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  • What's wrong with JavaScript

    - by ts01
    There is a lot of buzz around Dart recently, often questioning Google motivations and utility of Dart as replacement for JavaScript. I was searching for rationale of creating Dart rather than investing more effort in ECMAScript. In well known leaked mail its author is saying that Javascript has historical baggage that cannot be solved without a clean break. But there is only one concrete example given (apart of performance concerns) of "fundamental language problems", which is an existence of a single Number primitive So, my questions are: How an existence of a single Number primitive can be a "fundamental problem"? Are there other known "fundamental problems" in JavaScript?

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  • ldirectord ipvsadm not show reals ip and not work wtih pacemaker and corosync

    - by miguer27
    first thanks for your time. I'm having a problem with ldirectord that I can not solve, I comment my situation: I have two nodes with pace maker and corosync and configure somes resources: root@ldap1:/home/mamartin# crm status Last updated: Tue Jun 3 12:58:30 2014 Last change: Tue Jun 3 12:23:47 2014 via cibadmin on ldap1 Stack: openais Current DC: ldap2 - partition with quorum Version: 1.1.7-ee0730e13d124c3d58f00016c3376a1de5323cff 2 Nodes configured, 2 expected votes 7 Resources configured. Online: [ ldap1 ldap2 ] Resource Group: IPV_LVS IPV_4 (ocf::heartbeat:IPaddr2): Started ldap1 IPV_6 (ocf::heartbeat:IPv6addr): Started ldap1 lvs (ocf::heartbeat:ldirectord): Started ldap1 Clone Set: clon_IPV_lo [IPV_lo] Started: [ ldap2 ] Stopped: [ IPV_lo:1 ] root@ldap1:/home/mamartin# crm configure show node ldap2 \ attributes standby="off" node ldap1 \ attributes standby="off" primitive IPV-lo_4 ocf:heartbeat:IPaddr \ params ip="192.168.1.10" cidr_netmask="32" nic="lo" \ op monitor interval="5s" primitive IPV-lo_6 ocf:heartbeat:IPv6addrLO \ params ipv6addr="[fc00:1::3]" cidr_netmask="64" \ op monitor interval="5s" primitive IPV_4 ocf:heartbeat:IPaddr2 \ params ip="192.168.1.10" nic="eth0" cidr_netmask="25" lvs_support="true" \ op monitor interval="5s" primitive IPV_6 ocf:heartbeat:IPv6addr \ params ipv6addr="[fc00:1::3]" nic="eth0" cidr_netmask="64" \ op monitor interval="5s" primitive lvs ocf:heartbeat:ldirectord \ params configfile="/etc/ldirectord.cf" \ op monitor interval="20" timeout="10" \ meta target-role="Started" group IPV_LVS IPV_4 IPV_6 lvs group IPV_lo IPV-lo_6 IPV-lo_4 clone clon_IPV_lo IPV_lo \ meta interleave="true" target-role="Started" location cli-prefer-IPV_LVS IPV_LVS \ rule $id="cli-prefer-rule-IPV_LVS" inf: #uname eq ldap1 colocation LVS_no_IPV_lo -inf: clon_IPV_lo IPV_LVS property $id="cib-bootstrap-options" \ dc-version="1.1.7-ee0730e13d124c3d58f00016c3376a1de5323cff" \ cluster-infrastructure="openais" \ expected-quorum-votes="2" \ no-quorum-policy="ignore" \ stonith-enabled="false" \ last-lrm-refresh="1401264327" rsc_defaults $id="rsc-options" \ resource-stickiness="1000" The problem is in the ipvsadm only show a one real IP, when i configured two now, show the ldirector.cf: root@ldap1:/home/mamartin# ipvsadm IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags - RemoteAddress:Port Forward Weight ActiveConn InActConn TCP ldap-maqueta.cica.es:ldap wrr - ldap2.cica.es:ldap Route 4 0 0 TCP [[fc00:1::3]]:ldap wrr - [[fc00:1::2]]:ldap Route 4 0 0 root@ldap1:/home/mamartin# cat /etc/ldirectord.cf checktimeout=10 checkinterval=2 autoreload=yes logfile="/var/log/ldirectord.log" quiescent=yes #ipv4 virtual=192.168.1.10:389 real=192.168.1.11:389 gate 4 real=192.168.1.12:389 gate 4 scheduler=wrr protocol=tcp checktype=on #ipv6 virtual6=[[fc00:1::3]]:389 real6=[[fc00:1::1]]:389 gate 4 real6=[[fc00:1::2]]:389 gate 4 scheduler=wrr protocol=tcp checkport=389 checktype=on and in the logs I see nothing clear: root@ldap1:/home/mamartin# ldirectord -d /etc/ldirectord.cf start DEBUG2: Running system(/sbin/ipvsadm -a -t 192.168.1.10:389 -r 192.168.1.11:389 -g -w 0) Running system(/sbin/ipvsadm -a -t 192.168.1.10:389 -r 192.168.1.11:389 -g -w 0) DEBUG2: Quiescent real server: 192.168.1.11:389 (192.168.1.10:389) (Weight set to 0) Quiescent real server: 192.168.1.11:389 (192.168.1.10:389) (Weight set to 0) DEBUG2: Disabled real server=on:tcp:192.168.1.11:389:::4:gate:\/: (virtual=tcp:192.168.1.10:389) DEBUG2: Running system(/sbin/ipvsadm -a -t 192.168.1.10:389 -r 192.168.1.12:389 -g -w 0) Running system(/sbin/ipvsadm -a -t 192.168.1.10:389 -r 192.168.1.12:389 -g -w 0) DEBUG2: Quiescent real server: 192.168.1.12:389 (192.168.1.10:389) (Weight set to 0) Quiescent real server: 192.168.1.12:389 (192.168.1.10:389) (Weight set to 0) DEBUG2: Disabled real server=on:tcp:192.168.1.12:389:::4:gate:\/: (virtual=tcp:192.168.1.10:389) DEBUG2: Checking on: Real servers are added without any checks DEBUG2: Resetting soft failure count: 192.168.1.12:389 (tcp:192.168.1.10:389) Resetting soft failure count: 192.168.1.12:389 (tcp:192.168.1.10:389) DEBUG2: Running system(/sbin/ipvsadm -a -t 192.168.1.10:389 -r 192.168.1.12:389 -g -w 4) Running system(/sbin/ipvsadm -a -t 192.168.1.10:389 -r 192.168.1.12:389 -g -w 4) Destination already exists root@ldap1:/home/mamartin# cat /var/log/ldirectord.log [Tue Jun 3 09:39:29 2014|ldirectord.cf|19266] Quiescent real server: 192.168.1.11:389 (192.168.1.10:389) (Weight set to 0) [Tue Jun 3 09:39:29 2014|ldirectord.cf|19266] Quiescent real server: 192.168.1.12:389 (192.168.1.10:389) (Weight set to 0) [Tue Jun 3 09:39:29 2014|ldirectord.cf|19266] Resetting soft failure count: 192.168.1.12:389 (tcp:192.168.1.10:389) [Tue Jun 3 09:39:29 2014|ldirectord.cf|19266] system(/sbin/ipvsadm -a -t 192.168.1.10:389 -r 192.168.1.12:389 -g -w 4) failed: [Tue Jun 3 09:39:29 2014|ldirectord.cf|19266] Added real server: 192.168.1.12:389 (192.168.1.10:389) (Weight set to 4) [Tue Jun 3 09:39:29 2014|ldirectord.cf|19266] Resetting soft failure count: 192.168.1.11:389 (tcp:192.168.1.10:389) [Tue Jun 3 09:39:29 2014|ldirectord.cf|19266] Restored real server: 192.168.1.11:389 (192.168.1.10:389) (Weight set to 4) [Tue Jun 3 09:39:29 2014|ldirectord.cf|19266] Resetting soft failure count: [[fc00:1::2]]:389 (tcp:[[fc00:1::3]]:389) [Tue Jun 3 09:39:29 2014|ldirectord.cf|19266] system(/sbin/ipvsadm -a -t [[fc00:1::3]]:389 -r [[fc00:1::2]]:389 -g -w 4) failed: [Tue Jun 3 09:39:29 2014|ldirectord.cf|19266] Added real server: [[fc00:1::2]]:389 ([[fc00:1::3]]:389) (Weight set to 4) [Tue Jun 3 09:39:29 2014|ldirectord.cf|19266] Resetting soft failure count: [[fc00:1::1]]:389 (tcp:[[fc00:1::3]]:389) [Tue Jun 3 09:39:29 2014|ldirectord.cf|19266] Restored real server: [[fc00:1::1]]:389 ([[fc00:1::3]]:389) (Weight set to 4) do not know if this is a bug or a configuration error, can anyone help? Regards.

