?? display.php-n=9-10&f=09-defineclass.js.htm
字號:
<html><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Keywords" name="Keywords"content="JavaScript, examples, JavaScript: The Definitive Guide"><title>Example 9-10 from JavaScript: The Definitive Guide, Fifth Edition</title><style>body { font-family: arial, sans-serif}.lefttitle { font: bold x-small arial, sans-serif; margin: 5px; letter-spacing: .15em; text-transform:uppercase;}.leftcaption { font: italic x-small sans-serif; margin-bottom: 20px;}#banner { font-family:sans-serif; color:#333; font-size:x-large; font-weight:normal; padding:15px; padding-top: 3px; border-bottom:4px double #666;}#banner h1 { font-size: x-large; margin: 0px; padding: 0px;}#banner .description { font-size:large; margin-left: 2px;}pre { border: solid black 1px; background-color: #ddd; padding: 10px; margin: 0px;} </style></script></head><body><div id="banner"><h1>davidflanagan.com/javascript5</h1><span class="description">Example 9-10 from<i>JavaScript: The Definitive Guide, Fifth Edition</i></span></div><div style="float: left; text-align: center; width:200px; margin-right:20px"><div class="lefttitle">Buy The Book</div><iframe src="../../rcm.amazon.com/e/cm-t=davidflanagancom&o=1&p=8&l=as1&asins=0596101996&fc1=000000&IS2=1<1=_blank&lc1=0000ff&bc1=000000&bg1=ffffff&f=ifr" tppabs="http://rcm.amazon.com/e/cm?t=davidflanagancom&o=1&p=8&l=as1&asins=0596101996&fc1=000000&IS2=1<1=_blank&lc1=0000ff&bc1=000000&bg1=ffffff&f=ifr" style="width:120px;height:240px;" scrolling="no" marginwidth="0" marginheight="0" frameborder="0"></iframe><div class="leftcaption">This example is posted here for the convenienceof my readers.</div><div class="lefttitle">Tip the Author</div><form action="https://www.paypal.com/cgi-bin/webscr" method="post"><input type="hidden" name="cmd" value="_s-xclick"><input type="image" src="../../www.paypal.com/en_US/i/btn/x-click-but21.gif" tppabs="https://www.paypal.com/en_US/i/btn/x-click-but21.gif" border="0" name="submit" alt="Make payments with PayPal - it's fast, free and secure!"><img alt="" border="0" src="../../www.paypal.com/en_US/i/scr/pixel.gif" tppabs="https://www.paypal.com/en_US/i/scr/pixel.gif" width="1" height="1"><input type="hidden" name="encrypted" value="-----BEGIN PKCS7-----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-----END PKCS7-----"></form><div class="leftcaption">Found a helpful example, but don't own the book?</div><div class="lefttitle">Advertising</div><script type="text/javascript"><!--google_ad_client = "pub-5162555666633441";google_alternate_color = "ffffff";google_ad_width = 160;google_ad_height = 600;google_ad_format = "160x600_as";google_ad_type = "text_image";google_ad_channel ="";//--></script><script type="text/javascript" src="../../pagead2.googlesyndication.com/pagead/show_ads.js" tppabs="http://pagead2.googlesyndication.com/pagead/show_ads.js"></script></div><div style="margin-left: 220px;"><div class="lefttitle" style="padding:0px; text-align: right"><a href="index.html" tppabs="http://www.davidflanagan.com/javascript5/index.html">Table of Examples</a></div><pre>/** * defineClass() -- a utility function for defining JavaScript classes. * * This function expects a single object as its only argument. It defines * a new JavaScript class based on the data in that object and returns the * constructor function of the new class. This function handles the repetitive * tasks of defining classes: setting up the prototype object for correct * inheritance, copying methods from other types, and so on. * * The object passed as an argument should have some or all of the * following properties: * * name: the name of the class being defined. * If specified, this value will be stored in the classname * property of the prototype object. * * extend: The constructor of the class to be extended. If omitted, * the Object() constructor will be used. This value will * be stored in the superclass property of the prototype object. * * construct: The constructor function for the class. If omitted, a new * empty function will be used. This value becomes the return * value of the function, and is also stored in the constructor * property of the prototype object. * * methods: An object that specifies the instance methods (and other shared * properties) for the class. The properties of this object are * copied into the prototype object of the class. If omitted, * an empty object is used instead. Properties named * "classname", "superclass", and "constructor" are reserved * and should not be used in this object. * * statics: An object that specifies the static methods (and other static * properties) for