Offline data synchronization

Question

We are trying to use the offline data synchronization feature of DMS using data modeling.
Below is the only example we found on adobe site and its working.
http://help.adobe.com/en_US/LiveCycleDataServicesES/3.1/Developing/WS4ba8596dc6a25eff-56f1 c8f4126dcd963c6-8000.html
Also we have read “occasionally connected client”  and Model driver applications documentation in lcds31 user guide.
Is there any other example to demonstrate how to use the offline data sync?. We don’t want to generate the  Java code and use assembler class for this .
In our example we are implementing the SearchCustomerList Funcationality. Based of search criteria a list of customers is displayed to the user.
Beloew are the configuration settings
                        var cs:ChannelSet = new ChannelSet();
                        var customChannel:Channel = new RTMPChannel("my-rtmp",
                                    "rtmp://wpuag85393:2038");
                        cs.addChannel(customChannel);
                        this.serviceControl.channelSet=cs;
                        this.serviceControl.autoCommit = false;
                        this.serviceControl.autoConnect = false;
                        this.serviceControl.autoSaveCache = true;
                        this.serviceControl.offlineAdapter = new
                                    com.deere.itarch.adapter.MaintainCustomerBeanOfflineAdapter();
                        this.serviceControl.fallBackToLocalFill=true;
                        this.serviceControl.encryptLocalCache = true;
                        this.serviceControl.cacheID = "localCache";
CASE I:
Below is our understanding of offline data sync. for our implementation.
·          LCDS server is started and application is connected to the server.
·          User enters search criteria and clicks the Search Button.
·          Data is fetched and displayed on the screen.
As autoSaveCache is set to true it should automatically save result in local cache
·          Shut down the LCDS server.
·          Close the earlier Search Window.
·          Run the application and open the customer search page.
·          Enter the same search criteria and click search.
·          Result : Nothing is displayed on screen. ( No data fetched from local cache)
Many times we are getting error cannot connect to server ( when server is running 50% of times)
We also tried setting reconnect strategy to instance. ( but this is also not working)
Also can you please provide end-to-end sample for data synchronization.