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  • Is this way of storing typed objects in memory good?

    - by Pindatjuh
    This is an "is this okay, or can it be done better" question. Topic: Storing typed objects in memory. Background information: I'm building a compiler for the x86-32 platform for my language. My goal includes typed objects. Idea: Every primitive is a semi-class (it can be used as if it was a normal class, but it's stored more compact). Every class is represented by primitives and some meta-data (containing class-properties, inheritance stuff, etc.). The meta-data is complex: it doesn't use fields but instead context-switches. For primitives, the meta-data is very small, compared to a "real" class, which is alot bigger. This enables another idea that "primitives are objects", in my language, which I found nessecairy. Example: If I have an array of 32 booleans, then the pure content of this array is exactly 4 byte (32 bits of booleans). The meta-data will contain flags that the type is an array of booleans, which contains 32 entries. The meta-data is very compacted, on bit-level: using a sort of "packing" mechanism, which is read by a FSM at runtime, when doing inspection of the type (like when passing the object to methods for checking, etc.) For instance (read from left to right, top to bottom, remember vertical possition when going to the right, and check nearest column header for meaning of switch): Primitive? Array? Type-Meta 1 Byte? || Size (1 byte) 1 1 [...] 1 [...] done 0 2 Bytes? || Size (2 bytes) 1 [...] done || Size (4 bytes) 0 [...] done Integer? 1 Byte? 2 Bytes? 0 1 0 1 done 1 done 0 done Boolean? Byte? 0 1 0 done 1 done More-Primitives 0 .... Class-Stuff (Huge) 0 ... (After reaching done the data is inserted. || = byte alignement. [...] is variable sized. ... is not described here, for simplicity. And let's call them cost-based-data-structures.) For an array of 32 booleans containing all true values, the memory for this type would be (read top-down): 1 Primitive 1 Array 1 ArrayType: Primitive 0 Not-Array 0 Not-Integer 1 Boolean 0 Not-Byte (thus bit) 1 Integer Size: 1 Byte 00100000 Array size 11111111 11111111 11111111 11111111 Data Thus, 8 bytes represent 32 booleans in an array: 11100101 00100000 11111111 11111111 11111111 11111111 Is this okay, or can it be done better?

