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  • How to I serialize a large graph of .NET object into a SQL Server BLOB without creating a large bu

    - by Ian Ringrose
    We have code like: ms = New IO.MemoryStream bin = New System.Runtime.Serialization.Formatters.Binary.BinaryFormatter bin.Serialize(ms, largeGraphOfObjects) dataToSaveToDatabase = ms.ToArray() // put dataToSaveToDatabase in a Sql server BLOB But the memory steam allocates a large buffer from the large memory heap that is giving us problems. So how can we stream the data without needing enough free memory to hold the serialized objects. I am looking for a way to get a Stream from SQL server that can then be passed to bin.Serialize() so avoiding keeping all the data in my processes memory. Likewise for reading the data back... Some more background. This is part of a complex numerical processing system that processes data in near real time looking for equipment problems etc, the serialization is done to allow a restart when there is a problem with data quality from a data feed etc. (We store the data feeds and can rerun them after the operator has edited out bad values.) Therefore we serialize the object a lot more often then we de-serialize them. The objects we are serializing include very large arrays mostly of doubles as well as a lot of small “more normal” objects. We are pushing the memory limit on a 32 bit system and make the garage collector work very hard. (Effects are being made elsewhere in the system to improve this, e.g. reusing large arrays rather then create new arrays.) Often the serialization of the state is the last straw that courses an out of memory exception; our peak memory usage is while this serialization is being done. I think we get large memory pool fragmentation when we de-serialize the object, I expect there are also other problem with large memory pool fragmentation given the size of the arrays. (This has not yet been investigated, as the person that first looked at this is a numerical processing expert, not a memory management expert.) Are customers use a mix of Sql Server 2000, 2005 and 2008 and we would rather not have different code paths for each version of Sql Server if possible. We can have many active models at a time (in different process, across many machines), each model can have many saved states. Hence the saved state is stored in a database blob rather then a file. As the spread of saving the state is important, I would rather not serialize the object to a file, and then put the file in a BLOB one block at a time. Other related questions I have asked How to Stream data from/to SQL Server BLOB fields? Is there a SqlFileStream like class that works with Sql Server 2005?

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  • What is the equivalent to Java's canvas object in C#?

    - by Winston
    I'm working on creating a basic application that will let a user draw (using a series of points) and I plan to do something with these points. If this were Java, I think I would probably use a canvas object and some Java2D calls to draw what I want. All the tutorials I've read on C#/Drawing involve writing your own paint method and adding it to the paint event for the form. However, I'm interested in having some traditional Form controls as well and I don't want to be drawing over them. So, is there a "Canvas" object where I can constrain what I'm drawing on? Also, is WinForms a poor choice given this use case? Would WPF have more features that would help enable me to do what I want? Or Silverlight?

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  • Is there a better way to create an object-oriented class with jquery?

    - by Devon
    I use the jquery extend function to extend a class prototype. For example: MyWidget = function(name_var) { this.init(name_var); } $.extend(MyWidget.prototype, { // object variables widget_name: '', init: function(widget_name) { // do initialization here this.widget_name = widget_name; }, doSomething: function() { // an example object method alert('my name is '+this.widget_name); } }); // example of using the class built above var widget1 = new MyWidget('widget one'); widget1.doSomething(); Is there a better way to do this? Is there a cleaner way to create the class above with only one statement instead of two?

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  • How to handle optional variables of an object in Java?

    - by Arvanem
    Hi folks, For my trading program, I have a Merchant class. A given Merchant object may or may not have a particular special quality or bundle of special qualities. For example, one Merchant object may have the Stockbroker quality, another Merchant may have the Financial Services and Stockbroker qualities, and another Merchant may have no special qualities at all. My initial thought was to create a HashMap and a Qualities class as follows: Map<Qualities, Boolean> merchantQualities = new HashMap<Qualities, Boolean>(); The only problem is, there are at least 50 possible special qualities for Merchants, such that it would be extremely tiresome to subclass all the qualities from the Quality class. Is there a better way of coding for these optional special qualities and representing them in the Merchants class than a HashMap and subclassing a Qualities class?

