abstract factory pattern - Page 300

how to retrieve data from db and display it in list?

- by raji

In the below code I am passing catID to db.getNews(catID) super.onCreate(savedInstanceState); setContentView(R.layout.newslist); Bundle extras = getIntent().getExtras(); int catID = extras.getInt("cat_id"); mInflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE); final ListView lv = (ListView) findViewById(R.id.category); lv.setAdapter(new ArrayAdapter<String>(this, R.layout.newslist, db.getNews(catID)){ public View getView(int position, View convertView, ViewGroup parent) { View row; if (null == convertView) { row = mInflater.inflate(R.layout.newslist, null); } else { row = convertView; } TextView tv = (TextView) row.findViewById(R.id.newslist_text); tv.setText(getItem(position)); return row; } }); the getnews(int catid) function is below: public NewsItemCursor getNews(int catID) { String sql = "SELECT title FROM news WHERE catid = " + catID + " ORDER BY id ASC"; SQLiteDatabase d = getReadableDatabase(); NewsItemCursor c = (NewsItemCursor) d.rawQueryWithFactory( new NewsItemCursor.Factory(), sql, null, null); c.moveToFirst(); d.close(); return c; } But I'm getting bug as array adapter undefined... Can anyone help me to resolve this, and retrieve data to make it display in list.

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const pod and std::vector

- by Baz

To get this code to compile: std::vector<Foo> factory() { std::vector<Foo> data; return data; } I have to define my POD like this: struct Foo { const int i; const int j; Foo(const int _i, const int _j): i(_i), j(_j) {} Foo(Foo& foo): i(foo.i), j(foo.j){} Foo operator=(Foo& foo) { Foo f(foo.i, foo.j); return f; } }; Is this the correct approach for defining a pod where I'm not interested in changing the pod members after creation? Why am I forced to define a copy constructor and overload the assignment operator? Is this compatible for different platform implementations of std::vector? Is it wrong in your opinion to have const PODS like this? Should I just leave them as non-const?

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BlackBerry Field class extension will not paint.

- by jlindenbaum

Using JRE 5.0.0, simulator device is an 8520. On a screen I am using a FlowFieldManager(Manager.VERTICAL_SCROLL) and adding Fields to it to show data. When I do this.flowManager = new FlowFieldManager(Manager.VERTICAL_SCROLL); Field field = new Field() { protected void paint(Graphics graphics) { graphics.drawTest("Test", 0, 0); } protected void layout(int width, int height) { this.setExtend(300, 300); // just testing } } this.flowManager.add(field); The screen renders correctly and 'Test' appears on the screen. If, on the other hand, I try and abstract this into a class called CustomField with the same properties and add it to the flow manager the render will not happen. Debugging shows that the device enters into the Object, into the layout function, but not the paint function. I can't figure out why the paint function is not called when I extend Field. The 4.5 API says that layout and paint are the only functions that I really need to extend. (getPreferredWidth and getPreferredHeight will be used to calculate screen sizes etc.) Thanks in advance.

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Checking if a function has C-linkage at compile-time [unsolvable]

- by scjohnno

Is there any way to check if a given function is declared with C-linkage (that is, with extern "C") at compile-time? I am developing a plugin system. Each plugin can supply factory functions to the plugin-loading code. However, this has to be done via name (and subsequent use of GetProcAddress or dlsym). This requires that the functions be declared with C-linkage so as to prevent name-mangling. It would be nice to be able to throw a compiler error if the referred-to function is declared with C++-linkage (as opposed to finding out at runtime when a function with that name does not exist). Here's a simplified example of what I mean: extern "C" void my_func() { } void my_other_func() { } // Replace this struct with one that actually works template<typename T> struct is_c_linkage { static const bool value = true; }; template<typename T> void assertCLinkage(T *func) { static_assert(is_c_linkage<T>::value, "Supplied function does not have C-linkage"); } int main() { assertCLinkage(my_func); // Should compile assertCLinkage(my_other_func); // Should NOT compile } Is there a possible implementation of is_c_linkage that would throw a compiler error for the second function, but not the first? I'm not sure that it's possible (though it may exist as a compiler extension, which I'd still like to know of). Thanks.

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Is Maven really flexible?

- by Dima

I understand how Maven works with .java files in src/java/main. But may it be used for a more general case? Let us put it more abstract: Suppose I already have some a.exe that read some (not necessarily only .java) sources from directories A1, A2, A3 and puts some files (maybe some are generated .java) to directories B1, B2. I also have some b.exe that currently reads files from B1, B2, B3 and generates something else. Some more similar steps. (A real life problem stands behind). I would like to right POM.xml file so that maven will do this work. Is that possible? I assume that a.exe and b.exe should be warped as maven plugings. Next, in Maven docs I see : <build> <sourceDirectory>${basedir}/src/main/java</sourceDirectory> <scriptSourceDirectory>${basedir}/src/main/scripts</scriptSourceDirectory> <testSourceDirectory>${basedir}/src/test/java</testSourceDirectory> <outputDirectory>${basedir}/target/classes</outputDirectory> <testOutputDirectory>${basedir}/target/test-classes</testOutputDirectory> ... </build> What bothers me is that "sourceDirectory" looks by itself as a hard coded name. Will Maven accept A1 and A2 tags instead?

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Dont understand the concept of extends in URL.openConnection() in JAVA

- by user1722361

Hi I am trying to learn JAVA deeply and so I am digging into the JDK source code in the following lines: URL url = new URL("http://www.google.com"); URLConnection tmpConn = url.openConnection(); I attached the source code and set the breakpoint at the second line and stepped into the code. I can see the code flow is: URL.openConnection() - sun.net.www.protocol.http.Handler.openConnection() I have two questions about this First In URL.openConnection() the code is: public URLConnection openConnection() throws java.io.IOException { return handler.openConnection(this); } handler is an object of URLStreamHandler, define as blow transient URLStreamHandler handler; But URLStreamHandler is a abstract class and method openConnection() is not implement in it so when handler calls this method, it should go to find a subclass who implement this method, right? But there are a lot classes who implement this methods in sun.net.www.protocol (like http.Hanlder, ftp.Handler ) How should the code know which "openConnection" method it should call? In this example, this handler.openConnection() will go into http.Handler and it is correct. (if I set the url as ftp://www.google.com, it will go into ftp.Handler) I cannot understand the mechanism. second. I have attached the source code so I can step into the JDK and see the variables but for many classes like sun.net.www.protocol.http.Handler, there are not source code in src.zip. I googled this class and there is source code online I can get but why they did not put it (and many other classes) in the src.zip? Where can I find a comprehensive version of source code? Thanks!

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Force the use of interface instead of concrete implementation in declaration (.NET)

- by gammelgul

In C++, you can do the following: class base_class { public: virtual void do_something() = 0; }; class derived_class : public base_class { private: virtual void do_something() { std::cout << "do_something() called"; } }; The derived_class overrides the method do_something() and makes it private. The effect is, that the only way to call this method is like this: base_class *object = new derived_class(); object->do_something(); If you declare the object as of type derived_class, you can't call the method because it's private: derived_class *object = new derived_class(); object->do_something(); // --> error C2248: '::derived_class::do_something' : cannot access private member declared in class '::derived_class' I think this is quite nice, because if you create an abstract class that is used as an interface, you can make sure that nobody accidentally declares a field as the concrete type, but always uses the interface class. Since in C# / .NET in general, you aren't allowed to narrow the access from public to private when overriding a method, is there a way to achieve a similar effect here?

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Node.js Adventure - When Node Flying in Wind

- by Shaun

In the first post of this series I mentioned some popular modules in the community, such as underscore, async, etc.. I also listed a module named “Wind (zh-CN)”, which is created by one of my friend, Jeff Zhao (zh-CN). Now I would like to use a separated post to introduce this module since I feel it brings a new async programming style in not only Node.js but JavaScript world. If you know or heard about the new feature in C# 5.0 called “async and await”, or you learnt F#, you will find the “Wind” brings the similar async programming experience in JavaScript. By using “Wind”, we can write async code that looks like the sync code. The callbacks, async stats and exceptions will be handled by “Wind” automatically and transparently. What’s the Problem: Dense “Callback” Phobia Let’s firstly back to my second post in this series. As I mentioned in that post, when we wanted to read some records from SQL Server we need to open the database connection, and then execute the query. In Node.js all IO operation are designed as async callback pattern which means when the operation was done, it will invoke a function which was taken from the last parameter. For example the database connection opening code would be like this. 1: sql.open(connectionString, function(error, conn) { 2: if(error) { 3: // some error handling code 4: } 5: else { 6: // connection opened successfully 7: } 8: }); And then if we need to query the database the code would be like this. It nested in the previous function. 1: sql.open(connectionString, function(error, conn) { 2: if(error) { 3: // some error handling code 4: } 5: else { 6: // connection opened successfully 7: conn.queryRaw(command, function(error, results) { 8: if(error) { 9: // failed to execute this command 10: } 11: else { 12: // records retrieved successfully 13: } 14: }; 15: } 16: }); Assuming if we need to copy some data from this database to another then we need to open another connection and execute the command within the function under the query function. 1: sql.open(connectionString, function(error, conn) { 2: if(error) { 3: // some error handling code 4: } 5: else { 6: // connection opened successfully 7: conn.queryRaw(command, function(error, results) { 8: if(error) { 9: // failed to execute this command 10: } 11: else { 12: // records retrieved successfully 13: target.open(targetConnectionString, function(error, t_conn) { 14: if(error) { 15: // connect failed 16: } 17: else { 18: t_conn.queryRaw(copy_command, function(error, results) { 19: if(error) { 20: // copy failed 21: } 22: else { 23: // and then, what do you want to do now... 24: } 25: }; 26: } 27: }; 28: } 29: }; 30: } 31: }); This is just an example. In the real project the logic would be more complicated. This means our application might be messed up and the business process will be fragged by many callback functions. I would like call this “Dense Callback Phobia”. This might be a challenge how to make code straightforward and easy to read, something like below. 1: try 2: { 3: // open source connection 4: var s_conn = sqlConnect(s_connectionString); 5: // retrieve data 6: var results = sqlExecuteCommand(s_conn, s_command); 7: 8: // open target connection 9: var t_conn = sqlConnect(t_connectionString); 10: // prepare the copy command 11: var t_command = getCopyCommand(results); 12: // execute the copy command 13: sqlExecuteCommand(s_conn, t_command); 14: } 15: catch (ex) 16: { 17: // error handling 18: } What’s the Problem: Sync-styled Async Programming Similar as the previous problem, the callback-styled async programming model makes the upcoming operation as a part of the current operation, and mixed with the error handling code. So it’s very hard to understand what on earth this code will do. And since Node.js utilizes non-blocking IO mode, we cannot invoke those operations one by one, as they will be executed concurrently. For example, in this post when I tried to copy the records from Windows Azure SQL Database (a.k.a. WASD) to Windows Azure Table Storage, if I just insert the data into table storage one by one and then print the “Finished” message, I will see the message shown before the data had been copied. This is because all operations were executed at the same time. In order to make the copy operation and print operation executed synchronously I introduced a module named “async” and the code was changed as below. 1: async.forEach(results.rows, 2: function (row, callback) { 3: var resource = { 4: "PartitionKey": row[1], 5: "RowKey": row[0], 6: "Value": row[2] 7: }; 8: client.insertEntity(tableName, resource, function (error) { 9: if (error) { 10: callback(error); 11: } 12: else { 13: console.log("entity inserted."); 14: callback(null); 15: } 16: }); 17: }, 18: function (error) { 19: if (error) { 20: error["target"] = "insertEntity"; 21: res.send(500, error); 22: } 23: else { 24: console.log("all done."); 25: res.send(200, "Done!"); 26: } 27: }); It ensured that the “Finished” message will be printed when all table entities had been inserted. But it cannot promise that the records will be inserted in sequence. It might be another challenge to make the code looks like in sync-style? 1: try 2: { 3: forEach(row in rows) { 4: var entity = { /* ... */ }; 5: tableClient.insert(tableName, entity); 6: } 7: 8: console.log("Finished"); 9: } 10: catch (ex) { 11: console.log(ex); 12: } How “Wind” Helps “Wind” is a JavaScript library which provides the control flow with plain JavaScript for asynchronous programming (and more) without additional pre-compiling steps. It’s available in NPM so that we can install it through “npm install wind”. Now let’s create a very simple Node.js application as the example. This application will take some website URLs from the command arguments and tried to retrieve the body length and print them in console. Then at the end print “Finish”. I’m going to use “request” module to make the HTTP call simple so I also need to install by the command “npm install request”. The code would be like this. 1: var request = require("request"); 2: 3: // get the urls from arguments, the first two arguments are `node.exe` and `fetch.js` 4: var args = process.argv.splice(2); 5: 6: // main function 7: var main = function() { 8: for(var i = 0; i < args.length; i++) { 9: // get the url 10: var url = args[i]; 11: // send the http request and try to get the response and body 12: request(url, function(error, response, body) { 13: if(!error && response.statusCode == 200) { 14: // log the url and the body length 15: console.log( 16: "%s: %d.", 17: response.request.uri.href, 18: body.length); 19: } 20: else { 21: // log error 22: console.log(error); 23: } 24: }); 25: } 26: 27: // finished 28: console.log("Finished"); 29: }; 30: 31: // execute the main function 32: main(); Let’s execute this application. (I made them in multi-lines for better reading.) 1: node fetch.js 2: "http://www.igt.com/us-en.aspx" 3: "http://www.igt.com/us-en/games.aspx" 4: "http://www.igt.com/us-en/cabinets.aspx" 5: "http://www.igt.com/us-en/systems.aspx" 6: "http://www.igt.com/us-en/interactive.aspx" 7: "http://www.igt.com/us-en/social-gaming.aspx" 8: "http://www.igt.com/support.aspx" Below is the output. As you can see the finish message was printed at the beginning, and the pages’ length retrieved in a different order than we specified. This is because in this code the request command, console logging command are executed asynchronously and concurrently. Now let’s introduce “Wind” to make them executed in order, which means it will request the websites one by one, and print the message at the end. First of all we need to import the “Wind” package and make sure the there’s only one global variant named “Wind”, and ensure it’s “Wind” instead of “wind”. 1: var Wind = require("wind"); Next, we need to tell “Wind” which code will be executed asynchronously so that “Wind” can control the execution process. In this case the “request” operation executed asynchronously so we will create a “Task” by using a build-in helps function in “Wind” named Wind.Async.Task.create. 1: var requestBodyLengthAsync = function(url) { 2: return Wind.Async.Task.create(function(t) { 3: request(url, function(error, response, body) { 4: if(error || response.statusCode != 200) { 5: t.complete("failure", error); 6: } 7: else { 8: var data = 9: { 10: uri: response.request.uri.href, 11: length: body.length 12: }; 13: t.complete("success", data); 14: } 15: }); 16: }); 17: }; The code above created a “Task” from the original request calling code. In “Wind” a “Task” means an operation will be finished in some time in the future. A “Task” can be started by invoke its start() method, but no one knows when it actually will be finished. The Wind.Async.Task.create helped us to create a task. The only parameter is a function where we can put the actual operation in, and then notify the task object it’s finished successfully or failed by using the complete() method. In the code above I invoked the request method. If it retrieved the response successfully I set the status of this task as “success” with the URL and body length. If it failed I set this task as “failure” and pass the error out. Next, we will change the main() function. In “Wind” if we want a function can be controlled by Wind we need to mark it as “async”. This should be done by using the code below. 1: var main = eval(Wind.compile("async", function() { 2: })); When the application is running, Wind will detect “eval(Wind.compile(“async”, function” and generate an anonymous code from the body of this original function. Then the application will run the anonymous code instead of the original one. In our example the main function will be like this. 1: var main = eval(Wind.compile("async", function() { 2: for(var i = 0; i < args.length; i++) { 3: try 4: { 5: var result = $await(requestBodyLengthAsync(args[i])); 6: console.log( 7: "%s: %d.", 8: result.uri, 9: result.length); 10: } 11: catch (ex) { 12: console.log(ex); 13: } 14: } 15: 16: console.log("Finished"); 17: })); As you can see, when I tried to request the URL I use a new command named “$await”. It tells Wind, the operation next to $await will be executed asynchronously, and the main thread should be paused until it finished (or failed). So in this case, my application will be pause when the first response was received, and then print its body length, then try the next one. At the end, print the finish message. Finally, execute the main function. The full code would be like this. 1: var request = require("request"); 2: var Wind = require("wind"); 3: 4: var args = process.argv.splice(2); 5: 6: var requestBodyLengthAsync = function(url) { 7: return Wind.Async.Task.create(function(t) { 8: request(url, function(error, response, body) { 9: if(error || response.statusCode != 200) { 10: t.complete("failure", error); 11: } 12: else { 13: var data = 14: { 15: uri: response.request.uri.href, 16: length: body.length 17: }; 18: t.complete("success", data); 19: } 20: }); 21: }); 22: }; 23: 24: var main = eval(Wind.compile("async", function() { 25: for(var i = 0; i < args.length; i++) { 26: try 27: { 28: var result = $await(requestBodyLengthAsync(args[i])); 29: console.log( 30: "%s: %d.", 31: result.uri, 32: result.length); 33: } 34: catch (ex) { 35: console.log(ex); 36: } 37: } 38: 39: console.log("Finished"); 40: })); 41: 42: main().start(); Run our new application. At the beginning we will see the compiled and generated code by Wind. Then we can see the pages were requested one by one, and at the end the finish message was printed. Below is the code Wind generated for us. As you can see the original code, the output code were shown. 1: // Original: 2: function () { 3: for(var i = 0; i < args.length; i++) { 4: try 5: { 6: var result = $await(requestBodyLengthAsync(args[i])); 7: console.log( 8: "%s: %d.", 9: result.uri, 10: result.length); 11: } 12: catch (ex) { 13: console.log(ex); 14: } 15: } 16: 17: console.log("Finished"); 18: } 19: 20: // Compiled: 21: /* async << function () { */ (function () { 22: var _builder_$0 = Wind.builders["async"]; 23: return _builder_$0.Start(this, 24: _builder_$0.Combine( 25: _builder_$0.Delay(function () { 26: /* var i = 0; */ var i = 0; 27: /* for ( */ return _builder_$0.For(function () { 28: /* ; i < args.length */ return i < args.length; 29: }, function () { 30: /* ; i ++) { */ i ++; 31: }, 32: /* try { */ _builder_$0.Try( 33: _builder_$0.Delay(function () { 34: /* var result = $await(requestBodyLengthAsync(args[i])); */ return _builder_$0.Bind(requestBodyLengthAsync(args[i]), function (result) { 35: /* console.log("%s: %d.", result.uri, result.length); */ console.log("%s: %d.", result.uri, result.length); 36: return _builder_$0.Normal(); 37: }); 38: }), 39: /* } catch (ex) { */ function (ex) { 40: /* console.log(ex); */ console.log(ex); 41: return _builder_$0.Normal(); 42: /* } */ }, 43: null 44: ) 45: /* } */ ); 46: }), 47: _builder_$0.Delay(function () { 48: /* console.log("Finished"); */ console.log("Finished"); 49: return _builder_$0.Normal(); 50: }) 51: ) 52: ); 53: /* } */ }) How Wind Works Someone may raise a big concern when you find I utilized “eval” in my code. Someone may assume that Wind utilizes “eval” to execute some code dynamically while “eval” is very low performance. But I would say, Wind does NOT use “eval” to run the code. It only use “eval” as a flag to know which code should be compiled at runtime. When the code was firstly been executed, Wind will check and find “eval(Wind.compile(“async”, function”. So that it knows this function should be compiled. Then it utilized parse-js to analyze the inner JavaScript and generated the anonymous code in memory. Then it rewrite the original code so that when the application was running it will use the anonymous one instead of the original one. Since the code generation was done at the beginning of the application was started, in the future no matter how long our application runs and how many times the async function was invoked, it will use the generated code, no need to generate again. So there’s no significant performance hurt when using Wind. Wind in My Previous Demo Let’s adopt Wind into one of my previous demonstration and to see how it helps us to make our code simple, straightforward and easy to read and understand. In this post when I implemented the functionality that copied the records from my WASD to table storage, the logic would be like this. 1, Open database connection. 2, Execute a query to select all records from the table. 3, Recreate the table in Windows Azure table storage. 4, Create entities from each of the records retrieved previously, and then insert them into table storage. 5, Finally, show message as the HTTP response. But as the image below, since there are so many callbacks and async operations, it’s very hard to understand my logic from the code. Now let’s use Wind to rewrite our code. First of all, of course, we need the Wind package. Then we need to include the package files into project and mark them as “Copy always”. Add the Wind package into the source code. Pay attention to the variant name, you must use “Wind” instead of “wind”. 1: var express = require("express"); 2: var async = require("async"); 3: var sql = require("node-sqlserver"); 4: var azure = require("azure"); 5: var Wind = require("wind"); Now we need to create some async functions by using Wind. All async functions should be wrapped so that it can be controlled by Wind which are open database, retrieve records, recreate table (delete and create) and insert entity in table. Below are these new functions. All of them are created by using Wind.Async.Task.create. 1: sql.openAsync = function (connectionString) { 2: return Wind.Async.Task.create(function (t) { 3: sql.open(connectionString, function (error, conn) { 4: if (error) { 5: t.complete("failure", error); 6: } 7: else { 8: t.complete("success", conn); 9: } 10: }); 11: }); 12: }; 13: 14: sql.queryAsync = function (conn, query) { 15: return Wind.Async.Task.create(function (t) { 16: conn.queryRaw(query, function (error, results) { 17: if (error) { 18: t.complete("failure", error); 19: } 20: else { 21: t.complete("success", results); 22: } 23: }); 24: }); 25: }; 26: 27: azure.recreateTableAsync = function (tableName) { 28: return Wind.Async.Task.create(function (t) { 29: client.deleteTable(tableName, function (error, successful, response) { 30: console.log("delete table finished"); 31: client.createTableIfNotExists(tableName, function (error, successful, response) { 32: console.log("create table finished"); 33: if (error) { 34: t.complete("failure", error); 35: } 36: else { 37: t.complete("success", null); 38: } 39: }); 40: }); 41: }); 42: }; 43: 44: azure.insertEntityAsync = function (tableName, entity) { 45: return Wind.Async.Task.create(function (t) { 46: client.insertEntity(tableName, entity, function (error, entity, response) { 47: if (error) { 48: t.complete("failure", error); 49: } 50: else { 51: t.complete("success", null); 52: } 53: }); 54: }); 55: }; Then in order to use these functions we will create a new function which contains all steps for data copying. 1: var copyRecords = eval(Wind.compile("async", function (req, res) { 2: try { 3: } 4: catch (ex) { 5: console.log(ex); 6: res.send(500, "Internal error."); 7: } 8: })); Let’s execute steps one by one with the “$await” keyword introduced by Wind so that it will be invoked in sequence. First is to open the database connection. 1: var copyRecords = eval(Wind.compile("async", function (req, res) { 2: try { 3: // connect to the windows azure sql database 4: var conn = $await(sql.openAsync(connectionString)); 5: console.log("connection opened"); 6: } 7: catch (ex) { 8: console.log(ex); 9: res.send(500, "Internal error."); 10: } 11: })); Then retrieve all records from the database connection. 1: var copyRecords = eval(Wind.compile("async", function (req, res) { 2: try { 3: // connect to the windows azure sql database 4: var conn = $await(sql.openAsync(connectionString)); 5: console.log("connection opened"); 6: // retrieve all records from database 7: var results = $await(sql.queryAsync(conn, "SELECT * FROM [Resource]")); 8: console.log("records selected. count = %d", results.rows.length); 9: } 10: catch (ex) { 11: console.log(ex); 12: res.send(500, "Internal error."); 13: } 14: })); After recreated the table, we need to create the entities and insert them into table storage. 1: var copyRecords = eval(Wind.compile("async", function (req, res) { 2: try { 3: // connect to the windows azure sql database 4: var conn = $await(sql.openAsync(connectionString)); 5: console.log("connection opened"); 6: // retrieve all records from database 7: var results = $await(sql.queryAsync(conn, "SELECT * FROM [Resource]")); 8: console.log("records selected. count = %d", results.rows.length); 9: if (results.rows.length > 0) { 10: // recreate the table 11: $await(azure.recreateTableAsync(tableName)); 12: console.log("table created"); 13: // insert records in table storage one by one 14: for (var i = 0; i < results.rows.length; i++) { 15: var entity = { 16: "PartitionKey": results.rows[i][1], 17: "RowKey": results.rows[i][0], 18: "Value": results.rows[i][2] 19: }; 20: $await(azure.insertEntityAsync(tableName, entity)); 21: console.log("entity inserted"); 22: } 23: } 24: } 25: catch (ex) { 26: console.log(ex); 27: res.send(500, "Internal error."); 28: } 29: })); Finally, send response back to the browser. 1: var copyRecords = eval(Wind.compile("async", function (req, res) { 2: try { 3: // connect to the windows azure sql database 4: var conn = $await(sql.openAsync(connectionString)); 5: console.log("connection opened"); 6: // retrieve all records from database 7: var results = $await(sql.queryAsync(conn, "SELECT * FROM [Resource]")); 8: console.log("records selected. count = %d", results.rows.length); 9: if (results.rows.length > 0) { 10: // recreate the table 11: $await(azure.recreateTableAsync(tableName)); 12: console.log("table created"); 13: // insert records in table storage one by one 14: for (var i = 0; i < results.rows.length; i++) { 15: var entity = { 16: "PartitionKey": results.rows[i][1], 17: "RowKey": results.rows[i][0], 18: "Value": results.rows[i][2] 19: }; 20: $await(azure.insertEntityAsync(tableName, entity)); 21: console.log("entity inserted"); 22: } 23: // send response 24: console.log("all done"); 25: res.send(200, "All done!"); 26: } 27: } 28: catch (ex) { 29: console.log(ex); 30: res.send(500, "Internal error."); 31: } 32: })); If we compared with the previous code we will find now it became more readable and much easy to understand. It’s very easy to know what this function does even though without any comments. When user go to URL “/was/copyRecords” we will execute the function above. The code would be like this. 1: app.get("/was/copyRecords", function (req, res) { 2: copyRecords(req, res).start(); 3: }); And below is the logs printed in local compute emulator console. As we can see the functions executed one by one and then finally the response back to me browser. Scaffold Functions in Wind Wind provides not only the async flow control and compile functions, but many scaffold methods as well. We can build our async code more easily by using them. I’m going to introduce some basic scaffold functions here. In the code above I created some functions which wrapped from the original async function such as open database, create table, etc.. All of them are very similar, created a task by using Wind.Async.Task.create, return error or result object through Task.complete function. In fact, Wind provides some functions for us to create task object from the original async functions. If the original async function only has a callback parameter, we can use Wind.Async.Binding.fromCallback method to get the task object directly. For example the code below returned the task object which wrapped the file exist check function. 1: var Wind = require("wind"); 2: var fs = require("fs"); 3: 4: fs.existsAsync = Wind.Async.Binding.fromCallback(fs.exists); In Node.js a very popular async function pattern is that, the first parameter in the callback function represent the error object, and the other parameters is the return values. In this case we can use another build-in function in Wind named Wind.Async.Binding.fromStandard. For example, the open database function can be created from the code below. 1: sql.openAsync = Wind.Async.Binding.fromStandard(sql.open); 2: 3: /* 4: sql.openAsync = function (connectionString) { 5: return Wind.Async.Task.create(function (t) { 6: sql.open(connectionString, function (error, conn) { 7: if (error) { 8: t.complete("failure", error); 9: } 10: else { 11: t.complete("success", conn); 12: } 13: }); 14: }); 15: }; 16: */ When I was testing the scaffold functions under Wind.Async.Binding I found for some functions, such as the Azure SDK insert entity function, cannot be processed correctly. So I personally suggest writing the wrapped method manually. Another scaffold method in Wind is the parallel tasks coordination. In this example, the steps of open database, retrieve records and recreated table should be invoked one by one, but it can be executed in parallel when copying data from database to table storage. In Wind there’s a scaffold function named Task.whenAll which can be used here. Task.whenAll accepts a list of tasks and creates a new task. It will be returned only when all tasks had been completed, or any errors occurred. For example in the code below I used the Task.whenAll to make all copy operation executed at the same time. 1: var copyRecordsInParallel = eval(Wind.compile("async", function (req, res) { 2: try { 3: // connect to the windows azure sql database 4: var conn = $await(sql.openAsync(connectionString)); 5: console.log("connection opened"); 6: // retrieve all records from database 7: var results = $await(sql.queryAsync(conn, "SELECT * FROM [Resource]")); 8: console.log("records selected. count = %d", results.rows.length); 9: if (results.rows.length > 0) { 10: // recreate the table 11: $await(azure.recreateTableAsync(tableName)); 12: console.log("table created"); 13: // insert records in table storage in parallal 14: var tasks = new Array(results.rows.length); 15: for (var i = 0; i < results.rows.length; i++) { 16: var entity = { 17: "PartitionKey": results.rows[i][1], 18: "RowKey": results.rows[i][0], 19: "Value": results.rows[i][2] 20: }; 21: tasks[i] = azure.insertEntityAsync(tableName, entity); 22: } 23: $await(Wind.Async.Task.whenAll(tasks)); 24: // send response 25: console.log("all done"); 26: res.send(200, "All done!"); 27: } 28: } 29: catch (ex) { 30: console.log(ex); 31: res.send(500, "Internal error."); 32: } 33: })); 34: 35: app.get("/was/copyRecordsInParallel", function (req, res) { 36: copyRecordsInParallel(req, res).start(); 37: }); Besides the task creation and coordination, Wind supports the cancellation solution so that we can send the cancellation signal to the tasks. It also includes exception solution which means any exceptions will be reported to the caller function. Summary In this post I introduced a Node.js module named Wind, which created by my friend Jeff Zhao. As you can see, different from other async library and framework, adopted the idea from F# and C#, Wind utilizes runtime code generation technology to make it more easily to write async, callback-based functions in a sync-style way. By using Wind there will be almost no callback, and the code will be very easy to understand. Currently Wind is still under developed and improved. There might be some problems but the author, Jeff, should be very happy and enthusiastic to learn your problems, feedback, suggestion and comments. You can contact Jeff by - Email: [email protected] - Group: https://groups.google.com/d/forum/windjs - GitHub: https://github.com/JeffreyZhao/wind/issues Source code can be download here. Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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Red Gate Coder interviews: Alex Davies

