What's new in DWR version 3

What’s new in DWR v3 Joe Walker DWR Lead Developer SitePen UK

Recap Since we last talked ... Named Parameters Binary Files JavaScript Extending Java Better Reverse Ajax Data Sync: Dojo Data Store JSON / JSONP / JSON-RPC Varargs and Overloaded Methods What’s Next © SitePen, Inc. 2008. All Rights Reserved

Marshalling Types Primitive types, and their Object counterparts int, boolean, long, ﬂoat, double, etc Obvious classes String, Date, BigDecimal, BigInteger, Enum, etc Arrays and Collections Map, List, Set, Iterator, ... JavaBeans and Objects XML objects DOM, XOM, JDom, Dom4J © SitePen, Inc. 2008. All Rights Reserved

Named Parameters Java: public interface Person { ... } public class Employee implements Person { ... } public class Manager extends Employee { ... } public HumanResources { public void addPerson(Person p) { ... } } JavaScript: Manager m = new Manager(); HumanResources.addPerson(m); © SitePen, Inc. 2008. All Rights Reserved

Lightweight Named Parameters Java: public interface Person { ... } public class Employee implements Person { ... } public class Manager extends Employee { ... } public HumanResources { public void addPerson(Person p) { ... } } JavaScript: var m = { $dwrClassName:'Manager', firstname:'Joe', ...}; HumanResources.addPerson(m); © SitePen, Inc. 2008. All Rights Reserved

Binary Files: File Upload DWR has always had a long list of things that it will marshall including Dates, DOM trees, etc In addition, DWR will now marshall binary ﬁles just as if they were the text resources it handles now © SitePen, Inc. 2008. All Rights Reserved

Binary Files: File Upload Java: public Remoted { public void receiveBinaryFile(byte[] uploaded) { ... } } HTML: <input id='fileId' type='file'/> JavaScript: var binary = dwr.util.getValue('fileId'); Remoted.receiveBinaryFile(binary); © SitePen, Inc. 2008. All Rights Reserved

Binary Files: File Upload Will marshall to: • byte[] • java.awt.BufferedImage • java.io.InputStream • org.directwebremoting.io.FileTransfer (gives access to ﬁlename and mime-type in addition to the contents) © SitePen, Inc. 2008. All Rights Reserved

Binary Files: Download Java: public Remoted { public void getPDF(String contents) { ByteArrayOutputStream buf = new ByteArrayOutputStream(); Document doc = new Document(); PdfWriter.getInstance(doc, buf); doc.open(); doc.add(new Paragraph(contents)); doc.close(); return new FileTransfer(\"ex.pdf\", \"application/pdf\", buf.toByteArray()); } JavaScript: Remoted.getPDF('Joe', function(data) { dwr.engine.openInDownload(data); }); © SitePen, Inc. 2008. All Rights Reserved

Javascript extending Java Java: public interface BazListener { void somethingChanged(String msg); } public class Remote { public void addBazListener(BazListener bl) { ... } public void calledLater() { for (BazListener bl : listeners) bl.somethingChanged(\"JS objects can implement Java interfaces\"); } ... } JavaScript: function BazListener() {this.$dwrByRef;} BazListener.prototype.somethingChanged = function(msg){alert(msg);}; var bl = new BazListener(); Remote.addBazListener(bl); © SitePen, Inc. 2008. All Rights Reserved

Scalable Reverse Ajax Reverse Ajax proxies no longer take a list of ScriptSessions in the constructor, they just write to the current ‘destination’ The Browser API allows you to change the current ‘destination’ © SitePen, Inc. 2008. All Rights Reserved

Scalable Reverse Ajax // The default destination is the browser // that caused the current action to happen. Window.alert(\"Hello\"); // Non DWR thread have no default destination Thread t = new Thread(new Runnable()) { public void run() { // Error Window.alert(\"Hello\"); } }); © SitePen, Inc. 2008. All Rights Reserved

Scalable Reverse Ajax // Set the destination to be all browsers that // are looking at the current page Browser.withCurrentPage(new Runnable()) { public void run() { Window.alert(\"Hello\"); } }); // Set the destination to be all browsers that // are looking at the current page Browser.withCurrentPage(\"index.html\", new Runnable()) { public void run() { Window.alert(\"Hello\"); } }); © SitePen, Inc. 2008. All Rights Reserved

Scalable Reverse Ajax // Broadcast to everyone Browser.withAllSessions(...); // Broadcast to subsets Browser.with*Filtered(scriptSesssionFilter, ...); // To a known individual Browser.withSession(sessionId, ...); © SitePen, Inc. 2008. All Rights Reserved

