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  • Time passage arithmetic explanation

    - by Cyber Axe
    I ported this from http://www.effectgames.com/effect/article.psp.html/joe/Old_School_Color_Cycling_with_HTML5 some time ago. However i'm now wanting to modify it for the purpose of changing it from floating point to fixed point maths for enhanced efficiency (for those who are going to talk about premature optimization and what not, i want to have my entire engine in fixed point both as a learning process for me and so i can port code more easily to systems in the future that dont have native floating points such as arm cpus) My initial conversion to fixed points just resulted in the cycling stuck on either the first or last frame of cycling. Plus it would be nice to understand better how it works so i can add more options and so forth in the future, my maths however sucks and the comments are limited so i don't really know how the maths work for determining the frame it shoud use (cycleAmount) I was also a beginner when i ported it as i had no idea between floating points and integers and what not. So in summary my question is, can anyone give an explination of the arithmatic used for determining the cycleAmount (which determings the "frame" of the cycle) This is the working floating point maths version of the code: public final void cycle(Colour[] sourceColours, double timeNow, double speedAdjust) { // Cycle all animated colour ranges in palette based on timestamp. sourceColours = sourceColours.clone(); int cycleSize; double cycleRate; double cycleAmount; Cycle cycle; for (int i = 0, len = cycles.length; i < len; ++i) { cycle = cycles[i]; cycleSize = (cycle.HIGH - cycle.LOW) + 1; cycleRate = cycle.RATE / (int) (CYCLE_SPEED / speedAdjust); cycleAmount = 0; if (cycle.REVERSE < 3) { // Standard Cycle cycleAmount = DFLOAT_MOD((timeNow / (1000 / cycleRate)), cycleSize); if (cycle.REVERSE < 1) { cycleAmount = cycleSize - cycleAmount; // If below 1 make sure its not reversed. } } else if (cycle.REVERSE == 3) { // Ping-Pong cycleAmount = DFLOAT_MOD((timeNow / (1000 / cycleRate)), cycleSize << 1); if (cycleAmount >= cycleSize) { cycleAmount = (cycleSize * 2) - cycleAmount; } } else if (cycle.REVERSE < 6) { // Sine Wave cycleAmount = DFLOAT_MOD((timeNow / (1000 / cycleRate)), cycleSize); cycleAmount = Math.sin((cycleAmount * 3.1415926 * 2) / cycleSize) + 1; if (cycle.REVERSE == 4) { cycleAmount *= (cycleSize / 4); } else if (cycle.REVERSE == 5) { cycleAmount *= (cycleSize >> 1); } } if (cycle.REVERSE == 2) { reverseColours(sourceColours, cycle); } if (USE_BLEND_SHIFT) { blendShiftColours(sourceColours, cycle, cycleAmount); } else { shiftColours(sourceColours, cycle, cycleAmount); } if (cycle.REVERSE == 2) { reverseColours(sourceColours, cycle); } } colours = sourceColours; } // This utility function allows for variable precision floating point modulus. private double DFLOAT_MOD(final double d, final double b) { return (Math.floor(d * PRECISION) % Math.floor(b * PRECISION)) / PRECISION; }

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  • ArchBeat Link-o-Rama for 11/17/2011

    - by Bob Rhubart
    Building an Infrastructure Cloud with Oracle VM for x86 + Enterprise Manager 12c | Richard Rotter Richard Rotter demonstrates "how easy it could be to build a cloud infrastructure with Oracle's solution for cloud computing." Article: Social + Lean = Agile | Dave Duggal In today’s increasingly dynamic business environment, organizations must continuously adapt to survive. Change management has become a major bottleneck. Organizations’ need a practical mechanism for managing controlled variance and change in-flight to break the logjam. This paper provides a foundation for applying lean and agile principles to achieve Enterprise Agility through social collaboration. Stress Testing Java EE 6 Applications - Free Article In Free Java Magazine : Adam Bien "It is strange," says Adam Bien, "everyone is obsessed about green bars and code coverage, but testing of multi threaded behavior is widely ignored - until the applications run into massive problems." Using Access Manager to Secure Applications Deployed on WebLogic | Rene van Wijk Another great how-to post from Oracle ACE Rene van Wijk, this time involving JBoss RichFaces, Facelets, Oracle Coherence, and Oracle WebLogic Server. DOAG 2011 vs. Devoxx - Value and Attraction | Markus Eisele Oracle ACE Director Markus Eisele compares and contrasts these popular conferences with the aim of helping others decide which to attend. SOA All the Time; Architects in AZ; Clearing Info Integration hurdles SOA all the Time; Architects in AZ; Clearing Info Integration Hurdles This week on the Architect Home Page on OTN. Webcast: Oracle Business Intelligence Mobile Event Date: Wednesday, December 7, 2011 Time: 10 a.m. PT/1 p.m. ET Featuring Manan Goel (Director BI Product Marketing, Oracle) and Shailesh Shedge (Director BI and Analytics Practice, Ascentt). Webcast: Maximum Availability on Private Clouds A discussion of Oracle’s Maximum Availability Architecture, Oracle Database 11g, Oracle Exadata Database Machine, and Oracle Database appliance, featuring Margaret Hamburger (Director, Product Marketing, Oracle) and Joe Meeks (Director, Product Management, Oracle). November 30, 2011 at 10:00am PT / 1:00pm ET. Oracle Technology Network Architect Day - Phoenix, AZ Wednesday December 14, 2011, 8:30am - 5:00pm. The Ritz-Carlton, Phoenix, 2401 East Camelback Road, Phoenix, AZ 85016. Registration is free, but seating is limited.

