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  • Java exception translations

    - by user3079275
    Apologies if this has been discussed on other threads but I find it helps clarify my thinking when I am forced to write down my questions. I am trying to properly understand the concept of checked vs unchecked exceptions and exception translation in Java but I am getting confused. So far I understood that checked exceptions are exceptions that need to be always caught in a try/catch block otherwise I get a compile time error. This is to force programmers to think about abnormal situations that might happen at run time (like disk full etc). Is this right? What I did not get was why we have unchecked exceptions, when are they useful? Is it only during development time to debug code that might access an illegal array index etc? This confusion is because I see that Error exceptions are also unchecked as is RunTimeException but its not clear to me why they are both lumped together into an unchecked category?

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  • Debugging in netbeans (java)

    - by Daen
    I have been asking this myself for a while. Debugging in visual studio goes smooth. But when i debugg in Netbeans(java) i find myself more then half of the time browsing trough the system code itself. This makes it almost unpossible for me to detect hard to find bugs, cause debugging simply is to tedious and unmanageable. How can this be avoided? Stepping out all the time takes a insane amount of time, and i only wish to debug the code i have written down. I usally add all the controls myself without using any drag and drop for forms if that makes any difference in the total picture. Regards.

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  • weird index behavior

    - by TasostheGreat
    I have set up my table with an index only on done_status(done_status =INT), when I use EXPLAIN SELECT * FROM reminder WHERE done_status=2 i get this back id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE reminder ALL done_status NULL NULL NULL 5 Using where but when I give this command EXPLAIN SELECT * FROM reminder WHERE done_status=1 that's what I get back: id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE reminder ref done_status done_status 4 const 2 first time it shows me it uses 5 rows second time 2 rows I don't think the index works, if I understood it right first time it should give me 3 rows. What do I do wrong? SHOW INDEX FROM reminder: Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment reminder 1 done_status 1 done_status A 5 NULL NULL BTREE

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  • Design by Contract with Microsoft .Net Code Contract

    - by Fredrik N
    I have done some talks on different events and summits about Defensive Programming and Design by Contract, last time was at Cornerstone’s Developer Summit 2010. Next time will be at SweNug (Sweden .Net User Group). I decided to write a blog post about of some stuffs I was talking about. Users are a terrible thing! Protect your self from them ”Human users have a gift for doing the worst possible thing at the worst possible time.” – Michael T. Nygard, Release It! The kind of users Michael T. Nygard are talking about is the users of a system. We also have users that uses our code, the users I’m going to focus on is the users of our code. Me and you and another developers. “Any fool can write code that a computer can understand. Good programmers write code that humans can understand.” – Martin Fowler Good programmers also writes code that humans know how to use, good programmers also make sure software behave in a predictable manner despise inputs or user actions. Design by Contract   Design by Contract (DbC) is a way for us to make a contract between us (the code writer) and the users of our code. It’s about “If you give me this, I promise to give you this”. It’s not about business validations, that is something completely different that should be part of the domain model. DbC is to make sure the users of our code uses it in a correct way, and that we can rely on the contract and write code in a way where we know that the users will follow the contract. It will make it much easier for us to write code with a contract specified. Something like the following code is something we may see often: public void DoSomething(Object value) { value.DoIKnowThatICanDoThis(); } .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; } Where “value” can be uses directly or passed to other methods and later be used. What some of us can easily forget here is that the “value” can be “null”. We will probably not passing a null value, but someone else that uses our code maybe will do it. I think most of you (including me) have passed “null” into a method because you don’t know if the argument need to be specified to a valid value etc. I bet most of you also have got the “Null reference exception”. Sometimes this “Null reference exception” can be hard and take time to fix, because we need to search among our code to see where the “null” value was passed in etc. Wouldn’t it be much better if we can as early as possible specify that the value can’t not be null, so the users of our code also know it when the users starts to use our code, and before run time execution of the code? This is where DbC comes into the picture. We can use DbC to specify what we need, and by doing so we can rely on the contract when we write our code. So the code above can actually use the DoIKnowThatICanDoThis() method on the value object without being worried that the “value” can be null. The contract between the users of the code and us writing the code, says that the “value” can’t be null.   Pre- and Postconditions   When working with DbC we are specifying pre- and postconditions.  Precondition is a condition that should be met before a query or command is executed. An example of a precondition is: “The Value argument of the method can’t be null”, and we make sure the “value” isn’t null before the method is called. Postcondition is a condition that should be met when a command or query is completed, a postcondition will make sure the result is correct. An example of a postconditon is “The method will return a list with at least 1 item”. Commands an Quires When using DbC, we need to know what a Command and a Query is, because some principles that can be good to follow are based on commands and queries. A Command is something that will not return anything, like the SQL’s CREATE, UPDATE and DELETE. There are two kinds of Commands when using DbC, the Creation commands (for example a Constructor), and Others. Others can for example be a Command to add a value to a list, remove or update a value etc. //Creation commands public Stack(int size) //Other commands public void Push(object value); public void Remove(); .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; }   A Query, is something that will return something, for example an Attribute, Property or a Function, like the SQL’s SELECT.   There are two kinds of Queries, the Basic Queries  (Quires that aren’t based on another queries), and the Derived Queries, queries that is based on another queries. Here is an example of queries of a Stack: //Basic Queries public int Count; public object this[int index] { get; } //Derived Queries //Is related to Count Query public bool IsEmpty() { return Count == 0; } .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; } To understand about some principles that are good to follow when using DbC, we need to know about the Commands and different Queries. The 6 Principles When working with DbC, it’s advisable to follow some principles to make it easier to define and use contracts. The following DbC principles are: Separate commands and queries. Separate basic queries from derived queries. For each derived query, write a postcondition that specifies what result will be returned, in terms of one or more basic queries. For each command, write a postcondition that specifies the value of every basic query. For every query and command, decide on a suitable precondition. Write invariants to define unchanging properties of objects. Before I will write about each of them I want you to now that I’m going to use .Net 4.0 Code Contract. I will in the rest of the post uses a simple Stack (Yes I know, .Net already have a Stack class) to give you the basic understanding about using DbC. A Stack is a data structure where the first item in, will be the first item out. Here is a basic implementation of a Stack where not contract is specified yet: public class Stack { private object[] _array; //Basic Queries public uint Count; public object this[uint index] { get { return _array[index]; } set { _array[index] = value; } } //Derived Queries //Is related to Count Query public bool IsEmpty() { return Count == 0; } //Is related to Count and this[] Query public object Top() { return this[Count]; } //Creation commands public Stack(uint size) { Count = 0; _array = new object[size]; } //Other commands public void Push(object value) { this[++Count] = value; } public void Remove() { this[Count] = null; Count--; } } .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; }   Note: The Stack is implemented in a way to demonstrate the use of Code Contract in a simple way, the implementation may not look like how you would implement it, so don’t think this is the perfect Stack implementation, only used for demonstration.   Before I will go deeper into the principles I will simply mention how we can use the .Net Code Contract. I mention before about pre- and postcondition, is about “Require” something and to “Ensure” something. When using Code Contract, we will use a static class called “Contract” and is located in he “System.Diagnostics.Contracts” namespace. The contract must be specified at the top or our member statement block. To specify a precondition with Code Contract we uses the Contract.Requires method, and to specify a postcondition, we uses the Contract.Ensure method. Here is an example where both a pre- and postcondition are used: public object Top() { Contract.Requires(Count > 0, "Stack is empty"); Contract.Ensures(Contract.Result<object>() == this[Count]); return this[Count]; } .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; }   The contract above requires that the Count is greater than 0, if not we can’t get the item at the Top of a Stack. We also Ensures that the results (By using the Contract.Result method, we can specify a postcondition that will check if the value returned from a method is correct) of the Top query is equal to this[Count].   1. Separate Commands and Queries   When working with DbC, it’s important to separate Command and Quires. A method should either be a command that performs an Action, or returning information to the caller, not both. By asking a question the answer shouldn’t be changed. The following is an example of a Command and a Query of a Stack: public void Push(object value) public object Top() .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; }   The Push is a command and will not return anything, just add a value to the Stack, the Top is a query to get the item at the top of the stack.   2. Separate basic queries from derived queries There are two different kinds of queries,  the basic queries that doesn’t rely on another queries, and derived queries that uses a basic query. The “Separate basic queries from derived queries” principle is about about that derived queries can be specified in terms of basic queries. So this principles is more about recognizing that a query is a derived query or a basic query. It will then make is much easier to follow the other principles. The following code shows a basic query and a derived query: //Basic Queries public uint Count; //Derived Queries //Is related to Count Query public bool IsEmpty() { return Count == 0; } .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; }   We can see that IsEmpty will use the Count query, and that makes the IsEmpty a Derived query.   3. For each derived query, write a postcondition that specifies what result will be returned, in terms of one or more basic queries.   When the derived query is recognize we can follow the 3ed principle. For each derived query, we can create a postcondition that specifies what result our derived query will return in terms of one or more basic queries. Remember that DbC is about contracts between the users of the code and us writing the code. So we can’t use demand that the users will pass in a valid value, we must also ensure that we will give the users what the users wants, when the user is following our contract. The IsEmpty query of the Stack will use a Count query and that will make the IsEmpty a Derived query, so we should now write a postcondition that specified what results will be returned, in terms of using a basic query and in this case the Count query, //Basic Queries public uint Count; //Derived Queries public bool IsEmpty() { Contract.Ensures(Contract.Result<bool>() == (Count == 0)); return Count == 0; } The Contract.Ensures is used to create a postcondition. The above code will make sure that the results of the IsEmpty (by using the Contract.Result to get the result of the IsEmpty method) is correct, that will say that the IsEmpty will be either true or false based on Count is equal to 0 or not. The postcondition are using a basic query, so the IsEmpty is now following the 3ed principle. We also have another Derived Query, the Top query, it will also need a postcondition and it uses all basic queries. The Result of the Top method must be the same value as the this[] query returns. //Basic Queries public uint Count; public object this[uint index] { get { return _array[index]; } set { _array[index] = value; } } //Derived Queries //Is related to Count and this[] Query public object Top() { Contract.Ensures(Contract.Result<object>() == this[Count]); return this[Count]; } .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; }   4. For each command, write a postcondition that specifies the value of every basic query.   For each command we will create a postconditon that specifies the value of basic queries. If we look at the Stack implementation we will have three Commands, one Creation command, the Constructor, and two others commands, Push and Remove. Those commands need a postcondition and they should include basic query to follow the 4th principle. //Creation commands public Stack(uint size) { Contract.Ensures(Count == 0); Count = 0; _array = new object[size]; } //Other commands public void Push(object value) { Contract.Ensures(Count == Contract.OldValue<uint>(Count) + 1); Contract.Ensures(this[Count] == value); this[++Count] = value; } public void Remove() { Contract.Ensures(Count == Contract.OldValue<uint>(Count) - 1); this[Count] = null; Count--; } .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; }   As you can see the Create command will Ensures that Count will be 0 when the Stack is created, when a Stack is created there shouldn’t be any items in the stack. The Push command will take a value and put it into the Stack, when an item is pushed into the Stack, the Count need to be increased to know the number of items added to the Stack, and we must also make sure the item is really added to the Stack. The postconditon of the Push method will make sure the that old value of the Count (by using the Contract.OldValue we can get the value a Query has before the method is called)  plus 1 will be equal to the Count query, this is the way we can ensure that the Push will increase the Count with one. We also make sure the this[] query will now contain the item we pushed into the Stack. The Remove method must make sure the Count is decreased by one when the top item is removed from the Stack. The Commands is now following the 4th principle, where each command now have a postcondition that used the value of basic queries. Note: The principle says every basic Query, the Remove only used one Query the Count, it’s because this command can’t use the this[] query because an item is removed, so the only way to make sure an item is removed is to just use the Count query, so the Remove will still follow the principle.   5. For every query and command, decide on a suitable precondition.   We have now focused only on postcondition, now time for some preconditons. The 5th principle is about deciding a suitable preconditon for every query and command. If we starts to look at one of our basic queries (will not go through all Queries and commands here, just some of them) the this[] query, we can’t pass an index that is lower then 1 (.Net arrays and list are zero based, but not the stack in this blog post ;)) and the index can’t be lesser than the number of items in the stack. So here we will need a preconditon. public object this[uint index] { get { Contract.Requires(index >= 1); Contract.Requires(index <= Count); return _array[index]; } } .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; } Think about the Contract as an documentation about how to use the code in a correct way, so if the contract could be specified elsewhere (not part of the method body), we could simply write “return _array[index]” and there is no need to check if index is greater or lesser than Count, because that is specified in a “contract”. The implementation of Code Contract, requires that the contract is specified in the code. As a developer I would rather have this contract elsewhere (Like Spec#) or implemented in a way Eiffel uses it as part of the language. Now when we have looked at one Query, we can also look at one command, the Remove command (You can see the whole implementation of the Stack at the end of this blog post, where precondition is added to more queries and commands then what I’m going to show in this section). We can only Remove an item if the Count is greater than 0. So we can write a precondition that will require that Count must be greater than 0. public void Remove() { Contract.Requires(Count > 0); Contract.Ensures(Count == Contract.OldValue<uint>(Count) - 1); this[Count] = null; Count--; } .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; }   6. Write invariants to define unchanging properties of objects.   The last principle is about making sure the object are feeling great! This is done by using invariants. When using Code Contract we can specify invariants by adding a method with the attribute ContractInvariantMethod, the method must be private or public and can only contains calls to Contract.Invariant. To make sure the Stack feels great, the Stack must have 0 or more items, the Count can’t never be a negative value to make sure each command and queries can be used of the Stack. Here is our invariant for the Stack object: [ContractInvariantMethod] private void ObjectInvariant() { Contract.Invariant(Count >= 0); } .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; }   Note: The ObjectInvariant method will be called every time after a Query or Commands is called. Here is the full example using Code Contract:   public class Stack { private object[] _array; //Basic Queries public uint Count; public object this[uint index] { get { Contract.Requires(index >= 1); Contract.Requires(index <= Count); return _array[index]; } set { Contract.Requires(index >= 1); Contract.Requires(index <= Count); _array[index] = value; } } //Derived Queries //Is related to Count Query public bool IsEmpty() { Contract.Ensures(Contract.Result<bool>() == (Count == 0)); return Count == 0; } //Is related to Count and this[] Query public object Top() { Contract.Requires(Count > 0, "Stack is empty"); Contract.Ensures(Contract.Result<object>() == this[Count]); return this[Count]; } //Creation commands public Stack(uint size) { Contract.Requires(size > 0); Contract.Ensures(Count == 0); Count = 0; _array = new object[size]; } //Other commands public void Push(object value) { Contract.Requires(value != null); Contract.Ensures(Count == Contract.OldValue<uint>(Count) + 1); Contract.Ensures(this[Count] == value); this[++Count] = value; } public void Remove() { Contract.Requires(Count > 0); Contract.Ensures(Count == Contract.OldValue<uint>(Count) - 1); this[Count] = null; Count--; } [ContractInvariantMethod] private void ObjectInvariant() { Contract.Invariant(Count >= 0); } } .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; } Summary By using Design By Contract we can make sure the users are using our code in a correct way, and we must also make sure the users will get the expected results when they uses our code. This can be done by specifying contracts. To make it easy to use Design By Contract, some principles may be good to follow like the separation of commands an queries. With .Net 4.0 we can use the Code Contract feature to specify contracts.