- by Michael Williamson

Alex Davies has been a software engineer at Red Gate since graduating from university, and is currently busy working on .NET Demon. We talked about tackling parallel programming with his actors framework, a scientific approach to debugging, and how JavaScript is going to affect the programming languages we use in years to come. So, if we start at the start, how did you get started in programming? When I was seven or eight, I was given a BBC Micro for Christmas. I had asked for a Game Boy, but my dad thought it would be better to give me a proper computer. For a year or so, I only played games on it, but then I found the user guide for writing programs in it. I gradually started doing more stuff on it and found it fun. I liked creating. As I went into senior school I continued to write stuff on there, trying to write games that weren’t very good. I got a real computer when I was fourteen and found ways to write BASIC on it. Visual Basic to start with, and then something more interesting than that. How did you learn to program? Was there someone helping you out? Absolutely not! I learnt out of a book, or by experimenting. I remember the first time I found a loop, I was like “Oh my God! I don’t have to write out the same line over and over and over again any more. It’s amazing!” When did you think this might be something that you actually wanted to do as a career? For a long time, I thought it wasn’t something that you would do as a career, because it was too much fun to be a career. I thought I’d do chemistry at university and some kind of career based on chemical engineering. And then I went to a careers fair at school when I was seventeen or eighteen, and it just didn’t interest me whatsoever. I thought “I could be a programmer, and there’s loads of money there, and I’m good at it, and it’s fun”, but also that I shouldn’t spoil my hobby. Now I don’t really program in my spare time any more, which is a bit of a shame, but I program all the rest of the time, so I can live with it. Do you think you learnt much about programming at university? Yes, definitely! I went into university knowing how to make computers do anything I wanted them to do. However, I didn’t have the language to talk about algorithms, so the algorithms course in my first year was massively important. Learning other language paradigms like functional programming was really good for breadth of understanding. Functional programming influences normal programming through design rather than actually using it all the time. I draw inspiration from it to write imperative programs which I think is actually becoming really fashionable now, but I’ve been doing it for ages. I did it first! There were also some courses on really odd programming languages, a bit of Prolog, a little bit of C. Having a little bit of each of those is something that I would have never done on my own, so it was important. And then there are knowledge-based courses which are about not programming itself but things that have been programmed like TCP. Those are really important for examples for how to approach things. Did you do any internships while you were at university? Yeah, I spent both of my summers at the same company. I thought I could code well before I went there. Looking back at the crap that I produced, it was only surpassed in its crappiness by all of the other code already in that company. I’m so much better at writing nice code now than I used to be back then. Was there just not a culture of looking after your code? There was, they just didn’t hire people for their abilities in that area. They hired people for raw IQ. The first indicator of it going wrong was that they didn’t have any computer scientists, which is a bit odd in a programming company. But even beyond that they didn’t have people who learnt architecture from anyone else. Most of them had started straight out of university, so never really had experience or mentors to learn from. There wasn’t the experience to draw from to teach each other. In the second half of my second internship, I was being given tasks like looking at new technologies and teaching people stuff. Interns shouldn’t be teaching people how to do their jobs! All interns are going to have little nuggets of things that you don’t know about, but they shouldn’t consistently be the ones who know the most. It’s not a good environment to learn. I was going to ask how you found working with people who were more experienced than you… When I reached Red Gate, I found some people who were more experienced programmers than me, and that was difficult. I’ve been coding since I was tiny. At university there were people who were cleverer than me, but there weren’t very many who were more experienced programmers than me. During my internship, I didn’t find anyone who I classed as being a noticeably more experienced programmer than me. So, it was a shock to the system to have valid criticisms rather than just formatting criticisms. However, Red Gate’s not so big on the actual code review, at least it wasn’t when I started. We did an entire product release and then somebody looked over all of the UI of that product which I’d written and say what they didn’t like. By that point, it was way too late and I’d disagree with them. Do you think the lack of code reviews was a bad thing? I think if there’s going to be any oversight of new people, then it should be continuous rather than chunky. For me I don’t mind too much, I could go out and get oversight if I wanted it, and in those situations I felt comfortable without it. If I was managing the new person, then maybe I’d be keener on oversight and then the right way to do it is continuously and in very, very small chunks. Have you had any significant projects you’ve worked on outside of a job? When I was a teenager I wrote all sorts of stuff. I used to write games, I derived how to do isomorphic projections myself once. I didn’t know what the word was so I couldn’t Google for it, so I worked it out myself. It was horrifically complicated. But it sort of tailed off when I started at university, and is now basically zero. If I do side-projects now, they tend to be work-related side projects like my actors framework, NAct, which I started in a down tools week. Could you explain a little more about NAct? It is a little C# framework for writing parallel code more easily. Parallel programming is difficult when you need to write to shared data. Sometimes parallel programming is easy because you don’t need to write to shared data. When you do need to access shared data, you could just have your threads pile in and do their work, but then you would screw up the data because the threads would trample on each other’s toes. You could lock, but locks are really dangerous if you’re using more than one of them. You get interactions like deadlocks, and that’s just nasty. Actors instead allows you to say this piece of data belongs to this thread of execution, and nobody else can read it. If you want to read it, then ask that thread of execution for a piece of it by sending a message, and it will send the data back by a message. And that avoids deadlocks as long as you follow some obvious rules about not making your actors sit around waiting for other actors to do something. There are lots of ways to write actors, NAct allows you to do it as if it was method calls on other objects, which means you get all the strong type-safety that C# programmers like. Do you think that this is suitable for the majority of parallel programming, or do you think it’s only suitable for specific cases? It’s suitable for most difficult parallel programming. If you’ve just got a hundred web requests which are all independent of each other, then I wouldn’t bother because it’s easier to just spin them up in separate threads and they can proceed independently of each other. But where you’ve got difficult parallel programming, where you’ve got multiple threads accessing multiple bits of data in multiple ways at different times, then actors is at least as good as all other ways, and is, I reckon, easier to think about. When you’re using actors, you presumably still have to write your code in a different way from you would otherwise using single-threaded code. You can’t use actors with any methods that have return types, because you’re not allowed to call into another actor and wait for it. If you want to get a piece of data out of another actor, then you’ve got to use tasks so that you can use “async” and “await” to await asynchronously for it. But other than that, you can still stick things in classes so it’s not too different really. Rather than having thousands of objects with mutable state, you can use component-orientated design, where there are only a few mutable classes which each have a small number of instances. Then there can be thousands of immutable objects. If you tend to do that anyway, then actors isn’t much of a jump. If I’ve already built my system without any parallelism, how hard is it to add actors to exploit all eight cores on my desktop? Usually pretty easy. If you can identify even one boundary where things look like messages and you have components where some objects live on one side and these other objects live on the other side, then you can have a granddaddy object on one side be an actor and it will parallelise as it goes across that boundary. Not too difficult. If we do get 1000-core desktop PCs, do you think actors will scale up? It’s hard. There are always in the order of twenty to fifty actors in my whole program because I tend to write each component as actors, and I tend to have one instance of each component. So this won’t scale to a thousand cores. What you can do is write data structures out of actors. I use dictionaries all over the place, and if you need a dictionary that is going to be accessed concurrently, then you could build one of those out of actors in no time. You can use queuing to marshal requests between different slices of the dictionary which are living on different threads. So it’s like a distributed hash table but all of the chunks of it are on the same machine. That means that each of these thousand processors has cached one small piece of the dictionary. I reckon it wouldn’t be too big a leap to start doing proper parallelism. Do you think it helps if actors get baked into the language, similarly to Erlang? Erlang is excellent in that it has thread-local garbage collection. C# doesn’t, so there’s a limit to how well C# actors can possibly scale because there’s a single garbage collected heap shared between all of them. When you do a global garbage collection, you’ve got to stop all of the actors, which is seriously expensive, whereas in Erlang garbage collections happen per-actor, so they’re insanely cheap. However, Erlang deviated from all the sensible language design that people have used recently and has just come up with crazy stuff. You can definitely retrofit thread-local garbage collection to .NET, and then it’s quite well-suited to support actors, even if it’s not baked into the language. Speaking of language design, do you have a favourite programming language? I’ll choose a language which I’ve never written before. I like the idea of Scala. It sounds like C#, only with some of the niggles gone. I enjoy writing static types. It means you don’t have to writing tests so much. When you say it doesn’t have some of the niggles? C# doesn’t allow the use of a property as a method group. It doesn’t have Scala case classes, or sum types, where you can do a switch statement and the compiler checks that you’ve checked all the cases, which is really useful in functional-style programming. Pattern-matching, in other words. That’s actually the major niggle. C# is pretty good, and I’m quite happy with C#. And what about going even further with the type system to remove the need for tests to something like Haskell? Or is that a step too far? I’m quite a pragmatist, I don’t think I could deal with trying to write big systems in languages with too few other users, especially when learning how to structure things. I just don’t know anyone who can teach me, and the Internet won’t teach me. That’s the main reason I wouldn’t use it. If I turned up at a company that writes big systems in Haskell, I would have no objection to that, but I wouldn’t instigate it. What about things in C#? For instance, there’s contracts in C#, so you can try to statically verify a bit more about your code. Do you think that’s useful, or just not worthwhile? I’ve not really tried it. My hunch is that it needs to be built into the language and be quite mathematical for it to work in real life, and that doesn’t seem to have ended up true for C# contracts. I don’t think anyone who’s tried them thinks they’re any good. I might be wrong. On a slightly different note, how do you like to debug code? I think I’m quite an odd debugger. I use guesswork extremely rarely, especially if something seems quite difficult to debug. I’ve been bitten spending hours and hours on guesswork and not being scientific about debugging in the past, so now I’m scientific to a fault. What I want is to see the bug happening in the debugger, to step through the bug happening. To watch the program going from a valid state to an invalid state. When there’s a bug and I can’t work out why it’s happening, I try to find some piece of evidence which places the bug in one section of the code. From that experiment, I binary chop on the possible causes of the bug. I suppose that means binary chopping on places in the code, or binary chopping on a stage through a processing cycle. Basically, I’m very stupid about how I debug. I won’t make any guesses, I won’t use any intuition, I will only identify the experiment that’s going to binary chop most effectively and repeat rather than trying to guess anything. I suppose it’s quite top-down. Is most of the time then spent in the debugger? Absolutely, if at all possible I will never debug using print statements or logs. I don’t really hold much stock in outputting logs. If there’s any bug which can be reproduced locally, I’d rather do it in the debugger than outputting logs. And with SmartAssembly error reporting, there’s not a lot that can’t be either observed in an error report and just fixed, or reproduced locally. And in those other situations, maybe I’ll use logs. But I hate using logs. You stare at the log, trying to guess what’s going on, and that’s exactly what I don’t like doing. You have to just look at it and see does this look right or wrong. We’ve covered how you get to grip with bugs. How do you get to grips with an entire codebase? I watch it in the debugger. I find little bugs and then try to fix them, and mostly do it by watching them in the debugger and gradually getting an understanding of how the code works using my process of binary chopping. I have to do a lot of reading and watching code to choose where my slicing-in-half experiment is going to be. The last time I did it was SmartAssembly. The old code was a complete mess, but at least it did things top to bottom. There wasn’t too much of some of the big abstractions where flow of control goes all over the place, into a base class and back again. Code’s really hard to understand when that happens. So I like to choose a little bug and try to fix it, and choose a bigger bug and try to fix it. Definitely learn by doing. I want to always have an aim so that I get a little achievement after every few hours of debugging. Once I’ve learnt the codebase I might be able to fix all the bugs in an hour, but I’d rather be using them as an aim while I’m learning the codebase. If I was a maintainer of a codebase, what should I do to make it as easy as possible for you to understand? Keep distinct concepts in different places. And name your stuff so that it’s obvious which concepts live there. You shouldn’t have some variable that gets set miles up the top of somewhere, and then is read miles down to choose some later behaviour. I’m talking from a very much SmartAssembly point of view because the old SmartAssembly codebase had tons and tons of these things, where it would read some property of the code and then deal with it later. Just thousands of variables in scope. Loads of things to think about. If you can keep concepts separate, then it aids me in my process of fixing bugs one at a time, because each bug is going to more or less be understandable in the one place where it is. And what about tests? Do you think they help at all? I’ve never had the opportunity to learn a codebase which has had tests, I don’t know what it’s like! What about when you’re actually developing? How useful do you find tests in finding bugs or regressions? Finding regressions, absolutely. Running bits of code that would be quite hard to run otherwise, definitely. It doesn’t happen very often that a test finds a bug in the first place. I don’t really buy nebulous promises like tests being a good way to think about the spec of the code. My thinking goes something like “This code works at the moment, great, ship it! Ah, there’s a way that this code doesn’t work. Okay, write a test, demonstrate that it doesn’t work, fix it, use the test to demonstrate that it’s now fixed, and keep the test for future regressions.” The most valuable tests are for bugs that have actually happened at some point, because bugs that have actually happened at some point, despite the fact that you think you’ve fixed them, are way more likely to appear again than new bugs are. Does that mean that when you write your code the first time, there are no tests? Often. The chance of there being a bug in a new feature is relatively unaffected by whether I’ve written a test for that new feature because I’m not good enough at writing tests to think of bugs that I would have written into the code. So not writing regression tests for all of your code hasn’t affected you too badly? There are different kinds of features. Some of them just always work, and are just not flaky, they just continue working whatever you throw at them. Maybe because the type-checker is particularly effective around them. Writing tests for those features which just tend to always work is a waste of time. And because it’s a waste of time I’ll tend to wait until a feature has demonstrated its flakiness by having bugs in it before I start trying to test it. You can get a feel for whether it’s going to be flaky code as you’re writing it. I try to write it to make it not flaky, but there are some things that are just inherently flaky. And very occasionally, I’ll think “this is going to be flaky” as I’m writing, and then maybe do a test, but not most of the time. How do you think your programming style has changed over time? I’ve got clearer about what the right way of doing things is. I used to flip-flop a lot between different ideas. Five years ago I came up with some really good ideas and some really terrible ideas. All of them seemed great when I thought of them, but they were quite diverse ideas, whereas now I have a smaller set of reliable ideas that are actually good for structuring code. So my code is probably more similar to itself than it used to be back in the day, when I was trying stuff out. I’ve got more disciplined about encapsulation, I think. There are operational things like I use actors more now than I used to, and that forces me to use immutability more than I used to. The first code that I wrote in Red Gate was the memory profiler UI, and that was an actor, I just didn’t know the name of it at the time. I don’t really use object-orientation. By object-orientation, I mean having n objects of the same type which are mutable. I want a constant number of objects that are mutable, and they should be different types. I stick stuff in dictionaries and then have one thing that owns the dictionary and puts stuff in and out of it. That’s definitely a pattern that I’ve seen recently. I think maybe I’m doing functional programming. Possibly. It’s plausible. If you had to summarise the essence of programming in a pithy sentence, how would you do it? Programming is the form of art that, without losing any of the beauty of architecture or fine art, allows you to produce things that people love and you make money from. So you think it’s an art rather than a science? It’s a little bit of engineering, a smidgeon of maths, but it’s not science. Like architecture, programming is on that boundary between art and engineering. If you want to do it really nicely, it’s mostly art. You can get away with doing architecture and programming entirely by having a good engineering mind, but you’re not going to produce anything nice. You’re not going to have joy doing it if you’re an engineering mind. Architects who are just engineering minds are not going to enjoy their job. I suppose engineering is the foundation on which you build the art. Exactly. How do you think programming is going to change over the next ten years? There will be an unfortunate shift towards dynamically-typed languages, because of JavaScript. JavaScript has an unfair advantage. JavaScript’s unfair advantage will cause more people to be exposed to dynamically-typed languages, which means other dynamically-typed languages crop up and the best features go into dynamically-typed languages. Then people conflate the good features with the fact that it’s dynamically-typed, and more investment goes into dynamically-typed languages. They end up better, so people use them. What about the idea of compiling other languages, possibly statically-typed, to JavaScript? It’s a reasonable idea. I would like to do it, but I don’t think enough people in the world are going to do it to make it pick up. The hordes of beginners are the lifeblood of a language community. They are what makes there be good tools and what makes there be vibrant community websites. And any particular thing which is the same as JavaScript only with extra stuff added to it, although it might be technically great, is not going to have the hordes of beginners. JavaScript is always to be quickest and easiest way for a beginner to start programming in the browser. And dynamically-typed languages are great for beginners. Compilers are pretty scary and beginners don’t write big code. And having your errors come up in the same place, whether they’re statically checkable errors or not, is quite nice for a beginner. If someone asked me to teach them some programming, I’d teach them JavaScript. If dynamically-typed languages are great for beginners, when do you think the benefits of static typing start to kick in? The value of having a statically typed program is in the tools that rely on the static types to produce a smooth IDE experience rather than actually telling me my compile errors. And only once you’re experienced enough a programmer that having a really smooth IDE experience makes a blind bit of difference, does static typing make a blind bit of difference. So it’s not really about size of codebase. If I go and write up a tiny program, I’m still going to get value out of writing it in C# using ReSharper because I’m experienced with C# and ReSharper enough to be able to write code five times faster if I have that help. Any other visions of the future? Nobody’s going to use actors. Because everyone’s going to be running on single-core VMs connected over network-ready protocols like JSON over HTTP. So, parallelism within one operating system is going to die. But until then, you should use actors. More Red Gater Coder interviews