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  • ArchBeat Link-o-Rama for 2012-06-14

    - by Bob Rhubart
    Duke's Choice Award Nominations Close Friday! | The Java Source The Duke's Choice Awards celebrate extreme innovation in the world of Java technology. Nominate an individual, a group or company who show the best in Java innovation. Nominate at Java.net/dukeschoice. Nominations are open until this Friday, June 15. Whole Lotta Virtualization Goin' On | Rick Ramsey The OTN Garage's Rick Ramsey shares a list of recent Virtualization articles available on OTN, along with a link to a video by The Killer, Mr Jerry Lee Lewis. A Pragmatic Path to Navigating your Infrastructure to the Cloud | The WebLogic Server Blog Ruma Sanyal offers an overview of a recent Oracle webcast featuring Gartner VP and Distinguished Analyst Andy Butler and Vice President and Gartner Fellow Massimo Pezzini. Migrating C/C++ embedded SQL code | Tom Laszewski Cloud migration expert Tom Laszewski explains the how-to in 5 easy steps. Aetna Dumps Its Siloed Enterprise Architecture for SOA | CIO.com CIO writer Stephanie Overby tells the story of how one major health insurance provider put the "Enterprise" back in Enterprise Architecture. (H/T to Joe McKendrick for this story.) Downloading specific video renditions in WebCenter Content | Kyle Hatlestad How-to from Oracle WebCenter & ADF A-Team blogger Kyle Hatlestad. Eclipse DemoCamp - June 2012 - Redwood Shores, CA Location: Oracle HQ - 10 Twin Dolphin Drive, Redwood Shores, CA (Map) Date and Time: Wednesday, June 13, 2012. From 6pm - 9pm Agenda: The evolution of Java persistence, Doug Clarke, EclipseLink Project Lead, Oracle Integrating BIRT into Applications, Ashwini Verma, Actuate Corporation Leveraging OSGi In The Enterprise, Kamal Muralidharan, Lead Engineer, eBay Developing Rich ADF Applications with Java EE, Greg Stachnick, Oracle NVIDIA® NsightTM Eclipse Edition, Goodwin (Tech lead - Visual tools), Eugene Ostroukhov (Senior engineer – Visual tools) 2012 Oracle Fusion Middleware Innovation Awards - Win a FREE Pass to Oracle OpenWorld 2012 in San Francisco Share your use of Oracle Fusion Middleware solutions and how they help your organization drive business innovation. You just might win a free pass to Oracle Openworld 2012 in San Francisco. Deadline for submissions in July 17, 2012. BI Architecture Master Class for Partners – Oracle Architecture Unplugged Date: June 21, 2012 No slides, no fluff. This workshop will be highly interactive and is aimed at Oracle OPN member partners who are IT Architects and BI+W specialists. The focus will be on architectural issues and considerations. DevOps: Evolving to Handle Disruption | JP Morgenthal The subject of DevOps came up this week during an OTN ArchBeat podcast interview with Ron Batra and James Baty on the role of the cloud architect (that program will be available in a few weeks). Morgenthal's article for InfoQ offers a good overview of what DevOps is and how it works. Thought for the Day "Elegance is not a dispensable luxury but a factor that decides between success and failure." — Edsger Dijkstra Source: softwarequotes.com

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  • ArchBeat Facebook Friday: Top 10 Posts - August 15-21, 2014

    - by Bob Rhubart-Oracle
    As hot as molten rock? Not quite. But among the 5,313 fans of the OTN ArchBeat Facebook Page these Top 10 items were the hottest over the past seven days, August 15-21, 2014. Oracle BPM 12c Gateways (Part 1 of 5): Exclusive Gateway | Antonis Antoniou Oracle ACE Associate Antonis Antoniou begins a five-part series with a look at In the gateway control flow components in Oracle BPM and how they can be used to process flow. Slicing the EDG: Different SOA Domain Configurations | Antony Reynolda Antony Reynolds introduces three different configurations for a SOA environment and identifies some of the advantages for each. How to introduce DevOps into a moribund corporate culture | ZDNet Confused about DevOPs? This post from ZDNet's Joe McKendrick -- which includes insight from Phil Whelan -- just might clear some of the fog. Oracle Identity Manager Role Management With API | Mustafa Kaya Mustafa Kaya shares some examples of role management using the Oracle Identity Management API. Podcast: Redefining Information Management Architecture Oracle Enterprise Architect Andrew Bond joins Oracle ACE Directors Mark Rittman and Stewart Bryson for a conversation about their collaboration on a new Oracle Information Management Reference Architecture. WebCenter Sites Demo Integration with Endeca Guided Search | Micheal Sullivan A-Team solution architect Michael Sullivan shares the details on a demo that illustrates the viability of integrating WebCenter Sites with Oracle Endeca. Wearables in the world of enterprise applications? Yep. Oh yeah, wearables are a THING. Here's a look at how the Oracle Applications User Experience team has been researching wearables for inclusion in your future enterprise applications. Getting Started With The Coherence Memcached Adaptor | David Felcey Let David Felcey show you how to configure the Coherence Memcached Adaptor, and take advantage of his simple PHP example that demonstrates how Memecached clients can connect to a Coherence cluster. OTN Architect Community Newsletter - August Edition A month's worth of hot stuff, all in one spot. Featuring articles on Java, Coherence, WebLogic, Mobile and much more. 8,853 Conversations About Oracle WebLogic Do you have a question about WebLogic? Do you have an answer to a question about WebLogic? You need to be here.

