / zoom, locInCtrl.Y / zoom); }

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• XamlParseException due to DatePicker from WPFToolKit

  - by baron

  Hello everyone, Error : UnhandledException: System.Windows.Markup.XamlParseException: '/WPFToolkit;component/DataGrid/Themes/Luna.NormalColor.xaml' value cannot be assigned to property 'Source' of object 'System.Windows.ResourceDictionary'. Could not load type 'System.Windows.Controls.Primitives.MultiSelector' from assembly 'PresentationFramework, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'. Error at object 'System.Windows.ComponentResourceKey' in markup file 'WPFToolkit;component/DataGrid/Themes/Luna.NormalColor.xaml'. Error at object 'System.Windows.ResourceDictionary'. ---> System.Windows.Markup.XamlParseException: Could not load type 'System.Windows.Controls.Primitives.MultiSelector' from assembly 'PresentationFramework, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'. Error at object 'System.Windows.ComponentResourceKey' in markup file 'WPFToolkit;component/DataGrid/Themes/Luna.NormalColor.xaml'. ---> System.TypeLoadException: Could not load type 'System.Windows.Controls.Primitives.MultiSelector' from assembly 'PresentationFramework, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'. I keep getting the following exception. I am getting the exception when I run the application exe from the Release folder. I do not get the exception at all when normally debugging the application in Visual Studio. I have worked out that the exception is because of a DatePicker control I am using - as if I remove the control (build and run the release exe again) the exception goes away. How on earth could I work out what is going wrong here? The datepicker looks so much better but for the effort this looks like it might be to fix I may be incline to switch for a textbox which I validate when the submit button is pressed! Dissapointing...

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• Any alternative to hide querystring from Html.actionlink on ASP.NET MVC Page?

  - by Madhavi

  Hi I have a page called SearchDcouments.aspx that displays all the matching documents as Hyperlinks in the table format as below. When the User clicks on any particular document, the sample url will be: http://localhost:52483/Home/ShowDocument?docID=280 So that the DocumentID is passed as Querystring to the ControllerMethod ShowDocument and the ID is visible in the URL. Now for Security purposes, I want to hide this way of passing the Querystring parameters. Wondering what are the alternatives to hide the DocID from the URL? Appreciate your responses. Thanks Code in the View: <tbody> <% foreach (var item in Model){ %> <tr> <% string actionTitle = item.DocumentType.ToLower() == "letter" ? "Request References" : "Request Slides"; %> <td> <%= Html.ActionLink(actionTitle, MVC.Home.ShowDocument(item.DocumentID))%> </td> </tr> <% } %> </tbody> Code in the Controller: [Authorize] [HttpGet] public virtual ActionResult ShowDocument(int docID) { Document document = miEntity.GetDocumentByID(docID); switch (document.DocType.ToLower()) { case "slide": SlideRequestViewModel slide = new SlideRequestViewModel(docID); return View(MVC.Home.Views.ShowSlideRequest, slide); case "letter": RefRequestViewModel rrq = new RefRequestViewModel(docID); return DoShowRefRequest(rrq); default: break; } // Here - let's get back home return RedirectToAction(MVC.Home.Default()); }

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• RadGrid Custom Filter

  - by Aaron

  I'm trying to add a custom filter to my RadGrid. I have a column, vendNum, which I want to allow users to filter on multiple vendNums with a comma-separated list. Basically, I want the same functionality as an "in" statement in SQL (where vendNum in (X,Y,Z)). I followed the tutorial on this site and came up with the following code to place in my RadGrid1_ItemCommand event. protected void RadGrid1_ItemCommand(object source, GridCommandEventArgs e) { if (e.CommandName == RadGrid.FilterCommandName) { Pair filterPair = (Pair)e.CommandArgument; switch (filterPair.Second.ToString()) { case "vendNum": TextBox tbPattern = (e.Item as GridFilteringItem)["vendNum"].Controls[0] as TextBox; if (tbPattern.Text.Contains(",")) { string[] values = tbPattern.Text.Split(','); if (values.Length >= 2) { e.Canceled = true; StringBuilder newFilter = new StringBuilder(); for (int i = 0; i < values.Length; i++) { if (i == values.Length - 1) newFilter.Append("[vendNum] = " + values[i]); else newFilter.Append("[vendNum] = " + values[i] + " OR "); } if (RadGrid1.MasterTableView.FilterExpression == "") RadGrid1.MasterTableView.FilterExpression = newFilter.ToString(); else RadGrid1.MasterTableView.FilterExpression = "((" + RadGrid1.MasterTableView.FilterExpression + ") AND (" + newFilter.ToString() + "))"; RadGrid1.Rebind(); } } break; default: break; } } } Doing this, though, keeps giving me an error "Expression Expected" when I try to filter with a comma separated list. I'm still able to filter a single vendNum. My FilterExpression does come out as expected. The code is failing on the RadGrid1.Rebind() statement. Has anyone dealt with this before? Any help is greatly appreciated. Thanks, Aaron