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AngularJS on top of ASP.NET: Moving the MVC framework out to the browser

- by Varun Chatterji

Heavily drawing inspiration from Ruby on Rails, MVC4’s convention over configuration model of development soon became the Holy Grail of .NET web development. The MVC model brought with it the goodness of proper separation of concerns between business logic, data, and the presentation logic. However, the MVC paradigm, was still one in which server side .NET code could be mixed with presentation code. The Razor templating engine, though cleaner than its predecessors, still encouraged and allowed you to mix .NET server side code with presentation logic. Thus, for example, if the developer required a certain <div> tag to be shown if a particular variable ShowDiv was true in the View’s model, the code could look like the following: Fig 1: To show a div or not. Server side .NET code is used in the View Mixing .NET code with HTML in views can soon get very messy. Wouldn’t it be nice if the presentation layer (HTML) could be pure HTML? Also, in the ASP.NET MVC model, some of the business logic invariably resides in the controller. It is tempting to use an antipattern like the one shown above to control whether a div should be shown or not. However, best practice would indicate that the Controller should not be aware of the div. The ShowDiv variable in the model should not exist. A controller should ideally, only be used to do the plumbing of getting the data populated in the model and nothing else. The view (ideally pure HTML) should render the presentation layer based on the model. In this article we will see how Angular JS, a new JavaScript framework by Google can be used effectively to build web applications where: 1. Views are pure HTML 2. Controllers (in the server sense) are pure REST based API calls 3. The presentation layer is loaded as needed from partial HTML only files. What is MVVM? MVVM short for Model View View Model is a new paradigm in web development. In this paradigm, the Model and View stuff exists on the client side through javascript instead of being processed on the server through postbacks. These frameworks are JavaScript frameworks that facilitate the clear separation of the “frontend” or the data rendering logic from the “backend” which is typically just a REST based API that loads and processes data through a resource model. The frameworks are called MVVM as a change to the Model (through javascript) gets reflected in the view immediately i.e. Model > View. Also, a change on the view (through manual input) gets reflected in the model immediately i.e. View > Model. The following figure shows this conceptually (comments are shown in red): Fig 2: Demonstration of MVVM in action In Fig 2, two text boxes are bound to the same variable model.myInt. Thus, changing the view manually (changing one text box through keyboard input) also changes the other textbox in real time demonstrating V > M property of a MVVM framework. Furthermore, clicking the button adds 1 to the value of model.myInt thus changing the model through JavaScript. This immediately updates the view (the value in the two textboxes) thus demonstrating the M > V property of a MVVM framework. Thus we see that the model in a MVVM JavaScript framework can be regarded as “the single source of truth“. This is an important concept. Angular is one such MVVM framework. We shall use it to build a simple app that sends SMS messages to a particular number. Application, Routes, Views, Controllers, Scope and Models Angular can be used in many ways to construct web applications. For this article, we shall only focus on building Single Page Applications (SPAs). Many of the approaches we will follow in this article have alternatives. It is beyond the scope of this article to explain every nuance in detail but we shall try to touch upon the basic concepts and end up with a working application that can be used to send SMS messages using Sent.ly Plus (a service that is itself built using Angular). Before you read on, we would like to urge you to forget what you know about Models, Views, Controllers and Routes in the ASP.NET MVC4 framework. All these words have different meanings in the Angular world. Whenever these words are used in this article, they will refer to Angular concepts and not ASP.NET MVC4 concepts. The following figure shows the skeleton of the root page of an SPA: Fig 3: The skeleton of a SPA The skeleton of the application is based on the Bootstrap starter template which can be found at: http://getbootstrap.com/examples/startertemplate/ Apart from loading the Angular, jQuery and Bootstrap JavaScript libraries, it also loads our custom scripts /app/js/controllers.js /app/js/app.js These scripts define the routes, views and controllers which we shall come to in a moment. Application Notice that the body tag (Fig. 3) has an extra attribute: ngapp=”smsApp” Providing this tag “bootstraps” our single page application. It tells Angular to load a “module” called smsApp. This “module” is defined /app/js/app.js angular.module('smsApp', ['smsApp.controllers', function () {}]) Fig 4: The definition of our application module The line shows above, declares a module called smsApp. It also declares that this module “depends” on another module called “smsApp.controllers”. The smsApp.controllers module will contain all the controllers for our SPA. Routing and Views Notice that in the Navbar (in Fig 3) we have included two hyperlinks to: “#/app” “#/help” This is how Angular handles routing. Since the URLs start with “#”, they are actually just bookmarks (and not server side resources). However, our route definition (in /app/js/app.js) gives these URLs a special meaning within the Angular framework. angular.module('smsApp', ['smsApp.controllers', function () { }]) //Configure the routes .config(['$routeProvider', function ($routeProvider) { $routeProvider.when('/binding', { templateUrl: '/app/partials/bindingexample.html', controller: 'BindingController' }); }]); Fig 5: The definition of a route with an associated partial view and controller As we can see from the previous code sample, we are using the $routeProvider object in the configuration of our smsApp module. Notice how the code “asks for” the $routeProvider object by specifying it as a dependency in the [] braces and then defining a function that accepts it as a parameter. This is known as dependency injection. Please refer to the following link if you want to delve into this topic: http://docs.angularjs.org/guide/di What the above code snippet is doing is that it is telling Angular that when the URL is “#/binding”, then it should load the HTML snippet (“partial view”) found at /app/partials/bindingexample.html. Also, for this URL, Angular should load the controller called “BindingController”. We have also marked the div with the class “container” (in Fig 3) with the ngview attribute. This attribute tells Angular that views (partial HTML pages) defined in the routes will be loaded within this div. You can see that the Angular JavaScript framework, unlike many other frameworks, works purely by extending HTML tags and attributes. It also allows you to extend HTML with your own tags and attributes (through directives) if you so desire, you can find out more about directives at the following URL: http://www.codeproject.com/Articles/607873/ExtendingHTMLwithAngularJSDirectives Controllers and Models We have seen how we define what views and controllers should be loaded for a particular route. Let us now consider how controllers are defined. Our controllers are defined in the file /app/js/controllers.js. The following snippet shows the definition of the “BindingController” which is loaded when we hit the URL http://localhost:port/index.html#/binding (as we have defined in the route earlier as shown in Fig 5). Remember that we had defined that our application module “smsApp” depends on the “smsApp.controllers” module (see Fig 4). The code snippet below shows how the “BindingController” defined in the route shown in Fig 5 is defined in the module smsApp.controllers: angular.module('smsApp.controllers', [function () { }]) .controller('BindingController', ['$scope', function ($scope) { $scope.model = {}; $scope.model.myInt = 6; $scope.addOne = function () { $scope.model.myInt++; } }]); Fig 6: The definition of a controller in the “smsApp.controllers” module. The pieces are falling in place! Remember Fig.2? That was the code of a partial view that was loaded within the container div of the skeleton SPA shown in Fig 3. The route definition shown in Fig 5 also defined that the controller called “BindingController” (shown in Fig 6.) was loaded when we loaded the URL: http://localhost:22544/index.html#/binding The button in Fig 2 was marked with the attribute ngclick=”addOne()” which added 1 to the value of model.myInt. In Fig 6, we can see that this function is actually defined in the “BindingController”. Scope We can see from Fig 6, that in the definition of “BindingController”, we defined a dependency on $scope and then, as usual, defined a function which “asks for” $scope as per the dependency injection pattern. So what is $scope? Any guesses? As you might have guessed a scope is a particular “address space” where variables and functions may be defined. This has a similar meaning to scope in a programming language like C#. Model: The Scope is not the Model It is tempting to assign variables in the scope directly. For example, we could have defined myInt as $scope.myInt = 6 in Fig 6 instead of $scope.model.myInt = 6. The reason why this is a bad idea is that scope in hierarchical in Angular. Thus if we were to define a controller which was defined within the another controller (nested controllers), then the inner controller would inherit the scope of the parent controller. This inheritance would follow JavaScript prototypal inheritance. Let’s say the parent controller defined a variable through $scope.myInt = 6. The child controller would inherit the scope through java prototypical inheritance. This basically means that the child scope has a variable myInt that points to the parent scopes myInt variable. Now if we assigned the value of myInt in the parent, the child scope would be updated with the same value as the child scope’s myInt variable points to the parent scope’s myInt variable. However, if we were to assign the value of the myInt variable in the child scope, then the link of that variable to the parent scope would be broken as the variable myInt in the child scope now points to the value 6 and not to the parent scope’s myInt variable. But, if we defined a variable model in the parent scope, then the child scope will also have a variable model that points to the model variable in the parent scope. Updating the value of $scope.model.myInt in the parent scope would change the model variable in the child scope too as the variable is pointed to the model variable in the parent scope. Now changing the value of $scope.model.myInt in the child scope would ALSO change the value in the parent scope. This is because the model reference in the child scope is pointed to the scope variable in the parent. We did no new assignment to the model variable in the child scope. We only changed an attribute of the model variable. Since the model variable (in the child scope) points to the model variable in the parent scope, we have successfully changed the value of myInt in the parent scope. Thus the value of $scope.model.myInt in the parent scope becomes the “single source of truth“. This is a tricky concept, thus it is considered good practice to NOT use scope inheritance. More info on prototypal inheritance in Angular can be found in the “JavaScript Prototypal Inheritance” section at the following URL: https://github.com/angular/angular.js/wiki/UnderstandingScopes. Building It: An Angular JS application using a .NET Web API Backend Now that we have a perspective on the basic components of an MVVM application built using Angular, let’s build something useful. We will build an application that can be used to send out SMS messages to a given phone number. The following diagram describes the architecture of the application we are going to build: Fig 7: Broad application architecture We are going to add an HTML Partial to our project. This partial will contain the form fields that will accept the phone number and message that needs to be sent as an SMS. It will also display all the messages that have previously been sent. All the executable code that is run on the occurrence of events (button clicks etc.) in the view resides in the controller. The controller interacts with the ASP.NET WebAPI to get a history of SMS messages, add a message etc. through a REST based API. For the purposes of simplicity, we will use an in memory data structure for the purposes of creating this application. Thus, the tasks ahead of us are: Creating the REST WebApi with GET, PUT, POST, DELETE methods. Creating the SmsView.html partial Creating the SmsController controller with methods that are called from the SmsView.html partial Add a new route that loads the controller and the partial. 1. Creating the REST WebAPI This is a simple task that should be quite straightforward to any .NET developer. The following listing shows our ApiController: public class SmsMessage { public string to { get; set; } public string message { get; set; } } public class SmsResource : SmsMessage { public int smsId { get; set; } } public class SmsResourceController : ApiController { public static Dictionary<int, SmsResource> messages = new Dictionary<int, SmsResource>(); public static int currentId = 0; // GET api/<controller> public List<SmsResource> Get() { List<SmsResource> result = new List<SmsResource>(); foreach (int key in messages.Keys) { result.Add(messages[key]); } return result; } // GET api/<controller>/5 public SmsResource Get(int id) { if (messages.ContainsKey(id)) return messages[id]; return null; } // POST api/<controller> public List<SmsResource> Post([FromBody] SmsMessage value) { //Synchronize on messages so we don't have id collisions lock (messages) { SmsResource res = (SmsResource) value; res.smsId = currentId++; messages.Add(res.smsId, res); //SentlyPlusSmsSender.SendMessage(value.to, value.message); return Get(); } } // PUT api/<controller>/5 public List<SmsResource> Put(int id, [FromBody] SmsMessage value) { //Synchronize on messages so we don't have id collisions lock (messages) { if (messages.ContainsKey(id)) { //Update the message messages[id].message = value.message; messages[id].to = value.message; } return Get(); } } // DELETE api/<controller>/5 public List<SmsResource> Delete(int id) { if (messages.ContainsKey(id)) { messages.Remove(id); } return Get(); } } Once this class is defined, we should be able to access the WebAPI by a simple GET request using the browser: http://localhost:port/api/SmsResource Notice the commented line: //SentlyPlusSmsSender.SendMessage The SentlyPlusSmsSender class is defined in the attached solution. We have shown this line as commented as we want to explain the core Angular concepts. If you load the attached solution, this line is uncommented in the source and an actual SMS will be sent! By default, the API returns XML. For consumption of the API in Angular, we would like it to return JSON. To change the default to JSON, we make the following change to WebApiConfig.cs file located in the App_Start folder. public static class WebApiConfig { public static void Register(HttpConfiguration config) { config.Routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); var appXmlType = config.Formatters.XmlFormatter. SupportedMediaTypes. FirstOrDefault( t => t.MediaType == "application/xml"); config.Formatters.XmlFormatter.SupportedMediaTypes.Remove(appXmlType); } } We now have our backend REST Api which we can consume from Angular! 2. Creating the SmsView.html partial This simple partial will define two fields: the destination phone number (international format starting with a +) and the message. These fields will be bound to model.phoneNumber and model.message. We will also add a button that we shall hook up to sendMessage() in the controller. A list of all previously sent messages (bound to model.allMessages) will also be displayed below the form input. The following code shows the code for the partial:  <div class="well" style="margin-top: 30px;"> <table style="width: 100%;"> <tr> <td style="width: 45%; text-align: center;"> <input type="text" placeholder="Phone number (eg; +44 7778 609466)" ng-model="model.phoneNumber" class="form-control" style="width: 90%" onkeypress="return checkPhoneInput();" /> </td> <td style="width: 45%; text-align: center;"> <input type="text" placeholder="Message" ng-model="model.message" class="form-control" style="width: 90%" /> </td> <td style="text-align: center;"> <button class="btn btn-danger" ng-click="sendMessage();" ng-disabled="model.isAjaxInProgress" style="marginright: 5px;">Send</button> <img src="/Content/ajax-loader.gif" ng-show="model.isAjaxInProgress" /> </td> </tr> </table> </div>  <div style="margin-top: 30px;">  <div ng-show="model.allMessages.length == 0"> No messages have been sent yet! </div>  <div ng-show="model.allMessages.length == 0"> <table style="width: 100%;" class="table table-striped"> <tr> <td>Phone Number</td> <td>Message</td> <td></td> </tr>  <tr ng-repeat="message in model.allMessages"> <td>{{ message.to }}</td> <td>{{ message.message }}</td> <td> <button class="btn btn-danger" ng-click="delete(message.smsId);" ng-disabled="model.isAjaxInProgress">Delete</button> </td> </tr> </table> </div> </div> The above code is commented and should be self explanatory. Conditional rendering is achieved through using the ng-show=”condition” attribute on various div tags. Input fields are bound to the model and the send button is bound to the sendMessage() function in the controller as through the ngclick=”sendMessage()” attribute defined on the button tag. While AJAX calls are taking place, the controller sets model.isAjaxInProgress to true. Based on this variable, buttons are disabled through the ng-disabled directive which is added as an attribute to the buttons. The ng-repeat directive added as an attribute to the tr tag causes the table row to be rendered multiple times much like an ASP.NET repeater. 3. Creating the SmsController controller The penultimate piece of our application is the controller which responds to events from our view and interacts with our MVC4 REST WebAPI. The following listing shows the code we need to add to /app/js/controllers.js. Note that controller definitions can be chained. Also note that this controller “asks for” the $http service. The $http service is a simple way in Angular to do AJAX. So far we have only encountered modules, controllers, views and directives in Angular. The $http is new entity in Angular called a service. More information on Angular services can be found at the following URL: http://docs.angularjs.org/guide/dev_guide.services.understanding_services. .controller('SmsController', ['$scope', '$http', function ($scope, $http) { //We define the model $scope.model = {}; //We define the allMessages array in the model //that will contain all the messages sent so far $scope.model.allMessages = []; //The error if any $scope.model.errorMessage = undefined; //We initially load data so set the isAjaxInProgress = true; $scope.model.isAjaxInProgress = true; //Load all the messages $http({ url: '/api/smsresource', method: "GET" }). success(function (data, status, headers, config) { this callback will be called asynchronously //when the response is available $scope.model.allMessages = data; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }). error(function (data, status, headers, config) { //called asynchronously if an error occurs //or server returns response with an error status. $scope.model.errorMessage = "Error occurred status:" + status; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); $scope.delete = function (id) { //We are making an ajax call so we set this to true $scope.model.isAjaxInProgress = true; $http({ url: '/api/smsresource/' + id, method: "DELETE" }). success(function (data, status, headers, config) { // this callback will be called asynchronously // when the response is available $scope.model.allMessages = data; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); error(function (data, status, headers, config) { // called asynchronously if an error occurs // or server returns response with an error status. $scope.model.errorMessage = "Error occurred status:" + status; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); } $scope.sendMessage = function () { $scope.model.errorMessage = undefined; var message = ''; if($scope.model.message != undefined) message = $scope.model.message.trim(); if ($scope.model.phoneNumber == undefined || $scope.model.phoneNumber == '' || $scope.model.phoneNumber.length < 10 || $scope.model.phoneNumber[0] != '+') { $scope.model.errorMessage = "You must enter a valid phone number in international format. Eg: +44 7778 609466"; return; } if (message.length == 0) { $scope.model.errorMessage = "You must specify a message!"; return; } //We are making an ajax call so we set this to true $scope.model.isAjaxInProgress = true; $http({ url: '/api/smsresource', method: "POST", data: { to: $scope.model.phoneNumber, message: $scope.model.message } }). success(function (data, status, headers, config) { // this callback will be called asynchronously // when the response is available $scope.model.allMessages = data; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }). error(function (data, status, headers, config) { // called asynchronously if an error occurs // or server returns response with an error status. $scope.model.errorMessage = "Error occurred status:" + status // We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); } }]); We can see from the previous listing how the functions that are called from the view are defined in the controller. It should also be evident how easy it is to make AJAX calls to consume our MVC4 REST WebAPI. Now we are left with the final piece. We need to define a route that associates a particular path with the view we have defined and the controller we have defined. 4. Add a new route that loads the controller and the partial This is the easiest part of the puzzle. We simply define another route in the /app/js/app.js file: $routeProvider.when('/sms', { templateUrl: '/app/partials/smsview.html', controller: 'SmsController' }); Conclusion In this article we have seen how much of the server side functionality in the MVC4 framework can be moved to the browser thus delivering a snappy and fast user interface. We have seen how we can build client side HTML only views that avoid the messy syntax offered by server side Razor views. We have built a functioning app from the ground up. The significant advantage of this approach to building web apps is that the front end can be completely platform independent. Even though we used ASP.NET to create our REST API, we could just easily have used any other language such as Node.js, Ruby etc without changing a single line of our front end code. Angular is a rich framework and we have only touched on basic functionality required to create a SPA. For readers who wish to delve further into the Angular framework, we would recommend the following URL as a starting point: http://docs.angularjs.org/misc/started. To get started with the code for this project: Sign up for an account at http://plus.sent.ly (free) Add your phone number Go to the “My Identies Page” Note Down your Sender ID, Consumer Key and Consumer Secret Download the code for this article at: https://docs.google.com/file/d/0BzjEWqSE31yoZjZlV0d0R2Y3eW8/edit?usp=sharing Change the values of Sender Id, Consumer Key and Consumer Secret in the web.config file Run the project through Visual Studio!