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  • ArchBeat Link-o-Rama for 2012-08-28

    - by Bob Rhubart
    You may be tempted by IaaS, but you should PaaS on that or your database cloud journey will be a short one "The better option [to IaaS] is to rationalize the deployment stack so that VMs are needed only for exceptional cases," says B. R. Clouse. "By settling on a standard operating system and patch level, you create an infrastructure that potentially all of your databases can share. Now, the building block will be database instances or possibly schemas within databases. These components are the platforms on which you will deploy workloads, hence this is known as Platform as a Service (PaaS)." 'Shadow IT' can be the cloud's best friend | David Linthicum "I do not advocate that IT give up control and allow business units to adopt any old technology they want," says Infoworld cloud computing blogger David Linthicum. "However, IT needs to face reality: For the past three decades or so, corporate IT has been slow on the uptake around the use of productive new technologies." Do you agree? 9 ways cloud will impact IT employment | ZDNet ZDNet blogger Joe McKendrick condenses information from a recent report on how cloud computing will impact IT jobs. Number one on the list: New categories of jobs arising from cloud computing, which include "private cloud developers and administrators, departmental liaisons, integration specialists, cloud architects, and compliance specialists." Yeah, that's right, cloud architects. For more on cloud architects, including what you need to up your game to thrive in the cloud, check out "The Role of the Cloud Architect" on the OTN ArchBeat Podcast. Decisions, Decisions: The art, science, and politics of technology selection "When the time comes for a solution architect to make the final decision about the technologies, standards, and other elements that are to be incorporated into a particular project, what factors weigh most heavily on that decision? It comes as no surprise that among the architects I contacted, business needs top the list." Managing Oracle Exalogic Elastic Cloud with Oracle Enterprise Manager Ops Center Anand Akela's byline is on this post, but "Dr. Jürgen Fleischer, Oracle Enterprise Manager Ops Center Engineering" appears at the end of the post, so it's anybody's guess as to who wrote this thing. But the content includes a complete listing of the Exalogic 2.0.1 Tea Break Snippets series written by a member of the Exalogic team who goes by the name "The Old Toxophilist." So maybe the best thing to do here is ignore the names and focus on the very useful conent. Boost your infrastructure with Coherence into the Cloud | Nino Guarnacci Nino Guarnacci describes a use case that involved managing a variety of data caches that process complex queries and parallel computational operations, in order to maintain the caches in a consistent state on different server instances. Thought for the Day "No one hates software more than software developers." — Jeff Atwood Source: SoftwareQuotes

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  • Subterranean IL: Volatile

    - by Simon Cooper
    This time, we'll be having a look at the volatile. prefix instruction, and one of the differences between volatile in IL and C#. The volatile. prefix volatile is a tricky one, as there's varying levels of documentation on it. From what I can see, it has two effects: It prevents caching of the load or store value; rather than reading or writing to a cached version of the memory location (say, the processor register or cache), it forces the value to be loaded or stored at the 'actual' memory location, so it is then immediately visible to other threads. It forces a memory barrier at the prefixed instruction. This ensures instructions don't get re-ordered around the volatile instruction. This is slightly more complicated than it first seems, and only seems to matter on certain architectures. For more details, Joe Duffy has a blog post going into the details. For this post, I'll be concentrating on the first aspect of volatile. Caching field accesses To demonstrate this, I created a simple multithreaded IL program. It boils down to the following code: .class public Holder { .field public static class Holder holder .field public bool stop .method public static specialname void .cctor() { newobj instance void Holder::.ctor() stsfld class Holder Holder::holder ret }}.method private static void Main() { .entrypoint // Thread t = new Thread(new ThreadStart(DoWork)) // t.Start() // Thread.Sleep(2000) // Console.WriteLine("Stopping thread...") ldsfld class Holder Holder::holder ldc.i4.1 stfld bool Holder::stop call instance void [mscorlib]System.Threading.Thread::Join() ret}.method private static void DoWork() { ldsfld class Holder Holder::holder // while (!Holder.holder.stop) {} DoWork: dup ldfld bool Holder::stop brfalse DoWork pop ret} If you compile and run this code, you'll find that the call to Thread.Join() never returns - the DoWork spinlock is reading a cached version of Holder.stop, which is never being updated with the new value set by the Main method. Adding volatile to the ldfld fixes this: dupvolatile.ldfld bool Holder::stopbrfalse DoWork The volatile ldfld forces the field access to read direct from heap memory, which is then updated by the main thread, rather than using a cached copy. volatile in C# This highlights one of the differences between IL and C#. In IL, volatile only applies to the prefixed instruction, whereas in C#, volatile is specified on a field to indicate that all accesses to that field should be volatile (interestingly, there's no mention of the 'no caching' aspect of volatile in the C# spec; it only focuses on the memory barrier aspect). Furthermore, this information needs to be stored within the assembly somehow, as such a field might be accessed directly from outside the assembly, but there's no concept of a 'volatile field' in IL! How this information is stored with the field will be the subject of my next post.

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  • Maximum Availability with Oracle GoldenGate

    - by Irem Radzik
    Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Oracle Database offers a variety of built-in and optional products for maximum availability, and it is well known for its robust high availability and disaster recovery solutions. With its heterogeneous, real-time, transactional data movement capabilities, Oracle GoldenGate is a key part of the Maximum Availability Architecture for Oracle Database. This week on Thursday Dec. 13th we will be presenting in a live webcast how Oracle GoldenGate fits into Oracle Database Maximum Availability Architecture (MAA). Joe Meeks from the Oracle Database High Availability team will discuss how Oracle GoldenGate complements other key products within MAA such as Active Data Guard. Nick Wagner from GoldenGate PM team will present how to upgrade to latest Oracle Database release without any downtime. Nick will also cover 2 new features of  Oracle GoldenGate 11gR2:  Integrated Capture for Oracle Database and Automated Conflict Detection and Resolution. Nick will provide in depth review of these new features with examples. Oracle GoldenGate also offers maximum availability for non-Oracle databases, such as HP NonStop, SQL Server, DB2 (LUW, iSeries, or zSeries) and more. The same robust, reliable real-time, bidirectional data movement capabilities apply to all supported databases.  I'd like to invite you to join us on Thursday Dec. 13th 10am PT/1pm ET to hear from the product experts on how to use GoldenGate for maximizing database availability and to ask your questions. You can find the registration link below. Webcast: Maximum Availability with Oracle GoldenGate Thursday Dec. 13th 10am PT/1pm ET Look forward to another great webcast with lots of interaction with the audience. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;}

