parse.js

对java中如何使用Ajax技术

/*
	Copyright (c) 2004-2006, The Dojo Foundation
	All Rights Reserved.

	Licensed under the Academic Free License version 2.1 or above OR the
	modified BSD license. For more information on Dojo licensing, see:

		http://dojotoolkit.org/community/licensing.shtml
*/

dojo.provide("dojo.widget.Parse");
dojo.require("dojo.widget.Manager");
dojo.require("dojo.dom");

//
// dojoML parser should be moved out of 'widget', codifying the difference between a 'component'
// and a 'widget'. A 'component' being anything that can be generated from a tag.
//
// a particular dojoML tag would be handled by a registered tagHandler with a hook for a default handler
// if the widget system is loaded, a widget builder would be attach itself as the default handler
// 
// widget tags are no longer registered themselves:
// they are now arbitrarily namespaced, so we cannot register them all, and the non-prefixed portions 
// are no longer guaranteed unique 
// 
// therefore dojo.widget.tags should go with this parser code out of the widget module
//

dojo.widget.Parse = function(/*Object*/fragment){
	this.propertySetsList = [];
	this.fragment = fragment;

	this.createComponents = function(/*Object*/frag, /*Object*/parentComp){
		var comps = [];
		var built = false;
		// if we have items to parse/create at this level, do it!
		try{
			if(frag && frag.tagName && (frag != frag.nodeRef)){
				
				// these are in fact, not ever for widgets per-se anymore, 
				// but for other markup elements (aka components)
				var djTags = dojo.widget.tags;
				
				// we split so that you can declare multiple 
				// non-destructive components from the same ctor node
				var tna = String(frag.tagName).split(";");
				for(var x=0; x<tna.length; x++){
					var ltn = tna[x].replace(/^\s+|\s+$/g, "").toLowerCase();
					// FIXME: unsure what this does
					frag.tagName = ltn;
					var ret;
					if(djTags[ltn]){
						built = true;
						ret = djTags[ltn](frag, this, parentComp, frag.index);
						comps.push(ret);
					}else{
						// we require a namespace prefix, default to dojo:
						if(ltn.indexOf(":") == -1){
							ltn = "dojo:"+ltn;
						}
						// FIXME: handling failure condition correctly?
						// ret = djTags[ltn](frag, this, parentComp, frag.index);
						ret = dojo.widget.buildWidgetFromParseTree(ltn, frag, this, parentComp, frag.index);
						if(ret){
							built = true;
							comps.push(ret);
						}
					}
				}
			}
		}catch(e){
			dojo.debug("dojo.widget.Parse: error:", e);
			// note, commenting out the next line is breaking several widgets for me
			// throw e;
			// IE is such a pain sometimes
		}
		// if there's a sub-frag, build widgets from that too
		if(!built){
			comps = comps.concat(this.createSubComponents(frag, parentComp));
		}
		return comps; // Array
	}

	this.createSubComponents = function(/*Object*/fragment, /*Object*/parentComp){
		// summary: recurses over a raw JavaScript object structure,
		// and calls the corresponding handler for its normalized tagName if it exists

		var frag, comps = [];
		for(var item in fragment){
			frag = fragment[item];
			if(frag && typeof frag == "object"
				&&(frag!=fragment.nodeRef)
				&&(frag!=fragment.tagName)
				&&(!dojo.dom.isNode(frag))){// needed in IE when we have event.connected to the domNode
				comps = comps.concat(this.createComponents(frag, parentComp));
			}
		}
		return comps; // Array
	}

	this.parsePropertySets = function(/*Object*/fragment){
		// summary: checks the top level of a raw JavaScript object
		//	structure for any propertySets.  It stores an array of references to 
		//	propertySets that it finds.
		return [];
		/*
		var propertySets = [];
		for(var item in fragment){
			if((fragment[item]["tagName"] == "dojo:propertyset")){
				propertySets.push(fragment[item]);
			}
		}
		// FIXME: should we store these propertySets somewhere for later retrieval
		this.propertySetsList.push(propertySets);
		return propertySets;
		*/
	}