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  • Javascript: addClassName if input is checked and removeClassName if it was un-checked

    - by BoDiE2003
    Im trying to select all the li tags of the document and check if it hasClassName('yes') so if it has, it will remove it. But im having a TypeError: Object [object HTMLLIElement], has no method 'hasClassName' error. This is the DOM method: document.observe("dom:loaded", function() { $(document.body).select('input').each(function(element) { element.observe('click', function() { init(); }); init(); }); }); The previous code will take the init fuction and check the if there are checked inputs and add them the 'yes' class name, but if I un-check those inputs, the class remains. This is the funcion that Im trying to do dynamic (add and remove class 'yes'); function init() { $(document.body).select('input').each(function(element) { if (element.checked) { element.up('li').addClassName('yes'); } if ($(document.body).select('li').hasClassName('yes')) { element.removeClassName('yes'); } }) } Can you help me solving the last part of this function, so the removeclassname method will work? Thank you

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  • How to convert an arbitrary object to String with JSTL? (calling toString())

    - by hstoerr
    Is there any way to call toString() on an object with the JSTL? (I need the String representation of an enum as index in a map in a JSP EL expression.) I hoped something like ${''+object} would work like in java, but JSTL isn't that nice, and there does not seem to be any function that does it. Clarification: I have a variable somemap that maps Strings to Strings, and I have a variable someenum that is an enumeration. I'd like to do something like ${somemap[someenum.toString()]}. (Of course .toString() does not work, but what does?)

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  • Changing property type in class that implements interface with object type property.

    - by used2could
    I know the title is a bit confusing but bare with me. (I'm up for suggestions on a new title lol) I'm writing a TemplateEngine that will allow me to use my own markup in text based files. I'm wanting to add controls as plugins as the application matures. Currently i've got a structure like the following: interface IControl string Id object Value class Label : IControl string Id string Value class Repeater : IControl string Id List<IControl> Value Now you'll see the strange part right away in the Repeater class with the Value property. I was hoping that having the Value type as object in the interface would allow me the flexibility to expand the controls as i go along. The compiler doesn't like this and for good reason i guess. Does anyone have any suggestions how to accomplish this? Note: Please don't go into suggesting things like use Spark View Engine for templating. There is a reason i'm creating extra work for myself.

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  • Another serialization ? - c#

    - by ltech
    I had asked this Yesterday If my xsd schema changes to <xs:element name="Document" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="MetaDoc" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="ATTRIBUTES" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="author" type="xs:string" minOccurs="0" /> <xs:element name="max_versions" type="xs:string" minOccurs="0" /> <xs:element name="summary" type="xs:string" minOccurs="0" /> </xs:sequence> </xs:complexType> </xs:element> </xs:sequence> </xs:complexType> </xs:element> </xs:sequence> </xs:complexType> </xs:element> My xsd - class generation becomes /// <remarks/> [System.Xml.Serialization.XmlArrayAttribute(Form=System.Xml.Schema.XmlSchemaForm.Unqualified)] [System.Xml.Serialization.XmlArrayItemAttribute("MetaDoc", typeof(DocumentMetaDocATTRIBUTES[]), Form=System.Xml.Schema.XmlSchemaForm.Unqualified, IsNullable=false)] [System.Xml.Serialization.XmlArrayItemAttribute("ATTRIBUTES", typeof(DocumentMetaDocATTRIBUTES), Form=System.Xml.Schema.XmlSchemaForm.Unqualified, IsNullable=false, NestingLevel=1)] public DocumentMetaDocATTRIBUTES[][][] Document { get { return this.documentField; } set { this.documentField = value; } } If I am deriving to CollectionBase, as shown in my previous post, how would I manage the XmlArrayItemAttribute ? so that I can read this part of my input xml into my strongly types object <Document> <MetaDoc> <ATTRIBUTES> <author>asas</author> <max_versions>1</max_versions> <summary>aasasqqqq</summary> </ATTRIBUTES> </MetaDoc> </Document>