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  • ArchBeat Link-o-Rama for November 16, 2012

    - by Bob Rhubart
    X.509 Certificate Revocation Checking Using OCSP protocol with Oracle WebLogic Server 12c | Abhijit Patil Abhijit Patil's article focuses on how to use X.509 Certificate Revocation Checking Functionality with the OCSP protocol to validate in-bound certificates. Although this article focuses on inbound OCSP validation using OCSP, Oracle WebLogic Server 12c also supports outbound OCSP validation. Leveraging Oracle Scorecard and Strategy Management for Everyday BI Needs "Oracle Scorecard and Strategy Management (OSSM) is built-upon the premise that a scorecard system should not be separate from the BI system, like many comparable tools are today," says author Kevin McGinely. "Instead of a separate application with its own data, its own data definitions, and its own front-end, Oracle made the choice to integrate OSSM directly into OBIEE." Applying BI for personal productivity recognition and gamification | Capgemini Oracle Blog "It is quite obvious that if you want people to participate you need an appealing and intuitive user interface," says Capgemini's Henk Vermeulen in this interesting exploration of gamification in the enterprise. Build and release OSB projects with Maven | Edwin Biemond "With Maven we are able to build and deploy OSB projects," says Oracle ACE Edwin Biemond. "The artifacts generated by Maven called snaphosts and releases can be automatically uploaded to a software repository. These versioned OSB jars can then be downloaded by the OSB Servers and deployed." Biemond shows you how in this detailed technical post. ADF Generator for Dynamic ADF BC and ADF UI | Andrejus Baranovskis Oracle ACE Director Andrejus Baranovskis' post is an extension of his OOW12 presentation, "Oracle ADF Implementations Around the Globe: Best Practices," and includes the sample application he promised to share. Service-oriented organizations have a head start in the cloud race | ZDNet ZDNet SOA blogger Joe McKendrick offers a snapshot of a recent report Forrester analyst James Staten. Oracle Fusion Middleware Security: X509 Fallback to Form | Debasish BhattacharyaOracle Fusion Middleware A-Team architect Debasish Bhattacharya shares a solution that resulted from brainstorming with colleagues Chris Johnson and Brian Eidelman. "The solution is not very difficult," says Bhattacharya, "though it needs some additional configurations and coding." It's all presented in this detailed post. Agile Architecture | David Sprott "There is ample evidence that Agile Architecture is a primary contributor to business agility, yet we do not have a well understood architecture management system that integrates with Agile methods," observes David Sprott in this extensive post. Thought for the Day "Operating systems are like underwear — nobody really wants to look at them." — Bill Joy Source: SoftwareQuotes.com

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  • Traditional POS is Dead

    - by David Dorf
    Traditional POS is dead -- I've heard that one before. Here's an excerpt from Joe Skorupa's blog over at RIS where he relayed ten trends that were presented at NRF. 7. Mobile POS signals death of traditional POS. Shoppers don't love self-checkout, but they prefer it to long queues or dealing with associates. Fixed POS is expensive and bulky. Mobile POS frees floor space for other purposes and converts associates from being cashiers to being sales assistants that provide new levels of customer service and incremental basket sales. In addition to unplugging the POS, new alternatives are starting to take hold - thin client, POS as a service, and replacing POS software with e-commerce platforms. I'll grant that in some situations for some retailers there might be an opportunity to to ditch the traditional POS, but for the majority of retailers that's just not practical. Take it from a guy that had to wake up at 3am after every Thanksgiving to monitor POS systems across the US on Black Friday. If a retailer's website goes down on Black Friday, they will take a significant hit. If a retailer's chain-wide POS system goes down on Black Friday, that retailer will cease to exist. Mobile POS works great for Apple because the majority of purchases are one or two big-ticket items that don't involve cash. There's still a traditional POS in every store to fall back on (its just hidden). Try this at home: Choose your favorite e-commerce site and add an item to the cart while timing how long it takes. Now multiply that by 15 to represent the 15 items you might buy at store like Target. The user interface isn't optimized for bulk purchases, and that's how it should be. The webstore and POS are designed for different purposes. Self-checkout is a great addition to POS and so is mobile checkout. But they add capabilities to POS, not replace it. Centralized architectures, even those based in the cloud, are quite viable as long as there's resiliency in the registers. You cannot assume perfect access to the network, so a POS must always be able to sell regardless of connectivity. Clearly the different selling channels should be sharing common functionality. Things like calculating tax, accepting coupons, and processing electronic payments can be shared, usually through a service-oriented architecture. This lowers costs and providers greater consistency, both of which help retailers. On paper these technologies look really good and we should continue to push boundaries, but I'm not ready to call the patient dead just yet.

