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  • How does Garbage Collection in Java work?

    - by Bright010957
    I was wondering how the garbage collector in Java deals with the following situation. Object A has a reference to Object B and Object B has a reference to Object C. The main program has a reference to Object A. So you can use Object B trough Object A, and Object C trough Object B trough Object A. What happens to Object B and Object C, if the link between Object A and Object B is set to null? Should Object B and Object C now been collected by the Garbage Collector? I mean there is still a connection between Object B and Object C.

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  • How to implement Object Databases in Asp.net MVC(c#)

    - by amexn
    I started my project in Asp.net MVC(c#) & MSSQL 2005.I want to implement Object Databases in my project. While searched in google i found "MongoDb" I didn't have enough knowledge in Object Databases & which one best suited for MSSQL 2005. Please suggest a good example/reference regarding Object Databases implementation in Asp.net MVC application

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  • doctrine findby relation

    - by iggnition
    I'm having trouble selecting a subset of data with doctrine. I have 3 tables Location Contact Contact_location The contact and location tables hold a name and an id the other table holds only ID's. For instance: Location loc_id: 1 name: detroit Contact contact_id: 1 name: Mike Contact_location loc_id: 1 contact_id: 1 In doctrine there is a many to many relation between the location and contact tables with contact_location as the ref_class. What i want to do is on my location page i want to find all contacts where for instance the loc_id = 1. I tried: $this->installedbases = Doctrine::getTable('contact')->findByloc_id(1); hoping doctrine would see the relation and get it, but it does not. How can i make doctrine search in relevant related tables? I read it can be done using Findby but i find the documentation unclear.

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  • Git: corrupt loose object

    - by NeoRiddle
    I was trying to merge my master branch with another one called pull-stage, but Git throws me this error: error: inflate: data stream error (invalid distance too far back) error: corrupt loose object '5a63450f4a0b72abbc1221ccb7d9f9bfef333250' fatal: loose object 5a63450f4a0b72abbc1221ccb7d9f9bfef333250 (stored in .git/objects/5a/63450f4a0b72abbc1221ccb7d9f9bfef333250) is corrupt How can I solve this issue? I have reviewed other posts, but with no successful results: How to replace corrupt Git objects with new ones created from my files, which are fine Git: "Corrupt loose object" Corrupted Git Repository (data stream error)

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  • Database structure - To join or not to join

    - by Industrial
    Hi! We're drawing up the database structure with the help of mySQL Workbench for a new app and the number of joins required to make a listing of the data is increasing drastically as the many-to-many relationships increases. The application will be quite read-heavy and have a couple of hundred thousand rows per table. The questions: Is it really that bad to merge tables where needed and thereby reducing joins? Should we start looking at horizontal partitioning? (in conjunction with merging tables) Is there a better way then pivot tables to take care of many-to-many relationships? We discussed about instead storing all data in serialized text columns and having the application make the sorting instead of the database, but this seems like a very bad idea, even though that the database will be heavily cached. What do you think? Thanks!

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  • Accessing an object's fields without an active session

    - by Dave
    I'm using Hibernate 4.0.1.Final. Is it possible to access an object's fields if that object has been loaded via the org.hibernate.Session.load(Class clazz, Serializable id) method and there is no active session? I use this code to access an object by id … protected Object find(Class clazz, Serializable id) { Object obj = null; try { startOperation(); obj = session.load(clazz, id); tx.commit(); } catch (HibernateException e) { handleException(e); } finally { session.close(); } return obj; } but if I have that object without an active session, like with this code … final Organization foundOrg = orgDao.findById(org.getOrganizationId()); System.out.println(foundOrg.getName()); I get this error on the "System.out" line … org.hibernate.LazyInitializationException: could not initialize proxy - no Session at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:149) at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:195) at org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.invoke(JavassistLazyInitializer.java:185) at org.myco.myproject.orgsclient.model.Organization_$$_javassist_0.getName(Organization_$$_javassist_0.java) at org.myco.myproject.orgsclient.dao.OrganizationDAOTest.testInsertSchool(OrganizationDAOTest.java:43) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20) at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184) at org.junit.runners.ParentRunner.run(ParentRunner.java:236) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

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  • Groovy Prototype Object

    - by Holden
    I have a method with an incoming variable, which represents a script. e.g. hello.groovy Foo.init(this) Foo.groovy class Foo { static init(app) { } } What is the best way to add a ton of new functionality to the app variable in the init method? Basically, I would like to add all the functionality of another object to the app object. For instance, if I had another class: class Bar { def a() { } def b() { } } I would like the app object to basically be a new Bar(). In JavaScript, this is easy by using the prototype object, but I cannot seem to get it working in groovy. What is the best way to accomplish this? Or should I be doing something differently?