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• SmartGWT TreeGrid, adding and editing

  - by Banang

  I'm trying to programmatically add a new TreeNode to a TreeGrid, and then turn on editing for the newly added node. This is my data source: DataSource ds = new DataSource(); DataSourceTextField idField = new DataSourceTextField("key", "Id"); DataSourceTextField nameField = new DataSourceTextField("name", "Name"); DataSourceTextField keyField = new DataSourceTextField("id", "Key"); keyField.setPrimaryKey(true); ds.setFields(idField, keyField, nameField); ds.setClientOnly(true); My fields: TreeGridField name = new TreeGridField("name", "Name"); TreeGridField id = new TreeGridField("id", "Id"); TreeGridField key = new TreeGridField("key", "Key"); key.setHidden(true); id.setHidden(true); And my code for adding a new record: TreeNode parent = (TreeNode) treeGrid.getSelectedRecord(); if (parent == null) parent = treeGrid.getData().getRoot(); Tree data = treeGrid.getData(); node = data.add(node, parent); Now, how on earth do I switch on editing for the added node? I've tried startEditing(), but that defaults to the first node, and I don't see any way of obtaining the row number for the newly added node, which would allow me to use startEditing(rowNum, colNum, suppressFocus). Using startEditNew() is not an option for many reasons, mainly because that method adds the new node to the bottom of the tree, which doesn't work at all with my app. How do I do this? Grateful for any help you guys can give me.

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• ASP.NET PowerShell Impersonation

  - by Ben

  I have developed an ASP.NET MVC Web Application to execute PowerShell scripts. I am using the VS web server and can execute scripts fine. However, a requirement is that users are able to execute scripts against AD to perform actions that their own user accounts are not allowed to do. Therefore I am using impersonation to switch the identity before creating the PowerShell runspace: Runspace runspace = RunspaceFactory.CreateRunspace(config); var currentuser = WindowsIdentity.GetCurrent().Name; if (runspace.RunspaceStateInfo.State == RunspaceState.BeforeOpen) { runspace.Open(); } I have tested using a domain admin account and I get the following exception when calling runspace.Open(): Security Exception Description: The application attempted to perform an operation not allowed by the security policy. To grant this application the required permission please contact your system administrator or change the application's trust level in the configuration file. Exception Details: System.Security.SecurityException: Requested registry access is not allowed. The web application is running in full trust and I have explicitly added the account I am using for impersonation to the local administrators group of the machine (even though the domain admins group was already there). I'm using advapi32.dll LogonUser call to perform the impersonation in a similar way to this post (http://blogs.msdn.com/webdav_101/archive/2008/09/25/howto-calling-exchange-powershell-from-an-impersonated-thead.aspx) Any help appreciated as this is a bit of a show stopper at the moment. Thanks Ben

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• DotNetOpenAuth: Message signature was incorrect

  - by Shawn Miller

  I'm getting a "Message signature was incorrect" exception when trying to authenticate with MyOpenID and Yahoo. I'm using pretty much the ASP.NET MVC sample code that came with DotNetOpenAuth 3.4.2 public ActionResult Authenticate(string openid) { var openIdRelyingParty = new OpenIdRelyingParty(); var authenticationResponse = openIdRelyingParty.GetResponse(); if (authenticationResponse == null) { // Stage 2: User submitting identifier Identifier identifier; if (Identifier.TryParse(openid, out identifier)) { var realm = new Realm(Request.Url.Root() + "openid"); var authenticationRequest = openIdRelyingParty.CreateRequest(openid, realm); authenticationRequest.RedirectToProvider(); } else { return RedirectToAction("login", "home"); } } else { // Stage 3: OpenID provider sending assertion response switch (authenticationResponse.Status) { case AuthenticationStatus.Authenticated: { // TODO } case AuthenticationStatus.Failed: { throw authenticationResponse.Exception; } } } return new EmptyResult(); } Working fine with Google, AOL and others. However, Yahoo and MyOpenID fall into the AuthenticationStatus.Failed case with the following exception: DotNetOpenAuth.Messaging.Bindings.InvalidSignatureException: Message signature was incorrect. at DotNetOpenAuth.OpenId.ChannelElements.SigningBindingElement.ProcessIncomingMessage(IProtocolMessage message) in c:\Users\andarno\git\dotnetopenid\src\DotNetOpenAuth\OpenId\ChannelElements\SigningBindingElement.cs:line 139 at DotNetOpenAuth.Messaging.Channel.ProcessIncomingMessage(IProtocolMessage message) in c:\Users\andarno\git\dotnetopenid\src\DotNetOpenAuth\Messaging\Channel.cs:line 992 at DotNetOpenAuth.OpenId.ChannelElements.OpenIdChannel.ProcessIncomingMessage(IProtocolMessage message) in c:\Users\andarno\git\dotnetopenid\src\DotNetOpenAuth\OpenId\ChannelElements\OpenIdChannel.cs:line 172 at DotNetOpenAuth.Messaging.Channel.ReadFromRequest(HttpRequestInfo httpRequest) in c:\Users\andarno\git\dotnetopenid\src\DotNetOpenAuth\Messaging\Channel.cs:line 386 at DotNetOpenAuth.OpenId.RelyingParty.OpenIdRelyingParty.GetResponse(HttpRequestInfo httpRequestInfo) in c:\Users\andarno\git\dotnetopenid\src\DotNetOpenAuth\OpenId\RelyingParty\OpenIdRelyingParty.cs:line 540 Appears that others are having the same problem: http://trac.dotnetopenauth.net:8000/ticket/172 Does anyone have a workaround?