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  • Custom byte size?

    - by thyrgle
    So, you know how the primitive of type char has the size of 1 byte? How would I make a primitive with a custom size? So like instead of an in int with the size of 4 bytes I make one with size of lets say 16. Is there a way to do this? Is there a way around it?

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  • What is the difference between the Boolean object and the Boolean data type in JavaScript?

    - by DarkLightA
    The Boolean type has two literal values: true and false. Do not confuse the primitive Boolean values true and false with the true and false values of the Boolean object. The Boolean object is a wrapper around the primitive Boolean data type. See Boolean Object for more information. What does this mean? What's the difference between the Boolean object and the Boolean data type??

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  • Can this way of storing typed objects be improved?

    - by Pindatjuh
    This is an "can it be improved"-question. Topic: Storing typed objects in memory. Background information: I'm building a compiler for the x86-32 Windows platform for my language. My goal includes typed objects. Idea: Every primitive is a semi-class (it can be used as if it was a normal class, but it's stored more compact). Every class is represented by primitives and some meta-data (containing class-properties, inheritance stuff, etc.). The meta-data is complex: it doesn't use fields but instead context-switches. For primitives, the meta-data is very small, compared to a "real" class, which is alot bigger. This enables another idea that "primitives are objects", in my language, which I found nessecairy. Example: If I have an array of 32 booleans, then the pure content of this array is exactly 4 byte (32 bits of booleans). The meta-data will contain flags that the type is an array of booleans, which contains 32 entries. The meta-data is very compacted, on bit-level: using a sort of "packing" mechanism, which is read by a FSM at runtime, when doing inspection of the type (like when passing the object to methods for checking, etc.) For instance (read from left to right, top to bottom, remember vertical position when going to the right, and check nearest column header for meaning of switch): Primitive? Array? Type-Meta 1 Byte? || Size (1 byte) 1 1 [...] 1 [...] done 0 2 Bytes? || Size (2 bytes) 1 [...] done || Size (4 bytes) 0 [...] done Integer? 1 Byte? 2 Bytes? 0 1 0 1 done 1 done 0 done Boolean? Byte? 0 1 0 done 1 done More-Primitives 0 .... Class-Stuff (Huge) 0 ... (After reaching done the data is inserted. || = byte alignment. [...] is variable sized. ... is not described here, for simplicity. And let's call them cost-based-data-structures.) For an array of 32 booleans containing all true values, the memory for this type would be (read top-down): 1 Primitive 1 Array 1 ArrayType: Primitive 0 Not-Array 0 Not-Integer 1 Boolean 0 Not-Byte (thus bit) 1 Integer Size: 1 Byte 00100000 Array size 01010101 01010101 01010101 01010101 Data (user defined) Thus, 8 bytes represent 32 booleans in an array: 11100101 00100000 01010101 01010101 01010101 01010101 How can I improve this? (Both performance- and memory-consumption wise)

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  • Java equivalent of C++ std::map?

    - by Rudiger
    I'm looking for a Java class with the characteristics of C++ std::map's usual implementation (as I understand it, a self-balancing binary search tree): O(log n) performance for insertion/removal/search Each element is composed of a unique key and a mapped value Keys follow a strict weak ordering I'm looking for implementations with open source or design documents; I'll probably end up rolling my own support for primitive keys/values. This question's style is similar to: Java equivalent of std::deque, whose answer was "ArrayDeque from Primitive Collections for Java".

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  • Synthesizing Singing

    - by anon
    So this is from the late 90s ... http://www.cs.princeton.edu/~prc/SingingSynth.html Why hasn't this taken off? (We can synthesize photorealistic like images, but the synthesis of singing ... still seems to be in very primitive stages). What exactly is it that makes the synthesis of singing difficult? http://www.interspeech2007.org/Technical/synthesis_of_singing_challenge.php <-- still seems primitive. Thanks!

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  • Can PHP and Oracle pass complex types to each other?

    - by RenderIn
    I want to pass/bind an array of (key1, key2) to an Oracle PL/SQL stored procedure using PHP. I'm able to bind primitive types and arrays of primitive types, but haven't found a way to pass complex datatypes back and forth. Is this unsupported? So far I've been having to pass along multiple arrays -- one for each subtype in my complex type -- and then depend on their indexes to reconstitute them in the procedure.

