Tuesday, October 21, 2008

Apache CXF: Open Source Service Framework - The Client

Earlier this year I posted Apache CXF: Open Source Service Framework to demonstrate how easy it is to create a simple echo Web Service with Apache CXF. Now I would like to post an example client for that service using Apache CXF.

First, we need our dependencies: (download them here)

...
commons-logging-1.1.1.jar
cxf-2.1.2.jar
FastInfoset-1.2.2.jar
geronimo-activation_1.1_spec-1.0.2.jar
geronimo-annotation_1.0_spec-1.1.1.jar
geronimo-javamail_1.4_spec-1.3.jar
geronimo-jaxws_2.1_spec-1.0.jar
geronimo-servlet_2.5_spec-1.2.jar
geronimo-stax-api_1.0_spec-1.0.1.jar
geronimo-ws-metadata_2.0_spec-1.1.2.jar
jaxb-api-2.1.jar
jaxb-impl-2.1.7.jar
jaxen-1.1.jar
jdom-1.0.jar
jetty-6.1.9.jar
jetty-util-6.1.9.jar
neethi-2.0.4.jar
saaj-api-1.3.jar
saaj-impl-1.3.jar
spring-beans-2.0.8.jar
spring-context-2.0.8.jar
spring-core-2.0.8.jar
spring-web-2.0.8.jar
stax-utils-20060502.jar
wsdl4j-1.6.2.jar
wstx-asl-3.2.4.jar
xml-resolver-1.2.jar
XmlSchema-1.4.2.jar
...

Then we need the Echo Service interface (this should be provided for us from our service providers) :

...
package com.thejavajar.service;

import javax.jws.WebService;

@WebService
public interface EchoServiceIfc {

    public String echo(String text);
    }
    ...

The last piece of the pie is our client that makes the call out to http://localhost:9000/echo, where our service lives, in order to invoke an operation on the service.

...
package com.thejavajar.client;

import org.apache.cxf.frontend.ClientProxyFactoryBean;
import com.thejavajar.service.EchoServiceIfc;

public class EchoClient {

    public static void main(String[] args) {

        String request = new String("test 1");

        ClientProxyFactoryBean factory = new ClientProxyFactoryBean();
        factory.setServiceClass(EchoServiceIfc.class);
        factory.setAddress("http://localhost:9000/echo");
        EchoServiceIfc client = (EchoServiceIfc) factory.create();

        System.out.println("Sending: " + request);
        String response = client.echo(request);
        System.out.println("Returned: " + response);

        System.exit(0);
    }
}
...

All we need to do is run our main method in our EchoClient class and we will get something like:

...
Sending: test 1
Returned: test 1
...


That's all folks. Obviously, this example, along with our previously posted service, is not solving complex problems that we might face in our current Java development endeavors but it provides us with peak into Apache CXF and opens up more people to a technology that I enjoy working with.

Eclipse Project: apache-cxf-echo-client.zip

Sunday, October 19, 2008

Editable Flex Datagrid and Grails

I have been really digging into Flex lately and I have been complimenting Flex's incredibly nice UI capabilities with services written on Grails. I am extremely impressed with Flex and Grails really helps me get things up and running very quickly (you already know this if you are using Grails). Let's look at a quick example of where I am using one domain class and a few simple Grails actions in a controller in order to provide search and editing capabilities to a simple Flex application based on a datagrid.

The Grails domain class, Item.groovy:

...
class Item {

    String name
    String brand
    String line
}
...

The Grails controller class ItemController.groovy:

...
class ItemController {

    def search = {
        if(!params.max) {
            params.max = 100
        }
        if(!params.name) {
            params.name = ""
        }

        def itemList = Item.findAllByNameLike("$params.name%",[max:params.max])

        render(contentType:"text/xml") {
            items {
                for(i in itemList) {
                    item {
                        id(i.id)
                        name(i.name)
                        brand(i.brand)
                        line(i.line)
                    }
                }
            }
        }
    }

    def save = {
        if(params.id) {
            def item = Item.get(params.id)

            if(item) {
                item.properties = params
                if(!item.hasErrors() && item.save()) {
                    render ""
                }
                else {
                    render ""
                }
            }
        }
    }
}
...