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  • How to use Object.GetHashCode() on a type that overrides GetHashCode()

    - by Jimmy
    Hi, I have a class A that implements IEquatable<, using its fields (say, A.b and A.c) for implementing/overriding Equals() and overriding GetHashCode(), and everything works fine, 99% of the time. Class A is part of a hierarchy (class B, C) that all inherit from interface D; they can all be stored together in a dictionary Dictionary, thus it's convenient when they all carry their own default Equals()/GetHashCode(). However, while constructing A I sometime need to do some work to get the values for A.b and A.c; while that's happening, I want to store a reference to the instance that's being built. In that case, I don't want to use the default Equals()/GetHashCode() overrides provided by A. Thus, I was thinking of implementing a ReferenceEqualityComparer, that's meant to force the use of Object's Equals()/GetHashCode(): private class ReferenceEqualityComparer<T> : IEqualityComparer<T> { #region IEqualityComparer<T> Members public bool Equals(T x, T y) { return System.Object.ReferenceEquals(x, y); } public int GetHashCode(T obj) { // what goes here? I want to do something like System.Object.GetHashCode(obj); } #endregion } The question is, since A overrides Object.GetHashCode(), how can I (outside of A) call Object.GetHashCode() for an instance of A? One way of course would be for A to not implement IEquatable< and always supply an IEqualityComparer< to any dictionary that I create, but I'm hoping for a different answer. Thanks

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  • Convert sqlalchemy row object to python dict

    - by Anurag Uniyal
    or a simple way to iterate over columnName, value pairs? My version of sqlalchemy is 0.5.6 Here is the sample code where I tried using dict(row), but it throws exception , TypeError: 'User' object is not iterable import sqlalchemy from sqlalchemy import * from sqlalchemy.ext.declarative import declarative_base from sqlalchemy.orm import sessionmaker print "sqlalchemy version:",sqlalchemy.__version__ engine = create_engine('sqlite:///:memory:', echo=False) metadata = MetaData() users_table = Table('users', metadata, Column('id', Integer, primary_key=True), Column('name', String), ) metadata.create_all(engine) class User(declarative_base()): __tablename__ = 'users' id = Column(Integer, primary_key=True) name = Column(String) def __init__(self, name): self.name = name Session = sessionmaker(bind=engine) session = Session() user1 = User("anurag") session.add(user1) session.commit() # uncommenting next line throws exception 'TypeError: 'User' object is not iterable' #print dict(user1) # this one also throws 'TypeError: 'User' object is not iterable' for u in session.query(User).all(): print dict(u) Running this code on my system outputs: sqlalchemy version: 0.5.6 Traceback (most recent call last): File "untitled-1.py", line 37, in <module> print dict(u) TypeError: 'User' object is not iterable

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  • How to test COM object integrity automatically?

    - by sharptooth
    Every COM object must have integrity. In simplified terms this means that if an object implements 3 interfaces - A, B and C and I have A* pointer to the object I must be able to successfully QueryInterface() both B and C and having B I must be able to retrieve A and C and having C I must be able to retrieve A and B. Now my object implements 5 interfaces and I want to test its integrity. Writing checks for all of the above myself will require a substantial effort. Is there a tool or some easily tweakable code or a code pattern that would do it?

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  • Building big, immutable objects without constructors having long parameter lists

    - by Malax
    Hi StackOverflow! I have some big (more than 3 fields) Objects which can and should be immutable. Every time I run into that case i tend to create constructor abominations with long parameter lists. It doesn't feel right, is hard to use and readability suffers. It is even worse if the fields are some sort of collection type like lists. A simple addSibling(S s) would ease the object creation so much but renders the object mutable. What do you guys use in such cases? I'm on Scala and Java, but i think the problem is language agnostic as long as the language is object oriented. Solutions I can think of: "Constructor abominations with long parameter lists" The Builder Pattern Thanks for your input!