Answer 1

Good to see you got a little further along with your application. I'm not sure why setting autoconnect to true helped.
Regarding your search, I'm not sure how you implemented that but the easiest way to do it with model-driven development is by using a criteria filter. It will result in a new query in your offline adapter. You just add a filter element to an entity in your model and in that filter you specify your like expression. I added one to the doc sample app as an example. When you generate code for the offline adapter, you'll be able to see the proper structure for the like clause too. I'm including my fml and offline adapter source below.I've also included the MXML so you can see how I called the new filter method from the client. After I saved to the local cache, and I went offline, I successfully performed the search in the client app. There were no issues with it.
Here's my fml. The new filter is in bold text. I should have chose a better filter name, since it will generate a method called byProductName, which is very close to the existing getByProductName. But you'll get the idea. Once you add the filter, just remember to redeploy your model and regenerate your code.
Regarding your question about associations, I'll look into that, but I think you would generate offline adapters for each entity involved in the association and your relationships should behave correctly offline.
<model xmlns="http://ns.adobe.com/Fiber/1.0">
    <annotation name="DMS">
        <item name="datasource">java:/comp/env/jdbc/ordersDB</item>
        <item name="hibernate.dialect">org.hibernate.dialect.HSQLDialect</item>
    </annotation>
    <entity name="Product" persistent="true">
        <annotation name="ServerProperties" ServerType="LCDS"/>
        <annotation name="DMS" Table="PRODUCT"/>
        <annotation name="VisualModeler" width="114" height="88" x="66" y="79"/>
        <annotation name="ActionScriptGeneration" GenerateOfflineAdapter="true" OfflineAdapterPackage="com.adobe.offline"/>
        <id name="productid" type="integer">
            <annotation name="DMS" ColumnName="PRODUCTID"/>
        </id>
        <property name="description" type="string" length="255">
            <annotation name="DMS" ColumnName="DESCRIPTION"/>
        </property>
        <property name="price" type="float">
            <annotation name="DMS" ColumnName="PRICE"/>
        </property>
        <property name="productname" type="string" length="255">
            <annotation name="DMS" ColumnName="PRODUCTNAME"/>
        </property>
        <filter name="byProductName" criteria="productname like"/>
    </entity>
</model>
Here's the new query for byProductName in my offline adapter, which contains a valid like clause. That section of the adapter is in bold text.
* This is an auto-generated offline adapter for the Product entity.
package com.adobe.offline
import mx.core.mx_internal;
import mx.data.SQLiteOfflineAdapter;
import mx.utils.StringUtil;
use namespace mx_internal;
public class ProductOfflineAdapter extends SQLiteOfflineAdapter
     * Return an appropriate SQL WHERE clause for a given set of fill parameters.
     * @param originalArgs fill parameters
     * @return String representing the WHERE clause for a SQLite SQL
    override protected function getQueryCriteria(originalArgs:Array):String
        var args:Array = originalArgs.concat();
        var filterName:String = args.shift();
        var names:Array = new Array();
        switch (filterName)
            case "byProductName":
                // JPQL: select Product_alias from Product Product_alias where Product_alias.productname like :productname
                // Preview: productname like :productname                
                names.push(getTargetColumnName(["productname"]));
                return StringUtil.substitute("{0} like :productname", names);
                break;
        return super.getQueryCriteria(originalArgs);
Here's my modified MXML. I'm still calling getAll(), but after that I use the new filter to filter the results/datagrid display to just the subset that matches the string I input in the search field. This results in a new call to productService.byProductName(), which is the client-side method generated from the filter element in my model.
<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009"
                       xmlns:s="library://ns.adobe.com/flex/spark"
                       xmlns:mx="library://ns.adobe.com/flex/mx" xmlns:OfflineAIRAPP="TestOfflineApp.*"
                       preinitialize="app_preinitializeHandler(event)"
                       creationComplete="windowedapplication1_creationCompleteHandler(event)">
    <fx:Script>
        <![CDATA[
            import com.adobe.offline.ProductOfflineAdapter;
            import mx.controls.Alert;
            import mx.events.FlexEvent;
            import mx.messaging.Channel;
            import mx.messaging.ChannelSet;
            import mx.messaging.channels.RTMPChannel;
            import mx.messaging.events.ChannelEvent;
            import mx.rpc.AsyncToken;
            import mx.rpc.events.FaultEvent;
            import mx.rpc.events.ResultEvent;
            public var myOfflineAdapter:ProductOfflineAdapter;
            public function channelConnectHandler(event:ChannelEvent):void
                productService.serviceControl.autoConnect=false;
            protected function 
                app_preinitializeHandler(event:FlexEvent):void
                var cs:ChannelSet = new ChannelSet();
                var customChannel:Channel = new RTMPChannel("my-rtmp",
                    "rtmp://localhost:2037");
                cs.addChannel(customChannel);
                productService.serviceControl.channelSet=cs;
                customChannel.addEventListener(ChannelEvent.CONNECT,
                    channelConnectHandler);
            protected function dataGrid_creationCompleteHandler(event:FlexEvent):void
                getAllResult.token = productService.getAll();
            protected function
                windowedapplication1_creationCompleteHandler(event:FlexEvent):void
                productService.serviceControl.autoCommit = false;
                productService.serviceControl.autoConnect = true;
                productService.serviceControl.autoSaveCache = true;                
                productService.serviceControl.fallBackToLocalFill=true;
                productService.serviceControl.encryptLocalCache = true;
                productService.serviceControl.cacheID = "myOfflineCache4";
            protected function connectBtn_clickHandler(event:MouseEvent):void
                productService.serviceControl.connect();
            protected function disconnectBtn_clickHandler(event:MouseEvent):void
                productService.serviceControl.disconnect();
            protected function commitBtn_clickHandler(event:MouseEvent):void
                productService.serviceControl.commit();
            protected function saveCacheBtn_clickHandler(event:MouseEvent):void
                productService.serviceControl.saveCache();
            protected function clearCacheBtn_clickHandler(event:MouseEvent):void
                productService.serviceControl.clearCache();
            protected function button_clickHandler(event:MouseEvent):void
                getAllResult.token = productService.byProductName("%"+key.text+"%");
        ]]>
    </fx:Script>
    <fx:Declarations>
        <mx:TraceTarget />       
        <s:CallResponder id="getAllResult" />
        <OfflineAIRAPP:ProductService id="productService"
                                      fault="Alert.show(event.fault.faultString + '\n' +
                                      event.fault.faultDetail)"/>
        <s:CallResponder id="byProductNameResult"/>
        </fx:Declarations>
    <mx:DataGrid editable="true" x="141" y="10" id="dataGrid"
                 creationComplete="dataGrid_creationCompleteHandler(event)"
                 dataProvider="{getAllResult.lastResult}">
        <mx:columns>
            <mx:DataGridColumn headerText="productid" dataField="productid"/>
            <mx:DataGridColumn headerText="description" dataField="description"/>
            <mx:DataGridColumn headerText="price" dataField="price"/>
            <mx:DataGridColumn headerText="productname" dataField="productname"/>
        </mx:columns>
    </mx:DataGrid>
    <s:Button x="10" y="246" label="Connect" click="connectBtn_clickHandler(event)"
              id="connectBtn" width="84" height="30"/>
    <s:Button x="112" y="204" label="Save to Local Cache" id="saveCacheBtn"
              click="saveCacheBtn_clickHandler(event)" height="30"/>
    <s:Button x="110" y="246" label="Commit to Server" id="commitBtn"
              click="commitBtn_clickHandler(event)" width="135" height="30"/>
    <s:Button x="10" y="204" label="Disconnect" id="DisconnectBtn"
              click="disconnectBtn_clickHandler(event)" height="30"/>
    <s:Label x="270" y="204" text="{'Commit Required: ' +
             productService.serviceControl.commitRequired}"/>
    <s:Label x="270" y="246" text="{'Connected: ' +
             productService.serviceControl.connected}"/>
    <s:TextInput x="10" y="19" id="key"/>
    <s:Button x="10" y="49" label="Search" id="button" click="button_clickHandler(event)"/>   
</s:WindowedApplication>