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  • Python equivalent of Java's compareTo()

    - by astay13
    I'm doing a project in Python (3.2) for which I need to compare user defined objects. I'm used to OOP in Java, where one would define a compareTo() method in the class that specifies the natural ordering of that class, as in the example below: public class Foo { int a, b; public Foo(int aa, int bb) { a = aa; b = bb; } public int compareTo(Foo that) { // return a negative number if this < that // return 0 if this == that // return a positive number if this > that if (this.a == that.a) return this.b - that.b; else return this.a - that.a; } } I'm fairly new to classes/objects in Python, so I'd like to know what is the "pythonic" way to define the natural ordering of a class?

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  • What do you do when every possible business idea is already taken?

    - by jonathanconway
    I have a bit of free time and lots of enthusiasm for software and the web. I want to make a start-up, to sell kind of product or online service, but I'm having a hard time coming up with business ideas that haven't already been implemented. For example, I thought of making an e-ordering website for ordering food from restaurants online. Good thing I typed it into Google, because the market is already full of hundreds of websites doing the same thing and competing heavily. The same thing has happened with so many other business ideas I've become excited and passionate about - they're all taken. What's your response to this? Do you agree that all the good ideas seem to be taken? Or do you think there is room for new businesses, and that I'm just not thinking (or looking) hard enough? Have you ever tried idea after idea, only to find that it was already being done, and you had to move onto something else?

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  • LINQ expression precedence with Skip(), Take() and OrderBy()

    - by Robert Koritnik
    I'm using LINQ to Entities and display paged results. But I'm having issues with the combination of Skip(), Take() and OrderBy() calls. Everything works fine, except that OrderBy() is assigned too late. It's executed after result set has been cut down by Skip() and Take(). So each page of results has items in order. But ordering is done on a page handful of data instead of ordering of the whole set and then limiting those records with Skip() and Take(). How do I set precedence with these statements? My example (simplified) var query = ctx.EntitySet.Where(/* filter */).OrderBy(/* expression */); int total = query.Count(); var result = query.Skip(n).Take(x).ToList();

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  • [Django] Change state of obiects

    - by gameboy
    hi I have following problem. I have model: class Towar(models.Model): nrSeryjny=models.CharField(max_length=100) opis=models.CharField(max_length=255) naStanie=models.NullBooleanField(null=True) def __unicode__(self): return "%s" % self.opis def lowerName(self): return self.__class__.__name__.lower() def checkState(self): return self.naStanie def changeState(self,state): self.naStanie=state class Meta: ordering=['nrSeryjny'] app_label = 'baza' permissions=(("view_towar","mozna miec podglad dla towar"),) and model : class Wypozyczenie(models.Model): dataPobrania=models.DateField() pracownik=models.ForeignKey(User,null=True) kontrahent=models.ForeignKey(Kontrahenci,null=True) towar=models.ForeignKey(Towar,null=True) objects=WypozyczenieManager() default_objects=models.Manager() ZwrotyObjects=WypozyczenieZwrotyManager() def lowerName(self): return self.__class__.__name__.lower() def __unicode__(self): if self.towar == None: return "Dla:%s -- Kto:%s -- Kiedy:%s -- Co:%s" % (self.kontrahent,self.pracownik,self.dataPobrania,"Brak") else: return "Dla:%s -- Kto:%s -- Kiedy:%s -- Co:%s" % (self.kontrahent,self.pracownik,self.dataPobrania,self.towar) class Meta: ordering=['dataPobrania'] app_label = 'baza' permissions=(("view_wypozyczenie","mozna miec podglad dla wypozyczenie"),) and view to adding models: def modelAdd(request,model,modelForm): mod=model() if request.user.has_perm('baza.add_%s' % mod.lowerName()): if request.method=='POST': form=modelForm(request.POST) if form.is_valid(): form.save() return HttpResponseRedirect('/'+ mod.lowerName() + '/') else: form=modelForm() v=RequestContext(request,{'form':form}) return render_to_response('add_form.html',v) and i whant do that, when i add Wypozyczenie and save it then the Towar that is stored by Wypozyczenie change his na stanie from True to False Greets