Reverse Ajax APIs: JS Level // Low level: Use server-side W3C DOM methods Element ele = doc.createElement(\"p\"); ScriptSessions.addFunctionCall( \"document.body.appendChild\", ele); © SitePen, Inc. 2008. All Rights Reserved

Reverse Ajax APIs: DOM Level // Some methods from Window and Document import javax.servlet.http.Cookie; import org.directwebremoting.ui.browser.Document; Cookie c = new Cookie(\"name\", \"value\"); Document.setCookie(c); © SitePen, Inc. 2008. All Rights Reserved

Reverse Ajax APIs: dwr.util // dwr.util in Java import org.directwebremoting.ui.dwr.Util; String[] opts = new String[] {\"one\",\"two\",...}; Util.addOptions(\"li\", opts); © SitePen, Inc. 2008. All Rights Reserved

Reverse Ajax APIs: TIBCO GI // TIBCO General Interface in Java import jsx3.GI; import jsx3.app.*; import jsx3.gui.*; Server server = GI.getServer(\"servername\"); TextBox phoneNum = server.getJSXByName(\"phoneNum\", TextBox.class); phoneNum.setValue(\"servername\"); © SitePen, Inc. 2008. All Rights Reserved

Reverse Ajax APIs: Dojo // Dojo in Java import org.dojotoolkit.dijit.Dijit; import org.dojotoolkit.dijit.Editor; Editor e = Dijit.byId(\"price\", Editor.class); e.setValue(42); © SitePen, Inc. 2008. All Rights Reserved

Scalable Reverse Ajax Why? • A full range of APIs for dynamically updating client data • DWR doesn’t do widgets, but it does talk to the people that do Drapgen can be used to create and maintain large APIs © SitePen, Inc. 2008. All Rights Reserved

Dojo Data Store Java: // Load the data somehow Map<String, Person> ppl = ...; // Create an implementation of StoreProvider to hold the data MapStoreProvider provider = new MapStoreProvider(ppl, Person.class); // Tell DWR to expose the data to the internet Directory.register(\"testServerData\", provider); © SitePen, Inc. 2008. All Rights Reserved

Dojo Data Store HTML: <table id=\"grid\" dojoType=\"dojox.grid.DataGrid\" ><tr> <th field=\"name\" width=\"120px\" editable=\"true\">Name</th> ... </tr></table> JavaScript: dojo.registerModulePath(\"dwr\", \"path/from/dojo/to/dwr\"); dojo.require(\"dwr.data.Store\"); dwrStore = new dwr.data.Store(\"testServerData\", { subscribe:true }); dijit.byId(\"grid\").setStore(dwrStore); © SitePen, Inc. 2008. All Rights Reserved

Dojo Data Store Java: // The StoreProvider from earlier MapStoreProvider provider = ... // Get a representation of the internal data Map<String, Person> data = provider.asMap(); // Mutate it data.addPerson(new Person(...)); // The browsers viewing the data automagically update © SitePen, Inc. 2008. All Rights Reserved

JSONP Java: public class Demo { public sayHello(String name) { return \"Hello, \" + name; } } Shell: $ wget http://example.com/app/dwr/jsonp/Demo/sayHello? ↩ callback=callback&param0=\"Joe\" -> callback(\"Hello, Joe\"); © SitePen, Inc. 2008. All Rights Reserved

JSONP Dojo: dojo.io.script.get({ url:'http://example.com/app/dwr/jsonp/Demo/sayHello', content:{param:'Joe'} }).addCallback(function() { ... }); JQuery: $.ajax({ dataType:'jsonp', data:'param=Joe', url:'http://example.com/app/dwr/jsonp/Demo/sayHello', success:function () { ... }, }); © SitePen, Inc. 2008. All Rights Reserved

JSON / JSONP / JSON-RPC Why? • To allow DWR to remote functions to things other than a DWR client • ‘DWRP’ is designed to be something we can change without a long deprecation process © SitePen, Inc. 2008. All Rights Reserved

Varargs Why? • It saves the hassle of wrapping options in an array or collection before a method is called Alert: • It could break some corner cases when mixing servlet parameters with normal parameters © SitePen, Inc. 2008. All Rights Reserved

Overloaded Methods Java: public Remoted { public void method(int num) { log.debug(\"int method called with \" + num); } public void method(String str) { log.debug(\"String method called with \" + str); } } JavaScript: Remoted.method(\"String Param\"); Remoted.method(42); © SitePen, Inc. 2008. All Rights Reserved

What's new in DWR version 3

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