I also added this to the conf/BootStrap.groovy so I would have some data to work with once I started up the Grails applicaiton. The code below creates 1,000 items during start-up:

...
def init = { servletContext ->

    (1..1000).each {
        new Item(name: "Item $it", brand: "My Brand", line: "My Line").save()
    }
}
...

I mostly worked with only 1,000 items, but I increased this up to 100,000 items to put it through some tests and it worked very nicely.

Now let's dive right into the MXML. Here is the entire itemlist.mxml file:

...
<?xml version="1.0"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">

<mx:Script>
<![CDATA[

import mx.controls.Alert;
import mx.events.DataGridEvent;
import mx.rpc.events.FaultEvent;
import mx.rpc.events.ResultEvent;

[Bindable]
private var itemId:String;

[Bindable]
private var itemName:String;

[Bindable]
private var itemBrand:String;

[Bindable]
private var itemLine:String;

private function sendItemData(event:DataGridEvent):void
{
var myEditor:TextInput = TextInput(event.currentTarget.itemEditorInstance);
itemName = myEditor.text;

itemId = event.currentTarget.editedItemRenderer.data["id"];
itemBrand = event.currentTarget.editedItemRenderer.data["brand"];
itemLine = event.currentTarget.editedItemRenderer.data["line"];

itemSaveService.send();
}

protected function filterList():void
{
itemSearchService.send();
}

private function fault_Handler(event:FaultEvent):void
{
Alert.show(event.fault.message, "Could not load items.");
}
]]>
</mx:Script>

<mx:HTTPService
id="itemSaveService"
method="POST"
url="http://localhost:8080/itemlist/item/save"
resultFormat="e4x"
fault="fault_Handler(event);"
showBusyCursor="true">
<mx:request xmlns="">
<id>{itemId}</id>
<name>{itemName}</name>
<brand>{itemBrand}</brand>
<line>{itemLine}</line>
</mx:request>
</mx:HTTPService>

<mx:HTTPService
id="itemSearchService"
method="GET"
url="http://localhost:8080/itemlist/item/search"
resultFormat="e4x"
fault="fault_Handler(event);"
showBusyCursor="true">
<mx:request xmlns="">
<name>{searchBox.text}</name>
</mx:request>
</mx:HTTPService>

<mx:Panel title="Item List" height="100%" width="100%" paddingTop="10" paddingLeft="10" paddingRight="10">

<mx:Label text="Search:"/><mx:TextInput id="searchBox" enter="filterList();"/>

<mx:DataGrid id="dg" width="100%" height="50%" rowCount="5"
dataProvider="{itemSearchService.lastResult.item}"
editable="true"
itemEditEnd="sendItemData(event);">
<mx:columns>
<mx:DataGridColumn dataField="id" headerText="Id" editable="false"/>
<mx:DataGridColumn dataField="name" headerText="Name"/>
<mx:DataGridColumn dataField="brand" headerText="Brand" editable="false"/>
<mx:DataGridColumn dataField="line" headerText="Line" editable="false"/>
</mx:columns>
</mx:DataGrid>

</mx:Panel>
</mx:Application>
...

Now that all of the code is out on the table, we can start to dissect what is happening with the Flex UI.

When the application starts up:




Once we type in "Item " and press enter:




When we click on a value under the "Name" column in our datagrid:




We have 2 HTTPService's setup to send requests back to our Grails controller at http://localhost:8080/itemlist/item/save and http://localhost:8080/itemlist/item/search. The first service call will send all the item data to the ItemController's save action and the second one will send our search box's text to the ItemController's search action. We have ActionScript functions that handle the "Enter" key press event on the search box and we also have a function that will be called after the datagrid field has been edited.

Most of the code is pretty self explanatory but if you have any questions, feel free to contact me. Also, Marcel Overdijk has some great posts on Grails and Flex that can really help out when you get stuck.