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  • Confused about GNU `sort(1)` of a numerical sub field

    - by Chen Levy
    I wish to sort a space separated table, with the numerical value that found on the 2nd field. I can assume that the 2nd field is always fooN but the length of N is unknown: antiq. foo11 girls colleaguing foo2 Leinsdorf Cousy foo0 Montgomeryville bowlegged foo1 pollack Chevrier foo10 ill-conceived candlebomb foo3 seventieths autochthony foo101 re-enable beneficiate foo100 osteometric I read man sort(1) and played with all sort of options. On my system I found the line: sort -n -k2.5 table to work. My question is why? According to the man page: -k, --key=POS1[,POS2] start a key at POS1, end it at POS 2 (origin 1) ... POS is F[.C][OPTS], where F is the field number and C the characterposition in the field. OPTS is one or more single-letter ordering options, which override global ordering options for that key. If no key is given, use the entire line as the key. So why sort -n -k2.4 table don't work and sort -n -k.5 does?

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  • JDO in Google App Engine: order of keys in unowned one-to-many relationship

    - by Kel
    I'm implementing web application with JDO in Google App Engine. According to documentation, in owned one-to-many relationships, order of elements in "owner" object collection is determined either by automatically created index field, or by information given in explicit ordering clause. For example: @PersistenceCapable public class Person { // ... @Order(extensions = @Extension(vendorName="datanucleus", key="list-ordering", value="country asc, city asc")) private List<ContactInfo> contacts = new List<ContactInfo>(); In unowned relationships, "owner" object contains collection of keys of "nested" objects, for example: @PersistenceCapable public class Author { // ... @Persistent private List<Key> books; Is order of keys preserved, if I use List<Key> collection in "owner" object for storing keys of "nested" elements? I could not find answer neither in JDO relationships article, nor in Data Classes article :(

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  • Import orders file on magento enterprise or community (product with customs options)

    - by wil
    Hello, We need to import some orders file on magento enterprise. In our file, products contains customs Options. We tried to make an extension but we have some problems to import Customs options. The import of standard product is successful but not for the product with customs options. For customs option, missing "info_buyRequest" valu in database. The technical support of magento we responded "the import process currently can't handle importing products with custom options". Magento use custom options when ordering a product with customs options on website. What features do magento use to fill in the fields "info_buyRequest" and "Product_options" when ordering? Have you see a extension pack for import file order with product contains customs options? Thanks for your help.

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  • Rewriting usort function because of fatal error (PHP bug)

    - by Lionel
    The two following usort functions throw fatal error Base lambda function for closure not found in our productive environment (PHP 5.4). This seems to be a known PHP bug that should be fixed by now (https://bugs.php.net/bug.php?id=52144), but it still occurs for us. Anyway, we unfortunately don't have time to figure out what's wrong with our PHP configurations etc. We would like to rewrite these two functions without the use of anonymous functions, so that the error doesn't occur anymore. Ordering of a multidimensional array ($array) by value of key "position": usort($array, function($a, $b) { return $a['position'] - $b['position']; }); Ordering of a multidimensional array ($array) according to the order of a second array ($position_order): usort($array, function($a, $b) use($position_order) { return (isset($position_order[$a['ftid']]) ? ($position_order[$a['ftid']] - $position_order[$b['ftid']]) : 1); }); Especially the latter causes some headache, as we don't know how to pass the "outside" array $position_order.

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  • Walking through an SQLite Table

    - by galford13x
    I would like to implement or use functionality that allows stepping through a Table in SQLite. If I have a Table Products that has 100k rows, I would like to retrive perhaps 10k rows at a time. Somthing similar to how a webpage would list data and have a < Previous .. Next > link to walk through the data. Are there select statements that can make this simple? I see and have tried using the ROWID in conjunction with LIMIT which seems ok if not ordering the data. // This seems works if not ordering. SELECT * FROM Products WHERE ROWID BETWEEN x AND y;

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  • Sorted sets and comparators