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  • Silverlight IConvertible TypeConverter

    - by codingbloke
    I recently answered the following question on stackoverflow:  Silverlight 3 custom control: only ‘int’ as numeric type for a property? [e.g. long or int64 seems to break] I quickly knocked up the class ConvertibleTypeConverter<T> that I posted in the question (listed later here as well). Afterward I fully expected to find that of the usual clever “bods who blog” to have covered this probably with a better solution than I.  So far though I’ve not found one so I thought I’d blog it myself. The Problem Here is a classic gotcha I’ve seen asked more than once on stackoverflow :- public class MyClass {     public float SomeValue { get; set; } } <local:MyClass SomeValue="45.15" /> This fails with the error  “Failed to create a 'System.Single' from the text '45.15'”  and results in much premature hair loss.  Fortunately this is SL4, in SL3 the error message is almost meaningless.  So what gives, how can it be that this fails when we can see other very similar values parsing happily all over the place? It comes down the fact that the Xaml parser only handles a few of the primitive data types namely: bool, int, string and double.  Since the parser has no idea how to convert a string to a float we get the above error. The Solution The sensible solution is “use double not float” but lets not dwell on that, there has to be occasions where such an answer isn’t acceptable. In order to achieve parsing of other types we need an implementation of TypeConverter for the type of the property and then we need to use the TypeConverterAttribute to decorate the property .  As an example the Silverlight SDK provides one for DateTime the DateTimeTypeConverter (yes I know DateTime isn’t really a primitive). The following class will parse in Xaml:- public class MyClass {     [TypeConverter(typeof(DateTimeTypeConverter))]     public DateTime SomeValue {get; set; } } So far though we would need to create a TypeConverter for each primitive type we are using, what if I had the following mad class to support in Xaml:- public class StrangePrimitives {     public Boolean BooleanProp { get; set; }     public Byte ByteProp { get; set; }     public Char CharProp { get; set; }     public DateTime DateTimeProp { get; set; }     public Decimal DecimalProp { get; set; }     public Double DoubleProp { get; set; }     public Int16 Int16Prop { get; set; }     public Int32 Int32Prop { get; set; }     public Int64 Int64Prop { get; set; }     public SByte SByteProp { get; set; }     public Single SingleProp { get; set; }     public String StringProp { get; set; }     public UInt16 UInt16Prop { get; set; }     public UInt32 UInt32Prop { get; set; }     public UInt64 UInt64Prop { get; set; } } Then I want to fill an instance of StrangePrimitives with the following Xaml which of course fails. <local:StrangePrimitives x:Key="MyStrangePrimitives"                          BooleanProp="True"                          ByteProp="156"                          CharProp="A"                          DateTimeProp="06 Jun 2010"                          DecimalProp="123.56"                          DoubleProp="8372.937803"                          Int16Prop="16532"                          Int32Prop="73738248"                          Int64Prop="12345678909298"                          SByteProp="-123"                          SingleProp="39.0"                          StringProp="Hello, World!"                          UInt16Prop="40000"                          UInt32Prop="4294967295"                          UInt64Prop="18446744073709551615"      /> I got to thinking, though, one thing all these primitive types have in common is that they all implement IConvertible so it should be possible to write just one converter to handle them all.  Here it is:- The ConvertibleTypeConverter public class ConvertibleTypeConverter<T> : TypeConverter where T : IConvertible {     public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)     {         return sourceType.GetInterface("IConvertible", false) != null;     }     public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)     {         return destinationType.GetInterface("IConvertible", false) != null;     }     public override object ConvertFrom(ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value)     {         return ((IConvertible)value).ToType(typeof(T), culture);     }     public override object ConvertTo(ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value, Type destinationType)     {         return ((IConvertible)value).ToType(destinationType, culture);     } } I won’t bore you with an explanation of how it works, it simply adapts one existing interface (the IConvertible) and exposes it as another (the TypeConverter).   With that in place the previous strange primitives class can be modified as:- public class StrangePrimitives {     public Boolean BooleanProp { get; set; }     [TypeConverter(typeof(ConvertibleTypeConverter<Byte>))]     public Byte ByteProp { get; set; }     [TypeConverter(typeof(ConvertibleTypeConverter<Char>))]     public Char CharProp { get; set; }     [TypeConverter(typeof(ConvertibleTypeConverter<DateTime>))]     public DateTime DateTimeProp { get; set; }     [TypeConverter(typeof(ConvertibleTypeConverter<Decimal>))]     public Decimal DecimalProp { get; set; }     public Double DoubleProp {get; set; }     [TypeConverter(typeof(ConvertibleTypeConverter<Int16>))]     public Int16 Int16Prop { get; set; }     public Int32 Int32Prop { get; set; }     [TypeConverter(typeof(ConvertibleTypeConverter<Int64>))]     public Int64 Int64Prop { get; set; }     [TypeConverter(typeof(ConvertibleTypeConverter<SByte>))]     public SByte SByteProp { get; set; }     [TypeConverter(typeof(ConvertibleTypeConverter<Single>))]     public Single SingleProp { get; set; }     public String StringProp { get; set; }     [TypeConverter(typeof(ConvertibleTypeConverter<UInt16>))]     public UInt16 UInt16Prop { get; set; }     [TypeConverter(typeof(ConvertibleTypeConverter<UInt32>))]     public UInt32 UInt32Prop { get; set; }     [TypeConverter(typeof(ConvertibleTypeConverter<UInt64>))]     public UInt64 UInt64Prop { get; set; } } This results in the previous Xaml parsing happily.  Now it seems such an obvious thing to do that one may wonder why such a class doesn’t already existing in Silverlight or at least in the SDK.   I would not be surprised if there were some very good reasons hence use the ConvertibleTypeConverter with caution.  It does seem to me to be a useful little class to have lying around in the toolbox for the odd occasion where it may be needed.