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Building applications with WCF - Intro

- by skjagini

I am going to write series of articles using Windows Communication Framework (WCF) to develop client and server applications and this is the first part of that series. What is WCF As Juwal puts in his Programming WCF book, WCF provides an SDK for developing and deploying services on Windows, provides runtime environment to expose CLR types as services and consume services as CLR types. Building services with WCF is incredibly easy and it’s implementation provides a set of industry standards and off the shelf plumbing including service hosting, instance management, reliability, transaction management, security etc such that it greatly increases productivity Scenario: Lets consider a typical bank customer trying to create an account, deposit amount and transfer funds between accounts, i.e. checking and savings. To make it interesting, we are going to divide the functionality into multiple services and each of them working with database directly. We will run test cases with and without transactional support across services. In this post we will build contracts, services, data access layer, unit tests to verify end to end communication etc, nothing big stuff here and we dig into other features of the WCF in subsequent posts with incremental changes. In any distributed architecture we have two pieces i.e. services and clients. Services as the name implies provide functionality to execute various pieces of business logic on the server, and clients providing interaction to the end user. Services can be built with Web Services or with WCF. Service built on WCF have the advantage of binding independent, i.e. can run against TCP and HTTP protocol without any significant changes to the code. Solution Services Profile: For creating a new bank customer, getting details about existing customer ProfileContract ProfileService Checking Account: To get checking account balance, deposit or withdraw amount CheckingAccountContract CheckingAccountService Savings Account: To get savings account balance, deposit or withdraw amount SavingsAccountContract SavingsAccountService ServiceHost: To host services, i.e. running the services at particular address, binding and contract where client can connect to Client: Helps end user to use services like creating account and amount transfer between the accounts BankDAL: Data access layer to work with database BankDAL It’s no brainer not to use an ORM as many matured products are available currently in market including Linq2Sql, Entity Framework (EF), LLblGenPro etc. For this exercise I am going to use Entity Framework 4.0, CTP 5 with code first approach. There are two approaches when working with data, data driven and code driven. In data driven we start by designing tables and their constrains in database and generate entities in code while in code driven (code first) approach entities are defined in code and the metadata generated from the entities is used by the EF to create tables and table constrains. In previous versions the entity classes had to derive from EF specific base classes. In EF 4 it is not required to derive from any EF classes, the entities are not only persistence ignorant but also enable full test driven development using mock frameworks. Application consists of 3 entities, Customer entity which contains Customer details; CheckingAccount and SavingsAccount to hold the respective account balance. We could have introduced an Account base class for CheckingAccount and SavingsAccount which is certainly possible with EF mappings but to keep it simple we are just going to follow 1 –1 mapping between entity and table mappings. Lets start out by defining a class called Customer which will be mapped to Customer table, observe that the class is simply a plain old clr object (POCO) and has no reference to EF at all. using System; namespace BankDAL.Model { public class Customer { public int Id { get; set; } public string FullName { get; set; } public string Address { get; set; } public DateTime DateOfBirth { get; set; } } } In order to inform EF about the Customer entity we have to define a database context with properties of type DbSet<> for every POCO which needs to be mapped to a table in database. EF uses convention over configuration to generate the metadata resulting in much less configuration. using System.Data.Entity; namespace BankDAL.Model { public class BankDbContext: DbContext { public DbSet<Customer> Customers { get; set; } } } Entity constrains can be defined through attributes on Customer class or using fluent syntax (no need to muscle with xml files), CustomerConfiguration class. By defining constrains in a separate class we can maintain clean POCOs without corrupting entity classes with database specific information. using System; using System.Data.Entity.ModelConfiguration; namespace BankDAL.Model { public class CustomerConfiguration: EntityTypeConfiguration<Customer> { public CustomerConfiguration() { Initialize(); } private void Initialize() { //Setting the Primary Key this.HasKey(e => e.Id); //Setting required fields this.HasRequired(e => e.FullName); this.HasRequired(e => e.Address); //Todo: Can't create required constraint as DateOfBirth is not reference type, research it //this.HasRequired(e => e.DateOfBirth); } } } Any queries executed against Customers property in BankDbContext are executed against Cusomers table. By convention EF looks for connection string with key of BankDbContext when working with the context. We are going to define a helper class to work with Customer entity with methods for querying, adding new entity etc and these are known as repository classes, i.e., CustomerRepository using System; using System.Data.Entity; using System.Linq; using BankDAL.Model; namespace BankDAL.Repositories { public class CustomerRepository { private readonly IDbSet<Customer> _customers; public CustomerRepository(BankDbContext bankDbContext) { if (bankDbContext == null) throw new ArgumentNullException(); _customers = bankDbContext.Customers; } public IQueryable<Customer> Query() { return _customers; } public void Add(Customer customer) { _customers.Add(customer); } } } From the above code it is observable that the Query methods returns customers as IQueryable i.e. customers are retrieved only when actually used i.e. iterated. Returning as IQueryable also allows to execute filtering and joining statements from business logic using lamba expressions without cluttering the data access layer with tens of methods. Our CheckingAccountRepository and SavingsAccountRepository look very similar to each other using System; using System.Data.Entity; using System.Linq; using BankDAL.Model; namespace BankDAL.Repositories { public class CheckingAccountRepository { private readonly IDbSet<CheckingAccount> _checkingAccounts; public CheckingAccountRepository(BankDbContext bankDbContext) { if (bankDbContext == null) throw new ArgumentNullException(); _checkingAccounts = bankDbContext.CheckingAccounts; } public IQueryable<CheckingAccount> Query() { return _checkingAccounts; } public void Add(CheckingAccount account) { _checkingAccounts.Add(account); } public IQueryable<CheckingAccount> GetAccount(int customerId) { return (from act in _checkingAccounts where act.CustomerId == customerId select act); } } } The repository classes look very similar to each other for Query and Add methods, with the help of C# generics and implementing repository pattern (Martin Fowler) we can reduce the repeated code. Jarod from ElegantCode has posted an article on how to use repository pattern with EF which we will implement in the subsequent articles along with WCF Unity life time managers by Drew Contracts It is very easy to follow contract first approach with WCF, define the interface and append ServiceContract, OperationContract attributes. IProfile contract exposes functionality for creating customer and getting customer details. using System; using System.ServiceModel; using BankDAL.Model; namespace ProfileContract { [ServiceContract] public interface IProfile { [OperationContract] Customer CreateCustomer(string customerName, string address, DateTime dateOfBirth); [OperationContract] Customer GetCustomer(int id); } } ICheckingAccount contract exposes functionality for working with checking account, i.e., getting balance, deposit and withdraw of amount. ISavingsAccount contract looks the same as checking account. using System.ServiceModel; namespace CheckingAccountContract { [ServiceContract] public interface ICheckingAccount { [OperationContract] decimal? GetCheckingAccountBalance(int customerId); [OperationContract] void DepositAmount(int customerId,decimal amount); [OperationContract] void WithdrawAmount(int customerId, decimal amount); } } Services Having covered the data access layer and contracts so far and here comes the core of the business logic, i.e. services. .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } ProfileService implements the IProfile contract for creating customer and getting customer detail using CustomerRepository. using System; using System.Linq; using System.ServiceModel; using BankDAL; using BankDAL.Model; using BankDAL.Repositories; using ProfileContract; namespace ProfileService { [ServiceBehavior(IncludeExceptionDetailInFaults = true)] public class Profile: IProfile { public Customer CreateAccount( string customerName, string address, DateTime dateOfBirth) { Customer cust = new Customer { FullName = customerName, Address = address, DateOfBirth = dateOfBirth }; using (var bankDbContext = new BankDbContext()) { new CustomerRepository(bankDbContext).Add(cust); bankDbContext.SaveChanges(); } return cust; } public Customer CreateCustomer(string customerName, string address, DateTime dateOfBirth) { return CreateAccount(customerName, address, dateOfBirth); } public Customer GetCustomer(int id) { return new CustomerRepository(new BankDbContext()).Query() .Where(i => i.Id == id).FirstOrDefault(); } } } From the above code you shall observe that we are calling bankDBContext’s SaveChanges method and there is no save method specific to customer entity because EF manages all the changes centralized at the context level and all the pending changes so far are submitted in a batch and it is represented as Unit of Work. Similarly Checking service implements ICheckingAccount contract using CheckingAccountRepository, notice that we are throwing overdraft exception if the balance falls by zero. WCF has it’s own way of raising exceptions using fault contracts which will be explained in the subsequent articles. SavingsAccountService is similar to CheckingAccountService. using System; using System.Linq; using System.ServiceModel; using BankDAL.Model; using BankDAL.Repositories; using CheckingAccountContract; namespace CheckingAccountService { [ServiceBehavior(IncludeExceptionDetailInFaults = true)] public class Checking:ICheckingAccount { public decimal? GetCheckingAccountBalance(int customerId) { using (var bankDbContext = new BankDbContext()) { CheckingAccount account = (new CheckingAccountRepository(bankDbContext) .GetAccount(customerId)).FirstOrDefault(); if (account != null) return account.Balance; return null; } } public void DepositAmount(int customerId, decimal amount) { using(var bankDbContext = new BankDbContext()) { var checkingAccountRepository = new CheckingAccountRepository(bankDbContext); CheckingAccount account = (checkingAccountRepository.GetAccount(customerId)) .FirstOrDefault(); if (account == null) { account = new CheckingAccount() { CustomerId = customerId }; checkingAccountRepository.Add(account); } account.Balance = account.Balance + amount; if (account.Balance < 0) throw new ApplicationException("Overdraft not accepted"); bankDbContext.SaveChanges(); } } public void WithdrawAmount(int customerId, decimal amount) { DepositAmount(customerId, -1*amount); } } } BankServiceHost The host acts as a glue binding contracts with it’s services, exposing the endpoints. The services can be exposed either through the code or configuration file, configuration file is preferred as it allows run time changes to service behavior even after deployment. We have 3 services and for each of the service you need to define name (the class that implements the service with fully qualified namespace) and endpoint known as ABC, i.e. address, binding and contract. We are using netTcpBinding and have defined the base address with for each of the contracts .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } <system.serviceModel> <services> <service name="ProfileService.Profile"> <endpoint binding="netTcpBinding" contract="ProfileContract.IProfile"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Profile"/> </baseAddresses> </host> </service> <service name="CheckingAccountService.Checking"> <endpoint binding="netTcpBinding" contract="CheckingAccountContract.ICheckingAccount"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Checking"/> </baseAddresses> </host> </service> <service name="SavingsAccountService.Savings"> <endpoint binding="netTcpBinding" contract="SavingsAccountContract.ISavingsAccount"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Savings"/> </baseAddresses> </host> </service> </services> </system.serviceModel> Have to open the services by creating service host which will handle the incoming requests from clients. using System; namespace ServiceHost { class Program { static void Main(string[] args) { CreateHosts(); Console.ReadLine(); } private static void CreateHosts() { CreateHost(typeof(ProfileService.Profile),"Profile Service"); CreateHost(typeof(SavingsAccountService.Savings), "Savings Account Service"); CreateHost(typeof(CheckingAccountService.Checking), "Checking Account Service"); } private static void CreateHost(Type type, string hostDescription) { System.ServiceModel.ServiceHost host = new System.ServiceModel.ServiceHost(type); host.Open(); if (host.ChannelDispatchers != null && host.ChannelDispatchers.Count != 0 && host.ChannelDispatchers[0].Listener != null) Console.WriteLine("Started: " + host.ChannelDispatchers[0].Listener.Uri); else Console.WriteLine("Failed to start:" + hostDescription); } } } BankClient The client has no knowledge about service business logic other than the functionality it exposes through the contract, end points and a proxy to work against. The endpoint data and server proxy can be generated by right clicking on the project reference and choosing ‘Add Service Reference’ and entering the service end point address. Or if you have access to source, you can manually reference contract dlls and update clients configuration file to point to the service end point if the server and client happens to be being built using .Net framework. One of the pros with the manual approach is you don’t have to work against messy code generated files. <system.serviceModel> <client> <endpoint name="tcpProfile" address="net.tcp://localhost:1000/Profile" binding="netTcpBinding" contract="ProfileContract.IProfile"/> <endpoint name="tcpCheckingAccount" address="net.tcp://localhost:1000/Checking" binding="netTcpBinding" contract="CheckingAccountContract.ICheckingAccount"/> <endpoint name="tcpSavingsAccount" address="net.tcp://localhost:1000/Savings" binding="netTcpBinding" contract="SavingsAccountContract.ISavingsAccount"/> </client> </system.serviceModel> The client uses a façade to connect to the services using System.ServiceModel; using CheckingAccountContract; using ProfileContract; using SavingsAccountContract; namespace Client { public class ProxyFacade { public static IProfile ProfileProxy() { return (new ChannelFactory<IProfile>("tcpProfile")).CreateChannel(); } public static ICheckingAccount CheckingAccountProxy() { return (new ChannelFactory<ICheckingAccount>("tcpCheckingAccount")) .CreateChannel(); } public static ISavingsAccount SavingsAccountProxy() { return (new ChannelFactory<ISavingsAccount>("tcpSavingsAccount")) .CreateChannel(); } } } With that in place, lets get our unit tests going using System; using System.Diagnostics; using BankDAL.Model; using NUnit.Framework; using ProfileContract; namespace Client { [TestFixture] public class Tests { private void TransferFundsFromSavingsToCheckingAccount(int customerId, decimal amount) { ProxyFacade.CheckingAccountProxy().DepositAmount(customerId, amount); ProxyFacade.SavingsAccountProxy().WithdrawAmount(customerId, amount); } private void TransferFundsFromCheckingToSavingsAccount(int customerId, decimal amount) { ProxyFacade.SavingsAccountProxy().DepositAmount(customerId, amount); ProxyFacade.CheckingAccountProxy().WithdrawAmount(customerId, amount); } [Test] public void CreateAndGetProfileTest() { IProfile profile = ProxyFacade.ProfileProxy(); const string customerName = "Tom"; int customerId = profile.CreateCustomer(customerName, "NJ", new DateTime(1982, 1, 1)).Id; Customer customer = profile.GetCustomer(customerId); Assert.AreEqual(customerName,customer.FullName); } [Test] public void DepositWithDrawAndTransferAmountTest() { IProfile profile = ProxyFacade.ProfileProxy(); string customerName = "Smith" + DateTime.Now.ToString("HH:mm:ss"); var customer = profile.CreateCustomer(customerName, "NJ", new DateTime(1982, 1, 1)); // Deposit to Savings ProxyFacade.SavingsAccountProxy().DepositAmount(customer.Id, 100); ProxyFacade.SavingsAccountProxy().DepositAmount(customer.Id, 25); Assert.AreEqual(125, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); // Withdraw ProxyFacade.SavingsAccountProxy().WithdrawAmount(customer.Id, 30); Assert.AreEqual(95, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); // Deposit to Checking ProxyFacade.CheckingAccountProxy().DepositAmount(customer.Id, 60); ProxyFacade.CheckingAccountProxy().DepositAmount(customer.Id, 40); Assert.AreEqual(100, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); // Withdraw ProxyFacade.CheckingAccountProxy().WithdrawAmount(customer.Id, 30); Assert.AreEqual(70, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); // Transfer from Savings to Checking TransferFundsFromSavingsToCheckingAccount(customer.Id,10); Assert.AreEqual(85, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); Assert.AreEqual(80, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); // Transfer from Checking to Savings TransferFundsFromCheckingToSavingsAccount(customer.Id, 50); Assert.AreEqual(135, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); Assert.AreEqual(30, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); } [Test] public void FundTransfersWithOverDraftTest() { IProfile profile = ProxyFacade.ProfileProxy(); string customerName = "Angelina" + DateTime.Now.ToString("HH:mm:ss"); var customerId = profile.CreateCustomer(customerName, "NJ", new DateTime(1972, 1, 1)).Id; ProxyFacade.SavingsAccountProxy().DepositAmount(customerId, 100); TransferFundsFromSavingsToCheckingAccount(customerId,80); Assert.AreEqual(20, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customerId)); Assert.AreEqual(80, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customerId)); try { TransferFundsFromSavingsToCheckingAccount(customerId,30); } catch (Exception e) { Debug.WriteLine(e.Message); } Assert.AreEqual(110, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customerId)); Assert.AreEqual(20, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customerId)); } } } We are creating a new instance of the channel for every operation, we will look into instance management and how creating a new instance of channel affects it in subsequent articles. The first two test cases deals with creation of Customer, deposit and withdraw of month between accounts. The last case, FundTransferWithOverDraftTest() is interesting. Customer starts with depositing $100 in SavingsAccount followed by transfer of $80 in to checking account resulting in $20 in savings account. Customer then initiates $30 transfer from Savings to Checking resulting in overdraft exception on Savings with $30 being deposited to Checking. As we are not running both the requests in transactions the customer ends up with more amount than what he started with $100. In subsequent posts we will look into transactions handling. Make sure the ServiceHost project is set as start up project and start the solution. Run the test cases either from NUnit client or TestDriven.Net/Resharper which ever is your favorite tool. Make sure you have updated the data base connection string in the ServiceHost config file to point to your local database