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  • Committed JDO writes do not apply on local GAE HRD, or possibly reused transaction

    - by eeeeaaii
    I'm using JDO 2.3 on app engine. I was using the Master/Slave datastore for local testing and recently switched over to using the HRD datastore for local testing, and parts of my app are breaking (which is to be expected). One part of the app that's breaking is where it sends a lot of writes quickly - that is because of the 1-second limit thing, it's failing with a concurrent modification exception. Okay, so that's also to be expected, so I have the browser retry the writes again later when they fail (maybe not the best hack but I'm just trying to get it working quickly). But a weird thing is happening. Some of the writes which should be succeeding (the ones that DON'T get the concurrent modification exception) are also failing, even though the commit phase completes and the request returns my success code. I can see from the log that the retried requests are working okay, but these other requests that seem to have committed on the first try are, I guess, never "applied." But from what I read about the Apply phase, writing again to that same entity should force the apply... but it doesn't. Code follows. Some things to note: I am attempting to use automatic JDO caching. So this is where JDO uses memcache under the covers. This doesn't actually work unless you wrap everything in a transaction. all the requests are doing is reading a string out of an entity, modifying part of the string, and saving that string back to the entity. If these requests weren't in transactions, you'd of course have the "dirty read" problem. But with transactions, isolation is supposed to be at the level of "serializable" so I don't see what's happening here. the entity being modified is a root entity (not in a group) I have cross-group transactions enabled Another weird thing is happening. If the concurrent modification thing happens, and I subsequently edit more than 5 more entities (this is the max for cross-group transactions), then nothing happens right away, but when I stop and restart the server I get "IllegalArgumentException: operating on too many entity groups in a single transaction". Could it be possible that the PMF is returning the same PersistenceManager every time, or the PM is reusing the same transaction every time? I don't see how I could possibly get the above error otherwise. The code inside the transaction just edits one root entity. I can't think of any other way that GAE would give me the "too many entity groups" error. The relevant code (this is a simplified version) PersistenceManager pm = PMF.getManager(); Transaction tx = pm.currentTransaction(); String responsetext = ""; try { tx.begin(); // I have extra calls to "makePersistent" because I found that relying // on pm.close didn't always write the objects to cache, maybe that // was only a DataNucleus 1.x issue though Key userkey = obtainUserKeyFromCookie(); User u = pm.getObjectById(User.class, userkey); pm.makePersistent(u); // to make sure it gets cached for next time Key mapkey = obtainMapKeyFromQueryString(); // this is NOT a java.util.Map, just FYI Map currentmap = pm.getObjectById(Map.class, mapkey); Text mapData = currentmap.getMapData(); // mapData is JSON stored in the entity Text newMapData = parseModifyAndReturn(mapData); // transform the map currentmap.setMapData(newMapData); // mutate the Map object pm.makePersistent(currentmap); // make sure to persist so there is a cache hit tx.commit(); responsetext = "OK"; } catch (JDOCanRetryException jdoe) { // log jdoe responsetext = "RETRY"; } catch (Exception e) { // log e responsetext = "ERROR"; } finally { if (tx.isActive()) { tx.rollback(); } pm.close(); } resp.getWriter().println(responsetext); EDIT: so I have verified that it fails after exactly 5 transactions. Here's what I do: I create a Foo (root entity), do a bunch of concurrent operations on that Foo, and some fail and get retried, and some commit but don't apply (as described above). Then, I start creating more Foos, and do a few operations on those new Foos. If I only create four Foos, stopping and restarting app engine does NOT give me the IllegalArgumentException. However if I create five Foos (which is the limit for cross-group transactions), then when I stop and restart app engine, I do get the exception. So it seems that somehow these new Foos I am creating are counting toward the limit of 5 max entities per transaction, even though they are supposed to be handled by separate transactions. It's as if a transaction is still open and is being reused by the servlet when it handles the new requests for the 2nd through 5th Foos. EDIT2: it looks like the IllegalArgument thing is independent of the other bug. In other words, it always happens when I create five Foos, even if I don't get the concurrent modification exception. I don't know if it's a symptom of the same problem or if it's unrelated. EDIT3: I found out what was causing the (unrelated) IllegalArgumentException, it was a dumb mistake on my part. But the other issue is still happening. EDIT4: added pseudocode for the datastore access EDIT5: I am pretty sure I know why this is happening, but I will still award the bounty to anyone who can confirm it. Basically, I think the problem is that transactions are not really implemented in the local version of the datastore. References: https://groups.google.com/forum/?fromgroups=#!topic/google-appengine-java/gVMS1dFSpcU https://groups.google.com/forum/?fromgroups=#!topic/google-appengine-java/deGasFdIO-M https://groups.google.com/forum/?hl=en&fromgroups=#!msg/google-appengine-java/4YuNb6TVD6I/gSttMmHYwo0J Because transactions are not implemented, rollback is essentially a no-op. Therefore, I get a dirty read when two transactions try to modify the record at the same time. In other words, A reads the data and B reads the data at the same time. A attempts to modify the data, and B attempts to modify a different part of the data. A writes to the datastore, then B writes, obliterating A's changes. Then B is "rolled back" by app engine, but since rollbacks are a no-op when running on the local datastore, B's changes stay, and A's do not. Meanwhile, since B is the thread that threw the exception, the client retries B, but does not retry A (since A was supposedly the transaction that succeeded).

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  • C++ function not found during compilation

    - by forthewinwin
    For a homework assignment: I'm supposed to create randomized alphabetial keys, print them to a file, and then hash each of them into a hash table using the function "goodHash", found in my below code. When I try to run the below code, it says my "goodHash" "identifier isn't found". What's wrong with my code? #include <iostream> #include <vector> #include <cstdlib> #include "math.h" #include <fstream> #include <time.h> using namespace std; // "makeKey" function to create an alphabetical key // based on 8 randomized numbers 0 - 25. string makeKey() { int k; string key = ""; for (k = 0; k < 8; k++) { int keyNumber = (rand() % 25); if (keyNumber == 0) key.append("A"); if (keyNumber == 1) key.append("B"); if (keyNumber == 2) key.append("C"); if (keyNumber == 3) key.append("D"); if (keyNumber == 4) key.append("E"); if (keyNumber == 5) key.append("F"); if (keyNumber == 6) key.append("G"); if (keyNumber == 7) key.append("H"); if (keyNumber == 8) key.append("I"); if (keyNumber == 9) key.append("J"); if (keyNumber == 10) key.append("K"); if (keyNumber == 11) key.append("L"); if (keyNumber == 12) key.append("M"); if (keyNumber == 13) key.append("N"); if (keyNumber == 14) key.append("O"); if (keyNumber == 15) key.append("P"); if (keyNumber == 16) key.append("Q"); if (keyNumber == 17) key.append("R"); if (keyNumber == 18) key.append("S"); if (keyNumber == 19) key.append("T"); if (keyNumber == 20) key.append("U"); if (keyNumber == 21) key.append("V"); if (keyNumber == 22) key.append("W"); if (keyNumber == 23) key.append("X"); if (keyNumber == 24) key.append("Y"); if (keyNumber == 25) key.append("Z"); } return key; } // "makeFile" function to produce the desired text file. // Note this only works as intended if you include the ".txt" extension, // and that a file of the same name doesn't already exist. void makeFile(string fileName, int n) { ofstream ourFile; ourFile.open(fileName); int k; // For use in below loop to compare with n. int l; // For use in the loop inside the below loop. string keyToPassTogoodHash = ""; for (k = 1; k <= n; k++) { for (l = 0; l < 8; l++) { // For-loop to write to the file ONE key ourFile << makeKey()[l]; keyToPassTogoodHash += (makeKey()[l]); } ourFile << " " << k << "\n";// Writes two spaces and the data value goodHash(keyToPassTogoodHash); // I think this has to do with the problem makeKey(); // Call again to make a new key. } } // Primary function to create our desired file! void mainFunction(string fileName, int n) { makeKey(); makeFile(fileName, n); } // Hash Table for Part 2 struct Node { int key; string value; Node* next; }; const int hashTableSize = 10; Node* hashTable[hashTableSize]; // "goodHash" function for Part 2 void goodHash(string key) { int x = 0; int y; int keyConvertedToNumber = 0; // For-loop to produce a numeric value based on the alphabetic key, // which is then hashed into hashTable using the hash function // declared below the loop (hashFunction). for (y = 0; y < 8; y++) { if (key[y] == 'A' || 'B' || 'C') x = 0; if (key[y] == 'D' || 'E' || 'F') x = 1; if (key[y] == 'G' || 'H' || 'I') x = 2; if (key[y] == 'J' || 'K' || 'L') x = 3; if (key[y] == 'M' || 'N' || 'O') x = 4; if (key[y] == 'P' || 'Q' || 'R') x = 5; if (key[y] == 'S' || 'T') x = 6; if (key[y] == 'U' || 'V') x = 7; if (key[y] == 'W' || 'X') x = 8; if (key[y] == 'Y' || 'Z') x = 9; keyConvertedToNumber = x + keyConvertedToNumber; } int hashFunction = keyConvertedToNumber % hashTableSize; Node *temp; temp = new Node; temp->value = key; temp->next = hashTable[hashFunction]; hashTable[hashFunction] = temp; } // First two lines are for Part 1, to call the functions key to Part 1. int main() { srand ( time(NULL) ); // To make sure our randomization works. mainFunction("sandwich.txt", 5); // To test program cin.get(); return 0; } I realize my code is cumbersome in some sections, but I'm a noob at C++ and don't know much to do it better. I'm guessing another way I could do it is to AFTER writing the alphabetical keys to the file, read them from the file and hash each key as I do that, but I wouldn't know how to go about coding that.

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  • Java: Cannot find a method's symbol even though that method is declared later in the class. The remaining code is looking for a class.