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  • JavaOne Tutorial Report - JavaFX 2 – A Java Developer’s Guide

    - by Janice J. Heiss
    Oracle Java Technology Evangelist Stephen Chin and Independent Consultant Peter Pilgrim presented a tutorial session intended to help developers get a handle on JavaFX 2. Stephen Chin, a Java Champion, is co-author of the Pro JavaFX Platform 2, while Java Champion Peter Pilgrim is an independent consultant who works out of London.NightHacking with Stephen ChinBefore discussing the tutorial, a note about Chin’s “NightHacking Tour,” wherein from 10/29/12 to 11/11/12, he will be traveling across Europe via motorcycle stopping at JUGs and interviewing Java developers and offering live video streaming of the journey. As he says, “Along the way, I will visit user groups, interviewing interesting folks, and hack on open source projects. The last stop will be the Devoxx conference in Belgium.”It’s a dirty job but someone’s got to do it. His trip will take him from the UK through the Netherlands, Germany, Switzerland, Italy, France, and finally to Devoxx in Belgium. He has interviews lined up with Ben Evans, Trisha Gee, Stephen Coulebourne, Martijn Verburg, Simon Ritter, Bert Ertman, Tony Epple, Adam Bien, Michael Hutterman, Sven Reimers, Andres Almiray, Gerrit Grunewald, Bertrand Boetzmann, Luc Duponcheel, Stephen Janssen, Cheryl Miller, and Andrew Phillips. If you expect to be in Chin’s vicinity at the end of October and in early November, by all means get in touch with him at his site and add your perspective. The more the merrier! Taking the JavaFX PlungeNow to the business at hand. The “JavaFX 2 – A Java Developer’s Guide” tutorial introduced Java developers to the JavaFX 2 platform from the perspective of seasoned Java developers. It demonstrated the breadth of the JavaFX APIs through examples that are built out in the course of the session in an effort to present the basic requirements in using JavaFX to build rich internet applications. Chin began with a quote from Oracle’s Christopher Oliver, the creator of F3, the original version of JavaFX, on the importance of GUIs:“At the end of the day, on the one hand we have computer systems, and on the other, people. Connecting them together, and allowing people to interact with computer systems in a compelling way, requires graphical user interfaces.”Chin explained that JavaFX is about producing an immersive application experience that involves cross-platform animation, video and charting. It can integrate Java, JavaScript and HTML in the same application. The new graphics stack takes advantage of hardware acceleration for 2D and 3D applications. In addition, we can integrate Swing applications using JFXPanel.He reminded attendees that they were building JavaFX apps using pure Java APIs that included builders for declarative construction; in addition, alternative languages can be used for simpler UI creation. In addition, developers can call upon alternative languages such as GroovyFX, ScalaFX and Visage, if they want simpler UI creation. He presented the fundamentals of JavaFX 2.0: properties, lists and binding and then explored primitive, object and FX list collection properties. Properties in JavaFX are observable, lazy and type safe. He then provided an example of property declaration in code.  Pilgrim and Chin explained the architectural structure of JavaFX 2 and its basic properties:JavaFX 2.0 properties – Primitive, Object, and FX List Collection properties. * Primitive Properties* Object Properties* FX List Collection Properties* Properties are:– Observable– Lazy– Type SafeChin and Pilgrim then took attendees through several participatory demos and got deep into the weeds of the code for the two-hour session. At the end, everyone knew a lot more about the inner workings of JavaFX 2.0.

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  • In .NET, What Is Fastest Way to Initialize Multi-Dimensional Array to Non-Default Value

    - by AMissico
    How do I initialize a multi-dimensional array of a primitive type as fast as possible? I am stuck with using multi-dimensional arrays. My problem is performance. The following routine initializes a 100x100 array in approx. 500 ticks. Removing the int.MaxValue initialization results in approx. 180 ticks just for the looping. Approximately 100 ticks to create the array without looping and without initializing to int.MaxValue. Routines similiar to this are called a few tens-of-thousands to several million times. I am open to suggestions on how to optimize this non-default initialization of an array. One idea I had is to use a smaller primitive type when available. For instance, using byte instead of int, saves 100 ticks. I would be happy with this, but I am hoping that I don't have to change the primitive data type. public int[,] CreateArray(Size size) { int[,] array = new int[size.Width, size.Height]; for (int x = 0; x < size.Width; x++) { for (int y = 0; y < size.Height; y++) { array[x, y] = int.MaxValue; } } return array; }

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  • Linux HA cluster w/Xen, Heartbeat, Pacemaker. domU does not failover to secondary node