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  • Call HttpWebRequest in another thread as UI with Task class - avoid to dispose object created in Task scope

    - by John
    I would like call HttpWebRequest on another thread as UI, because I must make 200 request or server and downloaded image. My scenation is that I make a request on server, create image and return image. This I make in another thread. I use Task class, but it call automaticaly Dispose method on all object created in task scope. So I return null object from this method. public BitmapImage CreateAvatar(Uri imageUri, int sex) { if (imageUri == null) return CreateDefaultAvatar(sex); BitmapImage image = null; new Task(() => { var request = WebRequest.Create(imageUri); var response = request.GetResponse(); using (var stream = response.GetResponseStream()) { Byte[] buffer = new Byte[response.ContentLength]; int offset = 0, actuallyRead = 0; do { actuallyRead = stream.Read(buffer, offset, buffer.Length - offset); offset += actuallyRead; } while (actuallyRead > 0); image = new BitmapImage { CreateOptions = BitmapCreateOptions.None, CacheOption = BitmapCacheOption.OnLoad }; image.BeginInit(); image.StreamSource = new MemoryStream(buffer); image.EndInit(); image.Freeze(); } }).Start(); return image; } How avoid it? Thank Mr. Jon Skeet try this: private Stream GetImageStream(Uri imageUri) { Byte[] buffer = null; //new Task(() => //{ var request = WebRequest.Create(imageUri); var response = request.GetResponse(); using (var stream = response.GetResponseStream()) { buffer= new Byte[response.ContentLength]; int offset = 0, actuallyRead = 0; do { actuallyRead = stream.Read(buffer, offset, buffer.Length - offset); offset += actuallyRead; } while (actuallyRead > 0); } //}).Start(); return new MemoryStream(buffer); } It return object which is null a than try this: private Stream GetImageStream(Uri imageUri) { Byte[] buffer = null; new Task(() => { var request = WebRequest.Create(imageUri); var response = request.GetResponse(); using (var stream = response.GetResponseStream()) { buffer= new Byte[response.ContentLength]; int offset = 0, actuallyRead = 0; do { actuallyRead = stream.Read(buffer, offset, buffer.Length - offset); offset += actuallyRead; } while (actuallyRead > 0); } }).Start(); return new MemoryStream(buffer); } Method above return null

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  • Is an IQueryable a query or just an object which can be queried?

    - by Albic
    I'm kinda confused what the IQueryable interface actually represents. The MSDN documentation for IQueryable says: "Provides functionality to evaluate queries against a specific data source." The documentation for IQueryProvider says: "Defines methods to create and execute queries that are described by an IQueryable object." The name and the documentation summary suggest that it is an object/data store which can be queried. The second quote and the fact the ObjectQuery class from the Entity Framework implements IQueryable suggest it is a query which can be executed. Did I misunderstood something or is it really kinda fuzzy?

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  • MongoDB RSS Feed Entries, Embed the Entries in the Feed Object?

    - by Patrick Klingemann
    I am saving a reference to an RSS Feed in MongoDB, each Feed has an ever growing list of Entries. As I'm designing my schema, I'm concerned about this statement from the MongoDB Schema Design - Embed vs. Reference Documentation: If the amount of data to embed is huge (many megabytes), you may read the limit on size of a single object. This will surely happen if I understand the statement correctly. So the question is, I am correct to assume that I should not embed the Feed Entries within a Feed because I'll eventually reach the limit on size of a single object?

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  • How to activate a solution in SharePoint 2010 using client object model?

    - by Boris
    Here's the situation: I have a customized SharePoint2010 site created. I saved that site as a site template, which has created a solution. I want to be able to activate that solution using SharePoint2010 client object model. Is that possible? If yes, could you show me how to do it? If no, then could you show me how it can be done using standard SharePoint object model, or any other method? Thank you for all the help.