    - by Midimistro
    This is an assignment that we use strings in Java to analyze a phone number. The error I am having is anything below tester=invalidCharacters(c); does not compile because every line past tester=invalidCharacters(c); is looking for a symbol or the class. In get invalidResults, all I am trying to do is evaluate a given string for non-alphabetical characters such as *,(,^,&,%,@,#,), and so on. What to answer: Why is it producing an error, what will work, and is there an easier method WITHOUT using regex. Here is the link to the assignment: http://cis.csuohio.edu/~hwang/teaching/cis260/assignments/assignment9.html public class PhoneNumber { private int areacode; private int number; private int ext; /////Constructors///// //Third Constructor (given one string arg) "xxx-xxxxxxx" where first three are numbers and the remaining (7) are numbers or letters public PhoneNumber(String newNumber){ //Note: Set default ext to 0 ext=0; ////Declare Temporary Storage and other variables//// //for the first three numbers String areaCodeString; //for the remaining seven characters String newNumberString; //For use in testing the second half of the string boolean containsLetters; boolean containsInvalid; /////Separate the two parts of string///// //Get the area code part of the string areaCodeString=newNumber.substring(0,2); //Convert the string and set it to the area code areacode=Integer.parseInt(areaCodeString); //Skip the "-" and Get the remaining part of the string newNumberString=newNumber.substring(4); //Create an array of characters from newNumberString to reuse in later methods for int length=newNumberString.length(); char [] myCharacters= new char [length]; int i; for (i=0;i<length;i++){ myCharacters [i]=newNumberString.charAt(i); } //Test if newNumberString contains letters & converting them into numbers String reNewNumber=""; //Test for invalid characters containsInvalid=getInvalidResults(newNumberString,length); if (containsInvalid==false){ containsLetters=getCharResults(newNumberString,length); if (containsLetters==true){ for (i=0;i<length;i++){ myCharacters [i]=(char)convertLetNum((myCharacters [i])); reNewNumber=reNewNumber+myCharacters[i]; } } } if (containsInvalid==false){ number=Integer.parseInt(reNewNumber); } else{ System.out.println("Error!"+"\t"+newNumber+" contains illegal characters. This number will be ignored and skipped."); } } //////Primary Methods/Behaviors/////// //Compare this phone number with the one passed by the caller public boolean equals(PhoneNumber pn){ boolean equal; String concat=(areacode+"-"+number); String pN=pn.toString(); if (concat==pN){ equal=true; } else{ equal=false; } return equal; } //Convert the stored number to a certain string depending on extension public String toString(){ String returned; if(ext==0){ returned=(areacode+"-"+number); } else{ returned=(areacode+"-"+number+" ext "+ext); } return returned; } //////Secondary Methods/////// //Method for testing if the second part of the string contains any letters public static boolean getCharResults(String newNumString,int getLength){ //Recreate a character array int i; char [] myCharacters= new char [getLength]; for (i=0;i<getLength;i++){ myCharacters [i]=newNumString.charAt(i); } boolean doesContainLetter=false; int j; for (j=0;j<getLength;j++){ if ((Character.isDigit(myCharacters[j])==true)){ doesContainLetter=false; } else{ doesContainLetter=true; return doesContainLetter; } } return doesContainLetter; } //Method for testing if the second part of the string contains any letters public static boolean getInvalidResults(String newNumString,int getLength){ boolean doesContainInvalid=false; int i; char c; boolean tester; char [] invalidCharacters= new char [getLength]; for (i=0;i<getLength;i++){ invalidCharacters [i]=newNumString.charAt(i); c=invalidCharacters [i]; tester=invalidCharacters(c); if(tester==true)){ doesContainInvalid=false; } else{ doesContainInvalid=true; return doesContainInvalid; } } return doesContainInvalid; } //Method for evaluating string for invalid characters public boolean invalidCharacters(char letter){ boolean returnNum=false; switch (letter){ case 'A': return returnNum; case 'B': return returnNum; case 'C': return returnNum; case 'D': return returnNum; case 'E': return returnNum; case 'F': return returnNum; case 'G': return returnNum; case 'H': return returnNum; case 'I': return returnNum; case 'J': return returnNum; case 'K': return returnNum; case 'L': return returnNum; case 'M': return returnNum; case 'N': return returnNum; case 'O': return returnNum; case 'P': return returnNum; case 'Q': return returnNum; case 'R': return returnNum; case 'S': return returnNum; case 'T': return returnNum; case 'U': return returnNum; case 'V': return returnNum; case 'W': return returnNum; case 'X': return returnNum; case 'Y': return returnNum; case 'Z': return returnNum; default: return true; } } //Method for converting letters to numbers public int convertLetNum(char letter){ int returnNum; switch (letter){ case 'A': returnNum=2;return returnNum; case 'B': returnNum=2;return returnNum; case 'C': returnNum=2;return returnNum; case 'D': returnNum=3;return returnNum; case 'E': returnNum=3;return returnNum; case 'F': returnNum=3;return returnNum; case 'G': returnNum=4;return returnNum; case 'H': returnNum=4;return returnNum; case 'I': returnNum=4;return returnNum; case 'J': returnNum=5;return returnNum; case 'K': returnNum=5;return returnNum; case 'L': returnNum=5;return returnNum; case 'M': returnNum=6;return returnNum; case 'N': returnNum=6;return returnNum; case 'O': returnNum=6;return returnNum; case 'P': returnNum=7;return returnNum; case 'Q': returnNum=7;return returnNum; case 'R': returnNum=7;return returnNum; case 'S': returnNum=7;return returnNum; case 'T': returnNum=8;return returnNum; case 'U': returnNum=8;return returnNum; case 'V': returnNum=8;return returnNum; case 'W': returnNum=9;return returnNum; case 'X': returnNum=9;return returnNum; case 'Y': returnNum=9;return returnNum; case 'Z': returnNum=9;return returnNum; default: return 0; } } } Note: Please Do not use this program to cheat in your own class. To ensure of this, I will take this question down if it has not been answered by the end of 2013, if I no longer need an explanation for it, or if the term for the class has ended.

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  • SQL SERVER – Out of the Box – Activty and Performance Reports from SSSMS

    - by pinaldave
    SQL Server management Studio 2008 is wonderful tool and has many different features. Many times, an average user does not use them as they are not aware about these features. Today, we will learn one such feature. SSMS comes with many inbuilt performance and activity reports, but we do not use it to the full potential. Let us see how we can access these standard reports. Connect to SQL Server Node >> Right Click on it >> Go to Reports >> Click on Standard Reports >> Pick Any Report. Click to Enlarge You can see there are many reports, which an average users needs right away, are available there. Let me list all the reports available. Server Dashboard Configuration Changes History Schema Changes History Scheduler Health Memory Consumption Activity – All Blocking Transactions Activity – All Cursors Activity – All Sessions Activity – Top Sessions Activity – Dormant Sessions Activity -  Top Connections Top Transactions by Age Top Transactions by Blocked Transactions Count Top Transactions by Locks Count Performance – Batch Execution Statistics Performance – Object Execution Statistics Performance – Top Queries by Average CPU Time Performance – Top Queries by Average IO Performance – Top Queries by Total CPU Time Performance – Top Queries by Total IO Service Broker Statistics Transactions Log Shipping Status In fact, when you look at the above list, it is fairly clear that they are very thought out and commonly needed reports that are available in SQL Server 2008. Let us run a couple of reports and observe their result. Performance – Top Queries by Total CPU Time Click to Enlarge Memory Consumption Click to Enlarge There are options for custom reports as well, which we can configure. We will learn about them in some other post. Additionally, you can right click on the reports and export in Excel or PDF. I think this tool can really help those who are just looking for some quick details. Does any of you use this feature, or this feature has some limitations and You would like to see more features? Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Server Management Studio, SQL Tips and Tricks, T SQL, Technology

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  • How to handle business rules with a REST API?

    - by Ciprio
    I have a REST API to manage a booking system I'm searching how to manage this situation : A customer can book a time slot : A TimeSlot resource is created and linked to a Person resource. In order to create the link between a time lot and a person, the REST client send a POST request on the TimeSlot resource But if too many people booked the same slot (let's say the limit is 5 links), it must be impossible to create more associations. How can I handle this business restriction ? Can I return a 404 status code with a JSON response detailing the error with a status code ? Is it a RESTFul approach ? EDIT : Like suggested below I used status 409 Conflict in addition to a JSON response detailing the error

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  • WebLogic Server Virtual Developer Day and Upcoming Developer Webcasts

    - by james.bayer
    We have a series of Virtual Developer Days for WebLogic for different geographies coming up as well as developer-oriented webcasts focusing on building a sample application with popular modern technologies.  The first one is Feb 1st, 2011 for North America, but there are others coming up through mid-March as well.  Check them out and register below. Virtual Developer Days for WebLogic AMER Conference begins: February 1, 2011 at 9:30am PST EUROPE/RUSSIA Conference begins: Thursday Feb 10, 2011 - 9:30 a.m. UK Time / 10:30 a.m. CET INDIA Conference begins: Thursday Feb 17, 2011 -  9:30am India time Register here for the Virtual Developer Day in your geography.   WebLogic Developer Webcasts Watch this brief video to learn more about the developer webcasts where we’ll build an application over several weeks focusing on different features like JPA, Data Grids, JMS, JAX-RS and more.  Register here for the WebLogic developer webcasts.

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  • Using LINQ Distinct: With an Example on ASP.NET MVC SelectListItem

    - by Joe Mayo
    One of the things that might be surprising in the LINQ Distinct standard query operator is that it doesn’t automatically work properly on custom classes. There are reasons for this, which I’ll explain shortly. The example I’ll use in this post focuses on pulling a unique list of names to load into a drop-down list. I’ll explain the sample application, show you typical first shot at Distinct, explain why it won’t work as you expect, and then demonstrate a solution to make Distinct work with any custom class. The technologies I’m using are  LINQ to Twitter, LINQ to Objects, Telerik Extensions for ASP.NET MVC, ASP.NET MVC 2, and Visual Studio 2010. The function of the example program is to show a list of people that I follow.  In Twitter API vernacular, these people are called “Friends”; though I’ve never met most of them in real life. This is part of the ubiquitous language of social networking, and Twitter in particular, so you’ll see my objects named accordingly. Where Distinct comes into play is because I want to have a drop-down list with the names of the friends appearing in the list. Some friends are quite verbose, which means I can’t just extract names from each tweet and populate the drop-down; otherwise, I would end up with many duplicate names. Therefore, Distinct is the appropriate operator to eliminate the extra entries from my friends who tend to be enthusiastic tweeters. The sample doesn’t do anything with the drop-down list and I leave that up to imagination for what it’s practical purpose could be; perhaps a filter for the list if I only want to see a certain person’s tweets or maybe a quick list that I plan to combine with a TextBox and Button to reply to a friend. When the program runs, you’ll need to authenticate with Twitter, because I’m using OAuth (DotNetOpenAuth), for authentication, and then you’ll see the drop-down list of names above the grid with the most recent tweets from friends. Here’s what the application looks like when it runs: As you can see, there is a drop-down list above the grid. The drop-down list is where most of the focus of this article will be. There is some description of the code before we talk about the Distinct operator, but we’ll get there soon. This is an ASP.NET MVC2 application, written with VS 2010. Here’s the View that produces this screen: <%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<TwitterFriendsViewModel>" %> <%@ Import Namespace="DistinctSelectList.Models" %> <asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server">     Home Page </asp:Content><asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">     <fieldset>         <legend>Twitter Friends</legend>         <div>             <%= Html.DropDownListFor(                     twendVM => twendVM.FriendNames,                     Model.FriendNames,                     "<All Friends>") %>         </div>         <div>             <% Html.Telerik().Grid<TweetViewModel>(Model.Tweets)                    .Name("TwitterFriendsGrid")                    .Columns(cols =>                     {                         cols.Template(col =>                             { %>                                 <img src="<%= col.ImageUrl %>"                                      alt="<%= col.ScreenName %>" />                         <% });                         cols.Bound(col => col.ScreenName);                         cols.Bound(col => col.Tweet);                     })                    .Render(); %>         </div>     </fieldset> </asp:Content> As shown above, the Grid is from Telerik’s Extensions for ASP.NET MVC. The first column is a template that renders the user’s Avatar from a URL provided by the Twitter query. Both the Grid and DropDownListFor display properties that are collections from a TwitterFriendsViewModel class, shown below: using System.Collections.Generic; using System.Web.Mvc; namespace DistinctSelectList.Models { /// /// For finding friend info on screen /// public class TwitterFriendsViewModel { /// /// Display names of friends in drop-down list /// public List FriendNames { get; set; } /// /// Display tweets in grid /// public List Tweets { get; set; } } } I created the TwitterFreindsViewModel. The two Lists are what the View consumes to populate the DropDownListFor and Grid. Notice that FriendNames is a List of SelectListItem, which is an MVC class. Another custom class I created is the TweetViewModel (the type of the Tweets List), shown below: namespace DistinctSelectList.Models { /// /// Info on friend tweets /// public class TweetViewModel { /// /// User's avatar /// public string ImageUrl { get; set; } /// /// User's Twitter name /// public string ScreenName { get; set; } /// /// Text containing user's tweet /// public string Tweet { get; set; } } } The initial Twitter query returns much more information than we need for our purposes and this a special class for displaying info in the View.  Now you know about the View and how it’s constructed. Let’s look at the controller next. The controller for this demo performs authentication, data retrieval, data manipulation, and view selection. I’ll skip the description of the authentication because it’s a normal part of using OAuth with LINQ to Twitter. Instead, we’ll drill down and focus on the Distinct operator. However, I’ll show you the entire controller, below,  so that you can see how it all fits together: using System.Linq; using System.Web.Mvc; using DistinctSelectList.Models; using LinqToTwitter; namespace DistinctSelectList.Controllers { [HandleError] public class HomeController : Controller { private MvcOAuthAuthorization auth; private TwitterContext twitterCtx; /// /// Display a list of friends current tweets /// /// public ActionResult Index() { auth = new MvcOAuthAuthorization(InMemoryTokenManager.Instance, InMemoryTokenManager.AccessToken); string accessToken = auth.CompleteAuthorize(); if (accessToken != null) { InMemoryTokenManager.AccessToken = accessToken; } if (auth.CachedCredentialsAvailable) { auth.SignOn(); } else { return auth.BeginAuthorize(); } twitterCtx = new TwitterContext(auth); var friendTweets = (from tweet in twitterCtx.Status where tweet.Type == StatusType.Friends select new TweetViewModel { ImageUrl = tweet.User.ProfileImageUrl, ScreenName = tweet.User.Identifier.ScreenName, Tweet = tweet.Text }) .ToList(); var friendNames = (from tweet in friendTweets select new SelectListItem { Text = tweet.ScreenName, Value = tweet.ScreenName }) .Distinct() .ToList(); var twendsVM = new TwitterFriendsViewModel { Tweets = friendTweets, FriendNames = friendNames }; return View(twendsVM); } public ActionResult About() { return View(); } } } The important part of the listing above are the LINQ to Twitter queries for friendTweets and friendNames. Both of these results are used in the subsequent population of the twendsVM instance that is passed to the view. Let’s dissect these two statements for clarification and focus on what is happening with Distinct. The query for friendTweets gets a list of the 20 most recent tweets (as specified by the Twitter API for friend queries) and performs a projection into the custom TweetViewModel class, repeated below for your convenience: var friendTweets = (from tweet in twitterCtx.Status where tweet.Type == StatusType.Friends select new TweetViewModel { ImageUrl = tweet.User.ProfileImageUrl, ScreenName = tweet.User.Identifier.ScreenName, Tweet = tweet.Text }) .ToList(); The LINQ to Twitter query above simplifies what we need to work with in the View and the reduces the amount of information we have to look at in subsequent queries. Given the friendTweets above, the next query performs another projection into an MVC SelectListItem, which is required for binding to the DropDownList.  This brings us to the focus of this blog post, writing a correct query that uses the Distinct operator. The query below uses LINQ to Objects, querying the friendTweets collection to get friendNames: var friendNames = (from tweet in friendTweets select new SelectListItem { Text = tweet.ScreenName, Value = tweet.ScreenName }) .Distinct() .ToList(); The above implementation of Distinct seems normal, but it is deceptively incorrect. After running the query above, by executing the application, you’ll notice that the drop-down list contains many duplicates.  This will send you back to the code scratching your head, but there’s a reason why this happens. To understand the problem, we must examine how Distinct works in LINQ to Objects. Distinct has two overloads: one without parameters, as shown above, and another that takes a parameter of type IEqualityComparer<T>.  In the case above, no parameters, Distinct will call EqualityComparer<T>.Default behind the scenes to make comparisons as it iterates through the list. You don’t have problems with the built-in types, such as string, int, DateTime, etc, because they all implement IEquatable<T>. However, many .NET Framework classes, such as SelectListItem, don’t implement IEquatable<T>. So, what happens is that EqualityComparer<T>.Default results in a call to Object.Equals, which performs reference equality on reference type objects.  You don’t have this problem with value types because the default implementation of Object.Equals is bitwise equality. However, most of your projections that use Distinct are on classes, just like the SelectListItem used in this demo application. So, the reason why Distinct didn’t produce the results we wanted was because we used a type that doesn’t define its own equality and Distinct used the default reference equality. This resulted in all objects being included in the results because they are all separate instances in memory with unique references. As you might have guessed, the solution to the problem is to use the second overload of Distinct that accepts an IEqualityComparer<T> instance. If you were projecting into your own custom type, you could make that type implement IEqualityComparer<T>, but SelectListItem belongs to the .NET Framework Class Library.  Therefore, the solution is to create a custom type to implement IEqualityComparer<T>, as in the SelectListItemComparer class, shown below: using System.Collections.Generic; using System.Web.Mvc; namespace DistinctSelectList.Models { public class SelectListItemComparer : EqualityComparer { public override bool Equals(SelectListItem x, SelectListItem y) { return x.Value.Equals(y.Value); } public override int GetHashCode(SelectListItem obj) { return obj.Value.GetHashCode(); } } } The SelectListItemComparer class above doesn’t implement IEqualityComparer<SelectListItem>, but rather derives from EqualityComparer<SelectListItem>. Microsoft recommends this approach for consistency with the behavior of generic collection classes. However, if your custom type already derives from a base class, go ahead and implement IEqualityComparer<T>, which will still work. EqualityComparer is an abstract class, that implements IEqualityComparer<T> with Equals and GetHashCode abstract methods. For the purposes of this application, the SelectListItem.Value property is sufficient to determine if two items are equal.   Since SelectListItem.Value is type string, the code delegates equality to the string class. The code also delegates the GetHashCode operation to the string class.You might have other criteria in your own object and would need to define what it means for your object to be equal. Now that we have an IEqualityComparer<SelectListItem>, let’s fix the problem. The code below modifies the query where we want distinct values: var friendNames = (from tweet in friendTweets select new SelectListItem { Text = tweet.ScreenName, Value = tweet.ScreenName }) .Distinct(new SelectListItemComparer()) .ToList(); Notice how the code above passes a new instance of SelectListItemComparer as the parameter to the Distinct operator. Now, when you run the application, the drop-down list will behave as you expect, showing only a unique set of names. In addition to Distinct, other LINQ Standard Query Operators have overloads that accept IEqualityComparer<T>’s, You can use the same techniques as shown here, with SelectListItemComparer, with those other operators as well. Now you know how to resolve problems with getting Distinct to work properly and also have a way to fix problems with other operators that require equality comparisons. @JoeMayo