    - by Jack
    Hello, I'm working with a TreeSetthat is meant to store pathfind locations used during the execution of a A* algorithm. Basically until there are "open" elements (still to be exhaustively visited) the neighbours of every open element are taken into consideration and added to a SortedSetthat keeps them ordered by their cost and heuristic cost. This means that I have a class like: public class PathTileInfo implements Comparable<PathTileInfo> { int cost; int hCost; final int x, y; @Override public int compareTo(PathTileInfo t2) { int c = cost + hCost; int c2 = t2.cost + t2.hCost; int costComp = c < c2 ? -1 : (c > c2 ? 1: 0); return costComp != 0 ? costComp : (x < t2.x || y < t2.y ? -1 : (x > t2.x || y > t2.y ? 1 : 0)); } @Override public boolean equals(Object o2) { if (o2 instanceof PathTileInfo) { PathTileInfo i = (PathTileInfo)o2; return i.cost + i.hCost == cost + hCost && x == i.x && y == i.y; } return false; } } In this way first the total cost is considered, then, since a total ordering is needed (consistency with equals) a ordering according to the x,y coordinate is taken into account. This should work but simply it doesn't, if I iterate over the TreeSet during the algorithm execution like in for (PathTileInfo t : openSet) System.out.print("("+t.x+","+t.y+","+(t.cost+t.hCost)+") "); I get results in which the right ordering is not kept, eg: (7,7,6) (7,6,7) (6,8,6) (6,6,7) (5,8,7) (5,7,7) (6,7,6) (6,6,7) (6,5,7) (5,7,7) (5,5,8) (4,7,7) (4,6,8) (4,5,8) is there something subtle I am missing? Thanks!

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  • Import orders file on magento enterprise 1.7 (product with customs options)

    - by wil
    Hello, We need to import some orders file on magento enterprise. In our file, products contains customs Options. We tried to make an extension but we have some problems to import Customs options. The import of standard product is successful but not for the product with customs options. For customs option, missing "info_buyRequest" valu in database. The technical support of magento we responded "the import process currently can't handle importing products with custom options". Magento use custom options when ordering a product with customs options on website. What features do magento use to fill in the fields "info_buyRequest" and "Product_options" when ordering? Have you see a extension pack for import file order with product contains customs options? Thanks for your help.

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  • How to print a specific value in array in PHP?

    - by cateye
    array(2) { [0]=> object(stdClass)#144 (7) { ["id"]=> string(1) "2" ["name"]=> string(8) "name1" ["value"]=> string(22) "Lorem Ipsum Dolar Amet" ["type"]=> string(8) "textarea" ["group"]=> string(1) "1" ["published"]=> string(1) "1" ["ordering"]=> string(1) "1" } [1]=> object(stdClass)#145 (7) { ["id"]=> string(1) "4" ["name"]=> string(6) "Link1" ["value"]=> string(36) "abcabcab" ["type"]=> string(4) "link" ["group"]=> string(1) "1" ["published"]=> string(1) "1" ["ordering"]=> string(1) "2" } } I want to print only "value" (abcabcab) of id=4. How can I achieve this?

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  • How to save an order (permutation) in an sql db

    - by Bendlas
    I have a tree structure in an sql table like so: CREATE TABLE containers ( container_id serial NOT NULL PRIMARY KEY, parent integer REFERENCES containers (container_id)) Now i want to define an ordering between nodes with the same parent. I Have thought of adding a node_index column, to ORDER BY, but that seem suboptimal, since that involves modifying the index of a lot of nodes when modifying the stucture. That could include adding, removing, reordering or moving nodes from some subtree to another. Is there a sql datatype for an ordered sequence, or an efficient way to emulate one? Doesn't need to be fully standard sql, I just need a solution for mssql and hopefully postgresql EDIT To make it clear, the ordering is arbitrary. Actually, the user will be able to drag'n'drop tree nodes in the GUI

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  • How to implement collection with covariance when delegating to another collection for storage?

    - by memelet
    I'm trying to implement a type of SortedMap with extended semantics. I'm trying to delegate to SortedMap as the storage but can't get around the variance constraints: class IntervalMap[A, +B](implicit val ordering: Ordering[A]) //extends ... { var underlying = SortedMap.empty[A, List[B]] } Here is the error I get. I understand why I get the error (I understand variance). What I don't get is how to implement this type of delegation. And yes, the covariance on B is required. error: covariant type B occurs in contravariant position in type scala.collection.immutable.SortedMap[A,List[B]] of parameter of setter underlying_=

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  • Any way for linq query to check against existing select?