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  • Can I mix static and shared-object libraries when linking?

    - by SiegeX
    I have a C project that produces ten executables, all of which I would like to be statically linked. The problem I am facing is that one of these executables uses a 3rd-party library of which only the shared-object version is available. If I pass the -static flag to gcc, ld will error saying it can't find the library in question (I presume it's looking for the .a version) and the executable will not be built. Ideally, I would like to be able to tell 'ld' to statically link as much as it can and fail over to the shared object library if a static library cannot be found. In the interium I tried something like gcc -static -lib1 -lib2 -shared -lib3rdparty foo.c -o foo.exe in hopes that 'ld' would statically link in lib1 and lib2 but only have a run-time dependence on lib3rdparty. Unfortunatly, this did not work as I intended; instead the -shared flag overwrote the -static flag and everything was compiled as shared-objects. Is statically linking an all-or-nothing deal, or is there some way I can mix and match?

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  • QtScript: Passing an array of objects to C++

    - by Plow
    Hi, I want to pass an array of objects from my QtScript to C++ but I have not been able to figure out how to achieve this. As soon as I create an array, the elements inside it are converted to strings before I can access them. This is what I have been trying so far: class myObject : public QObject, public QScriptable { Q_OBJECT public Q_SLOTS: void test(QVariantList list); }; void myObject::test(QVariantList list) { for (QVariantList::const_iterator it = list.begin(); it != list.end(); ++it) { QVariant element = *it; qDebug() << "List element type: " << element.typeName(); if (element.canConvert<QVariantMap>()) { // Not getting here } } } The following script myObject.test([{"foo": 1, "bar": 2}, {"baaz": 3, "baaaz": 4}]); prints List element type: "QString" List element type: "QString" I am using Qt 4.6...

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  • Question about [Pure] methods

    - by devoured elysium
    Is the following method Pure? I'd say so, as it doesn't change in anyway the current class, thus, everything we can now currenly "see" in the class, before running this method will still be exactly the same after. Am I correct? class Set { ... public ISet<T> UnionWith(ISet<T> set) { ISet<T> unionSet = ... foreach (Element element in this) { unionSet.Add(element); } foreach (Element element in set) { unionSet.Add(element); } return unionSet; } }

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  • Can an Excel VBA UDF called from the worksheet ever be passed an instance of any Excel VBA object mo

    - by jtolle
    I'm 99% sure that the answer is "no", but I'm wondering if someone who is 100% sure can say so. Consider a VBA UDF: Public Function f(x) End Function When you call this from the worksheet, 'x' will be a number, string, boolean, error, array, or object of type 'Range'. Can it ever be, say, an instance of 'Chart', 'ListObject', or any other Excel-VBA object model class? (The question arose from me moving to Excel 2007 and playing with Tables, and wondering if I could write UDFs that accept them as parameters instead of Ranges. The answer to that seems to be no, but then I realized I didn't know for sure in general.)

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  • Why is activeX failing to create an object from a Labview executable?

    - by user360734
    Here is my scenario. I am using Quicktest Pro (VB) to create an ActiveX object from a Labview VI that I built into an executable. In the build specs of the VI I have enabled ActiveX server option (ActiveX server name: "MyLabviewProgram") and in the VI ToolsOptionsVI Server: Configuration the ActiveX box is checked. So in QTP my code is: Set IvApp = CreateObject("MyLabviewProgram.Application") Set Vi = IvApp.getVIReference("MyLabviewVI.vi") Vi.Call ParamNames, ParamVals Upon running this I get a Run Error on the first line: ActiveX component can't create object: 'MyLabviewProgram.Application' I am having trouble figuring out why it errors. From National Instruments website they have a step in on one of their community pages about "LabVIEW Executable Used as ActiveX Server". The step is after building the EXE, 5. Run the EXE at least once on the target to activate the .TLB file. I've run the executable but not sure what they mean by on the target. Does anyone have a suggestion on what I need to do to get this working?