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Node.js Adventure - Storage Services and Service Runtime

- by Shaun

When I described on how to host a Node.js application on Windows Azure, one of questions might be raised about how to consume the vary Windows Azure services, such as the storage, service bus, access control, etc.. Interact with windows azure services is available in Node.js through the Windows Azure Node.js SDK, which is a module available in NPM. In this post I would like to describe on how to use Windows Azure Storage (a.k.a. WAS) as well as the service runtime. Consume Windows Azure Storage Let’s firstly have a look on how to consume WAS through Node.js. As we know in the previous post we can host Node.js application on Windows Azure Web Site (a.k.a. WAWS) as well as Windows Azure Cloud Service (a.k.a. WACS). In theory, WAWS is also built on top of WACS worker roles with some more features. Hence in this post I will only demonstrate for hosting in WACS worker role. The Node.js code can be used when consuming WAS when hosted on WAWS. But since there’s no roles in WAWS, the code for consuming service runtime mentioned in the next section cannot be used for WAWS node application. We can use the solution that I created in my last post. Alternatively we can create a new windows azure project in Visual Studio with a worker role, add the “node.exe” and “index.js” and install “express” and “node-sqlserver” modules, make all files as “Copy always”. In order to use windows azure services we need to have Windows Azure Node.js SDK, as knows as a module named “azure” which can be installed through NPM. Once we downloaded and installed, we need to include them in our worker role project and make them as “Copy always”. You can use my “Copy all always” tool mentioned in my last post to update the currently worker role project file. You can also find the source code of this tool here. The source code of Windows Azure SDK for Node.js can be found in its GitHub page. It contains two parts. One is a CLI tool which provides a cross platform command line package for Mac and Linux to manage WAWS and Windows Azure Virtual Machines (a.k.a. WAVM). The other is a library for managing and consuming vary windows azure services includes tables, blobs, queues, service bus and the service runtime. I will not cover all of them but will only demonstrate on how to use tables and service runtime information in this post. You can find the full document of this SDK here. Back to Visual Studio and open the “index.js”, let’s continue our application from the last post, which was working against Windows Azure SQL Database (a.k.a. WASD). The code should looks like this. 1: var express = require("express"); 2: var sql = require("node-sqlserver"); 3: 4: var connectionString = "Driver={SQL Server Native Client 10.0};Server=tcp:ac6271ya9e.database.windows.net,1433;Database=synctile;Uid=shaunxu@ac6271ya9e;Pwd={PASSWORD};Encrypt=yes;Connection Timeout=30;"; 5: var port = 80; 6: 7: var app = express(); 8: 9: app.configure(function () { 10: app.use(express.bodyParser()); 11: }); 12: 13: app.get("/", function (req, res) { 14: sql.open(connectionString, function (err, conn) { 15: if (err) { 16: console.log(err); 17: res.send(500, "Cannot open connection."); 18: } 19: else { 20: conn.queryRaw("SELECT * FROM [Resource]", function (err, results) { 21: if (err) { 22: console.log(err); 23: res.send(500, "Cannot retrieve records."); 24: } 25: else { 26: res.json(results); 27: } 28: }); 29: } 30: }); 31: }); 32: 33: app.get("/text/:key/:culture", function (req, res) { 34: sql.open(connectionString, function (err, conn) { 35: if (err) { 36: console.log(err); 37: res.send(500, "Cannot open connection."); 38: } 39: else { 40: var key = req.params.key; 41: var culture = req.params.culture; 42: var command = "SELECT * FROM [Resource] WHERE [Key] = '" + key + "' AND [Culture] = '" + culture + "'"; 43: conn.queryRaw(command, function (err, results) { 44: if (err) { 45: console.log(err); 46: res.send(500, "Cannot retrieve records."); 47: } 48: else { 49: res.json(results); 50: } 51: }); 52: } 53: }); 54: }); 55: 56: app.get("/sproc/:key/:culture", function (req, res) { 57: sql.open(connectionString, function (err, conn) { 58: if (err) { 59: console.log(err); 60: res.send(500, "Cannot open connection."); 61: } 62: else { 63: var key = req.params.key; 64: var culture = req.params.culture; 65: var command = "EXEC GetItem '" + key + "', '" + culture + "'"; 66: conn.queryRaw(command, function (err, results) { 67: if (err) { 68: console.log(err); 69: res.send(500, "Cannot retrieve records."); 70: } 71: else { 72: res.json(results); 73: } 74: }); 75: } 76: }); 77: }); 78: 79: app.post("/new", function (req, res) { 80: var key = req.body.key; 81: var culture = req.body.culture; 82: var val = req.body.val; 83: 84: sql.open(connectionString, function (err, conn) { 85: if (err) { 86: console.log(err); 87: res.send(500, "Cannot open connection."); 88: } 89: else { 90: var command = "INSERT INTO [Resource] VALUES ('" + key + "', '" + culture + "', N'" + val + "')"; 91: conn.queryRaw(command, function (err, results) { 92: if (err) { 93: console.log(err); 94: res.send(500, "Cannot retrieve records."); 95: } 96: else { 97: res.send(200, "Inserted Successful"); 98: } 99: }); 100: } 101: }); 102: }); 103: 104: app.listen(port); Now let’s create a new function, copy the records from WASD to table service. 1. Delete the table named “resource”. 2. Create a new table named “resource”. These 2 steps ensures that we have an empty table. 3. Load all records from the “resource” table in WASD. 4. For each records loaded from WASD, insert them into the table one by one. 5. Prompt to user when finished. In order to use table service we need the storage account and key, which can be found from the developer portal. Just select the storage account and click the Manage Keys button. Then create two local variants in our Node.js application for the storage account name and key. Since we need to use WAS we need to import the azure module. Also I created another variant stored the table name. In order to work with table service I need to create the storage client for table service. This is very similar as the Windows Azure SDK for .NET. As the code below I created a new variant named “client” and use “createTableService”, specified my storage account name and key. 1: var azure = require("azure"); 2: var storageAccountName = "synctile"; 3: var storageAccountKey = "/cOy9L7xysXOgPYU9FjDvjrRAhaMX/5tnOpcjqloPNDJYucbgTy7MOrAW7CbUg6PjaDdmyl+6pkwUnKETsPVNw=="; 4: var tableName = "resource"; 5: var client = azure.createTableService(storageAccountName, storageAccountKey); Now create a new function for URL “/was/init” so that we can trigger it through browser. Then in this function we will firstly load all records from WASD. 1: app.get("/was/init", function (req, res) { 2: // load all records from windows azure sql database 3: sql.open(connectionString, function (err, conn) { 4: if (err) { 5: console.log(err); 6: res.send(500, "Cannot open connection."); 7: } 8: else { 9: conn.queryRaw("SELECT * FROM [Resource]", function (err, results) { 10: if (err) { 11: console.log(err); 12: res.send(500, "Cannot retrieve records."); 13: } 14: else { 15: if (results.rows.length > 0) { 16: // begin to transform the records into table service 17: } 18: } 19: }); 20: } 21: }); 22: }); When we succeed loaded all records we can start to transform them into table service. First I need to recreate the table in table service. This can be done by deleting and creating the table through table client I had just created previously. 1: app.get("/was/init", function (req, res) { 2: // load all records from windows azure sql database 3: sql.open(connectionString, function (err, conn) { 4: if (err) { 5: console.log(err); 6: res.send(500, "Cannot open connection."); 7: } 8: else { 9: conn.queryRaw("SELECT * FROM [Resource]", function (err, results) { 10: if (err) { 11: console.log(err); 12: res.send(500, "Cannot retrieve records."); 13: } 14: else { 15: if (results.rows.length > 0) { 16: // begin to transform the records into table service 17: // recreate the table named 'resource' 18: client.deleteTable(tableName, function (error) { 19: client.createTableIfNotExists(tableName, function (error) { 20: if (error) { 21: error["target"] = "createTableIfNotExists"; 22: res.send(500, error); 23: } 24: else { 25: // transform the records 26: } 27: }); 28: }); 29: } 30: } 31: }); 32: } 33: }); 34: }); As you can see, the azure SDK provide its methods in callback pattern. In fact, almost all modules in Node.js use the callback pattern. For example, when I deleted a table I invoked “deleteTable” method, provided the name of the table and a callback function which will be performed when the table had been deleted or failed. Underlying, the azure module will perform the table deletion operation in POSIX async threads pool asynchronously. And once it’s done the callback function will be performed. This is the reason we need to nest the table creation code inside the deletion function. If we perform the table creation code after the deletion code then they will be invoked in parallel. Next, for each records in WASD I created an entity and then insert into the table service. Finally I send the response to the browser. Can you find a bug in the code below? I will describe it later in this post. 1: app.get("/was/init", function (req, res) { 2: // load all records from windows azure sql database 3: sql.open(connectionString, function (err, conn) { 4: if (err) { 5: console.log(err); 6: res.send(500, "Cannot open connection."); 7: } 8: else { 9: conn.queryRaw("SELECT * FROM [Resource]", function (err, results) { 10: if (err) { 11: console.log(err); 12: res.send(500, "Cannot retrieve records."); 13: } 14: else { 15: if (results.rows.length > 0) { 16: // begin to transform the records into table service 17: // recreate the table named 'resource' 18: client.deleteTable(tableName, function (error) { 19: client.createTableIfNotExists(tableName, function (error) { 20: if (error) { 21: error["target"] = "createTableIfNotExists"; 22: res.send(500, error); 23: } 24: else { 25: // transform the records 26: for (var i = 0; i < results.rows.length; i++) { 27: var entity = { 28: "PartitionKey": results.rows[i][1], 29: "RowKey": results.rows[i][0], 30: "Value": results.rows[i][2] 31: }; 32: client.insertEntity(tableName, entity, function (error) { 33: if (error) { 34: error["target"] = "insertEntity"; 35: res.send(500, error); 36: } 37: else { 38: console.log("entity inserted"); 39: } 40: }); 41: } 42: // send the 43: console.log("all done"); 44: res.send(200, "All done!"); 45: } 46: }); 47: }); 48: } 49: } 50: }); 51: } 52: }); 53: }); Now we can publish it to the cloud and have a try. But normally we’d better test it at the local emulator first. In Node.js SDK there are three build-in properties which provides the account name, key and host address for local storage emulator. We can use them to initialize our table service client. We also need to change the SQL connection string to let it use my local database. The code will be changed as below. 1: // windows azure sql database 2: //var connectionString = "Driver={SQL Server Native Client 10.0};Server=tcp:ac6271ya9e.database.windows.net,1433;Database=synctile;Uid=shaunxu@ac6271ya9e;Pwd=eszqu94XZY;Encrypt=yes;Connection Timeout=30;"; 3: // sql server 4: var connectionString = "Driver={SQL Server Native Client 11.0};Server={.};Database={Caspar};Trusted_Connection={Yes};"; 5: 6: var azure = require("azure"); 7: var storageAccountName = "synctile"; 8: var storageAccountKey = "/cOy9L7xysXOgPYU9FjDvjrRAhaMX/5tnOpcjqloPNDJYucbgTy7MOrAW7CbUg6PjaDdmyl+6pkwUnKETsPVNw=="; 9: var tableName = "resource"; 10: // windows azure storage 11: //var client = azure.createTableService(storageAccountName, storageAccountKey); 12: // local storage emulator 13: var client = azure.createTableService(azure.ServiceClient.DEVSTORE_STORAGE_ACCOUNT, azure.ServiceClient.DEVSTORE_STORAGE_ACCESS_KEY, azure.ServiceClient.DEVSTORE_TABLE_HOST); Now let’s run the application and navigate to “localhost:12345/was/init” as I hosted it on port 12345. We can find it transformed the data from my local database to local table service. Everything looks fine. But there is a bug in my code. If we have a look on the Node.js command window we will find that it sent response before all records had been inserted, which is not what I expected. The reason is that, as I mentioned before, Node.js perform all IO operations in non-blocking model. When we inserted the records we executed the table service insert method in parallel, and the operation of sending response was also executed in parallel, even though I wrote it at the end of my logic. The correct logic should be, when all entities had been copied to table service with no error, then I will send response to the browser, otherwise I should send error message to the browser. To do so I need to import another module named “async”, which helps us to coordinate our asynchronous code. Install the module and import it at the beginning of the code. Then we can use its “forEach” method for the asynchronous code of inserting table entities. The first argument of “forEach” is the array that will be performed. The second argument is the operation for each items in the array. And the third argument will be invoked then all items had been performed or any errors occurred. Here we can send our response to browser. 1: app.get("/was/init", function (req, res) { 2: // load all records from windows azure sql database 3: sql.open(connectionString, function (err, conn) { 4: if (err) { 5: console.log(err); 6: res.send(500, "Cannot open connection."); 7: } 8: else { 9: conn.queryRaw("SELECT * FROM [Resource]", function (err, results) { 10: if (err) { 11: console.log(err); 12: res.send(500, "Cannot retrieve records."); 13: } 14: else { 15: if (results.rows.length > 0) { 16: // begin to transform the records into table service 17: // recreate the table named 'resource' 18: client.deleteTable(tableName, function (error) { 19: client.createTableIfNotExists(tableName, function (error) { 20: if (error) { 21: error["target"] = "createTableIfNotExists"; 22: res.send(500, error); 23: } 24: else { 25: async.forEach(results.rows, 26: // transform the records 27: function (row, callback) { 28: var entity = { 29: "PartitionKey": row[1], 30: "RowKey": row[0], 31: "Value": row[2] 32: }; 33: client.insertEntity(tableName, entity, function (error) { 34: if (error) { 35: callback(error); 36: } 37: else { 38: console.log("entity inserted."); 39: callback(null); 40: } 41: }); 42: }, 43: // send reponse 44: function (error) { 45: if (error) { 46: error["target"] = "insertEntity"; 47: res.send(500, error); 48: } 49: else { 50: console.log("all done"); 51: res.send(200, "All done!"); 52: } 53: } 54: ); 55: } 56: }); 57: }); 58: } 59: } 60: }); 61: } 62: }); 63: }); Run it locally and now we can find the response was sent after all entities had been inserted. Query entities against table service is simple as well. Just use the “queryEntity” method from the table service client and providing the partition key and row key. We can also provide a complex query criteria as well, for example the code here. In the code below I queried an entity by the partition key and row key, and return the proper localization value in response. 1: app.get("/was/:key/:culture", function (req, res) { 2: var key = req.params.key; 3: var culture = req.params.culture; 4: client.queryEntity(tableName, culture, key, function (error, entity) { 5: if (error) { 6: res.send(500, error); 7: } 8: else { 9: res.json(entity); 10: } 11: }); 12: }); And then tested it on local emulator. Finally if we want to publish this application to the cloud we should change the database connection string and storage account. For more information about how to consume blob and queue service, as well as the service bus please refer to the MSDN page. Consume Service Runtime As I mentioned above, before we published our application to the cloud we need to change the connection string and account information in our code. But if you had played with WACS you should have known that the service runtime provides the ability to retrieve configuration settings, endpoints and local resource information at runtime. Which means we can have these values defined in CSCFG and CSDEF files and then the runtime should be able to retrieve the proper values. For example we can add some role settings though the property window of the role, specify the connection string and storage account for cloud and local. And the can also use the endpoint which defined in role environment to our Node.js application. In Node.js SDK we can get an object from “azure.RoleEnvironment”, which provides the functionalities to retrieve the configuration settings and endpoints, etc.. In the code below I defined the connection string variants and then use the SDK to retrieve and initialize the table client. 1: var connectionString = ""; 2: var storageAccountName = ""; 3: var storageAccountKey = ""; 4: var tableName = ""; 5: var client; 6: 7: azure.RoleEnvironment.getConfigurationSettings(function (error, settings) { 8: if (error) { 9: console.log("ERROR: getConfigurationSettings"); 10: console.log(JSON.stringify(error)); 11: } 12: else { 13: console.log(JSON.stringify(settings)); 14: connectionString = settings["SqlConnectionString"]; 15: storageAccountName = settings["StorageAccountName"]; 16: storageAccountKey = settings["StorageAccountKey"]; 17: tableName = settings["TableName"]; 18: 19: console.log("connectionString = %s", connectionString); 20: console.log("storageAccountName = %s", storageAccountName); 21: console.log("storageAccountKey = %s", storageAccountKey); 22: console.log("tableName = %s", tableName); 23: 24: client = azure.createTableService(storageAccountName, storageAccountKey); 25: } 26: }); In this way we don’t need to amend the code for the configurations between local and cloud environment since the service runtime will take care of it. At the end of the code we will listen the application on the port retrieved from SDK as well. 1: azure.RoleEnvironment.getCurrentRoleInstance(function (error, instance) { 2: if (error) { 3: console.log("ERROR: getCurrentRoleInstance"); 4: console.log(JSON.stringify(error)); 5: } 6: else { 7: console.log(JSON.stringify(instance)); 8: if (instance["endpoints"] && instance["endpoints"]["nodejs"]) { 9: var endpoint = instance["endpoints"]["nodejs"]; 10: app.listen(endpoint["port"]); 11: } 12: else { 13: app.listen(8080); 14: } 15: } 16: }); But if we tested the application right now we will find that it cannot retrieve any values from service runtime. This is because by default, the entry point of this role was defined to the worker role class. In windows azure environment the service runtime will open a named pipeline to the entry point instance, so that it can connect to the runtime and retrieve values. But in this case, since the entry point was worker role and the Node.js was opened inside the role, the named pipeline was established between our worker role class and service runtime, so our Node.js application cannot use it. To fix this problem we need to open the CSDEF file under the azure project, add a new element named Runtime. Then add an element named EntryPoint which specify the Node.js command line. So that the Node.js application will have the connection to service runtime, then it’s able to read the configurations. Start the Node.js at local emulator we can find it retrieved the connections, storage account for local. And if we publish our application to azure then it works with WASD and storage service through the configurations for cloud. Summary In this post I demonstrated how to use Windows Azure SDK for Node.js to interact with storage service, especially the table service. I also demonstrated on how to use WACS service runtime, how to retrieve the configuration settings and the endpoint information. And in order to make the service runtime available to my Node.js application I need to create an entry point element in CSDEF file and set “node.exe” as the entry point. I used five posts to introduce and demonstrate on how to run a Node.js application on Windows platform, how to use Windows Azure Web Site and Windows Azure Cloud Service worker role to host our Node.js application. I also described how to work with other services provided by Windows Azure platform through Windows Azure SDK for Node.js. Node.js is a very new and young network application platform. But since it’s very simple and easy to learn and deploy, as well as, it utilizes single thread non-blocking IO model, Node.js became more and more popular on web application and web service development especially for those IO sensitive projects. And as Node.js is very good at scaling-out, it’s more useful on cloud computing platform. Use Node.js on Windows platform is new, too. The modules for SQL database and Windows Azure SDK are still under development and enhancement. It doesn’t support SQL parameter in “node-sqlserver”. It does support using storage connection string to create the storage client in “azure”. But Microsoft is working on make them easier to use, working on add more features and functionalities. PS, you can download the source code here. You can download the source code of my “Copy all always” tool here. Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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Maven Error - Expected START_TAG or END_TAG not TEXT