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  • Primefaces tabview: set the active index on tab change

    - by Virgi
    I've got a tab view that contains two tab. When I switch from tab 1 to tab 2, I'm calling some code that executes a validation and updates some values. Depending on the result of this validation, I would like to stay on tab 1, or go to tab 2, and refresh the tabs' content. My tabview: <h:form id="form"> <p:tabView id="tabview" activeIndex="#{ctrl.idx}" dynamic="true" cache="false"> <p:ajax event="tabChange" listener="#{ctrl.doStuff}" update=":form:tabview"/> <p:tab title="Tab 1" id="t1"> <h:panelGrid columns="1" cellpadding="10"> <h:outputText value="#{ctrl.s1}"/> </h:panelGrid> </p:tab> <p:tab title="Tab 2" id="t2"> <h:panelGrid columns="1" cellpadding="10"> <h:outputText value="#{ctrl.s2}"/> </h:panelGrid> </p:tab> </p:tabView> </h:form> My test code that simly changes the values: public void doStuff() { s1 = String.valueOf(Math.random()); s2 = String.valueOf(Math.random()); } I thought that changing the active tab index in my method would be enough, like that: public void doStuff() { // ... idx = 0; } On tabChange event, the method is called but the tabview components goes to the clicked tab, ignoring the idx new value. I thought adding an update attribute to p:ajax would render the whole tabview but only the tabs and/or the tabs' content is re rendered. And weirdest of all, if I change update=":form:tabview" to update=":form" or update="@form", I only receive the tab's content in the ajax response - the component disappears from the page! My bean is viewscoped, I'm using Primefaces 3.5, JSF 2.1 and Tomcat 7. Any idea? Thanks.

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  • Moq how to correctly mock read-only properties or set only properies

    - by Chris Marisic
    What is the correct way for dealing with interfaces the expose only read-only or set-only properties with Moq? Previously I've added the other accessor but this has bleed into my domain too far with random throw new NotImplementedException() statements throughout. I just want to do something simple like mock.VerifySet(view => view.SetOnlyValue, Times.Never()); But this is a compile error of The property 'SetOnlyValue' has no getter

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  • Implementation of ZipCrypto / Zip 2.0 encryption in java

    - by gomesla
    I'm trying o implement the zipcrypto / zip 2.0 encryption algoritm to deal with encrypted zip files as discussed in http://www.pkware.com/documents/casestudies/APPNOTE.TXT I believe I've followed the specs but just can't seem to get it working. I'm fairly sure the issue has to do with my interpretation of the crc algorithm. The documentation states CRC-32: (4 bytes) The CRC-32 algorithm was generously contributed by David Schwaderer and can be found in his excellent book "C Programmers Guide to NetBIOS" published by Howard W. Sams & Co. Inc. The 'magic number' for the CRC is 0xdebb20e3. The proper CRC pre and post conditioning is used, meaning that the CRC register is pre-conditioned with all ones (a starting value of 0xffffffff) and the value is post-conditioned by taking the one's complement of the CRC residual. Here is the snippet that I'm using for the crc32 public class PKZIPCRC32 { private static final int CRC32_POLYNOMIAL = 0xdebb20e3; private int crc = 0xffffffff; private int CRCTable[]; public PKZIPCRC32() { buildCRCTable(); } private void buildCRCTable() { int i, j; CRCTable = new int[256]; for (i = 0; i <= 255; i++) { crc = i; for (j = 8; j > 0; j--) if ((crc & 1) == 1) crc = (crc >>> 1) ^ CRC32_POLYNOMIAL; else crc >>>= 1; CRCTable[i] = crc; } } private int crc32(byte buffer[], int start, int count, int lastcrc) { int temp1, temp2; int i = start; crc = lastcrc; while (count-- != 0) { temp1 = crc >>> 8; temp2 = CRCTable[(crc ^ buffer[i++]) & 0xFF]; crc = temp1 ^ temp2; } return crc; } public int crc32(int crc, byte buffer) { return crc32(new byte[] { buffer }, 0, 1, crc); } } Below is my complete code. Can anyone see what I'm doing wrong. package org.apache.commons.compress.archivers.zip; import java.io.IOException; import java.io.InputStream; public class ZipCryptoInputStream extends InputStream { public class PKZIPCRC32 { private static final int CRC32_POLYNOMIAL = 0xdebb20e3; private int crc = 0xffffffff; private int CRCTable[]; public PKZIPCRC32() { buildCRCTable(); } private void buildCRCTable() { int i, j; CRCTable = new int[256]; for (i = 0; i <= 255; i++) { crc = i; for (j = 8; j > 0; j--) if ((crc & 1) == 1) crc = (crc >>> 1) ^ CRC32_POLYNOMIAL; else crc >>>= 1; CRCTable[i] = crc; } } private int crc32(byte buffer[], int start, int count, int lastcrc) { int temp1, temp2; int i = start; crc = lastcrc; while (count-- != 0) { temp1 = crc >>> 8; temp2 = CRCTable[(crc ^ buffer[i++]) & 0xFF]; crc = temp1 ^ temp2; } return crc; } public int crc32(int crc, byte buffer) { return crc32(new byte[] { buffer }, 0, 1, crc); } } private static final long ENCRYPTION_KEY_1 = 0x12345678; private static final long ENCRYPTION_KEY_2 = 0x23456789; private static final long ENCRYPTION_KEY_3 = 0x34567890; private InputStream baseInputStream = null; private final PKZIPCRC32 checksumEngine = new PKZIPCRC32(); private long[] keys = null; public ZipCryptoInputStream(ZipArchiveEntry zipEntry, InputStream inputStream, String passwd) throws Exception { baseInputStream = inputStream; // Decryption // ---------- // PKZIP encrypts the compressed data stream. Encrypted files must // be decrypted before they can be extracted. // // Each encrypted file has an extra 12 bytes stored at the start of // the data area defining the encryption header for that file. The // encryption header is originally set to random values, and then // itself encrypted, using three, 32-bit keys. The key values are // initialized using the supplied encryption password. After each byte // is encrypted, the keys are then updated using pseudo-random number // generation techniques in combination with the same CRC-32 algorithm // used in PKZIP and described elsewhere in this document. // // The following is the basic steps required to decrypt a file: // // 1) Initialize the three 32-bit keys with the password. // 2) Read and decrypt the 12-byte encryption header, further // initializing the encryption keys. // 3) Read and decrypt the compressed data stream using the // encryption keys. // Step 1 - Initializing the encryption keys // ----------------------------------------- // // Key(0) <- 305419896 // Key(1) <- 591751049 // Key(2) <- 878082192 // // loop for i <- 0 to length(password)-1 // update_keys(password(i)) // end loop // // Where update_keys() is defined as: // // update_keys(char): // Key(0) <- crc32(key(0),char) // Key(1) <- Key(1) + (Key(0) & 000000ffH) // Key(1) <- Key(1) * 134775813 + 1 // Key(2) <- crc32(key(2),key(1) >> 24) // end update_keys // // Where crc32(old_crc,char) is a routine that given a CRC value and a // character, returns an updated CRC value after applying the CRC-32 // algorithm described elsewhere in this document. keys = new long[] { ENCRYPTION_KEY_1, ENCRYPTION_KEY_2, ENCRYPTION_KEY_3 }; for (int i = 0; i < passwd.length(); ++i) { update_keys((byte) passwd.charAt(i)); } // Step 2 - Decrypting the encryption header // ----------------------------------------- // // The purpose of this step is to further initialize the encryption // keys, based on random data, to render a plaintext attack on the // data ineffective. // // Read the 12-byte encryption header into Buffer, in locations // Buffer(0) thru Buffer(11). // // loop for i <- 0 to 11 // C <- buffer(i) ^ decrypt_byte() // update_keys(C) // buffer(i) <- C // end loop // // Where decrypt_byte() is defined as: // // unsigned char decrypt_byte() // local unsigned short temp // temp <- Key(2) | 2 // decrypt_byte <- (temp * (temp ^ 1)) >> 8 // end decrypt_byte // // After the header is decrypted, the last 1 or 2 bytes in Buffer // should be the high-order word/byte of the CRC for the file being // decrypted, stored in Intel low-byte/high-byte order. Versions of // PKZIP prior to 2.0 used a 2 byte CRC check; a 1 byte CRC check is // used on versions after 2.0. This can be used to test if the password // supplied is correct or not. byte[] encryptionHeader = new byte[12]; baseInputStream.read(encryptionHeader); for (int i = 0; i < encryptionHeader.length; i++) { encryptionHeader[i] ^= decrypt_byte(); update_keys(encryptionHeader[i]); } } protected byte decrypt_byte() { byte temp = (byte) (keys[2] | 2); return (byte) ((temp * (temp ^ 1)) >> 8); } @Override public int read() throws IOException { // // Step 3 - Decrypting the compressed data stream // ---------------------------------------------- // // The compressed data stream can be decrypted as follows: // // loop until done // read a character into C // Temp <- C ^ decrypt_byte() // update_keys(temp) // output Temp // end loop int read = baseInputStream.read(); read ^= decrypt_byte(); update_keys((byte) read); return read; } private final void update_keys(byte ch) { keys[0] = checksumEngine.crc32((int) keys[0], ch); keys[1] = keys[1] + (byte) keys[0]; keys[1] = keys[1] * 134775813 + 1; keys[2] = checksumEngine.crc32((int) keys[2], (byte) (keys[1] >> 24)); } }