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  • Copy all childNodes to an other element. In javascript native way.

    - by kroko
    Hello I have to change "unknown" contents of XML. The structure and content itself is valid. Original <blabla foo="bar"> <aa>asas</aa> <ff> <cc> <dd /> </cc> </ff> <gg attr2="2"> </gg> ... ... </blabla> becomes <blabla foo="bar"> <magic> <aa>asas</aa> <ff> <cc> <dd /> </cc> </ff> <gg attr2="2"> </gg> ... ... </magic> </blabla> thus, adding a child straight under document root node (document.documentElement) and "pushing" the "original" children under that. Here it has to be done in plain javascript (ecmascript). The idea now is to // Get the root node RootNode = mymagicdoc.documentElement; // Create new magic element (that will contain contents of original root node) var magicContainer = mymagicdoc.createElement("magic"); // Copy all root node children (and their sub tree - deep copy) to magic node /* ????? here RootNodeClone = RootNode.cloneNode(true); RootNodeClone.childNodes...... */ // Remove all children from root node while(RootNode.hasChildNodes()) RootNode.removeChild(RootNode.firstChild); // Now when root node is empty add the magicContainer // node in it that contains all the children of original root node RootNode.appendChild(magicContainer); How to do that /* */ step? Or maybe someone has a much better solution in general for achieving the desirable result? Thank you in advance!

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  • How should I delete a child object from within a parent's slot? Possibly boost::asio specific.

    - by kaliatech
    I have written a network server class that maintains a std::set of network clients. The network clients emit a signal to the network server on disconnect (via boost::bind). When a network client disconnects, the client instance needs to be removed from the Set and eventually deleted. I would think this is a common pattern, but I am having problems that might, or might not, be specific to ASIO. I've tried to trim down to just the relevant code: /** NetworkServer.hpp **/ class NetworkServices : private boost::noncopyable { public: NetworkServices(void); ~NetworkServices(void); private: void run(); void onNetworkClientEvent(NetworkClientEvent&); private: std::set<boost::shared_ptr<const NetworkClient>> clients; }; /** NetworkClient.cpp **/ void NetworkServices::run() { running = true; boost::asio::io_service::work work(io_service); //keeps service running even if no operations // This creates just one thread for the boost::asio async network services boost::thread iot(boost::bind(&NetworkServices::run_io_service, this)); while (running) { boost::system::error_code err; try { tcp::socket* socket = new tcp::socket(io_service); acceptor->accept(*socket, err); if (!err) { NetworkClient* networkClient = new NetworkClient(io_service, boost::shared_ptr<tcp::socket>(socket)); networkClient->networkClientEventSignal.connect(boost::bind(&NetworkServices::onNetworkClientEvent, this, _1)); clients.insert(boost::shared_ptr<NetworkClient>(networkClient)); networkClient->init(); //kicks off 1st asynch_read call } } // etc... } } void NetworkServices::onNetworkClientEvent(NetworkClientEvent& evt) { switch(evt.getType()) { case NetworkClientEvent::CLIENT_ERROR : { boost::shared_ptr<const NetworkClient> clientPtr = evt.getClient().getSharedPtr(); // ------ THIS IS THE MAGIC LINE ----- // If I keep this, the io_service hangs. If I comment it out, // everything works fine (but I never delete the disconnected NetworkClient). // If actually deleted the client here I might expect problems because it is the caller // of this method via boost::signal and bind. However, The clientPtr is a shared ptr, and a // reference is being kept in the client itself while signaling, so // I would the object is not going to be deleted from the heap here. That seems to be the case. // Never-the-less, this line makes all the difference, most likely because it controls whether or not the NetworkClient ever gets deleted. clients.erase(clientPtr); //I should probably put this socket clean-up in NetworkClient destructor. Regardless by doing this, // I would expect the ASIO socket stuff to be adequately cleaned-up after this. tcp::socket& socket = clientPtr->getSocket(); try { socket.shutdown(boost::asio::socket_base::shutdown_both); socket.close(); } catch(...) { CommServerContext::error("Error while shutting down and closing socket."); } break; } default : { break; } } } /** NetworkClient.hpp **/ class NetworkClient : public boost::enable_shared_from_this<NetworkClient>, Client { NetworkClient(boost::asio::io_service& io_service, boost::shared_ptr<tcp::socket> socket); virtual ~NetworkClient(void); inline boost::shared_ptr<const NetworkClient> getSharedPtr() const { return shared_from_this(); }; boost::signal <void (NetworkClientEvent&)> networkClientEventSignal; void onAsyncReadHeader(const boost::system::error_code& error, size_t bytes_transferred); }; /** NetworkClient.cpp - onAsyncReadHeader method called from io_service.run() thread as result of an async_read operation. Error condition usually result of an unexpected client disconnect.**/ void NetworkClient::onAsyncReadHeader( const boost::system::error_code& error, size_t bytes_transferred) { if (error) { //Make sure this instance doesn't get deleted from parent/slot deferencing //Alternatively, somehow schedule for future delete? boost::shared_ptr<const NetworkClient> clientPtr = getSharedPtr(); //Signal to service that this client is disconnecting NetworkClientEvent evt(*this, NetworkClientEvent::CLIENT_ERROR); networkClientEventSignal(evt); networkClientEventSignal.disconnect_all_slots(); return; } I believe it's not safe to delete the client from within the slot handler because the function return would be ... undefined? (Interestingly, it doesn't seem to blow up on me though.) So I've used boost:shared_ptr along with shared_from_this to make sure the client doesn't get deleted until all slots have been signaled. It doesn't seem to really matter though. I believe this question is not specific to ASIO, but the problem manifests in a peculiar way when using ASIO. I have one thread executing io_service.run(). All ASIO read/write operations are performed asynchronously. Everything works fine with multiple clients connecting/disconnecting UNLESS I delete my client object from the Set per the code above. If I delete my client object, the io_service seemingly deadlocks internally and no further asynchronous operations are performed unless I start another thread. I have try/catches around the io_service.run() call and have not been able to detect any errors. Questions: Are there best practices for deleting child objects, that are also signal emitters, from within parent slots? Any ideas as to why the io_service is hanging when I delete my network client object?