- by onepotato

I am setting up a spring mvc web application + hibernate jpa + maven from scratch using Eclipse Indigo. I am stuck in this error when doing a Maven build. [ERROR] BUILD ERROR [INFO] ------------------------------------------------------------------------ [INFO] Error installing artifact's metadata: Error installing metadata: Error updating group repository metadata expected START_TAG or END_TAG not TEXT (position: TEXT seen ...<extension>war</... @13:25) [INFO] ------------------------------------------------------------------------ I tried googling but can't find a solution that works for me. I even search the whole project for the text <extension>war</ and mysteriously, there is no text like this in my project. However, in the tomcat web.xml there are a lot of <extension> tag, but I doubt that it has something to do in this error because I never touched that web.xml Here is my pom.xml <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.mycompany.applicationname</groupId> <artifactId>Application MVC</artifactId> <packaging>war</packaging> <version>0.0.1-SNAPSHOT</version> <name>Maven Application Webapp</name> <url>http://maven.apache.org</url> <properties> <spring.version>3.0.3.RELEASE</spring.version> </properties> <dependencies> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-web</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.hibernate.javax.persistence</groupId> <artifactId>hibernate-jpa-2.0-api</artifactId> <version>1.0.0.Final</version> </dependency> </dependencies> <build> <finalName>ApplicationName</finalName> </build> </project> As Funtik has suggested, I did a build with -X. Here is the stacktrace. [INFO] ------------------------------------------------------------------------ [ERROR] BUILD ERROR [INFO] ------------------------------------------------------------------------ [INFO] Error installing artifact's metadata: Error installing metadata: Error updating group repository metadata expected START_TAG or END_TAG not TEXT (position: TEXT seen ...<extension>war</... @13:25) [INFO] ------------------------------------------------------------------------ [DEBUG] Trace org.apache.maven.lifecycle.LifecycleExecutionException: Error installing artifact's metadata: Error installing metadata: Error updating group repository metadata at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:583) at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoalWithLifecycle(DefaultLifecycleExecutor.java:499) at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoal(DefaultLifecycleExecutor.java:478) at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoalAndHandleFailures(DefaultLifecycleExecutor.java:330) at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeTaskSegments(DefaultLifecycleExecutor.java:291) at org.apache.maven.lifecycle.DefaultLifecycleExecutor.execute(DefaultLifecycleExecutor.java:142) at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:336) at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:129) at org.apache.maven.cli.MavenCli.main(MavenCli.java:287) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:592) at org.codehaus.classworlds.Launcher.launchEnhanced(Launcher.java:315) at org.codehaus.classworlds.Launcher.launch(Launcher.java:255) at org.codehaus.classworlds.Launcher.mainWithExitCode(Launcher.java:430) at org.codehaus.classworlds.Launcher.main(Launcher.java:375) Caused by: org.apache.maven.plugin.MojoExecutionException: Error installing artifact's metadata: Error installing metadata: Error updating group repository metadata at org.apache.maven.plugin.install.InstallMojo.execute(InstallMojo.java:143) at org.apache.maven.plugin.DefaultPluginManager.executeMojo(DefaultPluginManager.java:451) at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:558) ... 16 more Caused by: org.apache.maven.artifact.installer.ArtifactInstallationException: Error installing artifact's metadata: Error installing metadata: Error updating group repository metadata at org.apache.maven.artifact.installer.DefaultArtifactInstaller.install(DefaultArtifactInstaller.java:91) at org.apache.maven.plugin.install.InstallMojo.execute(InstallMojo.java:105) ... 18 more Caused by: org.apache.maven.artifact.repository.metadata.RepositoryMetadataInstallationException: Error installing metadata: Error updating group repository metadata at org.apache.maven.artifact.repository.metadata.DefaultRepositoryMetadataManager.install(DefaultRepositoryMetadataManager.java:463) at org.apache.maven.artifact.installer.DefaultArtifactInstaller.install(DefaultArtifactInstaller.java:79) ... 19 more Caused by: org.apache.maven.artifact.repository.metadata.RepositoryMetadataStoreException: Error updating group repository metadata at org.apache.maven.artifact.repository.metadata.AbstractRepositoryMetadata.storeInLocalRepository(AbstractRepositoryMetadata.java:76) at org.apache.maven.artifact.repository.metadata.DefaultRepositoryMetadataManager.install(DefaultRepositoryMetadataManager.java:459) ... 20 more Caused by: org.codehaus.plexus.util.xml.pull.XmlPullParserException: expected START_TAG or END_TAG not TEXT (position: TEXT seen ...<extension>war</... @13:25) at org.codehaus.plexus.util.xml.pull.MXParser.nextTag(MXParser.java:1083) at org.apache.maven.artifact.repository.metadata.io.xpp3.MetadataXpp3Reader.parseVersioning(MetadataXpp3Reader.java:513) at org.apache.maven.artifact.repository.metadata.io.xpp3.MetadataXpp3Reader.parseMetadata(MetadataXpp3Reader.java:352) at org.apache.maven.artifact.repository.metadata.io.xpp3.MetadataXpp3Reader.read(MetadataXpp3Reader.java:866) at org.apache.maven.artifact.repository.metadata.AbstractRepositoryMetadata.updateRepositoryMetadata(AbstractRepositoryMetadata.java:98) at org.apache.maven.artifact.repository.metadata.AbstractRepositoryMetadata.storeInLocalRepository(AbstractRepositoryMetadata.java:68) ... 21 more [INFO] ------------------------------------------------------------------------ [INFO] Total time: 2 seconds [INFO] Finished at: Thu Jun 27 17:36:23 SGT 2013 [INFO] Final Memory: 9M/16M [INFO] ------------------------------------------------------------------------ web.xml <?xml version="1.0" encoding="UTF-8"?> <web-app id="WebApp_ID" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> <display-name>Adjustment Tool</display-name> <servlet> <servlet-name>mvc-dispatcher</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/spring-mvc.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>mvc-dispatcher</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> </web-app> Any ideas?

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error when I use GWT RPC

- by Sebe

Hello everyone... I have a problem with Eclipse when I use an RPC.. If I use a single method call it's all in the right direction but if I add a new method to handle the server I get the following error: com.google.gwt.core.client.JavaScriptException: (null): null at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:237) at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:126) at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:561) at com.google.gwt.dev.shell.ModuleSpace.invokeNativeBoolean(ModuleSpace.java:184) at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeBoolean(JavaScriptHost.java:35) at com.google.gwt.user.client.rpc.impl.RpcStatsContext.isStatsAvailable(RpcStatsContext.java) at com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter.onResponseReceived(RequestCallbackAdapter.java:221) at com.google.gwt.http.client.Request.fireOnResponseReceived(Request.java:287) at com.google.gwt.http.client.RequestBuilder$1.onReadyStateChange(RequestBuilder.java:395) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103) at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71) at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:157) at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:326) at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:207) at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:126) at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:561) at com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:269) at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91) at com.google.gwt.core.client.impl.Impl.apply(Impl.java) at com.google.gwt.core.client.impl.Impl.entry0(Impl.java:214) at sun.reflect.GeneratedMethodAccessor13.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103) at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71) at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:157) at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessages(BrowserChannelServer.java:281) at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:531) at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:352) at java.lang.Thread.run(Thread.java:619) Can I have more services in an asynchronous call right? Where am I wrong? This is my implementation MyService: package de.vogella.gwt.helloworld.client; import com.google.gwt.user.client.rpc.RemoteService; public interface MyService extends RemoteService { //chiamo i metodi presenti sul server public void creaXML(String nickname,String pass,String email2,String gio,String mes, String ann); public void setWeb(String userCorrect,String query, String titolo,String snippet,String url); } MyServiceAsync package de.vogella.gwt.helloworld.client; import com.google.gwt.user.client.rpc.AsyncCallback; public interface MyServiceAsync { void creaXML(String nickname,String pass,String email2,String gio,String mes, String ann,AsyncCallback<Void> callback); void setWeb(String userCorrect,String query, String titolo,String snippet,String url, AsyncCallback<Void> callback); } RPCService: package de.vogella.gwt.helloworld.client; import com.google.gwt.core.client.GWT; import com.google.gwt.user.client.rpc.AsyncCallback; import com.google.gwt.user.client.rpc.ServiceDefTarget; import com.google.gwt.user.client.ui.FlexTable; public class RPCService implements MyServiceAsync { MyServiceAsync service = (MyServiceAsync) GWT.create(MyService.class); ServiceDefTarget endpoint = (ServiceDefTarget) service; public RPCService() { endpoint.setServiceEntryPoint(GWT.getModuleBaseURL() + "rpc"); } public void creaXML(String nickname,String pass,String email2,String gio,String mes, String ann,AsyncCallback callback) { service.creaXML(nickname, pass, email2, gio, mes, ann, callback); } public void setWeb(String userCorrect,String query, String titolo,String snippet,String url,AsyncCallback callback) { service.setWeb(userCorrect,query, titolo,snippet,url,callback); } } MyServiceImpl package de.vogella.gwt.helloworld.server; import java.io.*; import org.w3c.dom.*; import org.xml.sax.SAXException; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import javax.xml.transform.*; import javax.xml.transform.dom.DOMSource; import javax.xml.transform.stream.StreamResult; import de.vogella.gwt.helloworld.client.MyService; import com.google.gwt.user.client.ui.FlexTable; import com.google.gwt.user.server.rpc.RemoteServiceServlet; import com.google.gwt.xml.client.Element; import com.google.gwt.xml.client.NodeList; public class MyServiceImpl extends RemoteServiceServlet implements MyService { //metodo che inserisce il nuovo iscritto public void creaXML(String nickname,String pass,String email2,String gio,String mes, String ann){ ....... } public void setWeb(String userCorrect,String query, String titolo,String snippet,String url) { ..... } In the app in client-side I do RPCService rpc2 = New RPCService() rpc2.setWeb(..,...,...,...,callback); and RPCService rpc = New RPCService() rpc.creaXML(..,...,...,...,callback); (in other posizions in the code...) and.. AsyncCallback callback = new AsyncCallback() { public void onFailure(Throwable caught) { Window.alert("Failure!"); } public void onSuccess(Object result) { Window.alert("Successoooooo"); } }; Web.xml: <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd"> <web-app>   <welcome-file-list> <welcome-file>De_vogella_gwt_helloworld.html</welcome-file> </welcome-file-list> <servlet> <servlet-name>rPCImpl</servlet-name> <servlet-class>de.vogella.gwt.helloworld.server.MyServiceImpl</servlet-class> </servlet> <servlet-mapping> <servlet-name>rPCImpl</servlet-name> <url-pattern>/de_vogella_gwt_helloworld/rpc</url-pattern> </servlet-mapping> </web-app> Thank you all for your attention Sebe

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Getting error while install mod_wsgi on centos6.3 with python 2.7

- by user825904

In initially installed yum install mod_wsgi and i think it was linked with python 2.6 Now is there any way to link it with 2.7 I tried configuring from the source and i get this error apxs -c -I/usr/local/include/python2.7 -DNDEBUG mod_wsgi.c -L/usr/local/lib -L/usr/local/lib/python2.7/config -lpython2.7 -lpthread -ldl -lutil -lm /usr/lib64/apr-1/build/libtool --silent --mode=compile gcc -prefer-pic -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic -Wformat-security -fno-strict-aliasing -DLINUX=2 -D_REENTRANT -D_GNU_SOURCE -pthread -I/usr/include/httpd -I/usr/include/apr-1 -I/usr/include/apr-1 -I/usr/local/include/python2.7 -DNDEBUG -c -o mod_wsgi.lo mod_wsgi.c && touch mod_wsgi.slo In file included from /usr/local/include/python2.7/Python.h:8, from mod_wsgi.c:142: /usr/local/include/python2.7/pyconfig.h:1161:1: warning: "_POSIX_C_SOURCE" redefined In file included from /usr/include/sys/types.h:26, from /usr/include/apr-1/apr-x86_64.h:127, from /usr/include/apr-1/apr.h:19, from /usr/include/httpd/ap_config.h:25, from /usr/include/httpd/httpd.h:43, from mod_wsgi.c:34: /usr/include/features.h:162:1: warning: this is the location of the previous definition In file included from /usr/local/include/python2.7/Python.h:8, from mod_wsgi.c:142: /usr/local/include/python2.7/pyconfig.h:1183:1: warning: "_XOPEN_SOURCE" redefined In file included from /usr/include/sys/types.h:26, from /usr/include/apr-1/apr-x86_64.h:127, from /usr/include/apr-1/apr.h:19, from /usr/include/httpd/ap_config.h:25, from /usr/include/httpd/httpd.h:43, from mod_wsgi.c:34: /usr/include/features.h:164:1: warning: this is the location of the previous definition mod_wsgi.c: In function ‘wsgi_server_group’: mod_wsgi.c:991: warning: unused variable ‘value’ mod_wsgi.c: In function ‘Log_isatty’: mod_wsgi.c:1665: warning: unused variable ‘result’ mod_wsgi.c: In function ‘Log_writelines’: mod_wsgi.c:1802: warning: unused variable ‘msg’ mod_wsgi.c: In function ‘Adapter_output’: mod_wsgi.c:3087: warning: unused variable ‘n’ mod_wsgi.c: In function ‘Adapter_file_wrapper’: mod_wsgi.c:4138: warning: unused variable ‘result’ mod_wsgi.c: In function ‘wsgi_python_term’: mod_wsgi.c:5850: warning: unused variable ‘tstate’ mod_wsgi.c:5849: warning: unused variable ‘interp’ mod_wsgi.c: In function ‘wsgi_python_child_init’: mod_wsgi.c:7050: warning: unused variable ‘l’ mod_wsgi.c:6948: warning: unused variable ‘interp’ mod_wsgi.c: In function ‘wsgi_add_import_script’: mod_wsgi.c:7701: warning: unused variable ‘error’ mod_wsgi.c: In function ‘wsgi_add_handler_script’: mod_wsgi.c:8179: warning: unused variable ‘dconfig’ mod_wsgi.c:8178: warning: unused variable ‘sconfig’ mod_wsgi.c: In function ‘wsgi_hook_handler’: mod_wsgi.c:9375: warning: suggest parentheses around assignment used as truth value mod_wsgi.c:9377: warning: suggest parentheses around assignment used as truth value mod_wsgi.c:9379: warning: suggest parentheses around assignment used as truth value mod_wsgi.c:9383: warning: suggest parentheses around assignment used as truth value mod_wsgi.c:9403: warning: suggest parentheses around assignment used as truth value mod_wsgi.c:9405: warning: suggest parentheses around assignment used as truth value mod_wsgi.c:9408: warning: suggest parentheses around assignment used as truth value mod_wsgi.c: In function ‘wsgi_daemon_worker’: mod_wsgi.c:10819: warning: unused variable ‘duration’ mod_wsgi.c:10818: warning: unused variable ‘start’ mod_wsgi.c: In function ‘wsgi_hook_daemon_handler’: mod_wsgi.c:13172: warning: unused variable ‘i’ mod_wsgi.c:13170: warning: unused variable ‘elts’ mod_wsgi.c:13169: warning: unused variable ‘head’ mod_wsgi.c: At top level: mod_wsgi.c:8142: warning: ‘wsgi_set_user_authoritative’ defined but not used mod_wsgi.c:15251: warning: ‘wsgi_hook_check_user_id’ defined but not used /usr/lib64/apr-1/build/libtool --silent --mode=link gcc -o mod_wsgi.la -rpath /usr/lib64/httpd/modules -module -avoid-version mod_wsgi.lo -L/usr/local/lib -L/usr/local/lib/python2.7/config -lpython2.7 -lpthread -ldl -lutil -lm /usr/bin/ld: /usr/local/lib/libpython2.7.a(abstract.o): relocation R_X86_64_32 against `.rodata.str1.8' can not be used when making a shared object; recompile with -fPIC /usr/local/lib/libpython2.7.a: could not read symbols: Bad value collect2: ld returned 1 exit status apxs:Error: Command failed with rc=65536 . make: *** [mod_wsgi.la] Error 1 Waiting for Graham

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javax.validation.ConstraintViolationException: validation failed for classes during update time for groups