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  • mysql Delete and Database Relationships

    - by Colin
    If I'm trying to delete multiple rows from a table and one of those rows can't be deleted because of a database relationship, what will happen? Will the rows that aren't constrained by a relationship still be deleted? Or will the entire delete fail? Thanks, Colin

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  • SqlCommandBuilder.DeriveParameters(command) and IsNullable

    - by Andrey
    I have written an O/R database wrapper that generates some wrapper methods for stored procs it reads from the database. Now I need to produce some custom wrapper code if an input parameter of a stored proc is defaulted to NULL. The problem is - I get stored proc parameters using: SqlCommandBuilder.DeriveParameters(command) and it doesn't bring parameter defaults. Is there any way to look up those defaults? Are they stored anywhere in the database? BTW, I'm using SQL Server 2008

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  • How to troubleshoot deallocation of object in uitableview?

    - by 4thSpace
    I have a table view with tall cells. About 300 in height. The cells are custom and have an associated nib. In cellForRowAtIndexPath, I access an object in an array using indexPath.row. The object has properties, which I assign to labels on the custom cell. This works fine for the first two cells. Once I scroll enough for the third cell to get created, the app crashes. I have NSZombieEnabled set and here is the output: 2010-04-19 21:48:13.360 MyApp[54463:207] *** -[CALayer release]: message sent to deallocated instance 0xfc4e50 (gdb) continue 2010-04-19 21:48:18.382 MyApp[54463:207] *** NSInvocation: warning: object 0xfc4e50 of class '_NSZombie_CALayer' does not implement methodSignatureForSelector: -- trouble ahead 2010-04-19 21:48:18.383 MyApp[54463:207] *** NSInvocation: warning: object 0xfc4e50 of class '_NSZombie_CALayer' does not implement doesNotRecognizeSelector: -- abort (gdb) continue Program received signal: “EXC_BAD_ACCESS”. (gdb) I'm not sure what is deallocated. How can I trace this to the source?

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  • iPhone JSON Object

    - by Cosizzle
    Hello, I'm trying to create a application that will retrieve JSON data from an HTTP request, send it to a the application main controller as a JSON object then from there do further processing with it. Where I'm stick is actually creating a class that will serve as a JSON class in which will take a URL, grab the data, and return that object. Alone, im able to make this class work, however I can not get the class to store the object for my main controller to retrieve it. Because im fairly new to Objective-C itself, my thoughts are that im messing up within my init call: -initWithURL:(NSString *) value { responseData = [[NSMutableData data] retain]; NSString *theURL = value; NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:theURL]]; [[NSURLConnection alloc] initWithRequest:request delegate:self]; return self; } The processing of the JSON object takes place here: - (void)connectionDidFinishLoading:(NSURLConnection *)connection { [connection release]; NSString *responseString = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding]; [responseData release]; NSError *jsonError; SBJSON *json = [[SBJSON new] autorelease]; NSDictionary *parsedJSON = [json objectWithString:responseString error:&jsonError]; // NSArray object. listings = [parsedJSON objectForKey:@"posts"]; NSEnumerator *enumerator = [listings objectEnumerator]; NSDictionary* item; // to prove that it does work. while (item = (NSDictionary*)[enumerator nextObject]) { NSLog(@"posts:id = %@", [item objectForKey:@"id"]); NSLog(@"posts:address = %@", [item objectForKey:@"address"]); NSLog(@"posts:lat = %@", [item objectForKey:@"lat"]); NSLog(@"posts:lng = %@", [item objectForKey:@"lng"]); } [responseString release]; } Now when calling the object within the main controller I have this bit of code in the viewDidLoad method call: - (void)viewDidLoad { [super viewDidLoad]; JSON_model *jsonObj = [[JSON_model alloc] initWithURL:@"http://localhost/json/faith_json.php?user=1&format=json"]; NSEnumerator *enumerator = [[jsonObj listings] objectEnumerator]; NSDictionary* item; // while (item = (NSDictionary*)[enumerator nextObject]) { NSLog(@"posts:id = %@", [item objectForKey:@"id"]); NSLog(@"posts:address = %@", [item objectForKey:@"address"]); NSLog(@"posts:lat = %@", [item objectForKey:@"lat"]); NSLog(@"posts:lng = %@", [item objectForKey:@"lng"]); } }