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  • Upgrading Team Foundation Server 2008 to 2010

    - by Martin Hinshelwood
    I am sure you will have seen my posts on upgrading our internal Team Foundation Server from TFS2008 to TFS2010 Beta 2, RC and RTM, but what about a fresh upgrade of TFS2008 to TFS2010 using the RTM version of TFS. One of our clients is taking the plunge with TFS2010, so I have the job of doing the upgrade. It is sometimes very useful to have a team member that starts work when most of the Sydney workers are heading home as I can do the upgrade without impacting them. The down side is that if you have any blockers then you can be pretty sure that everyone that can deal with your problem is asleep I am starting with an existing blank installation of TFS 2010, but Adam Cogan let slip that he was the one that did the install so I thought it prudent to make sure that it was OK. Verifying Team Foundation Server 2010 We need to check that TFS 2010 has been installed correctly. First, check the Admin console and have a root about for any errors. Figure: Even the SQL Setup looks good. I don’t know how Adam did it! Backing up the Team Foundation Server 2008 Databases As we are moving from one server to another (recommended method) we will be taking a backup of our TFS2008 databases and resorting them to the SQL Server for the new TFS2010 Server. Do not just detach and reattach. This will cause problems with the version of the database. If you are running a test migration you just need to create a backup of the TFS 2008 databases, but if you are doing the live migration then you should stop IIS on the TFS 2008 server before you backup the databases. This will stop any inadvertent check-ins or changes to TFS 2008. Figure: Stop IIS before you take a backup to prevent any TFS 2008 changes being written to the database. It is good to leave a little time between taking the TFS 2008 server offline and commencing the upgrade as there is always one developer who has not finished and starts screaming. This time it was John Liu that needed 10 more minutes to make his changes and check-in, so I always give it 30 minutes and see if anyone screams. John Liu [SSW] said:   are you doing something to TFS :-O MrHinsh [SSW UK][VS ALM MVP] said:   I have stopped TFS 2008 as per my emails John Liu [SSW] said:   haven't finish check in @_@   can we have it for 10mins? :) MrHinsh [SSW UK][VS ALM MVP] said:   TFS 2008 has been started John Liu [SSW] said:   I love you! -IM conversation at TFS Upgrade +25 minutes After John confirmed that he had everything done I turned IIS off again and made a cup of tea. There were no more screams so the upgrade can continue. Figure: Backup all of the databases for TFS and include the Reporting Services, just in case.   Figure: Check that all the backups have been taken Once you have your backups, you need to copy them to your new TFS2010 server and restore them. This is a good way to proceed as if we have any problems, or just plain run out of time, then you just turn the TFS 2008 server back on and all you have lost is one upgrade day, and not 10 developer days. As per the rules, you should record the number of files and the total number of areas and iterations before the upgrade so you have something to compare to: TFS2008 File count: Type Count 1 1845 2 15770 Areas & Iterations: 139 You can use this to verify that the upgrade was successful. it should however be noted that the numbers in TFS 2010 will be bigger. This is due to some of the sorting out that TFS does during the upgrade process. Restore Team Foundation Server 2008 Databases Restoring the databases is much more time consuming than just attaching them as you need to do them one at a time. But you may be taking a backup of an operational database and need to restore all your databases to a particular point in time instead of to the latest. I am doing latest unless I encounter any problems. Figure: Restore each of the databases to either a latest or specific point in time.     Figure: Restore all of the required databases Now that all of your databases are restored you now need to upgrade them to Team Foundation Server 2010. Upgrade Team Foundation Server 2008 Databases This is probably the easiest part of the process. You need to call a fire and forget command that will go off to the database specified, find the TFS 2008 databases and upgrade them to 2010. During this process all of the 6 main TFS 2008 databases are merged into the TfsVersionControl database, upgraded and then the database is renamed to TFS_[CollectionName]. The rename is only the database and not the physical files, so it is worth going back and renaming the physical file as well. This keeps everything neat and tidy. If you plan to keep the old TFS 2008 server around, for example if you are doing a test migration first, then you will need to change the TFS GUID. This GUID is unique to each TFS instance and is preserved when you upgrade. This GUID is used by the clients and they can get a little confused if there are two servers with the same one. To kick of the upgrade you need to open a command prompt and change the path to “C:\Program Files\Microsoft Team Foundation Server 2010\Tools” and run the “import” command in  “tfsconfig”. TfsConfig import /sqlinstance:<Previous TFS Data Tier>                  /collectionName:<Collection Name>                  /confirmed Imports a TFS 2005 or 2008 data tier as a new project collection. Important: This command should only be executed after adequate backups have been performed. After you import, you will need to configure portal and reporting settings via the administration console. EXAMPLES -------- TfsConfig import /sqlinstance:tfs2008sql /collectionName:imported /confirmed TfsConfig import /sqlinstance:tfs2008sql\Instance /collectionName:imported /confirmed OPTIONS: -------- sqlinstance         The sql instance of the TFS 2005 or 2008 data tier. The TFS databases at that location will be modified directly and will no longer be usable as previous version databases.  Ensure you have back-ups. collectionName      The name of the new Team Project Collection. confirmed           Confirm that you have backed-up databases before importing. This command will automatically look for the TfsIntegration database and verify that all the other required databases exist. In this case it took around 5 minutes to complete the upgrade as the total database size was under 700MB. This was unlike the upgrade of SSW’s production database with over 17GB of data which took a few hours. At the end of the process you should get no errors and no warnings. The Upgrade operation on the ApplicationTier feature has completed. There were 0 errors and 0 warnings. As this is a new server and not a pure upgrade there should not be a problem with the GUID. If you think at any point you will be doing this more than once, for example doing a test migration, or merging many TFS 2008 instances into a single one, then you should go back and rename the physical TfsVersionControl.mdf file to the same as the new collection. This will avoid confusion later down the line. To do this, detach the new collection from the server and rename the physical files. Then reattach and change the physical file locations to match the new name. You can follow http://www.mssqltips.com/tip.asp?tip=1122 for a more detailed explanation of how to do this. Figure: Stop the collection so TFS does not take a wobbly when we detach the database. When you try to start the new collection again you will get a conflict with project names and will require to remove the Test Upgrade collection. This is fine and it just needs detached. Figure: Detaching the test upgrade from the new Team Foundation Server 2010 so we can start the new Collection again. You will now be able to start the new upgraded collection and you are ready for testing. Do you remember the stats we took off the TFS 2008 server? TFS2008 File count: Type Count 1 1845 2 15770 Areas & Iterations: 139 Well, now we need to compare them to the TFS 2010 stats, remembering that there will probably be more files under source control. TFS2010 File count: Type Count 1 19288 Areas & Iterations: 139 Lovely, the number of iterations are the same, and the number of files is bigger. Just what we were looking for. Testing the upgraded Team Foundation Server 2010 Project Collection Can we connect to the new collection and project? Figure: We can connect to the new collection and project.   Figure: make sure you can connect to The upgraded projects and that you can see all of the files. Figure: Team Web Access is there and working. Note that for Team Web Access you now use the same port and URL as for TFS 2010. So in this case as I am running on the local box you need to use http://localhost:8080/tfs which will redirect you to http://localhost:8080/tfs/web for the web access. If you need to connect with a Visual Studio 2008 client you will need to use the full path of the new collection, http://[servername]/tfs/[collectionname] and this will work with all of your collections. With Visual Studio 2005 you will only be able to connect to the Default collection and in both VS2008 and VS2005 you will need to install the forward compatibility updates. Visual Studio Team System 2005 Service Pack 1 Forward Compatibility Update for Team Foundation Server 2010 Visual Studio Team System 2008 Service Pack 1 Forward Compatibility Update for Team Foundation Server 2010 To make sure that you have everything up to date, make sure that you run SSW Diagnostics and get all green ticks. Upgrade Done! At this point you can send out a notice to everyone that the upgrade is complete and and give them the connection details. You need to remember that at this stage we have 2008 project upgraded to run under TFS 2010 but it is still running under that same process template that it was running before. You can only “enable” 2010 features in a process template you can’t upgrade. So what to do? Well, you need to create a new project and migrate things you want to keep across. Souse code is easy, you can move or Branch, but Work Items are more difficult as you can’t move them between projects. This instance is complicated more as the old project uses the Conchango/EMC Scrum for Team System template and I will need to write a script/application to get the work items across with their attachments in tact. That is my next task! Technorati Tags: TFS 2010,TFS 2008,VS ALM

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  • Integrating WIF with WCF Data Services