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  • Unable to serialize correctly- c#

    - by ltech
    I had asked this Yesterday If my xsd schema changes to <xs:element name="Document" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="MetaDoc" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="ATTRIBUTES" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="author" type="xs:string" minOccurs="0" /> <xs:element name="max_versions" type="xs:string" minOccurs="0" /> <xs:element name="summary" type="xs:string" minOccurs="0" /> </xs:sequence> </xs:complexType> </xs:element> </xs:sequence> </xs:complexType> </xs:element> </xs:sequence> </xs:complexType> </xs:element> My xsd - class generation becomes /// <remarks/> [System.Xml.Serialization.XmlArrayAttribute(Form=System.Xml.Schema.XmlSchemaForm.Unqualified)] [System.Xml.Serialization.XmlArrayItemAttribute("MetaDoc", typeof(DocumentMetaDocATTRIBUTES[]), Form=System.Xml.Schema.XmlSchemaForm.Unqualified, IsNullable=false)] [System.Xml.Serialization.XmlArrayItemAttribute("ATTRIBUTES", typeof(DocumentMetaDocATTRIBUTES), Form=System.Xml.Schema.XmlSchemaForm.Unqualified, IsNullable=false, NestingLevel=1)] public DocumentMetaDocATTRIBUTES[][][] Document { get { return this.documentField; } set { this.documentField = value; } } If I am deriving to CollectionBase, as shown in my previous post, how would I manage the XmlArrayItemAttribute ? so that I can read this part of my input xml into my strongly types object <Document> <MetaDoc> <ATTRIBUTES> <author>asas</author> <max_versions>1</max_versions> <summary>aasasqqqq</summary> </ATTRIBUTES> </MetaDoc> </Document>

