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What are the default buffer size for java.io.BufferedInputStream on old and exotic JVMs?

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问题 I've been doing some research for a blog post regarding java.io.BufferedInputStream and buffers. Apparently, over the years, the default has grown from a measly 512 bytes to 8192 bytes as of (presumptuously) Sun's Java 7 implementation, and was even explicitly specified in the JavaDocs in JDK 1.1.8. My question has also brought up questions of who/what deciedes what the default should be--it's not as black-n-white as I had expected. I am curious as to what the default buffer size has been at

Java “ANSI constants”

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问题 I hit this little tidbit while browsing the Java Code Conventions: The names of variables declared class constants and of ANSI constants should be all uppercase with words separated by underscores ("_"). (ANSI constants should be avoided, for ease of debugging.) (From here.) What are these "ANSI constants" this document speaks of? And how do they make debugging harder? The text makes it sound as if there is a dichotomy between "variables declared class constants" (which I interpret as

Backbone routing/history issue with Jekyll static pages

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问题 I'm building a simple marketing website with Jekyll, and using Backbone's routing and history behind the scenes to handle navigation. Each page of my site is its own HTML file, and my strategy is to preventDefault() on links between pages, fire off a jQuery.get() to grab the new HTML, and replace my div.content with the information from the new page. I know this setup is a little out of the ordinary, but I have my reasons: a single-page structure is preferable because I want precise control

AJAX and back button

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问题 How can I save history with AJAX just how github or google+ do. I use jQuery and I do not want to use some kind of hack like the # and #! tricks, because if I do, I'll need to change my whole project and make my life much more complicated? 回答1: Github and Google+ are using history.pushState. You can change the current url like this: history.pushState(null, null, '/the-new-url'); This is supported by Firefox, Chrome, Opera, Safari; not IE. See https://developer.mozilla.org/en/DOM/Manipulating

Hashtable. Name history. Why not HashTable?

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问题 we know: ArrayList; LinkedList; TreeMap and other... and all names in CamelCase format, but why Hashtable , not HashTable ? it is unprincipled question, just wondering :) 回答1: Hashtable was created in Java v1. The consistent naming conventions for collections were established later, in Java2, when the other classes were published as part of the brand new Java Collection Framework. Which btw made Hashtable obsolete, so it should not be used in new code. 回答2: It's a typo. Same as Cloneable

Python object history

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问题 I am trying to come up with a way to keep track of various re-incarnations of an object in Python. For example, I would like to have a class for, say, a room. This room could start its existence as a 'kitchen', and then, at any given point in time, become a 'study'. I want to be able to track (or log) all these various phases in the life of my room. So, I came up with this, and am wondering if there is a better way to do this. Or maybe I'm missing something. From what I can tell, though, it

Can tmux save commands to a file, like .bash_history?

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问题 Does tmux support saving to a file the commands typed in "C-b :" mode ? I'd rather look through the ones I already typed than have to look each command up in the man page. 回答1: There is history-file option which does what you are looking for. history-file path If not empty, a file to which tmux will write command prompt history on exit and load it from on start. Add this to your .tmux.conf set -g history-file ~/.tmux_history Note it was added in 2.1 version. if you have older version of tmux

HTML5 History API

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引言 HTML5 History API 为开发者提供在不刷新浏览器页面的情况下修改 URL 的能力，在这之前，如果开发者修改 url 就会全页面刷新。History API 可以让我们灵活控制浏览器地址栏线上的内容，为我们的开发提供了更多的便利。在今天，单页面应用大行其道，除了 ajax 技术之外，History API 也功不可没，它为我们提供了更友好的地址栏接口，让地址栏地址更可读。 History 对象在浏览器的控制台中，查看history，我们可以看到 History 为我们提供的属性和方法。属性 history.lenght 历史回话个数，这个个数包括当前页，当打开一个浏览器的空白页面时，history.lenght = 1。 history.state 当前回话的 state，state 可以是任意类型，它有 history.pushState 或 history.replaceState 的第一个参数定义。方法 history.go([number]) 浏览器前进或回退指定步骤。参数小于 0 时，浏览器回退指定的步骤，参数大于 0 时，浏览器前进指定的步骤。如果参数值太大或者太小时，方法无效果。 history.back() 浏览器回退到前一个页面。相当于点击浏览器的回退按钮。等价于 history.go(-1) 。 history.forward()

Is “for(;;)” idiom for infinite loop correctly attributed to PDP-11 C compiler?

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问题 Recently I found this article that claims that the idea to prefer for(;;) over while(1) for infinite loop came because the C compiler originally available on PDP-11 generated an extra machine instruction for while(1) . Btw now even Visual C++ warnings tend to favor the former. How realistic is such attribution of for(;;) idiom? 回答1: Here's what the V7 Unix compiler cc produces (using SIMH and an image from TUHS): $ cat>a.c main(){ while(1); } $ cat>b.c main(){ for(;;); } $ cc -S a.c $ cc -S b

Database entries modification history

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问题 I am currently working on a big management system (in PHP using Zend Framework, but that is not really revelant of the solution to this question) in which I have to manage multiple entries. Each entry has many fields and span on two tables in a 1-to-many relationship (through a single foreign key). There is roughly 50 fields in the first table and 30 fields in the second one. I am now at the stage to implement a history tracking of the different modifications made by users (and some automated