    - by Kendall
    I am having the followig problem with an OenSuSE + Heartbeat + Pacemaker + Xen HA cluster: when the node a Xen domU is running on is "dead" the Xen domU running on it is not restarted on the second node. The cluster is setup with two nodes, each running OpenSuSE-11.3, Heartbeat 3.0, and Pacemaker 1.0 in CRM mode. For storage I am using a LUN on an iSCSI SAN device; the LUN is formatted with OCFS2 and managed with LVM. The Xen domU has two logical volumes; one for root and the other for swap. I am using IPMI cards for STONITH devices, and a dedicated ethernet link for heartbeat communications. The ha.cf file is as follows: keepalive 1 deadtime 10 warntime 5 udpport 694 ucast eth1 auto_failback off node dhcp-166 node stage use_logd yes crm yes My resources look as follows: shocrm(live)configure# show node $id="5c1aa924-bba4-4f95-a367-6c9a58ac4a38" dhcp-166 node $id="cebc92eb-af24-4833-aaf0-672adf80b58e" stage primitive Xen-Util ocf:heartbeat:Xen \ meta target-role="Started" \ operations $id="Xen-Util-operations" \ op start interval="0" timeout="60" start-delay="0" \ op stop interval="0" timeout="120" \ params xmfile="/etc/xen/vm/xen-util" primitive my-stonith stonith:external/ipmi \ params hostname="dhcp-166" ipaddr="192.168.3.106" userid="ADMIN" passwd="xxx" \ op monitor interval="2m" timeout="60s" primitive my-stonith2 stonith:external/ipmi \ params hostname="stage" ipaddr="192.168.3.105" userid="ADMIN" passwd="xxx" \ op monitor interval="2m" timeout="60s" property $id="cib-bootstrap-options" \ dc-version="1.0.9-89bd754939df5150de7cd76835f98fe90851b677" \ cluster-infrastructure="Heartbeat" The Xen domU config file is as follows: name = "xen-util" bootloader = "/usr/lib/xen/boot/domUloader.py" #bootargs = "xvda1:/vmlinuz-xen,/initrd-xen" bootargs = "--entry=xvda1:/boot/vmlinuz-xen,/boot/initrd-xen" memory = 4096 disk = [ 'phy:vg_xen/xen-util-root,xvda1,w', 'phy:vg_xen/xen-util-swap,xvda2,w', ] root = "/dev/xvda1" vif = [ 'mac=00:16:3e:42:42:06' ] #vfb = [ 'type=vnc,vncunused=0,vnclisten=192.168.3.172' ] extra = "" Say domU "Xen-Util" is running on node "stage"; if "stage" goes down, "Xen-Util" does not restart on node "dhcp-166". It seems to want to try as an "xm list" will show it for a few seconds and if you "xm console xen-util" it will give a message like "copying /boot/kernel.gz from xvda1 to /var/lib/xen/tmp/kernel.a53gs for booting". However, it never gets past that, eventually gives up, and no longer appears in "xm list". Now, when node "stage" comes back online after being power cycled, it detects that "Xen-Util" isn't running, and starts it (on stage). I've tried starting "Xen-Util" on node "dhcp-166" without the cluster running, and it works fine. No problems. So, I know it works in that respect. Any ideas? Thanks!

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  • When do domain concepts become application constructs?

    - by Noren
    I recently posted a question regarding recovering a DDD architecture that became an anemic domain model into a multitier architecture and this question is a follow-on of sorts. My question is when do domain concepts become application constructs. My application is a local client C# 4/WPF with the following architecture: Presentation Layer Views ViewModels Business Layer ??? Domain Layer Classes that take the POCOs with primitive types and create domain concepts (e.g. image, layer, etc) Sanity checks values (e.g. image width 0) Interfaces for DTOs Interface for a repository that abstracts the filesystem Data Access Layer Classes that parse the proprietary binary files into POCOs with primitive types by explicit knowledge of the file format Implementation of domain DTOs Implementation of domain repository class Local Filesystem Proprietary binary files When does the MyImageType domain class with Int32 width, height, and Int32[] pixels become a System.Windows.Media.ImageDrawing? If I put it in the domain layer, it seems like implemenation details are being leaked (what if I didn't want to use WPF?). If I put it in the presentation layer, it seems like it's doing too much. If I create a business layer, it seems like it would be doing too little since there are few "rules" given the CRUD nature of the application. I think all of my reading has lead to analysis paralysis, so I thought fresh eyes might lend some perspective.

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  • Am I the only one this anal / obsessive about code? [closed]

    - by Chris
    While writing a shared lock class for sql server for a web app tonight, I found myself writing in the code style below as I always do: private bool acquired; private bool disposed; private TimeSpan timeout; private string connectionString; private Guid instance = Guid.NewGuid(); private Thread autoRenewThread; Basically, whenever I'm declaring a group of variables or writing a sql statement or any coding activity involving multiple related lines, I always try to arrange them where possible so that they form a bell curve (imagine rotating the text 90deg CCW). As an example of something that peeves the hell out of me, consider the following alternative: private bool acquired; private bool disposed; private string connectionString; private Thread autoRenewThread; private Guid instance = Guid.NewGuid(); private TimeSpan timeout; In the above example, declarations are grouped (arbitrarily) so that the primitive types appear at the top. When viewing the code in Visual Studio, primitive types are a different color than non-primitives, so the grouping makes sense visually, if for no other reason. But I don't like it because the right margin is less of an aesthetic curve. I've always chalked this up to being OCD or something, but at least in my mind, the code is "prettier". Am I the only one?

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  • .NET 4: &ldquo;Slim&rdquo;-style performance boost!