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  • REXML Formatting issues

    - by dagda1
    Hi, I am using REXML to edit an xml file but have ran into difficulties with formatting. My original code looked like this: file = File.new( destination) doc = REXML::Document.new file doc.elements.each("configuration/continuity2") do |element| element.attributes["islive"] = "true" element.attributes["pagetitle"] = "#{@client.page_title}" element.attributes["clientname"] = "#{@client.name}" end doc.elements.each("configuration/continuity2/plans") do |element| element.attributes["storebasedir"] = "#{@client.store_dir}" end I first of all had to add the following code as REXML was adding single quotes instead of double quotes. I found the following via google: REXML::Attribute.class_eval( %q^ def to_string %Q[#@expanded_name="#{to_s().gsub(/"/, '&quot;')}"] end ^ ) I also have a problem in that REXML is reformatting the document. are there ways to stop this? Cheers Paul

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  • Why an object declared in method is subject to garbage collection before the method returns?

    - by SiLent SoNG
    Consider an object declared in a method: public void foo() { final Object obj = new Object(); // A long run job that consumes tons of memory and // triggers garbage collection } Will obj be subject to garbage collection before foo() returns? UPDATE: Previously I thought obj is not subject to garbage collection until foo() returns. However, today I find myself wrong. I have spend several hours in fixing a bug and finally found the problem is caused by obj garbage collected! Can anyone explain why this happens? And if I want obj to be pinned how to achieve it? Here is the code that has problem. public class Program { public static void main(String[] args) throws Exception { String connectionString = "jdbc:mysql://<whatever>"; // I find wrap is gc-ed somewhere SqlConnection wrap = new SqlConnection(connectionString); Connection con = wrap.currentConnection(); Statement stmt = con.createStatement(ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY); stmt.setFetchSize(Integer.MIN_VALUE); ResultSet rs = stmt.executeQuery("select instance_id, doc_id from crawler_archive.documents"); while (rs.next()) { int instanceID = rs.getInt(1); int docID = rs.getInt(2); if (docID % 1000 == 0) { System.out.println(docID); } } rs.close(); //wrap.close(); } } After running the Java program, it will print the following message before it crashes: 161000 161000 ******************************** Finalizer CALLED!! ******************************** ******************************** Close CALLED!! ******************************** 162000 Exception in thread "main" com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: And here is the code of class SqlConnection: class SqlConnection { private final String connectionString; private Connection connection; public SqlConnection(String connectionString) { this.connectionString = connectionString; } public synchronized Connection currentConnection() throws SQLException { if (this.connection == null || this.connection.isClosed()) { this.closeConnection(); this.connection = DriverManager.getConnection(connectionString); } return this.connection; } protected void finalize() throws Throwable { try { System.out.println("********************************"); System.out.println("Finalizer CALLED!!"); System.out.println("********************************"); this.close(); } finally { super.finalize(); } } public void close() { System.out.println("********************************"); System.out.println("Close CALLED!!"); System.out.println("********************************"); this.closeConnection(); } protected void closeConnection() { if (this.connection != null) { try { connection.close(); } catch (Throwable e) { } finally { this.connection = null; } } } }

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  • MVC2 IModelBinder and parsing a string to an object - How do I do it?

    - by burnt_hand
    I have an object called Time public class Time{ public int Hour {get;set;} public int Minute {get;set;} public static Time Parse(string timeString){ //reads the ToString()'s previous output and returns a Time object } override protected string ToString(){ //puts out something like 14:50 (as in 2:50PM) } } So what I want is for the automatic model binding on the Edit or Create action to set this Time instance up from a string (i.e. feed the Parse method with the string and return the result). The reason I am doing this is that I will have a DropDownList with selectable times. The value of each option will be the parser readable string. Can anyone provide an example BindModel method from the IModelBinder interface?

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