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  • Card Shuffling in C#

    - by Jeff
    I am trying to write a code for a project that lists the contents of a deck of cards, asks how much times the person wants to shuffle the deck, and then shuffles them. It has to use a method to create two random integers using the System.Random class. These are my classes: Program.cs: using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication3 { class Program { static void Main(string[] args) { Deck mydeck = new Deck(); foreach (Card c in mydeck.Cards) { Console.WriteLine(c); } Console.WriteLine("How Many Times Do You Want To Shuffle?"); } } } Deck.cs: using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication3 { class Deck { Card[] cards = new Card[52]; string[] numbers = new string[] { "2", "3", "4", "5", "6", "7", "8", "9", "J", "Q", "K" }; public Deck() { int i = 0; foreach(string s in numbers) { cards[i] = new Card(Suits.Clubs, s); i++; } foreach (string s in numbers) { cards[i] = new Card(Suits.Spades, s); i++; } foreach (string s in numbers) { cards[i] = new Card(Suits.Hearts, s); i++; } foreach (string s in numbers) { cards[i] = new Card(Suits.Diamonds, s); i++; } } public Card[] Cards { get { return cards; } } } } classes.cs: using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication3 { enum Suits { Hearts, Diamonds, Spades, Clubs } } Card.cs: using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication3 { class Card { protected Suits suit; protected string cardvalue; public Card() { } public Card(Suits suit2, string cardvalue2) { suit = suit2; cardvalue = cardvalue2; } public override string ToString() { return string.Format("{0} of {1}", cardvalue, suit); } } } Please tell me how to make the cards shuffle as much as the person wants and then list the shuffled cards. Sorry about the formatting im new to this site.

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  • HDF5 .Net wrapper

    - by UshaP
    I'm getting ( http://www.hdfgroup.org/projects/hdf.net/) The specified module could not be found. (Exception from HRESULT: 0x8007007E) from the dependency walker i'm seeing that SZLIBDLL.DLL is missing i tried to download it from random place but then i got another error. Does any one had that problem? i tried also vs2005 and vs2008 Thanks, Pini.

