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  • how to increase or decrease the quantity in a field in my sql when we enter the new quantity

    - by madhu
    I'm doing a project I'm encountering a problem in my project......... the problem is i would like to increase or decrease the quantity in my sql quantity field when i pass the issued or delivered quantity i.e.... initially the quantity in the quantity filed is 1 when i intake the product of a quantity 10 then automatically it should update the quantity as 10+1=11 so it must update as 11, if i remove a 1 quantity it should update as 0........ how to write a code in jsp.......... pls do help

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  • SQL Reporting Services 2005 - Date field based on a user entered date?

    - by Pierce
    Hi, I have a report in report services 2005 that has two date fields. The problem is that if users run this for a large section of time it uses too much resources on our server. It is possible to only allow the end user to enter the start date and then the end date be auto populated/derived from this field (for example they enter the 1st of a month and this automatically change the end date to the last of a month.)

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  • Why cant i use the field user in SQL Server 8?

    - by acidzombie24
    Maybe not literally but the query below gets an error near user. If i change it to userZ it works. WHY can i not use that name? Is there a way to specific its a field instead of a keyword? (or whatever it is) create table Post2 ( id INTEGER PRIMARY KEY NOT NULL, title nvarchar(max) NOT NULL, body nvarchar(max) NOT NULL, user integer REFERENCES Post1(id));

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  • Missing Fields and Default Values

    - by PointsToShare
    © 2011 By: Dov Trietsch. All rights reserved Dealing with Missing Fields and Default Values New fields and new default values are not propagated throughout the list. They only apply to new and updated items and not to items already entered. They are only prospective. We need to be able to deal with this issue. Here is a scenario. The user has an old list with old items and adds a new field. The field is not created for any of the old items. Trying to get its value raises an Argument Exception. Here is another: a default value is added to a field. All the old items, where the field was not assigned a value, do not get the new default value. The two can also happen in tandem – a new field is added with a default. The older items have neither. Even better, if the user changes the default value, the old items still carry the old defaults. Let’s go a bit further. You have already written code for the list, be it an event receiver, a feature receiver, a console app or a command extension, in which you span all the fields and run on selected items – some new (no problem) and some old (problems aplenty). Had you written defensive code, you would be able to handle the situation, including similar changes in the future. So, without further ado, here’s how. Instead of just getting the value of a field in an item – item[field].ToString() – use the function below. I use ItemValue(item, fieldname, “mud in your eye”) and if “mud in your eye” is what I get, I know that the item did not have the field.   /// <summary> /// Return the column value or a default value /// </summary> private static string ItemValue(SPItem item, string column, string defaultValue) {     try     {         return item[column].ToString();     }     catch (NullReferenceException ex)     {         return defaultValue;     }     catch (ArgumentException ex)     {         return defaultValue;     } } I also use a similar function to return the default and a funny default-default to ascertain that the default does not exist. Here it is:  /// <summary> /// return a fields default or the "default" default. /// </summary> public static string GetFieldDefault(SPField fld, string defValue) {     try     {         // -- Check if default exists.         return fld.DefaultValue.ToString();     }     catch (NullReferenceException ex)     {         return defValue;     }     catch (ArgumentException ex)     {         return defValue;     } } How is this defensive? You have trapped an expected error and dealt with it. Therefore the program did not stop cold in its track and the required code ran to its end. Now, take a further step - write to a log (See Logging – a log blog). Read your own log every now and then, and act accordingly. That’s all Folks!

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  • With Eclipselink/JPA, can I have a Foreign Composite Key that shares a field with a Primary Composit