    - by Vitus
    RTM version of .NET 4 and Visual Studio 2010 is available, and now we can do some test with it. Parallel Extensions is one of the most valuable part of .NET 4.0. It’s a set of good tools for easily consuming multicore hardware power. And it also contains some “upgraded” sync primitives – Slim-version. For example, it include updated variant of widely known ManualResetEvent. For people, who don’t know about it: you can sync concurrency execution of some pieces of code with this sync primitive. Instance of ManualResetEvent can be in 2 states: signaled and non-signaled. Transition between it possible by Set() and Reset() methods call. Some shortly explanation: Thread 1 Thread 2 Time mre.Reset(); mre.WaitOne(); //code execution 0 //wating //code execution 1 //wating //code execution 2 //wating //code execution 3 //wating mre.Set(); 4 //code execution //… 5 Upgraded version of this primitive is ManualResetEventSlim. The idea in decreasing performance cost in case, when only 1 thread use it. Main concept in the “hybrid sync schema”, which can be done as following:   internal sealed class SimpleHybridLock : IDisposable { private Int32 m_waiters = 0; private AutoResetEvent m_waiterLock = new AutoResetEvent(false);   public void Enter() { if (Interlocked.Increment(ref m_waiters) == 1) return; m_waiterLock.WaitOne(); }   public void Leave() { if (Interlocked.Decrement(ref m_waiters) == 0) return; m_waiterLock.Set(); }   public void Dispose() { m_waiterLock.Dispose(); } } It’s a sample from Jeffry Richter’s book “CLR via C#”, 3rd edition. Primitive SimpleHybridLock have two public methods: Enter() and Leave(). You can put your concurrency-critical code between calls of these methods, and it would executed in only one thread at the moment. Code is really simple: first thread, called Enter(), increase counter. Second thread also increase counter, and suspend while m_waiterLock is not signaled. So, if we don’t have concurrent access to our lock, “heavy” methods WaitOne() and Set() will not called. It’s can give some performance bonus. ManualResetEvent use the similar idea. Of course, it have more “smart” technics inside, like a checking of recursive calls, and so on. I want to know a real difference between classic ManualResetEvent realization, and new –Slim. I wrote a simple “benchmark”: class Program { static void Main(string[] args) { ManualResetEventSlim mres = new ManualResetEventSlim(false); ManualResetEventSlim mres2 = new ManualResetEventSlim(false);   ManualResetEvent mre = new ManualResetEvent(false);   long total = 0; int COUNT = 50;   for (int i = 0; i < COUNT; i++) { mres2.Reset(); Stopwatch sw = Stopwatch.StartNew();   ThreadPool.QueueUserWorkItem((obj) => { //Method(mres, true); Method2(mre, true); mres2.Set(); }); //Method(mres, false); Method2(mre, false);   mres2.Wait(); sw.Stop();   Console.WriteLine("Pass {0}: {1} ms", i, sw.ElapsedMilliseconds); total += sw.ElapsedMilliseconds; }   Console.WriteLine(); Console.WriteLine("==============================="); Console.WriteLine("Done in average=" + total / (double)COUNT); Console.ReadLine(); }   private static void Method(ManualResetEventSlim mre, bool value) { for (int i = 0; i < 9000000; i++) { if (value) { mre.Set(); } else { mre.Reset(); } } }   private static void Method2(ManualResetEvent mre, bool value) { for (int i = 0; i < 9000000; i++) { if (value) { mre.Set(); } else { mre.Reset(); } } } } I use 2 concurrent thread (the main thread and one from thread pool) for setting and resetting ManualResetEvents, and try to run test COUNT times, and calculate average execution time. Here is the results (I get it on my dual core notebook with T7250 CPU and Windows 7 x64): ManualResetEvent ManualResetEventSlim Difference is obvious and serious – in 10 times! So, I think preferable way is using ManualResetEventSlim, because not always on calling Set() and Reset() will be called “heavy” methods for working with Windows kernel-mode objects. It’s a small and nice improvement! ;)

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  • Optimizing if-else /switch-case with string options

    - by cc
    What modification would bring to this piece of code? In the last lines, should I use more if-else structures, instead of "if-if-if" if (action.equals("opt1")) { //something } else { if (action.equals("opt2")) { //something } else { if ((action.equals("opt3")) || (action.equals("opt4"))) { //something } if (action.equals("opt5")) { //something } if (action.equals("opt6")) { //something } } } Later Edit: This is Java. I don't think that switch-case structure will work with Strings. Later Edit 2: A switch works with the byte, short, char, and int primitive data types. It also works with enumerated types (discussed in Classes and Inheritance) and a few special classes that "wrap" certain primitive types: Character, Byte, Short, and Integer (discussed in Simple Data Objects ).

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  • BigInteger or not BigInteger?

    - by Alon
    In Java, most of the primitive types are signed (one bit is used to represent the +/-), and therefore when I am exceed the limits of this type, I can get many strange things, like negative numbers. In the BigInteger class, I have no limits and there are some helpful functions there but it is pretty depressing to convert your beautiful code to work with the BigInteger class, specially when primitive operators don't work there and you must use functions from this class. I was wondering if you had this problem, and if you have any better solution than the BigInteger class? Thank you.