	this.parseProperties = function(/*Object*/fragment){
		// summary: parseProperties checks a raw JavaScript object structure for
		//	properties, and returns a hash of properties that it finds.
		var properties = {};
		for(var item in fragment){
			// FIXME: need to check for undefined?
			// case: its a tagName or nodeRef
			if((fragment[item] == fragment.tagName)||(fragment[item] == fragment.nodeRef)){
				// do nothing
			}else{
				var frag = fragment[item];
				if(frag.tagName && dojo.widget.tags[frag.tagName.toLowerCase()]){
					// TODO: it isn't a property or property set, it's a fragment, 
					// so do something else
					// FIXME: needs to be a better/stricter check
					// TODO: handle xlink:href for external property sets
				}else if(frag[0] && frag[0].value!="" && frag[0].value!=null){
					try{
						// FIXME: need to allow more than one provider
						if(item.toLowerCase() == "dataprovider"){
							var _this = this;
							this.getDataProvider(_this, frag[0].value);
							properties.dataProvider = this.dataProvider;
						}
						properties[item] = frag[0].value;
						var nestedProperties = this.parseProperties(frag);
						// FIXME: this kind of copying is expensive and inefficient!
						for(var property in nestedProperties){
							properties[property] = nestedProperties[property];
						}
					}catch(e){ dojo.debug(e); }
				}
				switch(item.toLowerCase()){
				case "checked":
				case "disabled":
					if (typeof properties[item] != "boolean"){ 
						properties[item] = true;
					}
					break;
				}
			} 
		}
		return properties; // Object
	}

	this.getDataProvider = function(/*Object*/objRef, /*String*/dataUrl){
		// FIXME: this is currently sync.  To make this async, we made need to move 
		//this step into the widget ctor, so that it is loaded when it is needed 
		// to populate the widget
		dojo.io.bind({
			url: dataUrl,
			load: function(type, evaldObj){
				if(type=="load"){
					objRef.dataProvider = evaldObj;
				}
			},
			mimetype: "text/javascript",
			sync: true
		});
	}

	this.getPropertySetById = function(propertySetId){
		// summary: returns the propertySet that matches the provided id
		for(var x = 0; x < this.propertySetsList.length; x++){
			if(propertySetId == this.propertySetsList[x]["id"][0].value){
				return this.propertySetsList[x];
			}
		}
		return ""; // String
	}
	
	//FIXME: doesn't use the componentType param?
	this.getPropertySetsByType = function(componentType){
		// summary: returns the propertySet(s) that match(es) the
	 	// provided componentClass

		var propertySets = [];
		for(var x=0; x < this.propertySetsList.length; x++){
			var cpl = this.propertySetsList[x];
			var cpcc = cpl.componentClass || cpl.componentType || null; //FIXME: is componentType supposed to be an indirect reference?
			var propertySetId = this.propertySetsList[x]["id"][0].value;
			if(cpcc && (propertySetId == cpcc[0].value)){
				propertySets.push(cpl);
			}
		}
		return propertySets; // Array
	}

	this.getPropertySets = function(/*Object*/fragment){
		// summary: returns the propertySet for a given component fragment

		var ppl = "dojo:propertyproviderlist";
		var propertySets = [];
		var tagname = fragment.tagName;
		if(fragment[ppl]){ 
			var propertyProviderIds = fragment[ppl].value.split(" ");
			// FIXME: should the propertyProviderList attribute contain #
			// 		  syntax for reference to ids or not?
			// FIXME: need a better test to see if this is local or external
			// FIXME: doesn't handle nested propertySets, or propertySets that
			// 		  just contain information about css documents, etc.
			for(var propertySetId in propertyProviderIds){
				if((propertySetId.indexOf("..")==-1)&&(propertySetId.indexOf("://")==-1)){
					// get a reference to a propertySet within the current parsed structure
					var propertySet = this.getPropertySetById(propertySetId);
					if(propertySet != ""){
						propertySets.push(propertySet);
					}
				}else{
					// FIXME: add code to parse and return a propertySet from
					// another document
					// alex: is this even necessaray? Do we care? If so, why?
				}
			}
		}
		// we put the typed ones first so that the parsed ones override when
		// iteration happens.
		return this.getPropertySetsByType(tagname).concat(propertySets); // Array
	}