    - by cibrax
    A time ago I discussed how a custom REST Starter kit interceptor could be used to parse a SAML token in the Http Authorization header and wrap that into a ClaimsPrincipal that the WCF services could use. The thing is that code was initially created for Geneva framework, so it got deprecated quickly. I recently needed that piece of code for one of projects where I am currently working on so I decided to update it for WIF. As this interceptor can be injected in any host for WCF REST services, also represents an excellent solution for integrating claim-based security into WCF Data Services (previously known as ADO.NET Data Services). The interceptor basically expects a SAML token in the Authorization header. If a token is found, it is parsed and a new ClaimsPrincipal is initialized and injected in the WCF authorization context. public class SamlAuthenticationInterceptor : RequestInterceptor {   SecurityTokenHandlerCollection handlers;   public SamlAuthenticationInterceptor()     : base(false)   {     this.handlers = FederatedAuthentication.ServiceConfiguration.SecurityTokenHandlers;   }   public override void ProcessRequest(ref RequestContext requestContext)   {     SecurityToken token = ExtractCredentials(requestContext.RequestMessage);     if (token != null)     {       ClaimsIdentityCollection claims = handlers.ValidateToken(token);       var principal = new ClaimsPrincipal(claims);       InitializeSecurityContext(requestContext.RequestMessage, principal);     }     else     {       DenyAccess(ref requestContext);     }   }   private void DenyAccess(ref RequestContext requestContext)   {     Message reply = Message.CreateMessage(MessageVersion.None, null);     HttpResponseMessageProperty responseProperty = new HttpResponseMessageProperty() { StatusCode = HttpStatusCode.Unauthorized };     responseProperty.Headers.Add("WWW-Authenticate",           String.Format("Basic realm=\"{0}\"", ""));     reply.Properties[HttpResponseMessageProperty.Name] = responseProperty;     requestContext.Reply(reply);     requestContext = null;   }   private SecurityToken ExtractCredentials(Message requestMessage)   {     HttpRequestMessageProperty request = (HttpRequestMessageProperty)  requestMessage.Properties[HttpRequestMessageProperty.Name];     string authHeader = request.Headers["Authorization"];     if (authHeader != null && authHeader.Contains("<saml"))     {       XmlTextReader xmlReader = new XmlTextReader(new StringReader(authHeader));       var col = SecurityTokenHandlerCollection.CreateDefaultSecurityTokenHandlerCollection();       SecurityToken token = col.ReadToken(xmlReader);                                        return token;     }     return null;   }   private void InitializeSecurityContext(Message request, IPrincipal principal)   {     List<IAuthorizationPolicy> policies = new List<IAuthorizationPolicy>();     policies.Add(new PrincipalAuthorizationPolicy(principal));     ServiceSecurityContext securityContext = new ServiceSecurityContext(policies.AsReadOnly());     if (request.Properties.Security != null)     {       request.Properties.Security.ServiceSecurityContext = securityContext;     }     else     {       request.Properties.Security = new SecurityMessageProperty() { ServiceSecurityContext = securityContext };      }    }    class PrincipalAuthorizationPolicy : IAuthorizationPolicy    {      string id = Guid.NewGuid().ToString();      IPrincipal user;      public PrincipalAuthorizationPolicy(IPrincipal user)      {        this.user = user;      }      public ClaimSet Issuer      {        get { return ClaimSet.System; }      }      public string Id      {        get { return this.id; }      }      public bool Evaluate(EvaluationContext evaluationContext, ref object state)      {        evaluationContext.AddClaimSet(this, new DefaultClaimSet(System.IdentityModel.Claims.Claim.CreateNameClaim(user.Identity.Name)));        evaluationContext.Properties["Identities"] = new List<IIdentity>(new IIdentity[] { user.Identity });        evaluationContext.Properties["Principal"] = user;        return true;      }    } A WCF Data Service, as any other WCF Service, contains a service host where this interceptor can be injected. The following code illustrates how that can be done in the “svc” file. <%@ ServiceHost Language="C#" Debug="true" Service="ContactsDataService"                 Factory="AppServiceHostFactory" %> using System; using System.ServiceModel; using System.ServiceModel.Activation; using Microsoft.ServiceModel.Web; class AppServiceHostFactory : ServiceHostFactory {    protected override ServiceHost CreateServiceHost(Type serviceType, Uri[] baseAddresses)   {     WebServiceHost2 result = new WebServiceHost2(serviceType, true, baseAddresses);     result.Interceptors.Add(new SamlAuthenticationInterceptor());                 return result;   } } WCF Data Services includes an specific WCF host of out the box (DataServiceHost). However, the service is not affected at all if you replace it with a custom one as I am doing in the code above (WebServiceHost2 is part of the REST Starter kit). Finally, the client application needs to pass the SAML token somehow to the data service. In case you are using any Http client library for consuming the data service, that’s easy to do, you only need to include the SAML token as part of the “Authorization” header. If you are using the auto-generated data service proxy, a little piece of code is needed to inject a SAML token into the DataServiceContext instance. That class provides an event “SendingRequest” that any client application can leverage to include custom code that modified the Http request before it is sent to the service. So, you can easily create an extension method for the DataServiceContext that negotiates the SAML token with an existing STS, and adds that token as part of the “Authorization” header. public static class DataServiceContextExtensions {        public static void ConfigureFederatedCredentials(this DataServiceContext context, string baseStsAddress, string realm)   {     string address = string.Format(STSAddressFormat, baseStsAddress, realm);                  string token = NegotiateSecurityToken(address);     context.SendingRequest += (source, args) =>     {       args.RequestHeaders.Add("Authorization", token);     };   } private string NegotiateSecurityToken(string address) { } } I left the NegociateSecurityToken method empty for this extension as it depends pretty much on how you are negotiating tokens from an existing STS. In case you want to end-to-end REST solution that involves an Http endpoint for the STS, you should definitely take a look at the Thinktecture starter STS project in codeplex.

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  • Oracle Communications Data Model

    - by jean-pierre.dijcks
    I've mentioned OCDM in previous posts but found the following (see end of the post) podcast on the topic and figured it is worthwhile to spread the news some more. ORetailDM and OCommunicationsDM are the two data models currently available from Oracle. Both are intended to capture: Business best practices and industry knowledge Pre-built advanced analytics intended to predict future events before they happen (like the Churn model shown below) Oracle technology best practices to ensure optimal performance of the model All of this typically comes with a reduced time to implementation, or as the marketing slogan goes, reduced time to value. Here are the links: Podcast on OCDM OTN pages for OCDM and ORDM

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  • Ruby Drag-n-Drop IDE and Ruby programming related

    - by RPK
    I am writing a small desktop GUI application using Ruby and Gtk2. I am using RubyMine 3 on Linux (Fedora). I created a simple class to create a Gtk Window but now I feel it takes more time to just keep adding code for a Button, Drop Down and TextBox etc. I need to write even more code if the DropDown needs to be populated at run-time. Is there any Ruby Gtk IDE which supports adding Controls with simple drag-n-drop? At least I can focus on the business logic instead of just defining position and sizes of controls. One more question. I subscribed to Ruby-Forum mailing list but it is often flooded with Spam. Which is the official Ruby forum? Recently NetBeans has withdrawn support for Ruby. Is it worth to learn Ruby seriously and use it in commercial environment or not?

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  • SQLAuthority News – A Successful Community TechDays at Ahmedabad – December 11, 2010

    - by pinaldave
    We recently had one of the best community events in Ahmedabad. We were fortunate that we had SQL Experts from around the world to have presented at this event. This gathering was very special because besides Jacob Sebastian and myself, we had two other speakers traveling all the way from Florida (Rushabh Mehta) and Bangalore (Vinod Kumar).There were a total of nearly 170 attendees and the event was blast. Here are the details of the event. Pinal Dave Presenting at Community Tech Days On the day of the event, it seemed to be the coldest day in Ahmedabad but I was glad to see hundreds of people waiting for the doors to be opened some hours before. We started the day with hot coffee and cookies. Yes, food first; and it was right after my keynote. I could clearly see that the coffee did some magic right away; the hall was almost full after the coffee break. Jacob Sebastian Presenting at Community Tech Days Jacob Sebastian, an SQL Server MVP and a close friend of mine, had an unusual job of surprising everybody with an innovative topic accompanied with lots of question-and-answer portions. That’s definitely one thing to love Jacob, that is, the novelty of the subject. His presentation was entitled “Best Database Practices for the .Net”; it really created magic on the crowd. Pinal Dave Presenting at Community Tech Days Next to Jacob Sebastian, I presented “Best Database Practices for the SharePoint”. It was really fun to present Database with the perspective of the database itself. The main highlight of my presentation was when I talked about how one can speed up the database performance by 40% for SharePoint in just 40 seconds. It was fun because the most important thing was to convince people to use the recommendation as soon as they walk out of the session. It was really amusing and the response of the participants was remarkable. Pinal Dave Presenting at Community Tech Days My session was followed by the most-awaited session of the day: that of Rushabh Mehta. He is an international BI expert who traveled all the way from Florida to present “Self Service BI” session. This session was funny and truly interesting. In fact, no one knew BI could be this much entertaining and fascinating. Rushabh has an appealing style of presenting the session; he instantly got very much interaction from the audience. Rushabh Mehta Presenting at Community Tech Days We had a networking lunch break in-between, when we talked about many various topics. It is always interesting to get in touch with the Community and feel a part of it. I had a wonderful time during the break. Vinod Kumar Presenting at Community Tech Days After lunch was apparently the most difficult session for the presenter as during this time, many people started to fall sleep and get dizzy. This spot was requested by Microsoft SQL Server Evangelist Vinod Kumar himself. During our discussion he suggested that if he gets this slot he would make sure people are up and more interactive than during the morning session. Just like always, this session was one of the best sessions ever. Vinod is true to his word as he presented the subject of “Time Management for Developer”. This session was the biggest hit in the event because the subject was instilled in the mind of every participant. Vinod Kumar Presenting at Community Tech Days Vinod’s session was followed by his own small session. Due to “insistent public demand”, he presented an interesting subject, “Tricks and Tips of SQL Server“. In 20 minutes he has done another awesome job and all attendees wanted more of the tricks. Just as usual he promised to do that next time for us. Vinod’s session was succeeded by Prabhjot Singh Bakshi’s session. He presented an appealing Silverlight concept. Just the same, he did a great job and people cheered him. Prabhjot Presenting at Community Tech Days We had a special invited speaker, Dhananjay Kumar, traveling all the way from Pune. He always supports our cause to help the Community in empowering participants. He presented the topic about Win7 Mobile and SharePoint integration. This was something many did not even expect to be possible. Kudos to Dhananjay for doing a great job. Dhananjay Kumar Presenting at Community Tech Days All in all, this event was one of the best in the Community Tech Days series in Ahmedabad. We were fortunate that legends from the all over the world were present here to present to the Community. I’d say never underestimate the power of the Community and its influence over the direction of the technology. Vinod Kumar Presenting trophy to Pinal Dave Vinod Kumar Presenting trophy to Pinal Dave This event was a very special gathering to me personally because of your support to the vibrant Community. The following awards were won for last year’s performance: Ahmedabad SQL Server User Group (President: Jacob Sebastian; Leader: Pinal Dave) – Best Tier 2 User Group Best Development Community Individual Contributor – Pinal Dave Speakers I was very glad to receive the award for our entire Community. Attendees at Community Tech Days I want to say thanks to Rushabh Mehta, Vinod Kumar and Dhananjay Kumar for visiting the city and presenting various technology topics in Community Tech Days. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: MVP, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, SQLAuthority News, T SQL, Technology

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  • When should I use Areas in TFS instead of Team Projects

    - by Martin Hinshelwood
    Well, it depends…. If you are a small company that creates a finite number of internal projects then you will find it easier to create a single project for each of your products and have TFS do the heavy lifting with reporting, SharePoint sites and Version Control. But what if you are not… Update 9th March 2010 Michael Fourie gave me some feedback which I have integrated. Ed Blankenship via @edblankenship offered encouragement and a nice quote. Ewald Hofman gave me a couple of Cons, and maybe a few more soon. Ewald’s company, Avanade, currently uses Areas, but it looks like the manual management is getting too much and the project is getting cluttered. What if you are likely to have hundreds of projects, possibly with a multitude of internal and external projects? You might have 1 project for a customer or 10. This is the situation that most consultancies find themselves in and thus they need a more sustainable and maintainable option. What I am advocating is that we should have 1 “Team Project” per customer, and use areas to create “sub projects” within that single “Team Project”. "What you describe is what we generally do internally and what we recommend. We make very heavy use of area path to categorize the work within a larger project." - Brian Harry, Microsoft Technical Fellow & Product Unit Manager for Team Foundation Server   "We tend to use areas to segregate multiple projects in the same team project and it works well." - Tiago Pascoal, Visual Studio ALM MVP   "In general, I believe this approach provides consistency [to multi-product engagements] and lowers the administration and maintenance costs. All good." - Michael Fourie, Visual Studio ALM MVP   “@MrHinsh BTW, I'm very much a fan of very large, if not huge, team projects in TFS. Just FYI :) Use Areas & Iterations.” Ed Blankenship, Visual Studio ALM MVP   This would mean that SSW would have a single Team Project called “SSW” that contains all of our internal projects and consequently all of the Areas and Iteration move down one hierarchy to accommodate this. Where we would have had “\SSW\Sprint 1” we now have “\SSW\SqlDeploy\Sprint1” with “SqlDeploy” being our internal project. At the moment SSW has over 70 internal projects and more than 170 total projects in TFS. This method has long term benefits that help to simplify the support model for companies that often have limited internal support time and many projects. But, there are implications as TFS does not provide this model “out-of-the-box”. These implications stretch across Areas, Iterations, Queries, Project Portal and Version Control. Michael made a good comment, he said: I agree with your approach, assuming that in a multi-product engagement with a client, they are happy to adopt the same process template across all products. If they are not, then it’ll either be easy to convince them or there is a valid reason for having a different template - Michael Fourie, Visual Studio ALM MVP   At SSW we have a standard template that we use and this is applied across the board, to all of our projects. We even apply any changes to the core process template to all of our existing projects as well. If you have multiple projects for the same clients on multiple templates and you want to keep it that way, then this approach will not work for you. However, if you want to standardise as we have at SSW then this approach may benefit you as well. Implications around Areas Areas should be used for topological classification/isolation of work items. You can think of this as architecture areas, organisational areas or even the main features of your application. In our scenario there is an additional top level item that represents the Project / Product that we want to chop our Team Project into. Figure: Creating a sub area to represent a product/project is easy. <teamproject> <teamproject>\<Functional Area/module whatever> Becomes: <teamproject> <teamproject>\<ProjectName>\ <teamproject>\<ProjectName>\<Functional Area/module whatever> Implications around Iterations Iterations should be used for chronological classification/isolation of work items. This could include isolated time boxes, milestones or release timelines and really depends on the logical flow of your project or projects. Due to the new level in Area we need to add the same level to Iteration. This is primarily because it is unlikely that the sprints in each of your projects/products will start and end at the same time. This is just a reality of managing multiple projects. Figure: Adding the same Area value to Iteration as the top level item adds flexibility to Iteration. <teamproject>\Sprint 1 Or <teamproject>\Release 1\Sprint 1 Becomes: <teamproject>\<ProjectName>\Sprint 1 Or <teamproject>\<ProjectName>\Release 1\Sprint 1 Implications around Queries Queries are used to filter your work items based on a specified level of granularity. There are a number of queries that are built into a project created using the MSF Agile 5.0 template, but we now have multiple projects and it would be a pain to have to edit all of the work items every time we changed project, and that would only allow one team to work on one project at a time.   Figure: The Queries that are created in a normal MSF Agile 5.0 project do not quite suit our new needs. In order for project contributors to be able to query based on their project we need a couple of things. The first thing I did was to create an “_Area Template” folder that has a copy of the project layout with all the queries setup to filter based on the “_Area Template” Area and the “_Sprint template” you can see in the Area and Iteration views. Figure: The template is currently easily drag and drop, but you then need to edit the queries to point at the right Area and Iteration. This needs a tool. I then created an “Areas” folder to hold all of the area specific queries. So, when you go to create a new TFS Sub-Project you just drag “_Area Template” while holding “Ctrl” and drop it onto “Areas”. There is a little setup here. That said I managed it in around 10 minutes which is not so bad, and I can imagine it being quite easy to build a tool to create these queries Figure: These new queries can be configured in around 10 minutes, which includes setting up the Area and Iteration as well. Version Control What about your source code? Well, that is the easiest of the lot. Just create a sub folder for each of your projects/products.   Figure: Creating sub folders in source control is easy as “Right click | Create new folder”. <teamproject>\DEV\Main\ Becomes: <teamproject>\<ProjectName>\DEV\Main\ Conclusion I think it is up to each company to make a call on how you want to configure your Team Projects and it depends completely on how many projects/products you are going to have for each customer including yourself. If we decide to utilise this route it will require some configuration to get our 170+ projects into this format, and I will probably be writing some tools to help. Pros You only have one project to upgrade when a process template changes – After going through an upgrade of over 170 project prior to the changes in the RC I can tell you that that many projects is no fun. Standardises your Process Template – You will always have the same Process implementation across projects/products without exception You get tighter control over the permissions – Yes, you can do this on a standard Team Project, but it gets a lot easier with practice. You can “move” work items from one “product” to another – Have we not always wanted to do that. You can rename your projects – Wahoo: everyone wants to do this, now you can. One set of Reporting Services reports to manage – You set an area and iteration to run reports anyway, so you may as well set both. Simplified Check-In Policies– There is only one set of check-in policies per client. This simplifies administration of policies. Simplified Alerts – As alerts are applied across multiple projects this simplifies your alert rules as per client. Cons All of these cons could be mitigated by a custom tool that helps automate creation of “Sub-projects” within Team Projects. This custom tool could create areas, Iteration, permissions, SharePoint and queries. It just does not exist yet :) You need to configure the Areas and Iterations You need to configure the permissions You may need to configure sub sites for SharePoint (depends on your requirement) – If you have two projects/products in the same Team Project then you will not see the burn down for each one out-of-the-box, but rather a cumulative for the Team Project. This is not really that much of a problem as you would have to configure your burndown graphs for your current iteration anyway. note: When you create a sub site to a TFS linked portal it will inherit the settings of its parent site :) This is fantastic as it means that you can easily create sub sites and then set the Area and Iteration path in each of the reports to be the correct one. Every team wants their own customization (via Ewald Hofman) - small teams of 2 persons against teams of 30 – or even outsourcing – need their own process, you cannot allow that because everybody gets the same work item types. note: Luckily at SSW this is not a problem as our template is standardised across all projects and customers. Large list of builds (via Ewald Hofman) – As the build list in Team Explorer is just a flat list it can get very cluttered. note: I would mitigate this by removing any build that has not been run in over 30 days. The build template and workflow will still be available in version control, but it will clean the list. Feedback Now that I have explained this method, what do you think? What other pros and cons can you see? What do you think of this approach? Will you be using it? What tools would you like to support you?   Technorati Tags: Visual Studio ALM,TFS Administration,TFS,Team Foundation Server,Project Planning,TFS Customisation