    - by danrhul
    I have an an offer, that can be in any number of categories. I don't however want that offer to then appear twice or however more. I was wondering if its possible to have a where clause that ascertains whether that offer already exists in that select statement and if so obviously to ignore it. Here is the linq query: Offers = from o in offerCategories orderby o.RewardCategory.Ordering, o.Order where o.RewardOffer.IsDeleted == false select new OfferOverviewViewModel { Partner = o.RewardOffer.Partner, Description = String.Format("{0} {1}", o.RewardOffer.MainTitle, o.RewardOffer.SecondaryTitle), OfferId = o.OfferId, FeaturedOffer = o.RewardOffer.FeaturedOfferOrder.HasValue, Categories = from c in offerCategories.Where(oc => oc.OfferId == o.OfferId) orderby c.RewardCategory.Ordering select new CategoryDetailViewModel { Description = c.RewardCategory.DisplayName } },

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  • I was making this program and the server wont send to the client

    - by crstin
    void CApplication::SendData( const char pBuffer[] ) { if( pBuffer == NULL ) { Log()->Write( ELogMessageType_ERROR, "Cannot send NULL message."); return; } // calculate the size of that data unsigned long messageSize = strlen( pBuffer ); // fix our byte ordering messageSize = htonl( messageSize ); if( isServer == true ) { for( unsigned int i = ESocket_CLIENT0; i < ESocket_MAX; ++i ) { // send the message size if( m_Socket[ i ] > 0 ) { if( send( m_Socket[ i ], (char*)&messageSize, sizeof( messageSize ), 0 ) == SOCKET_ERROR ) { Log()->Write( ELogMessageType_ERROR, "[Application] Send error: %i to socket %i", WSAGetLastError(), m_Socket[ i ] ); continue; } // fix our message size back to host ordering messageSize = ntohl(messageSize); // send the actual message if( send( m_Socket[ i ], pBuffer, messageSize, 0 ) == SOCKET_ERROR ) { Log()->Write( ELogMessageType_ERROR, "[Application] Send error: %i to socket %i", WSAGetLastError(), m_Socket[ i ] ); continue; } Log()->Write( ELogMessageType_MESSAGE, "[Application] SEND: %s", pBuffer ); } } }

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  • LLBLGen Pro v3.1 released!