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  • Eclipse Search Menus disabled randomly

    - by MetroidFan2002
    I use Eclipse 3.3 in my daily work, and have also used Eclipse 3.2 extensively as well. In both versions, sometimes the Search options (Java Search, File Search, etc) in the menu get disabled, seemingly at random times. However, with CTRL + H, I am able to access the search functionality. Does anyone know why this happens? Has it been fixed in Eclipse 3.4?

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  • iphone: Help with AudioToolbox Leak: Stack trace/code included here...

    - by editor guy
    Part of this app is a "Scream" button that plays random screams from cast members of a TV show. I have to bang on the app quite a while to see a memory leak in Instruments, but it's there, occasionally coming up (every 45 seconds to 2 minutes.) The leak is 3.50kb when it occurs. Haven't been able to crack it for several hours. Any help appreciated. Instruments says this is the offending code line: [appSoundPlayer play]; that's linked to from line 9 of the below stack trace: 0 libSystem.B.dylib malloc 1 libSystem.B.dylib pthread_create 2 AudioToolbox CAPThread::Start() 3 AudioToolbox GenericRunLoopThread::Start() 4 AudioToolbox AudioQueueNew(bool, AudioStreamBasicDescription const*, TCACallback const&, CACallbackTarget const&, unsigned long, OpaqueAudioQueue*) 5 AudioToolbox AudioQueueNewOutput 6 AVFoundation allocAudioQueue(AVAudioPlayer, AudioPlayerImpl*) 7 AVFoundation prepareToPlayQueue(AVAudioPlayer*, AudioPlayerImpl*) 8 AVFoundation -[AVAudioPlayer prepareToPlay] 9 Scream Queens -[ScreamViewController scream:] /Users/laptop2/Desktop/ScreamQueens Versions/ScreamQueens25/Scream Queens/Classes/../ScreamViewController.m:210 10 CoreFoundation -[NSObject performSelector:withObject:withObject:] 11 UIKit -[UIApplication sendAction:to:from:forEvent:] 12 UIKit -[UIApplication sendAction:toTarget:fromSender:forEvent:] 13 UIKit -[UIControl sendAction:to:forEvent:] 14 UIKit -[UIControl(Internal) _sendActionsForEvents:withEvent:] 15 UIKit -[UIControl touchesEnded:withEvent:] 16 UIKit -[UIWindow _sendTouchesForEvent:] 17 UIKit -[UIWindow sendEvent:] 18 UIKit -[UIApplication sendEvent:] 19 UIKit _UIApplicationHandleEvent 20 GraphicsServices PurpleEventCallback 21 CoreFoundation CFRunLoopRunSpecific 22 CoreFoundation CFRunLoopRunInMode 23 GraphicsServices GSEventRunModal 24 UIKit -[UIApplication _run] 25 UIKit UIApplicationMain 26 Scream Queens main /Users/laptop2/Desktop/ScreamQueens Versions/ScreamQueens25/Scream Queens/main.m:14 27 Scream Queens start Here's .h: #import <UIKit/UIKit.h> #import <AVFoundation/AVFoundation.h> #import <MediaPlayer/MediaPlayer.h> #import <AudioToolbox/AudioToolbox.h> #import <MessageUI/MessageUI.h> #import <MessageUI/MFMailComposeViewController.h> @interface ScreamViewController : UIViewController <UIApplicationDelegate, AVAudioPlayerDelegate, MFMailComposeViewControllerDelegate> { //AudioPlayer related AVAudioPlayer *appSoundPlayer; NSURL *soundFileURL; BOOL interruptedOnPlayback; BOOL playing; //Scream button related IBOutlet UIButton *screamButton; int currentScreamIndex; NSString *currentScream; NSMutableArray *screams; NSMutableArray *personScreaming; NSMutableArray *photoArray; int currentSayingsIndex; NSString *currentButtonSaying; NSMutableArray *funnyButtonSayings; IBOutlet UILabel *funnyButtonSayingsLabel; IBOutlet UILabel *personScreamingField; IBOutlet UIImageView *personScreamingImage; //Mailing the scream related IBOutlet UILabel *mailStatusMessage; IBOutlet UIButton *shareButton; } //AudioPlayer related @property (nonatomic, retain) AVAudioPlayer *appSoundPlayer; @property (nonatomic, retain) NSURL *soundFileURL; @property (readwrite) BOOL interruptedOnPlayback; @property (readwrite) BOOL playing; //Scream button related @property (nonatomic, retain) UIButton *screamButton; @property (nonatomic, retain) NSMutableArray *screams; @property (nonatomic, retain) NSMutableArray *personScreaming; @property (nonatomic, retain) NSMutableArray *photoArray; @property (nonatomic, retain) UILabel *personScreamingField; @property (nonatomic, retain) UIImageView *personScreamingImage; @property (nonatomic, retain) NSMutableArray *funnyButtonSayings; @property (nonatomic, retain) UILabel *funnyButtonSayingsLabel; //Mailing the scream related @property (nonatomic, retain) IBOutlet UILabel *mailStatusMessage; @property (nonatomic, retain) IBOutlet UIButton *shareButton; //Scream Button - (IBAction) scream: (id) sender; //Mail the scream - (IBAction) showPicker: (id)sender; - (void)displayComposerSheet; - (void)launchMailAppOnDevice; @end Here's the top of .m: #import "ScreamViewController.h" //top of code has Audio session callback function for responding to audio route changes (from Apple's code), then my code continues... @implementation ScreamViewController @synthesize appSoundPlayer; // AVAudioPlayer object for playing the selected scream @synthesize soundFileURL; // Path to the scream @synthesize interruptedOnPlayback; // Was application interrupted during audio playback @synthesize playing; // Track playing/not playing state @synthesize screamButton; //Press this button, girls scream. @synthesize screams; //Mutable array holding strings pointing to sound files of screams. @synthesize personScreaming; //Mutable array tracking the person doing the screaming @synthesize photoArray; //Mutable array holding strings pointing to photos of screaming girls @synthesize personScreamingField; //Field updates to announce which