- by Tim

Hello all! I have a Java / Spring MVC 3 application, using Hibernate and a MySQL database. In my controller, I have this source code: Set<ConstraintViolation<Person>> failures = validator.validate(p); if (failures.isEmpty()) { Project project = this.projectService.findProjectById(projectid); Person newPerson = this.personService.addPerson(p); Set<Person> persons = this.personService.getAllPersonsByProjectId(projectid); persons.add(newPerson); project.setPersons(persons); Set<ConstraintViolation<Project>> failures1 = validator.validate(project); if (!failures1.isEmpty()) { System.out.println("ERROR"); } else { System.out.println("NO ERROR"); } this.projectService.updateProject(project); return Collections.singletonMap("person", newPerson); } Project and Person are a many-to-many relation annotated with @manytomany and Project is the mapping owner. The new Person is added, but on the line with this.projectService.updateProject(project); I get an error. What it does it this in a Dao Hibernate implementation: public void updateProject(Project p) { SessionFactory sessionFactory = HibernateUtil.getSessionFactory(); Session sess = sessionFactory.getCurrentSession(); Transaction tx = sess.beginTransaction(); sess.update(p); tx.commit(); } It failed on the line tx.commit();. My check with if (!failures1.isEmpty()) { tell me that there are nor errors in my project. So what's wrong here? And why there is a validation of my project? I did not call a validation method... so why is there a org.hibernate.cfg.beanvalidation.BeanValidationEventListener.validate()? I hope, someone can help me how to fix this! Best Regards, Tim. Here the full error stack trace: 13.01.2011 00:06:36 org.apache.catalina.core.ApplicationDispatcher invoke SERVE: Servlet.service() for servlet project3 threw exception javax.validation.ConstraintViolationException: validation failed for classes [com.mydomain.myproject.domain.Person] during update time for groups [javax.validation.groups.Default, ] at org.hibernate.cfg.beanvalidation.BeanValidationEventListener.validate(BeanValidationEventListener.java:155) at org.hibernate.cfg.beanvalidation.BeanValidationEventListener.onPreUpdate(BeanValidationEventListener.java:102) at org.hibernate.action.EntityUpdateAction.preUpdate(EntityUpdateAction.java:235) at org.hibernate.action.EntityUpdateAction.execute(EntityUpdateAction.java:86) at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:273) at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:265) at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:185) at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321) at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:51) at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1216) at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:383) at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:133) at com.mydomain.myproject.dao.impl.ProjectDaoImplHibernate.updateProject(ProjectDaoImplHibernate.java:44) at com.mydomain.myproject.service.impl.ProjectServiceImpl.updateProject(ProjectServiceImpl.java:39) at com.mydomain.myproject.controller.ProjectPersonController.addPerson(ProjectPersonController.java:189) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:176) at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:426) at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:414) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:790) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644) at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:560) at javax.servlet.http.HttpServlet.service(HttpServlet.java:637) at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:646) at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:436) at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:374) at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:302) at org.tuckey.web.filters.urlrewrite.NormalRewrittenUrl.doRewrite(NormalRewrittenUrl.java:195) at org.tuckey.web.filters.urlrewrite.RuleChain.handleRewrite(RuleChain.java:159) at org.tuckey.web.filters.urlrewrite.RuleChain.doRules(RuleChain.java:141) at org.tuckey.web.filters.urlrewrite.UrlRewriter.processRequest(UrlRewriter.java:90) at org.tuckey.web.filters.urlrewrite.UrlRewriteFilter.doFilter(UrlRewriteFilter.java:417) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:857) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489) at java.lang.Thread.run(Thread.java:619) 13.01.2011 00:06:36 org.apache.catalina.core.StandardWrapperValve invoke SERVE: Servlet.service() for servlet default threw exception javax.validation.ConstraintViolationException: validation failed for classes [com.mydomain.myproject.domain.Person] during update time for groups [javax.validation.groups.Default, ] at org.hibernate.cfg.beanvalidation.BeanValidationEventListener.validate(BeanValidationEventListener.java:155) at org.hibernate.cfg.beanvalidation.BeanValidationEventListener.onPreUpdate(BeanValidationEventListener.java:102) at org.hibernate.action.EntityUpdateAction.preUpdate(EntityUpdateAction.java:235) at org.hibernate.action.EntityUpdateAction.execute(EntityUpdateAction.java:86) at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:273) at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:265) at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:185) at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321) at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:51) at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1216) at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:383) at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:133) at com.mydomain.myproject.dao.impl.ProjectDaoImplHibernate.updateProject(ProjectDaoImplHibernate.java:44) at com.mydomain.myproject.service.impl.ProjectServiceImpl.updateProject(ProjectServiceImpl.java:39) at com.mydomain.myproject.controller.ProjectPersonController.addPerson(ProjectPersonController.java:189) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:176) at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:426) at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:414) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:790) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644) at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:560) at javax.servlet.http.HttpServlet.service(HttpServlet.java:637) at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:646) at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:436) at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:374) at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:302) at org.tuckey.web.filters.urlrewrite.NormalRewrittenUrl.doRewrite(NormalRewrittenUrl.java:195) at org.tuckey.web.filters.urlrewrite.RuleChain.handleRewrite(RuleChain.java:159) at org.tuckey.web.filters.urlrewrite.RuleChain.doRules(RuleChain.java:141) at org.tuckey.web.filters.urlrewrite.UrlRewriter.processRequest(UrlRewriter.java:90) at org.tuckey.web.filters.urlrewrite.UrlRewriteFilter.doFilter(UrlRewriteFilter.java:417) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:857) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489) at java.lang.Thread.run(Thread.java:619) UPDATE Before updating the Project where the error occurs, I add a person which have this annotated: @NotNull @Size(min = 1, max = 255) @Pattern(regexp="(?:[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*|\"(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21\\x23-\\x5b\\x5d-\\x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])*\")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21-\\x5a\\x53-\\x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])+)\\])", message="{my.email.error.message}") private String email; Without the @Pattern no error... So, what's wrong here? UPDATE-2: I use Hibernate 3.6.0.Final and I have these in my Maven pom.xml:  <dependency> <groupId>javax.validation</groupId> <artifactId>validation-api</artifactId> <version>1.0.0.GA</version> </dependency> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-validator</artifactId> <version>4.1.0.Final</version> </dependency>

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Error with JSF2 and RichFaces

- by Miguel Ping

Hi, I'm trying to use RichFaces on a working JSF2 application. I incorporated the RichFaces jars, changed the web.xml but got the following error: 17:49:13,097 SEVERE [javax.enterprise.resource.webcontainer.jsf.application] Error Rendering View[/login.xhtml]: java.lang.NullPointerExcept ion at com.sun.faces.application.ApplicationImpl.createComponent(ApplicationImpl.java:936) at com.sun.faces.facelets.tag.jsf.CompositeComponentTagHandler.createComponent(CompositeComponentTagHandler.java:154) at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.createComponent(ComponentTagHandlerDelegateImpl.java:311) at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:145) at javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:114) at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:91) at javax.faces.view.facelets.DelegatingMetaTagHandler.applyNextHandler(DelegatingMetaTagHandler.java:120) at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:204) at javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:114) at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:91) at com.sun.faces.facelets.compiler.NamespaceHandler.apply(NamespaceHandler.java:86) at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:91) at com.sun.faces.facelets.compiler.EncodingHandler.apply(EncodingHandler.java:75) at com.sun.faces.facelets.impl.DefaultFacelet.include(DefaultFacelet.java:301) at com.sun.faces.facelets.impl.DefaultFacelet.include(DefaultFacelet.java:360) at com.sun.faces.facelets.impl.DefaultFacelet.include(DefaultFacelet.java:339) at com.sun.faces.facelets.impl.DefaultFaceletContext.includeFacelet(DefaultFaceletContext.java:191) at com.sun.faces.facelets.tag.ui.CompositionHandler.apply(CompositionHandler.java:149) at com.sun.faces.facelets.compiler.NamespaceHandler.apply(NamespaceHandler.java:86) at com.sun.faces.facelets.compiler.EncodingHandler.apply(EncodingHandler.java:75) at com.sun.faces.facelets.impl.DefaultFacelet.apply(DefaultFacelet.java:145) at com.sun.faces.application.view.FaceletViewHandlingStrategy.buildView(FaceletViewHandlingStrategy.java:716) at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:351) at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:126) at org.ajax4jsf.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:100) at org.ajax4jsf.application.AjaxViewHandler.renderView(AjaxViewHandler.java:176) at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:127) at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101) at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139) at javax.faces.webapp.FacesServlet.service(FacesServlet.java:313) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:336) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:242) at org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:206) at org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:290) at org.ajax4jsf.webapp.BaseFilter.processUploadsAndHandleRequest(BaseFilter.java:388) at org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:515) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:274) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:242) at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:734) at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:541) at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:479) at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:407) at org.apache.catalina.authenticator.FormAuthenticator.forwardToLoginPage(FormAuthenticator.java:318) at org.apache.catalina.authenticator.FormAuthenticator.authenticate(FormAuthenticator.java:243) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:559) at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:95) at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.process(SecurityContextEstablishmentValve.java:126) at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:70) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:368) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:872) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:653) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:951) at java.lang.Thread.run(Thread.java:619) It seems that some jars are missing, but I cannot seem to find this cause. The above error is the only thing that the log spits out. Here's web.xml: <context-param> <param-name>javax.faces.FACELETS_LIBRARIES</param-name> <param-value>/WEB-INF/faces-validator-tags/general.taglib.xml; /WEB-INF/faces-converter-tags/general.converter.taglib.xml </param-value> </context-param>  <context-param> <param-name>javax.faces.DISABLE_FACELET_JSF_VIEWHANDLER</param-name> <param-value>true</param-value> </context-param> <context-param> <param-name>org.richfaces.SKIN</param-name> <param-value>blueSky</param-value> </context-param>  <context-param> <param-name>org.richfaces.CONTROL_SKINNING</param-name> <param-value>enable</param-value> </context-param> <context-param> <param-name>javax.faces.STATE_SAVING_METHOD</param-name> <param-value>server</param-value> </context-param> <context-param> <param-name>org.richfaces.SKIN</param-name> <param-value>blueSky</param-value> </context-param> <context-param> <param-name>org.richfaces.CONTROL_SKINNING</param-name> <param-value>enable</param-value> </context-param> <filter> <display-name>RichFaces Filter</display-name> <filter-name>richfaces</filter-name> <filter-class>org.ajax4jsf.Filter</filter-class> </filter> <filter-mapping> <filter-name>richfaces</filter-name> <servlet-name>Faces Servlet</servlet-name> <dispatcher>REQUEST</dispatcher> <dispatcher>FORWARD</dispatcher> <dispatcher>INCLUDE</dispatcher> </filter-mapping> <listener> <listener-class>com.sun.faces.config.ConfigureListener</listener-class> </listener>  <servlet> <servlet-name>Faces Servlet</servlet-name> <servlet-class>javax.faces.webapp.FacesServlet</servlet-class> <load-on-startup>1</load-on-startup> </servlet>  <servlet-mapping> <servlet-name>Faces Servlet</servlet-name> <url-pattern>*.jsf</url-pattern> </servlet-mapping> <login-config> <auth-method>FORM</auth-method> <form-login-config> <form-login-page>/login.jsf</form-login-page> <form-error-page>/loginError.jsf</form-error-page> </form-login-config> </login-config> <error-page> <exception-type>java.lang.Throwable</exception-type> <location>/errors/error.jsf</location> </error-page>

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spring mvc 3.0 small web application not quite working

- by lurscher

Hi, i'm creating a very simple (hello World quality) web application using spring mvc 3.0. when deploying the application on tomcat 6.0.26 and i try to open http://localhost:8080/protoweb/helloWorld.html i get 404, resource /protoweb/WEB-INF/jsp/helloWorld.jsp is not available. The funny thing is that there IS a helloWorld.jsp in there. any idea what i'm doing wrong? here is my web.xml <?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5"> <display-name>hello-spring3-RC1</display-name> <context-param> <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/yummy-servlet.xml</param-value> </context-param> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> <servlet> <servlet-name>yummy</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>yummy</servlet-name> <url-pattern>*.html</url-pattern> </servlet-mapping> <welcome-file-list> <welcome-file>index.html</welcome-file> </welcome-file-list> </web-app> my yummy-servlet.xml <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd"> <context:component-scan base-package="com.mine.web.controllers"/> <bean id="jspViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/> <property name="prefix" value="/WEB-INF/jsp/"/> <property name="suffix" value=".jsp"/> </bean> </beans> my very simple controller: package com.mine.web.controllers; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.servlet.ModelAndView; @Controller public class BasicController { @RequestMapping(value = "/helloWorld") public ModelAndView helloWorld() { ModelAndView mav = new ModelAndView(); mav.setViewName("helloWorld"); mav.addObject("message", "Hello some basic message for u"); return mav; } } and my webapp/jsp/helloWorld.jsp <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Hello</title> </head> <body> ${message} </body> </html> also, it might be helpful to post my pom.xml <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.mine</groupId> <artifactId>protoweb</artifactId> <packaging>war</packaging> <version>1.0-SNAPSHOT</version> <name>protoweb Maven Webapp</name> <url>http://maven.apache.org</url> <repositories> <repository> <id>springsource maven repo</id> <url>http://maven.springframework.org/milestone</url> </repository> </repositories> <dependencies> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>3.0.0.RC1</version> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>3.8.1</version> <scope>test</scope> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>jstl</artifactId> <version>1.1.2</version> <scope>compile</scope> </dependency> </dependencies> <build> <finalName>protoweb</finalName> <plugins> <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>tomcat-maven-plugin</artifactId> <configuration> <configurationDir>tomcat</configurationDir> <url>http://localhost:8080/manager</url> <username>test</username> <password>test</password> </configuration> </plugin> </plugins> </build> </project>

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Cannot access a very specific site from my router

- by DJDarkViper

This is a problem for me because this site is important to me. It's MY website. And sadly my email is hosted on my site (which I cant access either) When I try to access my website when connected to my Linksys E3000 router, these days it simply just doesn't go through. When I ping it, its all Request Timed Out, and when I tracert C:\Users\Kyle>tracert blackjaguarstudios.com Tracing route to blackjaguarstudios.com [199.188.204.228] over a maximum of 30 hops: 1 <1 ms <1 ms <1 ms CISCO26565 [192.168.1.1] 2 16 ms 15 ms 11 ms 11.4.64.1 3 11 ms 9 ms 11 ms rd1cs-ge1-2-1.ok.shawcable.net [64.59.169.2] 4 20 ms 21 ms 22 ms 66.163.76.98 5 37 ms 36 ms 35 ms rc1nr-tge0-9-2-0.wp.shawcable.net [66.163.77.54] 6 112 ms 84 ms 85 ms rc2ch-pos9-0.il.shawcable.net [66.163.76.174] 7 86 ms 89 ms 90 ms rc4as-ge12-0-0.vx.shawcable.net [66.163.64.46] 8 90 ms 84 ms 85 ms eqix.xe-3-3-0.cr2.iad1.us.nlayer.net [206.223.115.61] 9 97 ms 97 ms 99 ms xe-3-3-0.cr1.atl1.us.nlayer.net [69.22.142.105] 10 128 ms 128 ms 126 ms ae1-40g.ar1.atl1.us.nlayer.net [69.31.135.130] 11 101 ms 97 ms 96 ms as16626.xe-2-0-5-102.ar1.atl1.us.nlayer.net [69.31.135.46] 12 100 ms 97 ms 197 ms 6509-sc1.abstractdns.com [207.210.114.166] 13 * * * Request timed out. 14 * * * Request timed out. 15 * * * Request timed out. 16 * * * Request timed out. 17 * * * Request timed out. 18 * * * Request timed out. 19 * * * Request timed out. 20 * * * Request timed out. 21 * * * Request timed out. 22 * * * Request timed out. 23 * * * Request timed out. 24 * * * Request timed out. 25 * * * Request timed out. 26 * * * Request timed out. 27 * * * Request timed out. 28 * * * Request timed out. 29 * * * Request timed out. 30 * * * Request timed out. Trace complete. C:\Users\Kyle> SHAW Cable being my ISP. Figuring this was all something to do with some setting I made on the router, I reset the thing back to factory defaults. Nope. So I'm at a bit of a loss what to do here, as NO device (Computers, Laptops, Tablets, Phones, PS3/ 360, etc) can access my site or its features, so it's not just my computer either. But every other site is just fine. When I connect to my neighbors router, the site comes up just fine. And shes with SHAW as well. What should I do?!

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Python regex to parse text file, get the items in list and count the list

- by Nemo

I have a text file which contains some data. I m particularly interested in finding the count of the number of items in v_dims v_dims pattern in my text file looks like this : v_dims={ "Sales", "Product Family", "Sales Organization", "Region", "Sales Area", "Sales office", "Sales Division", "Sales Person", "Sales Channel", "Sales Order Type", "Sales Number", "Sales Person", "Sales Quantity", "Sales Amount" } So I m thinking of getting all the elements in v_dims and dumping them out in a Python list. Then compute the len(mylist) to get the count of the items. The challenge is in getting all the elements of v_dims from my text file and putting them in an empty list. I m particularly interested in items in v_dims in my text file. The text file has data in the form of v_dims pattern i showed in my original post. Some data has nested patterns of v_dims. Thanks. Here's what I have tried and failed. Any help is appreciated. TIA. import re fname = "C:\Users\XXXX\Test.mrk" with open(fname, "r") as fo: content_as_string = fo.read() match = re.findall(r'v_dims={\"(.+?)\"}',content_as_string) Though I have a big text file, Here's a snippet of what's the structure of my text file version "1"; // Computer generated object language file object 'MRKR' "Main" { Data_Type=2, HeaderBlock={ Version_String="6.3 (25)" }, Printer_Info={ Orientation=0, Page_Width=8.50000000, Page_Height=11.00000000, Page_Header="", Page_Footer="", Margin_type=0, Top_Margin=0.50000000, Left_Margin=0.50000000, Bottom_Margin=0.50000000, Right_Margin=0.50000000 }, Marker_Options={ Close_All="TRUE", Hide_Console="FALSE", Console_Left="FALSE", Console_Width=217, Main_Style="Maximized", MDI_Rect={ 0, 0, 892, 1063 } }, Dives={ { Dive="A", Windows={ { View_Index=0, Window_Info={ Window_Rect={ 0, -288, 400, 1008 }, Window_Style="Maximized Front", Window_Name="Theater [Previous Qtr Diveplan-Dive A]" }, Dependent_bool="FALSE", Colset={ Dive_Type="Normal", Dimension_Name="Theater", Action_List={ Actions={ { Action_Type="Select", select_type=5 }, { Action_Type="Select", select_type=0, Key_Names={ "Theater" }, Key_Indexes={ { "AMERICAS" } } }, { Action_Type="Focus", Focus_Rows="True" }, { Action_Type="Dimensions", v_dims={ "Theater", "Product Family", "Division", "Region", "Install at Country Name", "Connect Home Type", "Connect In Type", "SymmConnect Enabled", "Connect Home Refusal Reason", "Sales Order Channel Type", "Maintained By Group", "PS Flag", "Avalanche Flag", "Product Item Family" }, Xtab_Bool="False", Xtab_Flip="False" }, { Action_Type="Select", select_type=5 }, { Action_Type="Select", select_type=0, Key_Names={ "Theater", "Product Family", "Division", "Region", "Install at Country Name", "Connect Home Type", "Connect In Type", "SymmConnect Enabled", "Connect Home Refusal Reason", "Sales Order Channel Type", "Maintained By Group", "PS Flag", "Avalanche Flag" }, Key_Indexes={ { "AMERICAS", "ATMOS", "Latin America CS Division", "37000 CS Region", "Mexico", "", "", "", "", "DIRECT", "EMC", "N", "0" } } } } }, Num_Palette_cols=0, Num_Palette_rows=0 }, Format={ Window_Type="Tabular", Tabular={ Num_row_labels=8 } } } } } }, Widget_Set={ Widget_Layout="Vertical", Go_Button=1, Picklist_Width=0, Sort_Subset_Dimensions="TRUE", Order={ } }, Views={ { Data_Type=1, dbname="Previous Qtr Diveplan", diveline_dbname="Current Qtr Diveplan", logical_name="Current Qtr Diveplan", cols={ { name="Total TSS installs", column_type="Calc[Total TSS installs]", output_type="Number", format_string="." }, { name="TSS Valid Connectivity Records", column_type="Calc[TSS Valid Connectivity Records]", output_type="Number", format_string="." }, { name="% TSS Connectivity Record", column_type="Calc[% TSS Connectivity Record]", output_type="Number" }, { name="TSS Not Applicable", column_type="Calc[TSS Not Applicable]", output_type="Number", format_string="." }, { name="TSS Customer Refusals", column_type="Calc[TSS Customer Refusals]", output_type="Number", format_string="." }, { name="% TSS Refusals", column_type="Calc[% TSS Refusals]", output_type="Number" }, { name="TSS Eligible for Physical Connectivity", column_type="Calc[TSS Eligible for Physical Connectivity]", output_type="Number", format_string="." }, { name="TSS Boxes with Physical Connectivty", column_type="Calc[TSS Boxes with Physical Connectivty]", output_type="Number", format_string="." }, { name="% TSS Physical Connectivity", column_type="Calc[% TSS Physical Connectivity]", output_type="Number" } }, dim_cols={ { name="Model", column_type="Dimension[Model]", output_type="None" }, { name="Model", column_type="Dimension[Model]", output_type="None" }, { name="Connect In Type", column_type="Dimension[Connect In Type]", output_type="None" }, { name="Connect Home Type", column_type="Dimension[Connect Home Type]", output_type="None" }, { name="SymmConnect Enabled", column_type="Dimension[SymmConnect Enabled]", output_type="None" }, { name="Theater", column_type="Dimension[Theater]", output_type="None" }, { name="Division", column_type="Dimension[Division]", output_type="None" }, { name="Region", column_type="Dimension[Region]", output_type="None" }, { name="Sales Order Number", column_type="Dimension[Sales Order Number]", output_type="None" }, { name="Product Item Family", column_type="Dimension[Product Item Family]", output_type="None" }, { name="Item Serial Number", column_type="Dimension[Item Serial Number]", output_type="None" }, { name="Sales Order Deal Number", column_type="Dimension[Sales Order Deal Number]", output_type="None" }, { name="Item Install Date", column_type="Dimension[Item Install Date]", output_type="None" }, { name="SYR Last Dial Home Date", column_type="Dimension[SYR Last Dial Home Date]", output_type="None" }, { name="Maintained By Group", column_type="Dimension[Maintained By Group]", output_type="None" }, { name="PS Flag", column_type="Dimension[PS Flag]", output_type="None" }, { name="Connect Home Refusal Reason", column_type="Dimension[Connect Home Refusal Reason]", output_type="None", col_width=177 }, { name="Cust Name", column_type="Dimension[Cust Name]", output_type="None" }, { name="Sales Order Channel Type", column_type="Dimension[Sales Order Channel Type]", output_type="None" }, { name="Sales Order Type", column_type="Dimension[Sales Order Type]", output_type="None" }, { name="Part Model Key", column_type="Dimension[Part Model Key]", output_type="None" }, { name="Ship Date", column_type="Dimension[Ship Date]", output_type="None" }, { name="Model Number", column_type="Dimension[Model Number]", output_type="None" }, { name="Item Description", column_type="Dimension[Item Description]", output_type="None" }, { name="Customer Classification", column_type="Dimension[Customer Classification]", output_type="None" }, { name="CS Customer Name", column_type="Dimension[CS Customer Name]", output_type="None" }, { name="Install At Customer Number", column_type="Dimension[Install At Customer Number]", output_type="None" }, { name="Install at Country Name", column_type="Dimension[Install at Country Name]", output_type="None" }, { name="TLA Serial Number", column_type="Dimension[TLA Serial Number]", output_type="None" }, { name="Product Version", column_type="Dimension[Product Version]", output_type="None" }, { name="Avalanche Flag", column_type="Dimension[Avalanche Flag]", output_type="None" }, { name="Product Family", column_type="Dimension[Product Family]", output_type="None" }, { name="Project Number", column_type="Dimension[Project Number]", output_type="None" }, { name="PROJECT_STATUS", column_type="Dimension[PROJECT_STATUS]", output_type="None" } }, Available_Columns={ "Total TSS installs", "TSS Valid Connectivity Records", "% TSS Connectivity Record", "TSS Not Applicable", "TSS Customer Refusals", "% TSS Refusals", "TSS Eligible for Physical Connectivity", "TSS Boxes with Physical Connectivty", "% TSS Physical Connectivity", "Total Installs", "All Boxes with Valid Connectivty Record", "% All Connectivity Record", "Overall Refusals", "Overall Refusals %", "All Eligible for Physical Connectivty", "Boxes with Physical Connectivity", "% All with Physical Conectivity" }, Remaining_columns={ { name="Total Installs", column_type="Calc[Total Installs]", output_type="Number", format_string="." }, { name="All Boxes with Valid Connectivty Record", column_type="Calc[All Boxes with Valid Connectivty Record]", output_type="Number", format_string="." }, { name="% All Connectivity Record", column_type="Calc[% All Connectivity Record]", output_type="Number" }, { name="Overall Refusals", column_type="Calc[Overall Refusals]", output_type="Number", format_string="." }, { name="Overall Refusals %", column_type="Calc[Overall Refusals %]", output_type="Number" }, { name="All Eligible for Physical Connectivty", column_type="Calc[All Eligible for Physical Connectivty]", output_type="Number" }, { name="Boxes with Physical Connectivity", column_type="Calc[Boxes with Physical Connectivity]", output_type="Number" }, { name="% All with Physical Conectivity", column_type="Calc[% All with Physical Conectivity]", output_type="Number" } }, calcs={ { name="Total TSS installs", definition="Total[Total TSS installs]", ts_flag="Not TS Calc" }, { name="TSS Valid Connectivity Records", definition="Total[PS Boxes w/ valid connectivity record (1=yes)]", ts_flag="Not TS Calc" }, { name="% TSS Connectivity Record", definition="Total[PS Boxes w/ valid connectivity record (1=yes)] /Total[Total TSS installs]", ts_flag="Not TS Calc" }, { name="TSS Not Applicable", definition="Total[Bozes w/ valid connectivity record (1=yes)]-Total[Boxes Eligible (1=yes)]-Total[TSS Refusals]", ts_flag="Not TS Calc" }, { name="TSS Customer Refusals", definition="Total[TSS Refusals]", ts_flag="Not TS Calc" }, { name="% TSS Refusals", definition="Total[TSS Refusals]/Total[PS Boxes w/ valid connectivity record (1=yes)]", ts_flag="Not TS Calc" }, { name="TSS Eligible for Physical Connectivity", definition="Total[TSS Eligible]-Total[Exception]", ts_flag="Not TS Calc" }, { name="TSS Boxes with Physical Connectivty", definition="Total[PS Physical Connectivity] - Total[PS Physical Connectivity, SymmConnect Enabled=\"Capable not enabled\"]", ts_flag="Not TS Calc" }, { name="% TSS Physical Connectivity", definition="Total[Boxes w/ phys conn]/Total[Boxes Eligible (1=yes)]", ts_flag="Not TS Calc" }, { name="Total Installs", definition="Total[Total Installs]", ts_flag="Not TS Calc" }, { name="All Boxes with Valid Connectivty Record", definition="Total[Bozes w/ valid connectivity record (1=yes)]", ts_flag="Not TS Calc" }, { name="% All Connectivity Record", definition="Total[Bozes w/ valid connectivity record (1=yes)]/Total[Total Installs]", ts_flag="Not TS Calc" }, { name="Overall Refusals", definition="Total[Overall Refusals]", ts_flag="Not TS Calc" }, { name="Overall Refusals %", definition="Total[Overall Refusals]/Total[Bozes w/ valid connectivity record (1=yes)]", ts_flag="Not TS Calc" }, { name="All Eligible for Physical Connectivty", definition="Total[Boxes Eligible (1=yes)]-Total[Exception]", ts_flag="Not TS Calc" }, { name="Boxes with Physical Connectivity", definition="Total[Boxes w/ phys conn]-Total[Boxes w/ phys conn,SymmConnect Enabled=\"Capable not enabled\"]", ts_flag="Not TS Calc" }, { name="% All with Physical Conectivity", definition="Total[Boxes w/ phys conn]/Total[Boxes Eligible (1=yes)]", ts_flag="Not TS Calc" } }, merge_type="consolidate", merge_dbs={ { dbname="connectivityallproducts.mdl", diveline_dbname="/DI_PSREPORTING/connectivityallproducts.mdl" } }, skip_constant_columns="FALSE", categories={ { name="Geography", dimensions={ "Theater", "Division", "Region", "Install at Country Name" } }, { name="Mappings and Flags", dimensions={ "Connect Home Type", "Connect In Type", "SymmConnect Enabled", "Connect Home Refusal Reason", "Sales Order Channel Type", "Maintained By Group", "Customer Installable", "PS Flag", "Top Level Flag", "Avalanche Flag" } }, { name="Product Information", dimensions={ "Product Family", "Product Item Family", "Product Version", "Item Description" } }, { name="Sales Order Info", dimensions={ "Sales Order Deal Number", "Sales Order Number", "Sales Order Type" } }, { name="Dates", dimensions={ "Item Install Date", "Ship Date", "SYR Last Dial Home Date" } }, { name="Details", dimensions={ "Item Serial Number", "TLA Serial Number", "Part Model Key", "Model Number" } }, { name="Customer Infor", dimensions={ "CS Customer Name", "Install At Customer Number", "Customer Classification", "Cust Name" } }, { name="Other Dimensions", dimensions={ "Model" } } }, Maintain_Category_Order="FALSE", popup_info="false" } } };