    - by user107924
    My database has two entities; Company and Person. A Company can have many People, but a Person must have only one Company. The table structure looks as follows. COMPANY ---------- owner PK comp_id PK c_name PERSON ---------------- owner PK, FK1 personid PK comp_id FK1 p_fname p_sname It has occurred to me that I could remove PERSON.OWNER and derive it through the foreign key; however, I can't make this change without affecting legacy code. I have modeled these as JPA-annotated classes; @Entity @Table(name = "PERSON") @IdClass(PersonPK.class) public class Person implements Serializable { @Id private String owner; @Id private String personid; @ManyToOne @JoinColumns( {@JoinColumn(name = "owner", referencedColumnName = "OWNER", insertable = false, updatable = false), @JoinColumn(name = "comp_id", referencedColumnName = "COMP_ID", insertable = true, updatable = true)}) private Company company; private String p_fname; private String p_sname; ...and standard getters/setters... } @Entity @Table(name = "COMPANY") @IdClass(CompanyPK.class) public class Company implements Serializable { @Id private String owner; @Id private String comp_id; private String c_name; @OneToMany(mappedBy = "company", cascade=CascadeType.ALL) private List people; ...and standard getters/setters... } My PersonPK and CompanyPK classes are nothing special, they just serve as a struct holding owner and the ID field, and override hashCode and equals(o). So far so good. I come across a problem, however, when trying to deal with associations. It seems if I have an existing Company, and create a Person, and associate to the Person to the Company and persist the company, the association is not saved when the Person is inserted. For example, my main code looks like this: EntityManager em = emf.createEntityManager(); em.getTransaction().begin(); CompanyPK companyPK = new CompanyPK(); companyPK.owner="USA"; companyPK.comp_id="1102F3"; Company company = em.find(Company.class, companyPK); Person person = new Person(); person.setOwner("USA"); person.setPersonid("5116628123"); //some number that doesn't exist yet person.setP_fname("Hannah"); person.setP_sname("Montana"); person.setCompany(company); em.persist(person); This completes without error; however in the database I find that the Person record was inserted with a null in the COMP_ID field. With EclipseLink debug logging set to FINE, the SQL query is shown as: INSERT INTO PERSON (PERSONID,OWNER,P_SNAME,P_FNAME) VALUES (?,?,?,?) bind = [5116628123,USA,Montana,Hannah,] I would have expected this to be saved, and the query to be equivalent to INSERT INTO PERSON (PERSONID,OWNER,COMP_ID,P_SNAME,P_FNAME) VALUES (?,?,?,?,?) bind = [5116628123,USA,1102F3,Montana,Hannah,] What gives? Is it incorrect to say updatable/insertable=true for one half of a composite key and =false for the other half? If I have updatable/insertable=true for both parts of the foreign key, then Eclipselink fails to startup saying that I can not use the column twice without having one set to readonly by specifying these options.

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  • extensible database design: automatic ALTER TABLE or serialize() field BLOB ?

    - by mario
    I want an adaptable database scheme. But still use a simple table data gateway in my application, where I just pass an $data[] array for storing. The basic columns are settled in the initial table scheme. There will however arise a couple of meta fields later (ca 10-20). I want some flexibility there and not adapt the database manually each time, or -worse- change the application logic just because of new fields. So now there are two options which seem workable yet not overkill. But I'm not sure about the scalability or database drawbacks. (1) Automatic ALTER TABLE. Whenever the $data array is to be saved, the keys are compared against the current database columns. New columns get defined before the $data is INSERTed into the table. Actually seems simple enough in test code: function save($data, $table="forum") { // columns if ($new_fields = array_diff(array_keys($data), known_fields($table))) { extend_schema($table, $new_fields, $data); } // save $columns = implode("`, `", array_keys($data)); $qm = str_repeat(",?", count(array_keys($data)) - 1); echo ("INSERT INTO `$table` (`$columns`) VALUES (?$qm);"); function known_fields($table) { return unserialize(@file_get_contents("db:$table")) ?: array("id"); function extend_schema($table, $new_fields, $data) { foreach ($new_fields as $field) { echo("ALTER TABLE `$table` ADD COLUMN `$field` VARCHAR;"); Since it is mostly meta information fields, adding them just as VARCHAR seems sufficient. Nobody will query by them anyway. So the database is really just used as storage here. However, while I might want to add a lot of new $data fields on the go, they will not always be populated. (2) serialize() fields into BLOB. Any new/extraneous meta fields could be opaque to the database. Simply sorting out the virtual fields from the real database columns is simple. And the meta fields can just be serialize()d into a blob/text field then: function ext_save($data, $table="forum") { $db_fields = array("id", "content", "flags", "ext"); // disjoin foreach (array_diff(array_keys($data),$db_fields) as $key) { $data["ext"][$key] = $data[$key]; unset($data[$key]); } $data["ext"] = serialize($data["ext"]); Unserializing and unpacking this 'ext' column on read queries is a minor overhead. The advantage is that there won't be any sparsely filled columns in the database, so I guess it's compacter and faster than the AUTO ALTER TABLE approach. Of course, this method prevents ever using one of the new fields in a WHERE or GROUP BY clause. But I think none of the possible meta fields (user_agent, author_ip, author_img, votes, hits, last_modified, ..) would/should ever be used there anyway. So I currently prefer the 'ext' blob approach, even if it's a one-way ticket. How are such columns called usually? (looking for examples/doc) Would you use XML serialization for (very theoretical) in-database queries? The adapting table scheme seems a "cleaner" interface, even if most columns might remain empty then. How does that impact speed? How many such sparse VARCHAR fields can MySQL/innodb stomach? But most importantly: Is there any standard implementation for this? A pseudo ORM with automatic ALTER TABLE tricks? Storing a simple column list seems workable, but something like pdo::getColumnMeta would be more robust.