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• How to change StartupUri of WPF Application?

  - by Akash Kava

  I am trying to modify App.cs and load the WPF XAML files from code behind but its not working as it should. No matter whatever I try to set as StartupUri it doesnt start, the program quits after this. public partial class App : Application { protected override void OnStartup(StartupEventArgs e) { base.OnStartup(e); LoginDialog dlg = new LoginDialog(); if (dlg.ShowDialog() != true) return; switch (dlg.ChoiceApp) { case ChoiceApp.CustomerEntry: StartupUri = new Uri("/MyApp;component/Forms/CustomerEntry.xaml", UriKind.Relative); break; case ChoiceApp.VendorEntry: StartupUri = new Uri("/MyApp;component/Forms/VendorEntry.xaml", UriKind.Relative); break; } } } Now I even did trace and found out that LoginDialog is working correctly and is returning values correctly but setting "StartupUri" does not work. I checked in reverse assembly that DoStartup method of App gets called after OnStartup, so technically my StartupUri must load, but it doesnt, in App.xaml startup uri is not at all defined. Note: Bug Confirmed I noticed that ShowDialog sets Application.MainWindow and when dialog ends, it sets it back to null, and because of this setting StartupUri does not work after calling Modal Dialog in OnStartup or Startup event. There is no error or exception about invalid uri or anything like that. This method works without DialogBox being called in Startup event or OnStartup, i think calling showdialog on this method causes something like its mainwindow being set to expired window and it shuts down after this.

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• Unable to load UIView with initWithNibName in Apple SDK 3.1.3

  - by James Foster

  I am trying to load my UIViewController and corresponding UIView programmatically in the AppDelegate class. I have the following in the applicationDidFinishLaunchingMethod of the AppDelegate class: (void)applicationDidFinishLaunching:(UIApplication *)application { NSLog(@"--- AppDelegate applicationDidFinishLaunching Start"); // Override point for customization after application launch //MainController *controller = [[MainController alloc] initWithNibName:@"MainView" bundle:nil]; MainController2 *controller = [[MainController2 alloc] initWithNibName:@"MainView2" bundle:nil]; if (controller.view == nil) { NSLog(@"--- controller view is nil!!!!!!"); } [window addSubview:controller.view]; [window makeKeyAndVisible]; NSLog(@"--- AppDelegate applicationDidFinishLaunching End"); } Basically the view in the viewController doesn't load and when the application launches, it just shows the blank window. What is funny is that it worked before and then just stopped working. I am wondering if this is a bug in iPhone SDK 3.1.3??? This is a really annoying issue, and I was quite a ways along in a new project when I started having this problem and had to start over with a blank project and copy over all of my resources, when it started happening again... I have uninstalled iPhone OS 3.1.3 and reinstalled and the problem prevails... I also created a second UIViewController class and corresponding nib which DOES LOAD just fine... I am not sure why one works and the other doesn't it... You can download a sample project which demonstrates this issue at the following link: http://www.mediafire.com/?nmhnmhbeyki To switch back and forth between the working/nonworking UIViewController and UIView simply comment comment/comment out the initWithNibLine lines in the AppDelegate and the corresponding #import "MainController.h" statements in the appdelegate.h file... Any ideas??? The sample project I have linked to isolates the problem in as few files/lines of code as possible... I appreciate any help you might be able to provide. Thanks, James

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