Java Juice

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After trying many recipes, here is the one that I go back to each year.

Dave Lieberman's recipe makes makes a great pie out of simple ingredients and the crust is way better than the factory made pre-packaged ones that you would find on store shelves.

I usually make a lighter version by going light on butter and cream and using just egg whites.

Here is a possible solution to the Datatables - Spring MVC integration requirements that I had come up with earlier. I will walk through from the Controller to the Model objects and then the Datatables integration.

Step 1

Write your controller using semantic DataTablesRequest and DataTablesResponse classes as part of your controller methods.

@Controller @RequestMapping(value="/api") public class DataController { @RequestMapping(value="/data", method= RequestMethod.POST) public @ResponseBody DataTablesResponse<Object> getData(@RequestBody DataTablesRequest dtReq, HttpServletResponse response) { return new DataTablesResponse<Object>(); } }

Step 2

The DataTablesRequest and DataTablesResponse are the interface to Datatables in our Java system. I use standard Jackson annotations to serialize the JSON object into a Java object. Note that I have modified the standard Datatables API on the wire to make it possible to do a straight-forward serialization into a Java object.

The most notable change is how attributes such as sSearch_0=value1, sSearch_1=value2,...,sSearch_n=valuen are converted into an array like sSearch=[value1,value2,...,value3]

I am not handling all types of attributes and values right now, but this is the basic outline....

/** * { * "sEcho":1, * "iColumns":7, * "sColumns":"", * "iDisplayStart":0, * "iDisplayLength":10, * "amDataProp":[0,1,2,3,4,5,6], * "sSearch":"", * "bRegex":false, * "asSearch":["","","","","","",""], * "abRegex":[false,false,false,false,false,false,false], * "abSearchable":[true,true,true,true,true,true,true], * "iSortingCols":1, * "aiSortCol":[0], * "asSortDir":["asc"], * "abSortable":[true,true,true,true,true,true,true] * } * * @author inder */ public class DataTablesRequest implements Serializable{ @JsonProperty(value = "sEcho") public String echo; @JsonProperty(value = "iColumns") public int numColumns; @JsonProperty(value = "sColumns") public String columns; @JsonProperty(value = "iDisplayStart") public int displayStart; @JsonProperty(value = "iDisplayLength") public int displayLength; //has to be revisited for Object type dataProps. @JsonProperty(value = "amDataProp") public List<Integer> dataProp; @JsonProperty(value = "sSearch") public String searchQuery; @JsonProperty(value = "asSearch") public List<String> columnSearches; @JsonProperty(value = "bRegex") public boolean hasRegex; @JsonProperty (value = "abRegex") public List<Boolean> regexColumns; @JsonProperty (value = "abSearchable") public List<Boolean> searchColumns; @JsonProperty (value = "iSortingCols") public int sortingCols; @JsonProperty(value = "aiSortCol") public List<Integer> sortedColumns; @JsonProperty(value = "asSortDir") public List<String> sortDirections; @JsonProperty(value = "abSortable") public List<Boolean> sortableColumns; public DataTablesRequest() { } }

DataTablesResponse is represented here:

/** * The data tables response. * @author inder */ public class DataTablesResponse <T> implements Serializable { @JsonProperty(value = "iTotalRecords") public int totalRecords; @JsonProperty(value = "iTotalDisplayRecords") public int totalDisplayRecords; @JsonProperty(value = "sEcho") public String echo; @JsonProperty(value = "sColumns") public String columns; @JsonProperty(value = "aaData") public List<T> data = new ArrayList<T>(); public DataTablesResponse() { } }

Step 3

Finally the jQuery code which converts the Datatables request into a JSON object, which is POSTed to the server. Look closely at the stringify_aoData method - it will convert the various sub-attributes of the aoData object into an object represented that can be consumed easily by the server.

Also, you can convert the modifiers array into a dictionary/map to avoid the scan which is currently being done for each attribute.

$(document).ready(function() { var stringify_aoData = function (aoData) { var o = {}; var modifiers = ['mDataProp_', 'sSearch_', 'iSortCol_', 'bSortable_', 'bRegex_', 'bSearchable_', 'sSortDir_']; jQuery.each(aoData, function(idx,obj) { if (obj.name) { for (var i=0; i < modifiers.length; i++) { if (obj.name.substring(0, modifiers[i].length) == modifiers[i]) { var index = parseInt(obj.name.substring(modifiers[i].length)); var key = 'a' + modifiers[i].substring(0, modifiers[i].length-1); if (!o[key]) { o[key] = []; } console.log('index=' + index); o[key][index] = obj.value; //console.log(key + ".push(" + obj.value + ")"); return; } } //console.log(obj.name+"=" + obj.value); o[obj.name] = obj.value; } else { o[idx] = obj; } }); return JSON.stringify(o); }; $('#example').dataTable( { "bProcessing": true, "bServerSide": true, "sAjaxSource": "/api/data", "fnServerData": function ( sSource, aoData, fnCallback ) { $.ajax( { dataType: 'json', contentType: "application/json;charset=UTF-8", type: 'POST', url: sSource, data: stringify_aoData(aoData), success: fnCallback, error : function (e) { alert (e); } } ); } } ); } );

As I said in my earlier Kindle Fire review that this is a great device if you do not already own a tablet (iPad is the only other worthwhile tablet out there).

Unfortunately, I do own an iPad and love the responsiveness, ease of use and it's integration with Apple TV.

The sluggishness of the Kindle Fire just killed the deal for me - too slow to respond to touch which manifests itself in various ways - launching applications, editing emails, web browsing, multi-tasking - you name it!

Sorry, Jeff, but the "one last thing" was not good enough. This thing has a 1GHz dual-core processor for God's sake. I am sure you can do much better than that with it.

Good

great looking device with a rubber base which rests very well on any surface, including glass.

slick interface with no buttons on the device except power. Hardly feels like an Android device.

very easy migration from iphone to fire, although you will miss the home button and gestures like swipe to delete. I am pretty sure this is an Android limitation.

price!!

Not so good

not as smooth as the ipad experience, but great for version 1.

jitter when running multiple apps. I am not sure if this is due to low powered hardware or just bad software.

Bad

placement of the power button. It comes in the way of holding the device vertically. I have switched off the device accidentally many times because the thumb would just touch the button while reading a book or playing a game.

performance can get very sluggish at times. Again, if you have never used an ipad before, you will have a much easier time accepting/getting used to it.

Conclusion

if you donot already own a tablet, then buy the Fire. Its a no-brainer due to the price.