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  • Error occurred in deployment step 'Activate Features': The field with Id {GUID} defined in feature {GUID} was found in the current site collection or in a subsite.

    - by Jayant Sharma
    Hi all, In SharePoint 2010, This is rare error, I got when I deploy and activate Feature using VS2010. Deployment works file  but in activation process it get stuct and throws error. Error occurred in deployment step 'Activate Features': The field with Id {GUID} defined in feature {GUID} was found in the current site collection or in a subsite. When I googled I found very good solution  from Sandeep Snahta Blog. http://snahta.blogspot.hk/2011/10/error-in-activate-features-from-visual.html As suggested in this blog, there is two option to overcome this error; Close VS2010 and restart again. Or Kill VSSHost4 Process either through Task Manager or Via Power Shell Command    stop-process -processname vssphost4 -force   Jayant Sharma

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  • My boss decided to add a "person to blame" field to every bug report. How can I convince him that it's a bad idea?

    - by MK_Dev
    In one of the latest "WTF" moves, my boss decided that adding a "Person To Blame" field to our bug tracking template will increase accountability (although we already have a way of tying bugs to features/stories). My arguments that this will decrease morale, increase finger-pointing and would not account for missing/misunderstood features reported as bug have gone unheard. What are some other strong arguments against this practice that I can use? Is there any writing on this topic that I can share with the team and the boss? I find this sort of culture unacceptable to work in but want to try and change it before jumping ship. Any input is appreciated.

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  • Serialize C# dynamic object to JSON object to be consumed by javascript

    - by Jeff Jin
    Based on the example c# dynamic with XML, I modified DynamicXml.cs and parsed my xml string. the modified part is as follows public override bool TryGetMember(GetMemberBinder binder, out object result) { result = null; if (binder.Name == "Controls") result = new DynamicXml(_elements.Elements()); else if (binder.Name == "Count") result = _elements.Count; else { var attr = _elements[0].Attribute( XName.Get(binder.Name)); if (attr != null) result = attr.Value; else { var items = _elements.Descendants( XName.Get(binder.Name)); if (items == null || items.Count() == 0) return false; result = new DynamicXml(items); } } return true; } The xml string to parse: "< View runat='server' Name='Doc111'>" + "< Caption Name='Document.ConvertToPdf' Value='Allow Conversion to PDF'></ Caption>" + "< Field For='Document.ConvertToPdf' ReadOnly='False' DisplayAs='checkbox' EditAs='checkbox'></ Field>" + "< Field For='Document.Abstract' ReadOnly='False' DisplayAs='label' EditAs='textinput'></ Field>" + "< Field For='Document.FileName' ReadOnly='False' DisplayAs='label' EditAs='textinput'></ Field>" + "< Field For='Document.KeyWords' ReadOnly='False' DisplayAs='label' EditAs='textinput'></ Field>" + "< FormButtons SaveCaption='Save' CancelCaption='Cancel'></ FormButtons>" + "</ View>"; dynamic form = new DynamicXml(markup_fieldsOnly); is there a way to serialize the content of this dynamic object(name value pairs inside dynamic) form as JSON object and sent to client side(browser)?