    - by FransBouma
    Yesterday we released LLBLGen Pro v3.1! Version 3.1 comes with new features and enhancements, which I'll describe briefly below. v3.1 is a free upgrade for v3.x licensees. What's new / changed? Designer Extensible Import system. An extensible import system has been added to the designer to import project data from external sources. Importers are plug-ins which import project meta-data (like entity definitions, mappings and relational model data) from an external source into the loaded project. In v3.1, an importer plug-in for importing project elements from existing LLBLGen Pro v3.x project files has been included. You can use this importer to create source projects from which you import parts of models to build your actual project with. Model-only relationships. In v3.1, relationships of the type 1:1, m:1 and 1:n can be marked as model-only. A model-only relationship isn't required to have a backing foreign key constraint in the relational model data. They're ideal for projects which have to work with relational databases where changes can't always be made or some relationships can't be added to (e.g. the ones which are important for the entity model, but are not allowed to be added to the relational model for some reason). Custom field ordering. Although fields in an entity definition don't really have an ordering, it can be important for some situations to have the entity fields in a given order, e.g. when you use compound primary keys. Field ordering can be defined using a pop-up dialog which can be opened through various ways, e.g. inside the project explorer, model view and entity editor. It can also be set automatically during refreshes based on new settings. Command line relational model data refresher tool, CliRefresher.exe. The command line refresh tool shipped with v2.6 is now available for v3.1 as well Navigation enhancements in various designer elements. It's now easier to find elements like entities, typed views etc. in the project explorer from editors, to navigate to related entities in the project explorer by right clicking a relationship, navigate to the super-type in the project explorer when right-clicking an entity and navigate to the sub-type in the project explorer when right-clicking a sub-type node in the project explorer. Minor visual enhancements / tweaks LLBLGen Pro Runtime Framework Entity creation is now up to 30% faster and takes 5% less memory. Creating an entity object has been optimized further by tweaks inside the framework to make instantiating an entity object up to 30% faster. It now also takes up to 5% less memory than in v3.0 Prefetch Path node merging is now up to 20-25% faster. Setting entity references required the creation of a new relationship object. As this relationship object is always used internally it could be cached (as it's used for syncing only). This increases performance by 20-25% in the merging functionality. Entity fetches are now up to 20% faster. A large number of tweaks have been applied to make entity fetches up to 20% faster than in v3.0. Full WCF RIA support. It's now possible to use your LLBLGen Pro runtime framework powered domain layer in a WCF RIA application using the VS.NET tools for WCF RIA services. WCF RIA services is a Microsoft technology for .NET 4 and typically used within silverlight applications. SQL Server DQE compatibility level is now per instance. (Usable in Adapter). It's now possible to set the compatibility level of the SQL Server Dynamic Query Engine (DQE) per instance of the DQE instead of the global setting it was before. The global setting is still available and is used as the default value for the compatibility level per-instance. You can use this to switch between CE Desktop and normal SQL Server compatibility per DataAccessAdapter instance. Support for COUNT_BIG aggregate function (SQL Server specific). The aggregate function COUNT_BIG has been added to the list of available aggregate functions to be used in the framework. Minor changes / tweaks I'm especially pleased with the import system, as that makes working with entity models a lot easier. The import system lets you import from another LLBLGen Pro v3 project any entity definition, mapping and / or meta-data like table definitions. This way you can build repository projects where you store model fragments, e.g. the building blocks for a customer-order system, a user credential model etc., any model you can think of. In most projects, you'll recognize that some parts of your new model look familiar. In these cases it would have been easier if you would have been able to import these parts from projects you had pre-created. With LLBLGen Pro v3.1 you can. For example, say you have an Oracle schema called CRM which contains the bread 'n' butter customer-order-product kind of model. You create an entity model from that schema and save it in a project file. Now you start working on another project for another customer and you have to use SQL Server. You also start using model-first development, so develop the entity model from scratch as there's no existing database. As this customer also requires some CRM like entity model, you import the entities from your saved Oracle project into this new SQL Server targeting project. Because you don't work with Oracle this time, you don't import the relational meta-data, just the entities, their relationships and possibly their inheritance hierarchies, if any. As they're now entities in your project you can change them a bit to match the new customer's requirements. This can save you a lot of time, because you can re-use pre-fab model fragments for new projects. In the example above there are no tables yet (as you work model first) so using the forward mapping capabilities of LLBLGen Pro v3 creates the tables, PK constraints, Unique Constraints and FK constraints for you. This way you can build a nice repository of model fragments which you can re-use in new projects.

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  • All the posts in LINQ series

    - by vik20000in
    In Last few weeks I have done a few LINQ series Post. Here is a list of all the posts done.Filtering data in LINQ with the help of where clauseUsing Take and skip keyword to filter records in LINQ TakeWhile and SkipWhile method in LINQLINQ and ordering of the result setGrouping data in LINQ with the help of group keywordUsing set operation in LINQLINQ and conversion operatorsRetrieving only the first record or record at a certain index in LINQUsing Generation operator in LINQWorking with Joins in LINQLINQ and Aggregate function Vikram

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  • Sun Ray 3 Plus Unboxing video

    - by [email protected]
    Shot using a prototype Sun Ray 3 Plus weeks before the Oracle acquisition of Sun was completed, this video gives you the sense of how this newly announced Sun Ray 3 Plus is packaged when shipped.   It also shows what the bits of the SR 3 Plus are all about, including the most commonly asked about specs.  While the Production unit is available for ordering NOW, it will obviously have the Oracle logo in addition to the Sun logo.Enjoy the video here:

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  • Announcement Oracle Virtual Networking

    - by uwes
    Oracle Virtual Networking information and collateral are now available on Oracle.com and Oracle Technical Network (OTN). Oracle Virtual Networking revolutionizes data center economics with a complete portfolio of hardware and software products to provision and manage virtual I/O and networks for servers and storage. These products are available for ordering now. They were part of the Xsigo acquisition on November 6, 2012. For More Information Go To: Oracle Fabric Interconnect oracle.com OTN Oracle Fabric Manager oracle.com OTN Oracle Fabric Monitor oracle.com OTN Oracle SDN oracle.com OTN

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  • Does Ubuntu run on current Asus Transformer Prime?