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  • Turn Photos and Home Videos into Movies with Windows Live Movie Maker

    - by DigitalGeekery
    Are you looking for an easy way to take your digital photos and videos and turn them into a movie or slideshow? Today we’ll take a detailed look at how to do use Windows Live Movie Maker. Installation Windows Live Movie Maker comes bundled as part of the Windows Live Essentials suite (link below). However, you don’t have to install any of the programs you may not want. Take notice of the You’re almost done screen. Before clicking Continue, be sure to uncheck the boxes to set your search provider and homepage. Adding Pictures and Videos Open Windows Live Movie Maker. You can add videos or photos by simply dragging and dropping them onto the storyboard area. You can also click on the storyboard area or on the Add videos and photos button on the Home tab to browse for videos and photos. Windows Live Movie Maker supports most video, image, and audio file types. Select your files and add click Open to add them to Windows Live Movie Maker. By default WLMM doesn’t allow you to add files from network locations…so check out our article on how to add network support to Windows Live MovieMaker if the files you want to add are on a network drive. Layout All of your added clips will appear in the storyboard area on the right, while the currently selected clip will appear in the preview window on the left. You can adjust the size of the two areas by clicking and dragging the dividing line in the middle.    Make the clips on the storyboard bigger or smaller by clicking on the thumbnail size icon. The slider at the lower right adjusts the zoom time scale.   Previewing your Movie At any time, you can playback your movie and preview how it will look in the Preview window by clicking the space bar, or by pushing the play button under the preview window. You can also manually move the preview bar slider across the storyboard to view the clips as the video progresses. Adjusting Clips on the Storyboard You can click and drag clips on the storyboard to change the order in which the photos and videos appear.   Adding Music Nothing brings a movie to life quite like music. Selecting Add music will add your music to the beginning of the movie. Select Add music at the current point to include it in the movie to the current location of your preview bar slider, then browse for your music clip. WLMM supports many common audio files such as WAV, MP3, M4A, WMA, AIFF, and ASF. The music clip will appear above the video / photos clips on the storyboard.   You can change the location of music clips by clicking and dragging them to a different location on the storyboard. Add Titles, Captions, and Credits To add a Title screen to your movie, click the Title button on the Home tab. Type your title directly into the text box on the preview screen. The title will be placed at the location of the preview slider on the storyboard. However, you can change the location by clicking and dragging title to other areas of the storyboard. On the Format tab, there are a handful of text settings. You can change the font, color, size, alignment,  and transparency. The Adjust group allows you to change the background color, edit the text, and set the length of time the Title will appear in the movie.   The Effects group on the Format tab allows you to select an effect for your title screen. By hovering your cursor over each option, you will get a live preview of how each effect will appear in the preview window. Click to apply any of the effects. For captions, select where you want your caption to appear with the preview slider on the storyboard, then click the captions button on the Home tab. Just like the title, you type your caption directly into the text box on the preview screen, and you can make any adjustments by using the Font and Paragraph, Adjust, and Effects groups above. Credits are done the same as titles and captions, except they are automatically placed at the end of the movie.   Transitions Go to the Animation tab on the ribbon to apply transitions. Select a clip from the storyboard and hover over one of the transition to see it in the preview window. Click on the transition to apply it to the clip. You can apply transitions separately to clips or hold down Ctrl button while clicking to select multiple clips to which to apply the same transition. Pan and zoom effects are also located on the Animations tab, but can be applied to photos only. Like transition, you can apply them individually to a clip or hold down Ctrl button while clicking to select multiple clips to which to apply the same pan and zoom effect. Once applied, you can adjust the duration of the transitions and pan and zoom effects. You can also click the dropdown for additional transitions or effects. Visual Effects Similar to Pan and Zoom and Transitions, you can apply a variety of Visual Effects to individual or multiple clips. Editing Video and Music Note: This does not actually edit the original video you imported into your Windows Live Movie Maker project, only how it appears in your WLMM project. There are some very basic editing tools located on the Home tab. The Rotate left and Rotate right button will adjust any clip that may be oriented incorrectly. The Fit to music button will automatically adjust the duration of the photos (if you have any in your project) to fit the length of the music in your movie. Audio mix allows you to change the volume level   You can also do some slightly more advanced editing from the Edit tab. Select the video clip on the storyboard and click the Trim tool to edit or remove portions of a video clip. Next, click and drag the sliders in the preview windows to select the are you wish to keep. For example, the area outside the sliders is the area trimmed from the movie. The area inside is the section that is kept in the movie. You can also adjust the Start and End points manually on the ribbon.   When you are finished, click Save trim. You can also split your video clips. Move the preview slider to the location in the video clip where you’d like to split it, and select Split. Your video will be split into separate sections. Now you can apply different effects or move them to different locations on the storyboard. Editing Music Clips Select the music clip on the storyboard and then the Options tab on the ribbon. You can adjust the music volume by moving the slider right and left.   You can also choose to have your music clip fade in or out at the beginning and end of your movie. From the Fade in and Fade out dropdowns, select None, Slow, Medium, or Fast. To adjust the sound of your audio clips, click on the Edit tab, select the Video volume button, and adjust the slider. Move it all the way to the left to mute any background noise in your video clips.   AutoMovie As you have seen, Windows Live Movie Maker allows you to add effects, transitions, titles, and more. If you don’t want to do any of that stuff yourself, AutoMovie will automatically add title, credits, cross fade transitions between items, pan and zoom effects to photos, and fit your project to the music. Just select the AutoMovie button on the Home tab. You can go from zero to movie in literally a couple minutes.   Uploading to YouTube You can share your video on YouTube directly from Windows Live Movie Maker. Click on the YouTube icon in the Sharing group on the Home tab. You’ll be prompted for your YouTube username and password. Fill in the details about your movie and click Publish. The movie will be converted to WMV before being uploaded to YouTube. As soon as the YouTube conversion is complete, you’re new movie is live and ready to be viewed. Saving your Movie as a Video File Select the icon at the top left, then select Save movie. As you hover your mouse over each of the options, you will see the output display size, aspect ratio, and estimated file size per minute of video. All of these settings will output your movie as a WMV file. (Unfortunately, the only option is to save a movie as a WMV file.) The only difference is how they are encoded based on preset common settings. The Burn to DVD option also outputs a WMV file, but then opens Windows DVD Maker and walks you through the process of creating and burning a DVD.   If you choose the Burn to DVD option, close this window when the WMV file conversion is complete and the Windows DVD Maker will prompt you to begin. When your movie is finished, it’s time to relax and enjoy.   Conclusion Windows Live Movie Maker makes it easy for the average person to quickly churn out nice looking movies and slideshows from there own pictures and videos. However, long time users of previous editions (formerly called Windows Movie Maker) will likely be disappointed by some features missing in Windows Live Movie Maker that existed in earlier editions. Looking for details on burning your new project to DVD, check out our article on how to create and author DVDs with Windows DVD Maker. Download Windows Live Movie Maker Similar Articles Productive Geek Tips Family Fun: Share Photos with Photo Gallery and Windows Live SpacesCreate and Author DVDs in Windows 7Rotate a Video 90 degrees with VLC or Windows Live Movie MakerInstall Windows Live Essentials In Windows 7How to Make/Edit a movie with Windows Movie Maker in Windows Vista TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips CloudBerry Online Backup 1.5 for Windows Home Server Snagit 10 VMware Workstation 7 Acronis Online Backup Windows Firewall with Advanced Security – How To Guides Sculptris 1.0, 3D Drawing app AceStock, a Tiny Desktop Quote Monitor Gmail Button Addon (Firefox) Hyperwords addon (Firefox) Backup Outlook 2010

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  • Soluto’s New Quick Question Button Makes Family Tech Support Simple

    - by Jason Fitzpatrick
    Soluto, a computer and boot management tool, now features a Quick Question button that allows the people you help out to easily click a button and send you both a short message and a screenshot of the problem. Any time your friend or family member presses F8, Soluto will take a screenshot of the screen, the Task Manager history, and a note from the user highlighting what issue they’re experiencing, and then email it all to you. After reviewing the email you can easily login to Soluto to remotely manage your friend’s computer and help with the problem. For more information about Soluto you can check out our previous reviews of the service here and here, or just hit up the link below to read more and take Soluto for a test drive. Soluto is a free service (for the first 5 computers), Windows only. Introducing Quick Question [The Soluto Blog] Java is Insecure and Awful, It’s Time to Disable It, and Here’s How What Are the Windows A: and B: Drives Used For? HTG Explains: What is DNS?

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  • Fix Windows Computer Problems with Microsoft Fix it Center

    - by Matthew Guay
    Fixing computer problems can often be difficult, but Microsoft is aiming to make it as simple as a couple clicks with.  Here’s how you can easily fix computer problems with Microsoft’s new Fix it Center Beta. Last year Microsoft began offering small Fix it scripts that you could download and run to help solve common computer problems automatically.  These were added to some of the most visited Windows help pages, and helped fix problems with things such as printing errors and Aero glass support.  Now, the Fix it scripts have been bundled together with the Fix it Center, making fixing your computer even easier.  This free tool works great on all editions of Windows XP, Vista, and Windows 7. Note: The Fix it Center is currently in beta, so only run if you are comfortable running beta software. Getting Started Download the Fix it Center installer (link below), and install as normal. The installer will download the remaining components, and then finish the installation. In Windows XP, if you have not yet installed .NET 2.0, you may see the following prompt.  Click Yes to go to the download site, and once you’ve installed .NET 2.0, run the Fix it Center setup again. Also, the Fix it Center uses PowerShell to automate its fixes, but if it is not installed yet the installer will automatically download and install it. Find Fixes for Your PC Once Fix it Center is installed, you can personalize it for your computer.  Select Now, and the click Next. It will scan your computer for problems with known solutions, and will offer to go ahead and install these troubleshooters.  If you choose to not install them, you can always download them from within the Fix it Center at a later time. While those troubleshooters are downloading, you can create a Fix it account.  This will give you additional help and support, and let you review Fix it solutions for all your computers from an online dashboard.  You need a Windows Live ID to create an account. Also, choose whether or not to send information to Microsoft about your hardware and software problems. Get Problems Fixed Now that the Fix it Center is installed and has identified issues on your computer, it’s time to get the problems fixed.  Here’s the default front screen in Windows 7, showing all of the available fixes. And here’s the Fix it Center running in Windows XP. Select one of the Troubleshooters to see more information about it, and click Run to start it. You can choose to either detect problems and have them fixed automatically, or you can choose for the Fix it Center to show you the solutions and let you choose whether to apply them or not.  The defaults usually work good, and only take a couple minutes to apply the fixes, but you can select your own fixes if you’d rather be in control. It will scan your computer for known problems in this area, and then will show you the results.  Here, Fix it determined that startup programs may be causing performance issues.  Select Start System Configuration, and uncheck any of the programs you do not usually use. Once you’ve run a troubleshooter, you can see the issues it checked for and any problems it discovered. If you created the online account, you can also choose to view the details online.  This will show all of your computers with Fix it Center and the fixes you’ve run on them.   Conclusion Whether you’re a power user or new to computers, sometimes it’s best to just get your problems fixed and go on with life instead of digging through the registry, forums, and hacking your way to a solution.  Remember the service is still in beta and may not work perfectly or solve your issues every time. But it’s something cool and worth a look. Links Download Microsoft Fix it Center Beta Fix additional problems with Microsoft’s Fix it Center Online Similar Articles Productive Geek Tips Disable Windows Mobility Center in Windows 7 or VistaMake Outlook Faster by Disabling Unnecessary Add-InsUsing Netflix Watchnow in Windows Vista Media Center (Gmedia)Disable Security Center Popup Notifications in Windows VistaHow To Manage Action Center in Windows 7 TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Icelandic Volcano Webcams Open Multiple Links At One Go NachoFoto Searches Images in Real-time Office 2010 Product Guides Google Maps Place marks – Pizza, Guns or Strip Clubs Monitor Applications With Kiwi