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  • ExtJS: Combobox in EditorGridPanel not selecting the desired item (with test case)

    - by TomH
    I'm using ExtJS to create an EditorGridPanel with a combobox for an editor in a cell. The combobox in my EditorGridPanel that is not working as I'd expect it to. When the user types the first letter of an item in the drop down list, the combobox seems to ignore it and select the first item in the list. I can reproduce the error consistently and have put together a test case here: http://cluebucket.com/dev/testcase/testcase.html Load the page and reproduce the behavior by the following -- note that this is all done using the keyboard, no mouse clicks: Click 'Add Record' (A new row is added to the grid) enter text in the text field. TAB to the Priority field without selecting anything (None will remain selected) TAB out of the Priority field. (A new row is added to the grid) enter text and TAB to the Priority field TYPE v (Very High is selected) TAB out of the priority field (A new row is added to the grid) enter text and TAB to the Priority field Type v (None is selected, but Very High should have been) TAB out of the priority field Enter text and TAB to the priority field Type l ('el') (Low is selected) TAB out, enter text, TAB to priority Type l (None is selected) It appears that whenever the user attempts to select the same value that was selected in the previous row, the combobox selects None. Any ideas? The code is available at cluebucket.com/dev/testcase/js/testcase.js Thoughts/Pointers/Corrections are appreciated!! thanks tom

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  • Django 1.2 + South 0.7 + django-annoying's AutoOneToOneField leads to TypeError: 'LegacyConnection'

    - by konrad
    I'm using Django 1.2 trunk with South 0.7 and an AutoOneToOneField copied from django-annoying. South complained that the field does not have rules defined and the new version of South no longer has an automatic field type parser. So I read the South documentation and wrote the following definition (basically an exact copy of the OneToOneField rules): rules = [ ( (AutoOneToOneField), [], { "to": ["rel.to", {}], "to_field": ["rel.field_name", {"default_attr": "rel.to._meta.pk.name"}], "related_name": ["rel.related_name", {"default": None}], "db_index": ["db_index", {"default": True}], }, ) ] from south.modelsinspector import add_introspection_rules add_introspection_rules(rules, ["^myapp"]) Now South raises the following error when I do a schemamigration. Traceback (most recent call last): File "manage.py", line 11, in <module> execute_manager(settings) File "django/core/management/__init__.py", line 438, in execute_manager utility.execute() File "django/core/management/__init__.py", line 379, in execute self.fetch_command(subcommand).run_from_argv(self.argv) File "django/core/management/base.py", line 196, in run_from_argv self.execute(*args, **options.__dict__) File "django/core/management/base.py", line 223, in execute output = self.handle(*args, **options) File "South-0.7-py2.6.egg/south/management/commands/schemamigration.py", line 92, in handle (k, v) for k, v in freezer.freeze_apps([migrations.app_label()]).items() File "South-0.7-py2.6.egg/south/creator/freezer.py", line 33, in freeze_apps model_defs[model_key(model)] = prep_for_freeze(model) File "South-0.7-py2.6.egg/south/creator/freezer.py", line 65, in prep_for_freeze fields = modelsinspector.get_model_fields(model, m2m=True) File "South-0.7-py2.6.egg/south/modelsinspector.py", line 322, in get_model_fields args, kwargs = introspector(field) File "South-0.7-py2.6.egg/south/modelsinspector.py", line 271, in introspector arg_defs, kwarg_defs = matching_details(field) File "South-0.7-py2.6.egg/south/modelsinspector.py", line 187, in matching_details if any([isinstance(field, x) for x in classes]): TypeError: 'LegacyConnection' object is not iterable Is this related to a recent change in Django 1.2 trunk? How do I fix this? I use this field as follows: class Bar(models.Model): foo = AutoOneToOneField("foo.Foo", primary_key=True, related_name="bar") For reference the field code from django-tagging: class AutoSingleRelatedObjectDescriptor(SingleRelatedObjectDescriptor): def __get__(self, instance, instance_type=None): try: return super(AutoSingleRelatedObjectDescriptor, self).__get__(instance, instance_type) except self.related.model.DoesNotExist: obj = self.related.model(**{self.related.field.name: instance}) obj.save() return obj class AutoOneToOneField(OneToOneField): def contribute_to_related_class(self, cls, related): setattr(cls, related.get_accessor_name(), AutoSingleRelatedObjectDescriptor(related))

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  • Extract wrong data from a frame in C?