    - by Ubuntu User
    I've read instructions about dual boot Android / Transformer Prime (a significant factor in ordering one). Also about not working with /latest/ Transformer Prime (firmware / BIOS?) Also about imminent Ubuntu ARM support. Will I be able to run Ubuntu in a day or two when Transformer arrives? Also, am I right to assume I can restore Transformer to factory status if I break something in the attempt?

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  • C#/.NET Little Wonders: Comparer&lt;T&gt;.Default

    - by James Michael Hare
    I’ve been working with a wonderful team on a major release where I work, which has had the side-effect of occupying most of my spare time preparing, testing, and monitoring.  However, I do have this Little Wonder tidbit to offer today. Introduction The IComparable<T> interface is great for implementing a natural order for a data type.  It’s a very simple interface with a single method: 1: public interface IComparer<in T> 2: { 3: // Compare two instances of same type. 4: int Compare(T x, T y); 5: }  So what do we expect for the integer return value?  It’s a pseudo-relative measure of the ordering of x and y, which returns an integer value in much the same way C++ returns an integer result from the strcmp() c-style string comparison function: If x == y, returns 0. If x > y, returns > 0 (often +1, but not guaranteed) If x < y, returns < 0 (often –1, but not guaranteed) Notice that the comparison operator used to evaluate against zero should be the same comparison operator you’d use as the comparison operator between x and y.  That is, if you want to see if x > y you’d see if the result > 0. The Problem: Comparing With null Can Be Messy This gets tricky though when you have null arguments.  According to the MSDN, a null value should be considered equal to a null value, and a null value should be less than a non-null value.  So taking this into account we’d expect this instead: If x == y (or both null), return 0. If x > y (or y only is null), return > 0. If x < y (or x only is null), return < 0. But here’s the problem – if x is null, what happens when we attempt to call CompareTo() off of x? 1: // what happens if x is null? 2: x.CompareTo(y); It’s pretty obvious we’ll get a NullReferenceException here.  Now, we could guard against this before calling CompareTo(): 1: int result; 2:  3: // first check to see if lhs is null. 4: if (x == null) 5: { 6: // if lhs null, check rhs to decide on return value. 7: if (y == null) 8: { 9: result = 0; 10: } 11: else 12: { 13: result = -1; 14: } 15: } 16: else 17: { 18: // CompareTo() should handle a null y correctly and return > 0 if so. 19: result = x.CompareTo(y); 20: } Of course, we could shorten this with the ternary operator (?:), but even then it’s ugly repetitive code: 1: int result = (x == null) 2: ? ((y == null) ? 0 : -1) 3: : x.CompareTo(y); Fortunately, the null issues can be cleaned up by drafting in an external Comparer.  The Soltuion: Comparer<T>.Default You can always develop your own instance of IComparer<T> for the job of comparing two items of the same type.  The nice thing about a IComparer is its is independent of the things you are comparing, so this makes it great for comparing in an alternative order to the natural order of items, or when one or both of the items may be null. 1: public class NullableIntComparer : IComparer<int?> 2: { 3: public int Compare(int? x, int? y) 4: { 5: return (x == null) 6: ? ((y == null) ? 0 : -1) 7: : x.Value.CompareTo(y); 8: } 9: }  Now, if you want a custom sort -- especially on large-grained objects with different possible sort fields -- this is the best option you have.  But if you just want to take advantage of the natural ordering of the type, there is an easier way.  If the type you want to compare already implements IComparable<T> or if the type is System.Nullable<T> where T implements IComparable, there is a class in the System.Collections.Generic namespace called Comparer<T> which exposes a property called Default that will create a singleton that represents the default comparer for items of that type.  For example: 1: // compares integers 2: var intComparer = Comparer<int>.Default; 3:  4: // compares DateTime values 5: var dateTimeComparer = Comparer<DateTime>.Default; 6:  7: // compares nullable doubles using the null rules! 8: var nullableDoubleComparer = Comparer<double?>.Default;  This helps you avoid having to remember the messy null logic and makes it to compare objects where you don’t know if one or more of the values is null. This works especially well when creating say an IComparer<T> implementation for a large-grained class that may or may not contain a field.  For example, let’s say you want to create a sorting comparer for a stock open price, but if the market the stock is trading in hasn’t opened yet, the open price will be null.  We could handle this (assuming a reasonable Quote definition) like: 1: public class Quote 2: { 3: // the opening price of the symbol quoted 4: public double? Open { get; set; } 5:  6: // ticker symbol 7: public string Symbol { get; set; } 8:  9: // etc. 10: } 11:  12: public class OpenPriceQuoteComparer : IComparer<Quote> 13: { 14: // Compares two quotes by opening price 15: public int Compare(Quote x, Quote y) 16: { 17: return Comparer<double?>.Default.Compare(x.Open, y.Open); 18: } 19: } Summary Defining a custom comparer is often needed for non-natural ordering or defining alternative orderings, but when you just want to compare two items that are IComparable<T> and account for null behavior, you can use the Comparer<T>.Default comparer generator and you’ll never have to worry about correct null value sorting again.     Technorati Tags: C#,.NET,Little Wonders,BlackRabbitCoder,IComparable,Comparer