the class. The properties of this object become * properties of the constructor function. If omitted, an empty * object is used instead. * * borrows: A constructor function or array of constructor functions. * The instance methods of each of the specified classes are copied * into the prototype object of this new class so that the * new class borrows the methods of each specified class. * Constructors are processed in the order they are specified, * so the methods of a class listed at the end of the array may * overwrite the methods of those specified earlier. Note that * borrowed methods are stored in the prototype object before * the properties of the methods object above. Therefore, * methods specified in the methods object can overwrite borrowed * methods. If this property is not specified, no methods are * borrowed. * * provides: A constructor function or array of constructor functions. * After the prototype object is fully initialized, this function * verifies that the prototype includes methods whose names and * number of arguments match the instance methods defined by each * of these classes. No methods are copied; this is simply an * assertion that this class "provides" the functionality of the * specified classes. If the assertion fails, this method will * throw an exception. If no exception is thrown, any * instance of the new class can also be considered (using "duck * typing") to be an instance of these other types. If this * property is not specified, no such verification is performed. **/function defineClass(data) { // Set up default values. var classname = data.name; var superclass = data.extend || Object; var constructor = data.construct || function() {}; var methods = data.methods || {}; var statics = data.statics || {}; var borrows; var provides; // Borrows may be a single constructor or an array of them. if (!data.borrows) borrows = []; else if (data.borrows instanceof Array) borrows = data.borrows; else borrows = [ data.borrows ]; // Ditto for the provides property. if (!data.provides) provides = []; else if (data.provides instanceof Array) provides = data.provides; else provides = [ data.provides ]; // Create the object that will become the prototype for our class. var proto = new superclass(); // Delete any noninherited properties of this new prototype object. for(var p in proto) if (proto.hasOwnProperty(p)) delete proto[p]; // Borrow methods from "mixin" classes by copying to our prototype. for(var i = 0; i < borrows.length; i++) { var c = data.borrows[i]; borrows[i] = c; // Copy method properties from prototype of c to our prototype for(var p in c.prototype) { if (typeof c.prototype[p] != "function") continue; proto[p] = c.prototype[p]; } } // Copy instance methods to the prototype object // This may overwrite methods of the mixin classes for(var p in methods) proto[p] = methods[p]; // Set up the reserved "constructor", "superclass", and "classname" // properties of the prototype. proto.constructor = constructor; proto.superclass = superclass; // classname is set only if a name was actually specified. if (classname) proto.classname = classname; // Verify that our prototype provides all of the methods it is supposed to. for(var i = 0; i < provides.length; i++) { // for each class var c = provides[i]; for(var p in c.prototype) { // for each property if (typeof c.prototype[p] != "function") continue; // methods only if (p == "constructor" || p == "superclass") continue; // Check that we have a method with the same name and that // it has the same number of declared arguments. If so, move on if (p in proto && typeof proto[p] == "function" && proto[p].length == c.prototype[p].length) continue; // Otherwise, throw an exception throw new Error("Class " + classname + " does not provide method "+ c.classname + "." + p); } } // Associate the prototype object with the constructor function constructor.prototype = proto; // Copy static properties to the constructor for(var p in statics) constructor[p] = data.statics[p]; // Finally, return the constructor function return constructor;}</pre><div class="lefttitle" style="padding:0px; text-align: right"><a href="index.html" tppabs="http://www.davidflanagan.com/javascript5/index.html">Table of Examples</a></div><p><script type="text/javascript">amazon_ad_tag="davidflanagancom"; amazon_ad_width="300"; amazon_ad_height="250"; amazon_ad_logo="hide";</script><script type="text/javascript" src="../../www.assoc-amazon.com/s/ads.js" tppabs="http://www.assoc-amazon.com/s/ads.js"></script></div></body></html>?? 快捷鍵說明
復制代碼
Ctrl + C
搜索代碼
Ctrl + F
全屏模式
F11
切換主題
Ctrl + Shift + D
顯示快捷鍵
?
增大字號
Ctrl + =
減小字號
Ctrl + -