    - by ipkiss
    I am writing a program that reads the data from the serial port on Linux. The data are sent by another device with the following frame format: |start | Command | Data | CRC | End | |0x02 | 0x41 | (0-127 octets) | | 0x03| ---------------------------------------------------- The Data field contains 127 octets as shown and octet 1,2 contains one type of data; octet 3,4 contains another data. I need to get these data. Because in C, one byte can only holds one character and in the start field of the frame, it is 0x02 which means STX which is 3 characters. So, in order to test my program, On the sender side, I construct an array as the frame formatted above like: char frame[254]; frame[0] = 0x02; // starting field frame[1] = 0x41; // command field which is character 'A' ..so on.. And, then On the receiver side, I take out the fields like: char result[254]; // read data read(result); printf("command = %c", result[1]); // get the command field of the frame // get other field's values the command field value (result[1]) is not character 'A'. I think, this because the first field value of the frame is 0x02 (STX) occupying 3 first places in the array frame and leading to the wrong results on the receiver side. How can I correct the issue or am I doing something wrong at the sender side? Thanks all. related questions: http://stackoverflow.com/questions/2500567/parse-and-read-data-frame-in-c http://stackoverflow.com/questions/2531779/clear-data-at-serial-port-in-linux-in-c

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  • How to Import XML generated by TFPT into Excel 2007?

    - by keerthivasanp
    Below is the xml content generated by TFPT for the WIQL issued. When I try to import this XML into Excel 2007 XML source pane shows only "Id", "RefName" and "Value" as fields to be mapped. Whereas I would like to display System.Id, System.State, Microsoft.VSTS.Common.ResolvedDate, Microsoft.VSTS.Common.StateChangeDate as column headings and corresponding value as rows. Any idea how to achieve this using XML import in Excel 2007. <?xml version="1.0" encoding="utf-8"?> <WorkItems> <WorkItem Id="40100"> <Field RefName="System.Id" Value="40100" /> <Field RefName="System.State" Value="Closed" /> <Field RefName="Microsoft.VSTS.Common.ResolvedDate" Value="3/17/2010 9:39:04 PM" /> <Field RefName="Microsoft.VSTS.Common.StateChangeDate" Value="4/20/2010 9:15:32 PM" /> </WorkItem> <WorkItem Id="44077"> <Field RefName="System.Id" Value="44077" /> <Field RefName="System.State" Value="Closed" /> <Field RefName="Microsoft.VSTS.Common.ResolvedDate" Value="3/1/2010 4:26:47 PM" /> <Field RefName="Microsoft.VSTS.Common.StateChangeDate" Value="4/20/2010 7:32:12 PM" /> </WorkItem> </WorkItems> Thanks

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  • What data structure to use / data persistence

    - by Dave
    I have an app where I need one table of information with the following fields: field 1 - int or char field 2 - string (max 10 char) field 3 - string (max 20 char) field 4 - float I need the program to filter on field 1 based upon a segmented control and select a field 2 from a picker. From this data I need to look up field 4 to use in a calculation. Total records will be about 200. I never see it go above 400 - 500. I am going to use a singleton which I am able to do, I just need help with the structure for this with data persistence. What type of data structure should I use for this and should I use NSNumber, NSString, etc. or old data types like float, Char, etc. I thought about a struct put into an array but there is probably a better way. This is new to me so any help or reference to examples would be great. I also thought about a plist or dictionary but it looks like it is just a lookup and a field which obviously won't work. Core data looked like overkill to me. Also, with any recommendation how should I get initial data into it? I want the user to be able to edit and add to the database. Sorry for the old terms, you can see what generation I am from... Thanks in advance!!!!