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  • Save Web Articles to Read Later with Instapaper

    - by Mysticgeek
    Have you ever come across a bunch of great articles that you want to read online, but just don’t have the time? Today we take a look at an online service that allows you to read your articles later, either online, or on an iPhone, or eReader. Instapaper Instapaper is an awesome tool that allows you to save web pages so you can read them at a later time. Not only does it save an online article to read later, but also gives you several choices for where you want to read it. Sign up for a free account, and drag the “Read Later” bookmarklet to the bookmarks bar in your browser. To save a page you’ll need to be logged into your account. When you’re at a page that you can’t read right away, just click on the Read Later button in the bookmarks bar. After clicking the Read Later button, a small message is displayed indicating that the page has been saved to the Instapaper site. Save as many pages as you want, and when you’re ready to read them, go to the Instapaper site and you’ll see a list of the articles you saved. You can click on the link to go directly to the saved oage, read it as text (leaving out a bunch of images), or archive the article for later. One of the really appealing beta features is you can save the article in .mobi format for a Kindle, or ePub format for other eReaders such a the Sony Reader. Another neat feature is the “Instapaper Text” bookmarklet that lets you view an article on a graphics heavy page with only text, but doesn’t save it to your account. Before After There are also other cool features such as iPhone Apps, Kindle automatic wireless delivery, send items to Google Reader, and more. If you wish you could collect all of the neat articles you run across each day for reading later via multiple formats, Instapaper is a great tool for the job. Check Out Instapaper Similar Articles Productive Geek Tips Save Pages for Later With Reading List Extension for FirefoxGreat Geek SitesAbout the GeekHow-To Geek Changes in ProgressMake Outlook 2007 Mark Items as Read When Viewed in Reading Pane TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Classic Cinema Online offers 100’s of OnDemand Movies OutSync will Sync Photos of your Friends on Facebook and Outlook Windows 7 Easter Theme YoWindoW, a real time weather screensaver Optimize your computer the Microsoft way Stormpulse provides slick, real time weather data

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  • ARM TechCon 2013: Oracle, ARM expand collaboration on servers, Internet of Things

    - by Henrik Stahl
    If you have been following Java news, you are already aware of the fact that there has been a lot of investment in Java for ARM-based devices and servers over the last couple of years (news, more news, even more, and lots more). We have released Java ME Embedded binaries for ARM Cortex-M micro controllers, Java SE Embedded for ARM application processors, and a port of the Oracle JDK for ARM-based servers. We have been making Java available to the Beagleboard, Raspberry Pi and Lego Mindstorms/LeJOS communities and worked with them and the Java User Groups to evangelize Java as a great development environment for IoT devices. We have announced commercial relationships with Freescale, Qualcomm, Gemalto M2M, SIMCom to name a few. ARM and Freescale on their side have joined the JCP, recently been voted in as members of the Executive Committee, and have worked with Oracle to evangelize Java in their ecosystem. It is with this background, Nandini Ramani, Vice President, Java Platform at Oracle, announced a expanded collaboration with ARM in a TechCon 2013 keynote titled "Enabling Compelling Services for IoT". To summarize the announcement: ARM and Oracle will work together on interoperability between the ARM Sensinode communications stack (based on CoAP, DTLS and 6LoWPAN) and Oracle's Java ME, Java SE and middleware products. ARM will donate the Sensinode CoAP protocol engine to OpenJDK to stimulate broad adoption of the CoAP protocol, and work with Oracle to extend the relevant Java specifications with CoAP support. CoAP (Constrained Application Protocol) is an IETF specification that provides a low-bandwidth request/response protocol suitable for IoT applications. ARM will work with Oracle and Freescale to enable the mbed Hardware Abstraction Layer (HAL) to act as a portability layer for Java ME Embedded. Oracle will enable mbed as a tier one platform for Java ME Embedded. Over time, this effort will allow any mbed-enabled platforms (mostly based on Cortex-M microcontrollers) to work with off the shelf Java ME Embedded binaries, extending the reach of Java ME into IoT edge nodes. In Nandini's keynote, Oracle showed a roadmap to port the Oracle JDK for Linux on 64-bit ARMv8 servers in the 2015 time frame, preceded by an extended early access program. We expect this binary to have full feature parity with Oracle JDK on other platforms, and be available under the same royalty-free license. This effort has been going on for some time, but is now accelerated due to availability of hardware from Applied Micro. Oracle will be working with Applied Micro on the ARMv8 port, and on optimizing Java for their X-Gene products. Oracle and ARM will work closely on IoT architecture, and on evangelizing Java on ARM for both servers and IoT devices. These announcements reinforce Java's position as a first-class citizen in the ARM ecosystem, and signal a commitment from us to collaborate on driving standards and open ecosystem for the Internet of Things. If you are active in this area and not already in touch with us, or interested in learning more - please reach out to us!