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  • Disassemble Microsoft Visual Studio 2003 compiler output

    - by Carl Norum
    I'm seeing what I think is strange behaviour from object files output by the Microsoft Visual Studio 2003 tools. The file utility tells me: asmfile.obj: 80386 COFF executable not stripped - version 30821 For objects created by the assembler, but for objects coming from C files, I get just: cfile.obj: data Using Microsoft's dumpbin utility and the objdump I got from cygwin, I can disassemble the assembly-built file, but I get no useful results from either utility for the C-built files. I have a couple of questions related to this difference: What is the object file format generated by the MSVC2003 compiler? How can I disassemble that object file? I am particularly interested in getting the disassembly in AT&T syntax - I'm doing a port of a large source base to make it work with GCC, and I would like to use this method as a shortcut for some of the inline assembly routines in the project. Thanks!

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  • ORM market analysis

    - by bonefisher
    I would like to see your experience with popular ORM tools outhere, like NHibernate, LLBLGen, EF, S2Q, Genom-e, LightSpeed, DataObjects.NET, OpenAccess, ... From my exp: - Genom-e is quiet capable of Linq & performance, dev support - EF lacks on some key features like lazy loading, Poco support, pers.ignorance... but in 4.o it may have overcome .. - DataObjects.Net so far good, althrough I found some bugs - NHibernate steep learning curve, no 100% Linq support (like in Genom-e and DataObjects.Net), but very supportive, extensible and mature

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  • Persist an object that is not marked as serializable

    - by lasseeskildsen
    Hi, I need to persist an object that is not marked with the serializable attribute. The object is from a 3rd party library which I cannot change. I need to store it in a persist place, like for example the file system, so the optimal solution would be to serialize the object to a file, but since it isn't marked as serializable, that is not a straight forward solution. It's a pretty complex object, which also holds a collection of other objects. Do you guys have any input on how to solve this? The code will never run in a production environment, so I'm ok with almost any solution and performance.

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  • mysql, sqlite database source code

    - by Yang
    hi guys, i know implementing database is a huge topic, but i want to have a basic understanding of how database systems works (e.g. memory management, binary tree, transaction, sql parsing, multi-threading, partitions, etc) by investigating the source code of the database, since there are a few already proven very robust open source databases like mysql, sqlite and so on. however, the code are very complicated and i have no clue where to start. also i find that the old school database textbooks are only explaining the theory, not the implementation details. Can anyone suggest how should i get started and is there any books that emphasis on the technology and techniques of building dbms used in modern database industry? Thank in advance!

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  • Can't find how to import as one object or how to merge

    - by Aaron
    I need write a script in blender that creates some birds which fly around some obstacles. The problem is that I need to import a pretty large Collada model (a building) which consists of multiple objects. The import works fine, but the the building is not seen as 1 object. I need to resize and move this building, but I can only get the last object in the building (which is a camera)... Does anyone know how to merge this building in 1 object, group, variable... so I can resize and move it correctly? Part of the code I used: bpy.ops.wm.collada_import(filepath="C:\\Users\\me\\building.dae") building= bpy.context.object building.scale = (100, 100, 100) building.name = "building"

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  • Building big, immutable objects without using constructors having long parameter lists

    - by Malax
    Hi StackOverflow! I have some big (more than 3 fields) Objects which can and should be immutable. Every time I run into that case i tend to create constructor abominations with long parameter lists. It doesn't feel right, is hard to use and readability suffers. It is even worse if the fields are some sort of collection type like lists. A simple addSibling(S s) would ease the object creation so much but renders the object mutable. What do you guys use in such cases? I'm on Scala and Java, but i think the problem is language agnostic as long as the language is object oriented. Solutions I can think of: "Constructor abominations with long parameter lists" The Builder Pattern Thanks for your input!

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