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  • How to mark empty in a single element in a float array

    - by Vineeth Mohan
    I have a large float (primitive) array and not every element in the array is filled. How can i mark a particular element as EMPTY. I understand this can be achieved by some special symbols but still i would like to know the standard way. Even if i am using some special symbol , how will i handle a situation where the actual data item is the value of special symbol. In short my question is how to implement the NULL feature in a primitive type array in java. PS - The reason why i am not using Float object is to achieve a high memory and speed performance. Thanks Vineeth

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  • Create LINQ to entities OrderBy expression on the fly

    - by AyKarsi
    I'm trying to add the orderby expression on the fly. But when the query below is executed I get the following exception: System.NotSupportedException: Unable to create a constant value of type 'Closure type'. Only primitive types ('such as Int32, String, and Guid') are supported in this context. The strange thing is, I am query exactly those primitive types only. string sortBy = HttpContext.Current.Request.QueryString["sidx"]; ParameterExpression prm = Expression.Parameter(typeof(buskerPosting), "posting"); Expression orderByProperty = Expression.Property(prm, sortBy); // get the paged records IQueryable<PostingListItemDto> query = (from posting in be.buskerPosting where posting.buskerAccount.cmsMember.nodeId == m.Id orderby orderByProperty //orderby posting.Created select new PostingListItemDto { Set = posting }).Skip<PostingListItemDto>((page - 1) * pageSize).Take<PostingListItemDto>(pageSize); Hope somebody can shed some light on this!

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  • How does a custom accessor method implementation in Core Data look like?

    - by dontWatchMyProfile
    The documentation is pretty confusing on this one: The implementation of accessor methods you write for subclasses of NSManagedObject is typically different from those you write for other classes. If you do not provide custom instance variables, you retrieve property values from and save values into the internal store using primitive accessor methods. You must ensure that you invoke the relevant access and change notification methods (willAccessValueForKey:, didAccessValueForKey:, willChangeValueForKey:, didChangeValueForKey:, willChangeValueForKey:withSetMutation:usingObjects:, and didChangeValueForKey:withSetMutation:usingObjects:). NSManagedObject disables automatic key-value observing (KVO, see Key-Value Observing Programming Guide) change notifications, and the primitive accessor methods do not invoke the access and change notification methods. In accessor methods for properties that are not defined in the entity model, you can either enable automatic change notifications or invoke the appropriate change notification methods. Are there any examples that show how these look like?

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  • Java3d shape with Antlr

    - by Eldeus
    Well how to evaluate a very simple antlr grammar that does only this. Box(1,2,4) Cylinder(1,2) and builds java3d shapes, (given I have already built a canvas for java3d and have the code for creating each element in java, protected static BranchGroup addBox1(Float a, Float b, Float C){ // create branch for display TransformGroup bodyTransform = new TransformGroup(); BranchGroup bg = new BranchGroup(); bg.setCapability(BranchGroup.ALLOW_DETACH); bg.setUserData(shapeId); // set transformation bodyTransform = setTransformShape(0,0,0,0,0,0,0); // create box Box tmpBox = new Box(a,b,c, Primitive.GENERATE_NORMALS | Primitive.GENERATE_TEXTURE_COORDS,setAppearance(color)); getCoords(tmpBox); bodyTransform.addChild(tmpBox); trFormList.add(bodyTransform); shapeId++; //add box to branch bg.addChild(bodyTransform); return bg; } ) thanks

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  • Best way to test if a generic type is a string? (c#)

    - by Rex M
    I have a generic class that should allow any type, primitive or otherwise. The only problem with this is using default(T). When you call default on a value type or a string, it initializes it to a reasonable value (such as empty string). When you call default(T) on an object, it returns null. For various reasons we need to ensure that if it is not a primitive type, then we will have a default instance of the type, not null. Here is attempt 1: T createDefault() { if(typeof(T).IsValueType) { return default(T); } else { return Activator.CreateInstance<T>(); } } Problem - string is not a value type, but it does not have a parameterless constructor. So, the current solution is: T createDefault() { if(typeof(T).IsValueType || typeof(T).FullName == "System.String") { return default(T); } else { return Activator.CreateInstance<T>(); } } But this feels like a kludge. Is there a nicer way to handle the string case?

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  • is there some lightweight tecnique for adding type safety to identifier properties?

    - by shoren
    After using C++ I got used to the concept of Identifier which can be used with a class for the type, provides type safety and has no runtime overhead (the actual size is the size of the primitive). I want to do something like that, so I will not make mistakes like: personDao.find(book.getId());//I want compilation to fail personDao.find(book.getOwnerId());//I want compilation to succeed Possible solutuions that I don't like: For every entity have an entity id class wrapping the id primitive. I don't like the code bloat. Create a generic Identifier class. Code like this will not compile: void foo(Identifier book); void foo(Identifier person); Does anyone know of a better way? Is there a library with a utility such as this? Is implementing this an overkill? And the best of all, can this be done in Java without the object overhead like in C++?

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  • Is it guaranteed that new Integer(i) == i in Java?

    - by polygenelubricants
    Consider the following snippet: int i = 99999999; byte b = 99; short s = 9999; Integer ii = Integer.valueOf(9); // should be within cache System.out.println(new Integer(i) == i); // "true" System.out.println(new Integer(b) == b); // "true" System.out.println(new Integer(s) == s); // "true" System.out.println(new Integer(ii) == ii); // "false" It's obvious why the last line will ALWAYS prints "false": we're using == reference identity comparison, and a new object will NEVER be == to an already existing object. The question is about the first 3 lines: are those comparisons guaranteed to be on the primitive int, with the Integer auto-unboxed? Are there cases where the primitive would be auto-boxed instead, and reference identity comparisons are performed? (which would all then be false!)

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