	this.createComponentFromScript = function(/*Node*/nodeRef, /*String*/componentName, /*Object*/properties, /*String?*/ns){
		// summary:
		// nodeRef: the node to be replaced... in the future, we might want to add 
		// an alternative way to specify an insertion point
		// componentName: the expected dojo widget name, i.e. Button of ContextMenu
		// properties: an object of name value pairs
		// ns: the namespace of the widget.  Defaults to "dojo"

		properties.fastMixIn = true;			
		// FIXME: we pulled it apart and now we put it back together ... 
		var ltn = (ns || "dojo") + ":" + componentName.toLowerCase();
		if(dojo.widget.tags[ltn]){
			return [dojo.widget.tags[ltn](properties, this, null, null, properties)]; // Array
		}
		return [dojo.widget.buildWidgetFromParseTree(ltn, properties, this, null, null, properties)]; // Array
	}
}

dojo.widget._parser_collection = {"dojo": new dojo.widget.Parse() };

dojo.widget.getParser = function(/*String?*/name){
	if(!name){ name = "dojo"; }
	if(!this._parser_collection[name]){
		this._parser_collection[name] = new dojo.widget.Parse();
	}
	return this._parser_collection[name];
}

dojo.widget.createWidget = function(/*String*/name, /*String*/props, /*Node*/refNode, /*String*/position){
	// summary: Creates widget
	// name: The name of the widget to create with optional namespace prefix,
	//	e.g."ns:widget", namespace defaults to "dojo".
	// props: Key-Value pairs of properties of the widget
	// refNode: If the position argument is specified, this node is used as
	//	a reference for inserting this node into a DOM tree; else
	//	the widget becomes the domNode
	// position: The position to insert this widget's node relative to the
	//	refNode argument

	var isNode = false;
	var isNameStr = (typeof name == "string");
	if(isNameStr){
		var pos = name.indexOf(":");
		var ns = (pos > -1) ? name.substring(0,pos) : "dojo";
		if(pos > -1){ name = name.substring(pos+1); }
		var lowerCaseName = name.toLowerCase();
		var namespacedName = ns + ":" + lowerCaseName;
		isNode = (dojo.byId(name) && !dojo.widget.tags[namespacedName]); 
	}

	if((arguments.length == 1) && (isNode || !isNameStr)){
		// we got a DOM node 
		var xp = new dojo.xml.Parse(); 
		// FIXME: we should try to find the parent! 
		var tn = isNode ? dojo.byId(name) : name; 
		return dojo.widget.getParser().createComponents(xp.parseElement(tn, null, true))[0]; 
	}

	function fromScript(placeKeeperNode, name, props, ns){
		props[namespacedName] = { 
			dojotype: [{value: lowerCaseName}],
			nodeRef: placeKeeperNode,
			fastMixIn: true
		};
		props.ns = ns;
		return dojo.widget.getParser().createComponentFromScript(placeKeeperNode, name, props, ns);
	}

	props = props||{};
	var notRef = false;
	var tn = null;
	var h = dojo.render.html.capable;
	if(h){
		tn = document.createElement("span");
	}
	if(!refNode){
		notRef = true;
		refNode = tn;
		if(h){
			dojo.body().appendChild(refNode);
		}
	}else if(position){
		dojo.dom.insertAtPosition(tn, refNode, position);
	}else{ // otherwise don't replace, but build in-place
		tn = refNode;
	}
	var widgetArray = fromScript(tn, name.toLowerCase(), props, ns);
	if(	(!widgetArray)||(!widgetArray[0])||
		(typeof widgetArray[0].widgetType == "undefined") ){
		throw new Error("createWidget: Creation of \"" + name + "\" widget failed.");
	}
	try{
		if(notRef && widgetArray[0].domNode.parentNode){
			widgetArray[0].domNode.parentNode.removeChild(widgetArray[0].domNode);
		}
	}catch(e){
		/* squelch for Safari */
		dojo.debug(e);
	}
	return widgetArray[0]; // Widget
}