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  Python object creation sequence

[The Python version described in this article is 3.x] This article aims to explore the process of creating new objects in Python. As I explained in a previous article, object creation is just a special case of calling a callable. Consider this Python code: class Joe: pass j = Joe() What happens when j = Joe() is executed? Python sees it as a call to the callable Joe, and routes it to the internal function PyObject_Call, with Joe passed as the first argument. PyObject_Call looks at the ty...

   Python,Object creation     2012-04-16 15:03:55

  A trick of building multithreaded application on Solaris

Firstly, Let’s see a simple multithreaded application: #include <stdio.h> #include <pthread.h> #include <errno.h> void *thread1_func(void *p_arg) { errno = 0; sleep(3); errno = 1; printf("%s exit, errno is %d\n", (char*)p_arg, errno); } void *thread2_func(void *p_arg) { errno = 0; sleep(5); printf("%s exit, errno is %d\n", (char*)p_arg, errno); } int main(void) { pthread_t t1, t2; ...

   C, Solaris     2014-10-14 02:59:40

  Different types of keystore in Java -- BKS

BKS is a keystore format provided by the popular third party Java cryptographic library provider -- BouncyCastle. It is a keystore similar to the JKS provided by Oracle JDK.  Before starting to use BKS, the BouncyCastle provider has to be downloaded and installed. To download the provider, please go to BouncyCastle download page. The provider can be installed by adding an entry in the java.security file. security.provider.N=org.bouncycastle.jce.provider.BouncyCastleProvider N means the pr...

   JAVA,KEYSTORE,BOUNCYCASTLE,BKS     2016-07-03 03:00:18

  10 design flaws of JavaScript

JavaScript's design took only ten days. Moreover, the designer didn't want to design it initially, he just wanted to complete the task assigned by company. It is now a very powerful client side programming language used in almost all the websites. It's an excellent language, but it also has some flaws. 1. Not suitable for large projects JavaScript doesn't have namespace, it's hard to be modular, there is no standard for putting codes in multiple source files. It allows defining functions with th...

   JavaScript, Design flaw, Object     2012-11-29 11:39:35

  Build RPM package on Linux

1. Check the OS version and core version #uname -a #more /etc/redhat-release 2. Create relative directories /usr/src/redhat/SOURCES    //Store source codes, patches, icons etc /usr/src/redhat/SPECS        //Store specs about the process of building RPM packages /usr/src/redhat/BUILD     //File after uncompressed are stored here /usr/src/redhat/RPMS     //Store the binary files built with rpmbuild /usr/src/redhat/SRPMS&nbs...

   RPM,Linux,Build     2013-03-22 12:44:29

  Install Open webOS on Linux

HP has just released its first beta version of the webOS, It is said the user experience of webOS is quite impressive, so I immediately had it installed on my PC. There are two versions of Beta release,one embedded version and one Ubuntu version. I briefly share my installation experience of webOS in Linux. In the official document, it says "By 'Linux' we mean 'Ubuntu Linux'", it doesn't support server version and 64 bit version of Ubuntu. Here I use Mint 13. 1. Clone source code from github Add...

   Linux,webOS,Ubuntu,embedded,HP     2012-09-10 19:36:30

  Different types of keystore in Java -- PKCS11

PKCS11 keystore is designed for hardware storage modules（HSM）. It's an interface to talk to the HSMs. It doesn't actually store any keys but provide a set of classes to communicate with the underlying HSM. The actual keys and certificates are stored on the HSMs. The reason for storing the keys and materials is to ensure security and efficiency. Since the keys are on the HSMs, they are safe to be stolen. All encryption/decryption operations are performed on the HSMs as well, this incre...

   PKCS11,keystore,HSM,Java     2015-01-08 00:39:12

  passing parameters to XMLHttpRequest’s onreadystatechange function

I’ve been smashing my head against this all day – but I finally got something working consistently and reliable, so I better damn well document it. This is as good a place as any, and hopefully it will be useful to others.I needed to make an Ajax call, so I turned to my good friend XMLHttpRequest. One wrinkle was that I needed to pass in a parameter to it… so I tried:var test = "bar"; req = new XMLHttpRequest(); req.open("GET", myURL, true); req.foo = test; req.onreadystatech...

   JavaScript,AJAX,XMLHttpRequest,parameter,onreadystatechange     2011-10-09 01:32:09

  Why using + to concatenate string in Java loop is not a good option

String concatenation is a common operation in Java programming. It is to concatenate multiple strings into a single string. Java provides a String class which is an immutable class which means the object cannot be mutated once instantiated. Once a String object is instantiated, its properties cannot be changed anymore, so when concatenating strings, it's actually create a new String instance to store the concatenated string values. For example, below is a simple string concatenation example. Str...

   JAVA,STRING,JAVA 8     2019-01-18 22:07:12

  37 powerful Linux shell commands

To work on Linux platform, you cannot avoid using shell commands to complete some tasks. These tasks can be as simple as list files in some directories or find some text in some file, or can be as complex as monitoring processes. In this post, we will share 37 powerful Linux shell commands.   Task Commands 1 Delete file with 0 byte(empty file) find . -type f -size 0 -exec rm -rf {} \;find . type f -size 0 -delete 2 Check process memory consumption ps -e -o "%C : %p : %z : %a"|sort -k...

   Linux command,List     2013-09-16 07:47:16

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