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  • Common SOA Problems by C2B2

    - by JuergenKress
    SOA stands for Service Oriented Architecture and has only really come together as a concrete approach in the last 15 years or so, although the concepts involved have been around for longer. Oracle SOA Suite is based around the Service Component Architecture (SCA) devised by the Open SOA collaboration of companies including Oracle and IBM. SCA, as used in SOA suite, is designed as a way to crystallise the concepts of SOA into a standard which ensures that SOA principles like the separation of application and business logic are maintained. Orchestration or Integration? A common thing to see with many people who are beginning to either build a new SOA based infrastructure, or move an old system to be service oriented, is confusion in the purpose of SOA technologies like BPEL and enterprise service buses. For a lot of problems, orchestration tools like BPEL or integration tools like an ESB will both do the job and achieve the right objectives; however it’s important to remember that, although a hammer can be used to drive a screw into wood, that doesn’t mean it’s the best way to do it. Service Integration is the act of connecting components together at a low level, which usually results in a single external endpoint for you to expose to your customers or other teams within your organisation – a simple product ordering system, for example, might integrate a stock checking service and a payment processing service. Process Orchestration, however, is generally a higher level approach whereby the (often externally exposed) service endpoints are brought together to track an end-to-end business process. This might include the earlier example of a product ordering service and couple it with a business rules service and human task to handle edge-cases. A good (but not exhaustive) rule-of-thumb is that integrations performed by an ESB will usually be real-time, whereas process orchestration in a SOA composite might comprise processes which take a certain amount of time to complete, or have to wait pending manual intervention. BPEL vs BPMN For some, with pre-existing SOA or business process projects, this decision is effectively already made. For those embarking on new projects it’s certainly an important consideration for those using Oracle SOA software since, due to the components included in SOA Suite and BPM Suite, the choice of which to buy is determined by what they offer. Oracle SOA suite has no BPMN engine, whereas BPM suite has both a BPMN and a BPEL engine. SOA suite has the ESB component “Mediator”, whereas BPM suite has none. Decisions must be made, therefore, on whether just one or both process modelling languages are to be used. The wrong decision could be costly further down the line. Design for performance: Read the complete article here. SOA & BPM Partner Community For regular information on Oracle SOA Suite become a member in the SOA & BPM Partner Community for registration please visit www.oracle.com/goto/emea/soa (OPN account required) If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Facebook Wiki Technorati Tags: C2B2,SOA best practice,SOA Community,Oracle SOA,Oracle BPM,Community,OPN,Jürgen Kress

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