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  • Lucene and Special Characters

    - by Brandon
    I am using Lucene.Net 2.0 to index some fields from a database table. One of the fields is a 'Name' field which allows special characters. When I perform a search, it does not find my document that contains a term with special characters. I index my field as such: Directory DALDirectory = FSDirectory.GetDirectory(@"C:\Indexes\Name", false); Analyzer analyzer = new StandardAnalyzer(); IndexWriter indexWriter = new IndexWriter(DALDirectory, analyzer, true, IndexWriter.MaxFieldLength.UNLIMITED); Document doc = new Document(); doc.Add(new Field("Name", "Test (Test)", Field.Store.YES, Field.Index.TOKENIZED)); indexWriter.AddDocument(doc); indexWriter.Optimize(); indexWriter.Close(); And I search doing the following: value = value.Trim().ToLower(); value = QueryParser.Escape(value); Query searchQuery = new TermQuery(new Term(field, value)); Searcher searcher = new IndexSearcher(DALDirectory); TopDocCollector collector = new TopDocCollector(searcher.MaxDoc()); searcher.Search(searchQuery, collector); ScoreDoc[] hits = collector.TopDocs().scoreDocs; If I perform a search for field as 'Name' and value as 'Test', it finds the document. If I perform the same search as 'Name' and value as 'Test (Test)', then it does not find the document. Even more strange, if I remove the QueryParser.Escape line do a search for a GUID (which, of course, contains hyphens) it finds documents where the GUID value matches, but performing the same search with the value as 'Test (Test)' still yields no results. I am unsure what I am doing wrong. I am using the QueryParser.Escape method to escape the special characters and am storing the field and searching by the Lucene.Net's examples. Any thoughts?

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  • How does initializing inherited members inside base class constructor reduce the calls to…?

    - by flockofcode
    I’ve read that instead of initializing inherited members ( _c1 in our example ) inside derived constructor: class A { public int _c; } class B:A { public B(int c) { _c = c; } } we should initialize them inside base class constructor, since that way we reduce the calls to inherited members ( _c ): class A { public A(int c) { _c = c; } public int _c; } class B:A { public B(int c) : base(c) { } } If _c field is initialized inside base constructor, the order of initialization is the following: 1) First the field initializers of derived class B are called 2) Then field initializers of base class A are called (at this point _c is set to value 0) 3) B’s constructor is called, which in turn calls A’s custom constructor 4) _c field gets set to value of a parameter c ( inside A’s custom constructor ) 5) Once A’s custom constructor returns, B’s constructor executes its code. If _c field is initialized inside B's constructor, the order of initialization is the following: 1) First the field initializers of a derived class B are called 2) Then field initializers of a base class A are called(at this point _c is set to value 0) 3) B’s constructor is called, which in turn calls A’s default constructor 4) Once A’s custom constructor returns, B’s constructor sets _c field to a value of parameter c As far as I can tell, in both cases was _c called two times, so how exactly did we reduce calls to inherited member _c? thanx

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  • [iOS] becomeFirstResponder: automatically scroll to the UIControl that becomes first responder

    - by Manni
    I have a grouped UITableViewController with one section and many rows. Each cell consists of two elements: a UILabel with a description and a UITextField for an input. A form, I would say. On the bottom is a button "Next" the go to the next view. But before that, I validate the UITextField's: if the user hasn't filled a field, this field should get the focus, so that the user sees that he needs to enter something. I tried with this: [inputField becomeFirstResponder]; Remember, the button I pressed is on the bottom of my view and imagine that the UITextField is on the top. In this situation, the field doesn't get the focus because it is too far away. Now when I scroll up slowly and the field gets visible, the field becomes first responder and gets the cursor :-) Conclusion: The becomeFirstResponder worked, but does not exactly do what I wanted to. I don't want to scroll up with my finger, the field should get the focus and visible automatically. Is there any way to "jump" directly to my field? Use an alternative to becomeFirstResponder? Scroll to my field automatically? Thanks for your help!

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  • How to limit setAccessible to only "legitimate" uses?