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Using smartctl to get vendor specific Attributes from ssd drive behind a SmartArray P410 controller

- by Lairsdragon

Hi! Recently I have deployed some HP server with SSD's behind a SmartArray P410 controller. While not official supported from HP the server work well sofar. Now I like to get wear level info's, error statistics etc from the drive. While the SA P410 supports a passthru of the SMART Command to a single drive in the array the output I was not able to the the interesting things from the drive. In this case especially the value the Wear level indicator is from interest for me (Attr.ID 233), but this is ony present if the drive is directly attanched to a SATA Controller. smartctl on directly connected ssd: # smartctl -A /dev/sda smartctl version 5.38 [x86_64-unknown-linux-gnu] Copyright (C) 2002-8 Bruce Allen Home page is http://smartmontools.sourceforge.net/ === START OF READ SMART DATA SECTION === SMART Attributes Data Structure revision number: 5 Vendor Specific SMART Attributes with Thresholds: ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE 3 Spin_Up_Time 0x0000 100 000 000 Old_age Offline In_the_past 0 4 Start_Stop_Count 0x0000 100 000 000 Old_age Offline In_the_past 0 5 Reallocated_Sector_Ct 0x0002 100 100 000 Old_age Always - 0 9 Power_On_Hours 0x0002 100 100 000 Old_age Always - 8561 12 Power_Cycle_Count 0x0002 100 100 000 Old_age Always - 55 192 Power-Off_Retract_Count 0x0002 100 100 000 Old_age Always - 29 232 Unknown_Attribute 0x0003 100 100 010 Pre-fail Always - 0 233 Unknown_Attribute 0x0002 088 088 000 Old_age Always - 0 225 Load_Cycle_Count 0x0000 198 198 000 Old_age Offline - 508509 226 Load-in_Time 0x0002 255 000 000 Old_age Always In_the_past 0 227 Torq-amp_Count 0x0002 000 000 000 Old_age Always FAILING_NOW 0 228 Power-off_Retract_Count 0x0002 000 000 000 Old_age Always FAILING_NOW 0 smartctl on P410 connected ssd: # ./smartctl -A -d cciss,0 /dev/cciss/c1d0 smartctl 5.39.1 2010-01-28 r3054 [x86_64-unknown-linux-gnu] (local build) Copyright (C) 2002-10 by Bruce Allen, http://smartmontools.sourceforge.net (Right, it is complety empty) smartctl on P410 connected hdd: # ./smartctl -A -d cciss,0 /dev/cciss/c0d0 smartctl 5.39.1 2010-01-28 r3054 [x86_64-unknown-linux-gnu] (local build) Copyright (C) 2002-10 by Bruce Allen, http://smartmontools.sourceforge.net Current Drive Temperature: 27 C Drive Trip Temperature: 68 C Vendor (Seagate) cache information Blocks sent to initiator = 1871654030 Blocks received from initiator = 1360012929 Blocks read from cache and sent to initiator = 2178203797 Number of read and write commands whose size <= segment size = 46052239 Number of read and write commands whose size > segment size = 0 Vendor (Seagate/Hitachi) factory information number of hours powered up = 3363.25 number of minutes until next internal SMART test = 12 Do I hunt here a bug, or is this a limitation of the p410 SMART cmd Passthru?

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Class member functions instantiated by traits [policies, actually]

- by Jive Dadson

I am reluctant to say I can't figure this out, but I can't figure this out. I've googled and searched Stack Overflow, and come up empty. The abstract, and possibly overly vague form of the question is, how can I use the traits-pattern to instantiate member functions? [Update: I used the wrong term here. It should be "policies" rather than "traits." Traits describe existing classes. Policies prescribe synthetic classes.] The question came up while modernizing a set of multivariate function optimizers that I wrote more than 10 years ago. The optimizers all operate by selecting a straight-line path through the parameter space away from the current best point (the "update"), then finding a better point on that line (the "line search"), then testing for the "done" condition, and if not done, iterating. There are different methods for doing the update, the line-search, and conceivably for the done test, and other things. Mix and match. Different update formulae require different state-variable data. For example, the LMQN update requires a vector, and the BFGS update requires a matrix. If evaluating gradients is cheap, the line-search should do so. If not, it should use function evaluations only. Some methods require more accurate line-searches than others. Those are just some examples. The original version instantiates several of the combinations by means of virtual functions. Some traits are selected by setting mode bits that are tested at runtime. Yuck. It would be trivial to define the traits with #define's and the member functions with #ifdef's and macros. But that's so twenty years ago. It bugs me that I cannot figure out a whiz-bang modern way. If there were only one trait that varied, I could use the curiously recurring template pattern. But I see no way to extend that to arbitrary combinations of traits. I tried doing it using boost::enable_if, etc.. The specialized state information was easy. I managed to get the functions done, but only by resorting to non-friend external functions that have the this-pointer as a parameter. I never even figured out how to make the functions friends, much less member functions. The compiler (VC++ 2008) always complained that things didn't match. I would yell, "SFINAE, you moron!" but the moron is probably me. Perhaps tag-dispatch is the key. I haven't gotten very deeply into that. Surely it's possible, right? If so, what is best practice? UPDATE: Here's another try at explaining it. I want the user to be able to fill out an order (manifest) for a custom optimizer, something like ordering off of a Chinese menu - one from column A, one from column B, etc.. Waiter, from column A (updaters), I'll have the BFGS update with Cholesky-decompositon sauce. From column B (line-searchers), I'll have the cubic interpolation line-search with an eta of 0.4 and a rho of 1e-4, please. Etc... UPDATE: Okay, okay. Here's the playing-around that I've done. I offer it reluctantly, because I suspect it's a completely wrong-headed approach. It runs okay under vc++ 2008. #include <boost/utility.hpp> #include <boost/type_traits/integral_constant.hpp> namespace dj { struct CBFGS { void bar() {printf("CBFGS::bar %d\n", data);} CBFGS(): data(1234){} int data; }; template<class T> struct is_CBFGS: boost::false_type{}; template<> struct is_CBFGS<CBFGS>: boost::true_type{}; struct LMQN {LMQN(): data(54.321){} void bar() {printf("LMQN::bar %lf\n", data);} double data; }; template<class T> struct is_LMQN: boost::false_type{}; template<> struct is_LMQN<LMQN> : boost::true_type{}; // "Order form" struct default_optimizer_traits { typedef CBFGS update_type; // Selection from column A - updaters }; template<class traits> class Optimizer; template<class traits> void foo(typename boost::enable_if<is_LMQN<typename traits::update_type>, Optimizer<traits> >::type& self) { printf(" LMQN %lf\n", self.data); } template<class traits> void foo(typename boost::enable_if<is_CBFGS<typename traits::update_type>, Optimizer<traits> >::type& self) { printf("CBFGS %d\n", self.data); } template<class traits = default_optimizer_traits> class Optimizer{ friend typename traits::update_type; //friend void dj::foo<traits>(typename Optimizer<traits> & self); // How? public: //void foo(void); // How??? void foo() { dj::foo<traits>(*this); } void bar() { data.bar(); } //protected: // How? typedef typename traits::update_type update_type; update_type data; }; } // namespace dj int main() { dj::Optimizer<> opt; opt.foo(); opt.bar(); std::getchar(); return 0; }

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How to make Horde connect to mysql with UTF-8 character set?

- by jkj

How to tell horde 3.3.11 to use UTF-8 for it's mysql connection? The $conf['sql']['charset'] only tells horde what is expected from the database. Horde uses MDB2 to connect to mysql. Is there way to force MDB2 or mysql character_set_client from php.ini? So far I found two workarounds: Force mysql to ignore character set requested by client [mysqld] skip-character-set-client-handshake=1 default-character-set=utf8 Force mysql to run SET NAMES utf8 on every connection [mysqld] init-connect='SET NAMES utf8' Both have drawbacks on multi user mysql server. The first disables converting character sets alltogether and the second one forces every connection to produce UTF-8. [EDIT] Found the problem. The 'charset' parameter was unset the last minute before sending to SQL backend. This is probably due to mysql not being able to digest utf-8 but utf8. Mysql specific mapping is required to make it work. I just worked around it by translating utf-8 - utf8. Won't work with any other databases with this patch though. --- lib/Horde/Share/sql.php.orig 2011-07-04 17:09:33.349334890 +0300 +++ lib/Horde/Share/sql.php 2011-07-04 17:11:06.238636462 +0300 @@ -753,7 +753,13 @@ /* Connect to the sql server using the supplied parameters. */ require_once 'MDB2.php'; $params = $this->_params; - unset($params['charset']); + + if ($params['charset'] == 'utf-8') { + $params['charset'] = 'utf8'; + } else { + unset($params['charset']); + } + $this->_write_db = &MDB2::factory($params); if (is_a($this->_write_db, 'PEAR_Error')) { Horde::fatal($this->_write_db, __FILE__, __LINE__); @@ -792,7 +798,13 @@ /* Check if we need to set up the read DB connection seperately. */ if (!empty($this->_params['splitread'])) { $params = array_merge($params, $this->_params['read']); - unset($params['charset']); + + if ($params['charset'] == 'utf-8') { + $params['charset'] = 'utf8'; + } else { + unset($params['charset']); + } + $this->_db = &MDB2::singleton($params); if (is_a($this->_db, 'PEAR_Error')) { Horde::fatal($this->_db, __FILE__, __LINE__);

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Problems when trying to connect to a router wirelessly

- by Ruud Lenders

The situation - At my girlfriend's parents' place there are six Windows 7 devices that are wired or wireless connected to a router: 3 dekstops and 3 laptops. There are also several smartphones using the router. The router is secured with WPA2 (AES). The problem - We never had any problems with the router for over a year. But recently - about 3 weeks ago - my girlfriend's laptop (HP) and my laptop (ASUS) started to develop problems while trying to connect to the router. The router has stopped showing up from the network list. Sometimes it comes back and shows up, but then it keeps saying something along the lines of "Could not connect", and not long after that it dissapears again. The range of the router is not the problem here, because we experience the same when we sit next to the router. Sometimes, if we are lucky, and waited a long time (10-15 minutes) without using the laptop for anything, the laptop will eventually succesful connect to the router. The attempts - Of course, the Window 7 troubleshooter. We tried troubleshooting the connection problems and the wireless network adapter, but no luck. We also reset the router enough times to know that's not helping either. Here's the full list of things we tried, but did not help: Running the Windows 7 troubleshooter Resetting the router (more than once) Setting the router settings to factory defaults Disconnecting all other devices except one laptop Applying a system restore Trying static/dynamic IP/DNS - Dynamic is better, right? Enabling/disabling IPv6 - Should I keep IPv6 disabled? Running the command: netsh wlan stop hostednetwork Running the command: netsh wlan set hostednetwork mode=disallow Updating/reïnstalling wireless adapter drivers The tests - To help finding the core of the problem, we tested the following: Plugging an ethernet cable in the router and in our laptops - worked fine Connecting someone else's laptop to the router (wireless) - worked fine Connecting our laptops to someone else's router - worked fine The router - This information might be relevant: Router model: Sitecom 300N Wireless Router Router hardware: version 01 The DCHP Server's IPs range from 192.168.0.100 to 192.168.0.200. Router settings: Wireless channel: 12 Channel bandwidth: 20/40 MHz Extension channel: 8 Preamble type: Long 802.11g protection: Disabled UPnP: Enabled The laptops - If you are wondering about our laptops: My laptop model: ASUS Pro64JQ Girlfriend's laptop: HP Pavillion G6 OS: Both Windows 7 Professional x64 - with Service Pack 1 My wireless adapter: Atheros AR9285 AdHoc 11n: Enabled The question - Does anyone have experienced the same problems as I do? Or does someone know how to solve this? Are there more tricks I can try, or settings I should change? Note - Our laptops are not slow or old. My laptop is 1.5 years old, and the other laptop is just 5 months old. I know how to keep laptops clean and I'm pretty sure both laptops are not bloated with useless software.

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WiFi signal is lost every 3 minutes

- by Software Monkey

For several weeks now my Android phone has been losing it's WiFi signal momentarily, typically at about 3 minute intervals (about 3 minutes, 1.5 seconds) and occasionally at some longer interval that always seems to be just over 3 minutes. This causes an interruption of several seconds while the WiFi connection is re-established and typically fails any kind of download/streaming that is happening, makes web sites "unreachable" and generally makes the phone unusable as a data device due to the frequency. The signal remains down for about a second, but the phone takes a few more seconds to reconnect to the router. This happens regardless of proximity to the router, which otherwise show a very strong signal - usually -40 to -30 dBm or better in the same room, nowhere less than 060 dBm anywhere in the house. Changing channels does not help (I've tried 1, 4, 8 and 9). Nor does turning off the router's guest access. Nor does turning off the 5.0 GHz band. Monitoring the signal on my phone with WiFi analyzer, shows all WiFi signals on all channels drop to nothing when the WiFi connection is lost (there are two other networks on different channels which are strong enough to be relevant, with about 6 others constantly fading in and out). WiFi analyzer shows 3 separate signals for my router, the main 2.4 GHz, the guest 2.4 GHz and the 5.0 GHz. Using WiFi Analyzer on my wife's phone side-by-side shows no change in signal when my phone drops, nor does her phone drop. Monitoring the signal using our laptop, side-by-side likewise shows no signal loss and likewise the laptop does not lose it's WiFi connection. But, at work, the phone seems to not exhibit the same behavior, or, if it does, it's very occasional. Monitoring it all day at work I only saw the signal drop 3 or 4 times. The signal strength of the various networks there is comparatively weak. AT&T were super helpful: "Sorry, we can't help you with WiFi problems. You could try doing a factory reset on your phone". </sarcasm The router is relatively new, but has been working fine with this phone since last Dec. Phone : Motorola Atrix (about 8 months old). Router : Belkin N750 DB (F9K1103 v1 (01C)). Router Firmware: 1.00.46 (2011/10/28 6:37:11). Security : WPA/WPA2-Personal (PSK)

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