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  • Toorcon14

    - by danx
    Toorcon 2012 Information Security Conference San Diego, CA, http://www.toorcon.org/ Dan Anderson, October 2012 It's almost Halloween, and we all know what that means—yes, of course, it's time for another Toorcon Conference! Toorcon is an annual conference for people interested in computer security. This includes the whole range of hackers, computer hobbyists, professionals, security consultants, press, law enforcement, prosecutors, FBI, etc. We're at Toorcon 14—see earlier blogs for some of the previous Toorcon's I've attended (back to 2003). This year's "con" was held at the Westin on Broadway in downtown San Diego, California. The following are not necessarily my views—I'm just the messenger—although I could have misquoted or misparaphrased the speakers. Also, I only reviewed some of the talks, below, which I attended and interested me. MalAndroid—the Crux of Android Infections, Aditya K. Sood Programming Weird Machines with ELF Metadata, Rebecca "bx" Shapiro Privacy at the Handset: New FCC Rules?, Valkyrie Hacking Measured Boot and UEFI, Dan Griffin You Can't Buy Security: Building the Open Source InfoSec Program, Boris Sverdlik What Journalists Want: The Investigative Reporters' Perspective on Hacking, Dave Maas & Jason Leopold Accessibility and Security, Anna Shubina Stop Patching, for Stronger PCI Compliance, Adam Brand McAfee Secure & Trustmarks — a Hacker's Best Friend, Jay James & Shane MacDougall MalAndroid—the Crux of Android Infections Aditya K. Sood, IOActive, Michigan State PhD candidate Aditya talked about Android smartphone malware. There's a lot of old Android software out there—over 50% Gingerbread (2.3.x)—and most have unpatched vulnerabilities. Of 9 Android vulnerabilities, 8 have known exploits (such as the old Gingerbread Global Object Table exploit). Android protection includes sandboxing, security scanner, app permissions, and screened Android app market. The Android permission checker has fine-grain resource control, policy enforcement. Android static analysis also includes a static analysis app checker (bouncer), and a vulnerablity checker. What security problems does Android have? User-centric security, which depends on the user to grant permission and make smart decisions. But users don't care or think about malware (the're not aware, not paranoid). All they want is functionality, extensibility, mobility Android had no "proper" encryption before Android 3.0 No built-in protection against social engineering and web tricks Alternative Android app markets are unsafe. Simply visiting some markets can infect Android Aditya classified Android Malware types as: Type A—Apps. These interact with the Android app framework. For example, a fake Netflix app. Or Android Gold Dream (game), which uploads user files stealthy manner to a remote location. Type K—Kernel. Exploits underlying Linux libraries or kernel Type H—Hybrid. These use multiple layers (app framework, libraries, kernel). These are most commonly used by Android botnets, which are popular with Chinese botnet authors What are the threats from Android malware? These incude leak info (contacts), banking fraud, corporate network attacks, malware advertising, malware "Hackivism" (the promotion of social causes. For example, promiting specific leaders of the Tunisian or Iranian revolutions. Android malware is frequently "masquerated". That is, repackaged inside a legit app with malware. To avoid detection, the hidden malware is not unwrapped until runtime. The malware payload can be hidden in, for example, PNG files. Less common are Android bootkits—there's not many around. What they do is hijack the Android init framework—alteering system programs and daemons, then deletes itself. For example, the DKF Bootkit (China). Android App Problems: no code signing! all self-signed native code execution permission sandbox — all or none alternate market places no robust Android malware detection at network level delayed patch process Programming Weird Machines with ELF Metadata Rebecca "bx" Shapiro, Dartmouth College, NH https://github.com/bx/elf-bf-tools @bxsays on twitter Definitions. "ELF" is an executable file format used in linking and loading executables (on UNIX/Linux-class machines). "Weird machine" uses undocumented computation sources (I think of them as unintended virtual machines). Some examples of "weird machines" are those that: return to weird location, does SQL injection, corrupts the heap. Bx then talked about using ELF metadata as (an uintended) "weird machine". Some ELF background: A compiler takes source code and generates a ELF object file (hello.o). A static linker makes an ELF executable from the object file. A runtime linker and loader takes ELF executable and loads and relocates it in memory. The ELF file has symbols to relocate functions and variables. ELF has two relocation tables—one at link time and another one at loading time: .rela.dyn (link time) and .dynsym (dynamic table). GOT: Global Offset Table of addresses for dynamically-linked functions. PLT: Procedure Linkage Tables—works with GOT. The memory layout of a process (not the ELF file) is, in order: program (+ heap), dynamic libraries, libc, ld.so, stack (which includes the dynamic table loaded into memory) For ELF, the "weird machine" is found and exploited in the loader. ELF can be crafted for executing viruses, by tricking runtime into executing interpreted "code" in the ELF symbol table. One can inject parasitic "code" without modifying the actual ELF code portions. Think of the ELF symbol table as an "assembly language" interpreter. It has these elements: instructions: Add, move, jump if not 0 (jnz) Think of symbol table entries as "registers" symbol table value is "contents" immediate values are constants direct values are addresses (e.g., 0xdeadbeef) move instruction: is a relocation table entry add instruction: relocation table "addend" entry jnz instruction: takes multiple relocation table entries The ELF weird machine exploits the loader by relocating relocation table entries. The loader will go on forever until told to stop. It stores state on stack at "end" and uses IFUNC table entries (containing function pointer address). The ELF weird machine, called "Brainfu*k" (BF) has: 8 instructions: pointer inc, dec, inc indirect, dec indirect, jump forward, jump backward, print. Three registers - 3 registers Bx showed example BF source code that implemented a Turing machine printing "hello, world". More interesting was the next demo, where bx modified ping. Ping runs suid as root, but quickly drops privilege. BF modified the loader to disable the library function call dropping privilege, so it remained as root. Then BF modified the ping -t argument to execute the -t filename as root. It's best to show what this modified ping does with an example: $ whoami bx $ ping localhost -t backdoor.sh # executes backdoor $ whoami root $ The modified code increased from 285948 bytes to 290209 bytes. A BF tool compiles "executable" by modifying the symbol table in an existing ELF executable. The tool modifies .dynsym and .rela.dyn table, but not code or data. Privacy at the Handset: New FCC Rules? "Valkyrie" (Christie Dudley, Santa Clara Law JD candidate) Valkyrie talked about mobile handset privacy. Some background: Senator Franken (also a comedian) became alarmed about CarrierIQ, where the carriers track their customers. Franken asked the FCC to find out what obligations carriers think they have to protect privacy. The carriers' response was that they are doing just fine with self-regulation—no worries! Carriers need to collect data, such as missed calls, to maintain network quality. But carriers also sell data for marketing. Verizon sells customer data and enables this with a narrow privacy policy (only 1 month to opt out, with difficulties). The data sold is not individually identifiable and is aggregated. But Verizon recommends, as an aggregation workaround to "recollate" data to other databases to identify customers indirectly. The FCC has regulated telephone privacy since 1934 and mobile network privacy since 2007. Also, the carriers say mobile phone privacy is a FTC responsibility (not FCC). FTC is trying to improve mobile app privacy, but FTC has no authority over carrier / customer relationships. As a side note, Apple iPhones are unique as carriers have extra control over iPhones they don't have with other smartphones. As a result iPhones may be more regulated. Who are the consumer advocates? Everyone knows EFF, but EPIC (Electrnic Privacy Info Center), although more obsecure, is more relevant. What to do? Carriers must be accountable. Opt-in and opt-out at any time. Carriers need incentive to grant users control for those who want it, by holding them liable and responsible for breeches on their clock. Location information should be added current CPNI privacy protection, and require "Pen/trap" judicial order to obtain (and would still be a lower standard than 4th Amendment). Politics are on a pro-privacy swing now, with many senators and the Whitehouse. There will probably be new regulation soon, and enforcement will be a problem, but consumers will still have some benefit. Hacking Measured Boot and UEFI Dan Griffin, JWSecure, Inc., Seattle, @JWSdan Dan talked about hacking measured UEFI boot. First some terms: UEFI is a boot technology that is replacing BIOS (has whitelisting and blacklisting). UEFI protects devices against rootkits. TPM - hardware security device to store hashs and hardware-protected keys "secure boot" can control at firmware level what boot images can boot "measured boot" OS feature that tracks hashes (from BIOS, boot loader, krnel, early drivers). "remote attestation" allows remote validation and control based on policy on a remote attestation server. Microsoft pushing TPM (Windows 8 required), but Google is not. Intel TianoCore is the only open source for UEFI. Dan has Measured Boot Tool at http://mbt.codeplex.com/ with a demo where you can also view TPM data. TPM support already on enterprise-class machines. UEFI Weaknesses. UEFI toolkits are evolving rapidly, but UEFI has weaknesses: assume user is an ally trust TPM implicitly, and attached to computer hibernate file is unprotected (disk encryption protects against this) protection migrating from hardware to firmware delays in patching and whitelist updates will UEFI really be adopted by the mainstream (smartphone hardware support, bank support, apathetic consumer support) You Can't Buy Security: Building the Open Source InfoSec Program Boris Sverdlik, ISDPodcast.com co-host Boris talked about problems typical with current security audits. "IT Security" is an oxymoron—IT exists to enable buiness, uptime, utilization, reporting, but don't care about security—IT has conflict of interest. There's no Magic Bullet ("blinky box"), no one-size-fits-all solution (e.g., Intrusion Detection Systems (IDSs)). Regulations don't make you secure. The cloud is not secure (because of shared data and admin access). Defense and pen testing is not sexy. Auditors are not solution (security not a checklist)—what's needed is experience and adaptability—need soft skills. Step 1: First thing is to Google and learn the company end-to-end before you start. Get to know the management team (not IT team), meet as many people as you can. Don't use arbitrary values such as CISSP scores. Quantitive risk assessment is a myth (e.g. AV*EF-SLE). Learn different Business Units, legal/regulatory obligations, learn the business and where the money is made, verify company is protected from script kiddies (easy), learn sensitive information (IP, internal use only), and start with low-hanging fruit (customer service reps and social engineering). Step 2: Policies. Keep policies short and relevant. Generic SANS "security" boilerplate policies don't make sense and are not followed. Focus on acceptable use, data usage, communications, physical security. Step 3: Implementation: keep it simple stupid. Open source, although useful, is not free (implementation cost). Access controls with authentication & authorization for local and remote access. MS Windows has it, otherwise use OpenLDAP, OpenIAM, etc. Application security Everyone tries to reinvent the wheel—use existing static analysis tools. Review high-risk apps and major revisions. Don't run different risk level apps on same system. Assume host/client compromised and use app-level security control. Network security VLAN != segregated because there's too many workarounds. Use explicit firwall rules, active and passive network monitoring (snort is free), disallow end user access to production environment, have a proxy instead of direct Internet access. Also, SSL certificates are not good two-factor auth and SSL does not mean "safe." Operational Controls Have change, patch, asset, & vulnerability management (OSSI is free). For change management, always review code before pushing to production For logging, have centralized security logging for business-critical systems, separate security logging from administrative/IT logging, and lock down log (as it has everything). Monitor with OSSIM (open source). Use intrusion detection, but not just to fulfill a checkbox: build rules from a whitelist perspective (snort). OSSEC has 95% of what you need. Vulnerability management is a QA function when done right: OpenVas and Seccubus are free. Security awareness The reality is users will always click everything. Build real awareness, not compliance driven checkbox, and have it integrated into the culture. Pen test by crowd sourcing—test with logging COSSP http://www.cossp.org/ - Comprehensive Open Source Security Project What Journalists Want: The Investigative Reporters' Perspective on Hacking Dave Maas, San Diego CityBeat Jason Leopold, Truthout.org The difference between hackers and investigative journalists: For hackers, the motivation varies, but method is same, technological specialties. For investigative journalists, it's about one thing—The Story, and they need broad info-gathering skills. J-School in 60 Seconds: Generic formula: Person or issue of pubic interest, new info, or angle. Generic criteria: proximity, prominence, timeliness, human interest, oddity, or consequence. Media awareness of hackers and trends: journalists becoming extremely aware of hackers with congressional debates (privacy, data breaches), demand for data-mining Journalists, use of coding and web development for Journalists, and Journalists busted for hacking (Murdock). Info gathering by investigative journalists include Public records laws. Federal Freedom of Information Act (FOIA) is good, but slow. California Public Records Act is a lot stronger. FOIA takes forever because of foot-dragging—it helps to be specific. Often need to sue (especially FBI). CPRA is faster, and requests can be vague. Dumps and leaks (a la Wikileaks) Journalists want: leads, protecting ourselves, our sources, and adapting tools for news gathering (Google hacking). Anonomity is important to whistleblowers. They want no digital footprint left behind (e.g., email, web log). They don't trust encryption, want to feel safe and secure. Whistleblower laws are very weak—there's no upside for whistleblowers—they have to be very passionate to do it. Accessibility and Security or: How I Learned to Stop Worrying and Love the Halting Problem Anna Shubina, Dartmouth College Anna talked about how accessibility and security are related. Accessibility of digital content (not real world accessibility). mostly refers to blind users and screenreaders, for our purpose. Accessibility is about parsing documents, as are many security issues. "Rich" executable content causes accessibility to fail, and often causes security to fail. For example MS Word has executable format—it's not a document exchange format—more dangerous than PDF or HTML. Accessibility is often the first and maybe only sanity check with parsing. They have no choice because someone may want to read what you write. Google, for example, is very particular about web browser you use and are bad at supporting other browsers. Uses JavaScript instead of links, often requiring mouseover to display content. PDF is a security nightmare. Executible format, embedded flash, JavaScript, etc. 15 million lines of code. Google Chrome doesn't handle PDF correctly, causing several security bugs. PDF has an accessibility checker and PDF tagging, to help with accessibility. But no PDF checker checks for incorrect tags, untagged content, or validates lists or tables. None check executable content at all. The "Halting Problem" is: can one decide whether a program will ever stop? The answer, in general, is no (Rice's theorem). The same holds true for accessibility checkers. Language-theoretic Security says complicated data formats are hard to parse and cannot be solved due to the Halting Problem. W3C Web Accessibility Guidelines: "Perceivable, Operable, Understandable, Robust" Not much help though, except for "Robust", but here's some gems: * all information should be parsable (paraphrasing) * if not parsable, cannot be converted to alternate formats * maximize compatibility in new document formats Executible webpages are bad for security and accessibility. They say it's for a better web experience. But is it necessary to stuff web pages with JavaScript for a better experience? A good example is The Drudge Report—it has hand-written HTML with no JavaScript, yet drives a lot of web traffic due to good content. A bad example is Google News—hidden scrollbars, guessing user input. Solutions: Accessibility and security problems come from same source Expose "better user experience" myth Keep your corner of Internet parsable Remember "Halting Problem"—recognize false solutions (checking and verifying tools) Stop Patching, for Stronger PCI Compliance Adam Brand, protiviti @adamrbrand, http://www.picfun.com/ Adam talked about PCI compliance for retail sales. Take an example: for PCI compliance, 50% of Brian's time (a IT guy), 960 hours/year was spent patching POSs in 850 restaurants. Often applying some patches make no sense (like fixing a browser vulnerability on a server). "Scanner worship" is overuse of vulnerability scanners—it gives a warm and fuzzy and it's simple (red or green results—fix reds). Scanners give a false sense of security. In reality, breeches from missing patches are uncommon—more common problems are: default passwords, cleartext authentication, misconfiguration (firewall ports open). Patching Myths: Myth 1: install within 30 days of patch release (but PCI §6.1 allows a "risk-based approach" instead). Myth 2: vendor decides what's critical (also PCI §6.1). But §6.2 requires user ranking of vulnerabilities instead. Myth 3: scan and rescan until it passes. But PCI §11.2.1b says this applies only to high-risk vulnerabilities. Adam says good recommendations come from NIST 800-40. Instead use sane patching and focus on what's really important. From NIST 800-40: Proactive: Use a proactive vulnerability management process: use change control, configuration management, monitor file integrity. Monitor: start with NVD and other vulnerability alerts, not scanner results. Evaluate: public-facing system? workstation? internal server? (risk rank) Decide:on action and timeline Test: pre-test patches (stability, functionality, rollback) for change control Install: notify, change control, tickets McAfee Secure & Trustmarks — a Hacker's Best Friend Jay James, Shane MacDougall, Tactical Intelligence Inc., Canada "McAfee Secure Trustmark" is a website seal marketed by McAfee. A website gets this badge if they pass their remote scanning. The problem is a removal of trustmarks act as flags that you're vulnerable. Easy to view status change by viewing McAfee list on website or on Google. "Secure TrustGuard" is similar to McAfee. Jay and Shane wrote Perl scripts to gather sites from McAfee and search engines. If their certification image changes to a 1x1 pixel image, then they are longer certified. Their scripts take deltas of scans to see what changed daily. The bottom line is change in TrustGuard status is a flag for hackers to attack your site. Entire idea of seals is silly—you're raising a flag saying if you're vulnerable.

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  • The best terminal emulator for a heavy terminal user?

    - by Noah Goodrich
    I spend a lot of time at the command-line during the workday and at home too since I run Ubuntu exclusively. I've been using the default gnome terminal but I've reached a point where I'd really like to get my terminal tricked out so that my common tasks are as easy as possible. Specifically, I find that I spend of lot of time browsing code in the terminal and working in config files. On my wish list would be: Ability to have multiple screens, tabs, windows (I don't have a preference at this point) that I can easily switch between. Color coding for everything Easy to modify the aesthetics of the terminal (is it vain to want my terminal to look nice?) such as transparency, borders, etc.

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  • Ubuntu 14.04:LTS , HPLIP loses USB connection to HP laserjet

    - by Gareth
    This is my first post, so please let me know if i have inadvertanly broken any rules. Problem There seems to be a problem with HPLIP and USB connections in ubuntu 14.04LTS. After upgrading i managed to get the printing to work but today it has broken. Initial Issue (Solved) After upgrading to unbutntu 14.04 LTS my printer lHP LaserJet 1018 stopped printing (code=12) Looking through the Forumsthere are several issues with printitng and HPLIP so I was able to troubleshoot this. The steps I took were : Reran HPdoctor Ran hp-check Un-installed and installed the latest version of HPLIP (3.14.4) Checked the USB connections lsusb and lsusb-v Re-ran hpcheck Removed the printer from HPLIP Re-ran hpcheck Manually configued HPLIP to the printer hp-setup-g <xxx:yyy> And this worked HPLIP was able to see the printer in the USB , test page printed and was happily working for a few weeks. Current Issue Printer Not working However today my wife complains the printer is not working and checking see that although HPLIP has the same error code and did not seem to be able to see the printer although running lsusb could see the printer. Initially thought this may be due to usb given a new bus/device after being turned on and off and went to repeat the steps above at the moment still seeing an error in that the HPLIP is complaining that it cannot see the device **error: Device not found. Please make sure your printer is properly connected and powered-on.** current Observations lsusb output ## Bus 002 Device 007: ID 03f0:4117 Hewlett-Packard LaserJet 1018 sudo hp-check output *> "duan@duan-Lenovo-B550:~$ sudo hp-check [sudo] password for duan: Saving output in log file: /home/duan/hp-check.log HP Linux Imaging and Printing System (ver. 3.14.4) Dependency/Version Check Utility ver. 15.1 Copyright (c) 2001-13 Hewlett-Packard Development Company, LP This software comes with ABSOLUTELY NO WARRANTY. This is free software, and you are welcome to distribute it under certain conditions. See COPYING file for more details. Note: hp-check can be run in three modes: 1. Compile-time check mode (-c or --compile): Use this mode before compiling the HPLIP supplied tarball (.tar.gz or .run) to determine if the proper dependencies are installed to successfully compile HPLIP. Run-time check mode (-r or --run): Use this mode to determine if a distro supplied package (.deb, .rpm, etc) or an already built HPLIP supplied tarball has the proper dependencies installed to successfully run. Both compile- and run-time check mode (-b or --both) (Default): This mode will check both of the above cases (both compile- and run-time dependencies). Full Output output of hp-setup -g 002:007 window box "device not found please make sure your printer is properly connected and powered on" duan@duan-Lenovo-B550:~$ sudo hp-setup -g 002:007 [sudo] password for duan: > HP Linux Imaging and Printing System (ver. 3.14.4) Printer/Fax Setup > Utility ver. 9.0 > > Copyright (c) 2001-13 Hewlett-Packard Development Company, LP This > software comes with ABSOLUTELY NO WARRANTY. This is free software, and > you are welcome to distribute it under certain conditions. See COPYING > file for more details. > > hp-setup[18461]: debug: param=002:007 hp-setup[18461]: debug: > selected_device_name=None Fontconfig error: > "/etc/fonts/conf.d/65-khmer.conf", line 14: out of memory Fontconfig > error: "/etc/fonts/conf.d/65-khmer.conf", line 23: out of memory > Fontconfig error: "/etc/fonts/conf.d/65-khmer.conf", line 32: out of > memory hp-setup[18461]: debug: Sys.argv=['/usr/bin/hp-setup', '-g', > '002:007'] printer_name=None param=002:007 jd_port=1 device_uri=None > remove=False Searching for device... hp-setup[18461]: debug: Trying > USB with bus=002 dev=007... hp-setup[18461]: debug: Not found. > hp-setup[18461]: debug: Trying serial number 002:007 hp-setup[18461]: > debug: Probing bus: usb hp-setup[18461]: debug: Probing bus: par > error: Device not found. Please make sure your printer is properly > connected and powered-on. hp-setup[18461]: debug: Starting GUI loop. .. USB lead Works with the Windows 7 laptop Printer Works with windows 7 laptop Questions Is this a Bug with HPLIP or an issue with laptop/printer? Supplementary question if it is a bug what information is needed and where should it be sent ? Any suggestions on how to get the printer to work correctly with Ubuntu 14.04LTS/HPLIP 13.4.3 so that it stays working ?

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