    - by polygenelubricants
    The more I learned about the power of setAccessible, the more astonished I am at what it can do. This is adapted from my answer to the question (Using reflection to change static final File.separatorChar for unit testing). import java.lang.reflect.*; public class EverythingIsTrue { static void setFinalStatic(Field field, Object newValue) throws Exception { field.setAccessible(true); Field modifiersField = Field.class.getDeclaredField("modifiers"); modifiersField.setAccessible(true); modifiersField.setInt(field, field.getModifiers() & ~Modifier.FINAL); field.set(null, newValue); } public static void main(String args[]) throws Exception { setFinalStatic(Boolean.class.getField("FALSE"), true); System.out.format("Everything is %s", false); // "Everything is true" } } You can do truly outrageous stuff: public class UltimateAnswerToEverything { static Integer[] ultimateAnswer() { Integer[] ret = new Integer[256]; java.util.Arrays.fill(ret, 42); return ret; } public static void main(String args[]) throws Exception { EverythingIsTrue.setFinalStatic( Class.forName("java.lang.Integer$IntegerCache") .getDeclaredField("cache"), ultimateAnswer() ); System.out.format("6 * 9 = %d", 6 * 9); // "6 * 9 = 42" } } Presumably the API designers realize how abusable setAccessible can be, but must have conceded that it has legitimate uses to provide it. So my questions are: What are the truly legitimate uses for setAccessible? Could Java has been designed as to NOT have this need in the first place? What would the negative consequences (if any) of such design be? Can you restrict setAccessible to legitimate uses only? Is it only through SecurityManager? How does it work? Whitelist/blacklist, granularity, etc? Is it common to have to configure it in your applications?

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  • Django: returning a selection of fields from a model based on their values?

    - by AP257
    I am working with some data over which I have little control. I'd like to return ONLY the fields of my model that aren't certain 'uninteresting' values (e.g. '0', 'X' or '-'), and access them individually in the template. My model is like this: class Manors(models.Model): structidx = models.IntegerField(primary_key=True, verbose_name="ID") hills = models.CharField(max_length=100, null=True, blank=True, verbose_name="Number of fields") In my template, I return a QuerySet of Manors, and I'd like to output something like this if the hills field isn't uninteresting: {% for manor in manors %} {% if manor.hills %}<li>Hills blah blah: {{ manor.hills }}</li>{% endif %} {% endfor %} I want to avoid too much logic in the template. Ideally, the manor object would simply not return with the uninteresting fields attached, then I could just do {% if manor.hills %}. I tried writing a model method that returns a dictionary of the interesting values, like this: def get_field_dictionary(self): interesting_fields = {} for field in Manors._meta.fields: if field.value_to_string(self) != "N" and field.value_to_string(self) != "0" and field.value_to_string(self) != "-" and field.value_to_string(self) != "X": interesting_fields[field.name] = field.value_to_string(self) return interesting_fields But I don't know how to access individual values of the dictionary in the template: {% if manor.get_field_dictionary['hills'] %}<li>Hills blah blah: {{ manor.get_field_dictionary['hills'] }}</li>{% endif %} gives a TemplateSyntaxError. Is there a better way to do this?

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  • IPv6 multicast addresses: Is the Group ID field effectively 112 bits or 32 bits?

    - by Jeremy Friesner
    Hi all, I'm trying to understand the rules for choosing an IPv6 multicast address Group ID, and the RFC seems somewhat inconsistent. For example, in RFC 2373 section 2.7 this diagram is shown: | 8 | 4 | 4 | 112 bits | +------ -+----+----+---------------------------------------------+ |11111111|flgs|scop| group ID | +--------+----+----+---------------------------------------------+ ... but then in section 2.7.2 it shows this: | 8 | 4 | 4 | 80 bits | 32 bits | +------ -+----+----+---------------------------+-----------------+ |11111111|flgs|scop| reserved must be zero | group ID | +--------+----+----+---------------------------+-----------------+ So my question is, are the upper 80 bits of the Group ID field usable or not? If they are usable, is it only under certain circumstances (e.g. when using non-Ethernet networking technology?) What problems should I expect to experience if I set these bits when multicasting over an Ethernet LAN?

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