girl is screaming. @synthesize personScreamingImage; //Updates to show image of the screamer. @synthesize funnyButtonSayings; //Mutable array holding the sayings @synthesize funnyButtonSayingsLabel; //Label that updates with the funnyButtonSayings @synthesize mailStatusMessage; //did the email go out @synthesize shareButton; //share scream via email Next line begins the block with the offending code: - (IBAction) scream: (id) sender { //Play a click sound effect SystemSoundID soundID; NSString *sfxPath = [[NSBundle mainBundle] pathForResource:@"aClick" ofType:@"caf"]; AudioServicesCreateSystemSoundID((CFURLRef)[NSURL fileURLWithPath:sfxPath],&soundID); AudioServicesPlaySystemSound (soundID); // Because someone may slam the scream button over and over, //must stop current sound, then begin next if ([self appSoundPlayer] != nil) { [[self appSoundPlayer] setDelegate:nil]; [[self appSoundPlayer] stop]; [self setAppSoundPlayer: nil]; } //after selecting a random index in the array (did that in View Did Load), //we move to the next scream on each click. //First check... //Are we past the end of the array? if (currentScreamIndex == [screams count]) { currentScreamIndex = 0; } //Get the string at the index in the personScreaming array currentScream = [screams objectAtIndex: currentScreamIndex]; //Get the string at the index in the personScreaming array NSString *screamer = [personScreaming objectAtIndex:currentScreamIndex]; //Log the string to the console NSLog (@"playing scream: %@", screamer); // Display the string in the personScreamingField field NSString *listScreamer = [NSString stringWithFormat:@"scream by: %@", screamer]; [personScreamingField setText:listScreamer]; // Gets the file system path to the scream to play. NSString *soundFilePath = [[NSBundle mainBundle] pathForResource: currentScream ofType: @"caf"]; // Converts the sound's file path to an NSURL object NSURL *newURL = [[NSURL alloc] initFileURLWithPath: soundFilePath]; self.soundFileURL = newURL; [newURL release]; [[AVAudioSession sharedInstance] setDelegate: self]; [[AVAudioSession sharedInstance] setCategory: AVAudioSessionCategoryPlayback error: nil]; // Registers the audio route change listener callback function AudioSessionAddPropertyListener ( kAudioSessionProperty_AudioRouteChange, audioRouteChangeListenerCallback, self ); // Activates the audio session. NSError *activationError = nil; [[AVAudioSession sharedInstance] setActive: YES error: &activationError]; // Instantiates the AVAudioPlayer object, initializing it with the sound AVAudioPlayer *newPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL: soundFileURL error: nil]; //Error check and continue if (newPlayer != nil) { self.appSoundPlayer = newPlayer; [newPlayer release]; [appSoundPlayer prepareToPlay]; [appSoundPlayer setVolume: 1.0]; [appSoundPlayer setDelegate:self]; //NEXT LINE IS FLAGGED BY INSTRUMENTS AS LEAKY [appSoundPlayer play]; playing = YES; //Get the string at the index in the photoArray array NSString *screamerPic = [photoArray objectAtIndex:currentScreamIndex]; //Log the string to the console NSLog (@"displaying photo: %@", screamerPic); // Display the image of the person screaming personScreamingImage.image = [UIImage imageNamed:screamerPic]; //show the share button shareButton.hidden = NO; mailStatusMessage.hidden = NO; mailStatusMessage.text = @"share!"; //Get the string at the index in the funnySayings array currentSayingsIndex = random() % [funnyButtonSayings count]; currentButtonSaying = [funnyButtonSayings objectAtIndex: currentSayingsIndex]; NSString *theSaying = [funnyButtonSayings objectAtIndex:currentSayingsIndex]; [funnyButtonSayingsLabel setText: theSaying]; currentScreamIndex++; } } Here's my dealloc: - (void)dealloc { [appSoundPlayer stop]; [appSoundPlayer release], appSoundPlayer = nil; [screamButton release], screamButton = nil; [mailStatusMessage release], mailStatusMessage = nil; [personScreamingField release], personScreamingField = nil; [personScreamingImage release], personScreamingImage = nil; [funnyButtonSayings release], funnyButtonSayings = nil; [funnyButtonSayingsLabel release], funnyButtonSayingsLabel = nil; [screams release], screams = nil; [personScreaming release], personScreaming = nil; [soundFileURL release]; [super dealloc]; } @end Thanks so much for reading this far! Any input appreciated.

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  • Secure Delete PCI-DSS Windows Environment

    - by Brennan Mann
    Hello, I have been reviewing a number of applications for securing deleting files. I understand the concepts of overwriting the file several times with zeros and random characters; however, I don't understand the concept of renaming the file up to thirty times before actually deleting the file. Any feedback would greatly be appreciated. I am currently working on a PCI DSS project. URL - SDELETE by Sysinternals http://technet.microsoft.com/en-us/sysinternals/bb897443.aspx Thanks, Brennan

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  • SVN X remains in tree-conflict

    - by Paul Knopf
    I am using VisualSVN (which uses Tortoise). I accidentally move a folder to a different location. When tries to move it back, SVN pukes with this error. It happened once before and I managed to do some random updates/commits, not knowing what I was doing and it was "fixed". I cannot pull the same magic again, so I need to know how to get my files and directory and of tree-conflict. Thanks!

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  • Confusing Java syntax...

    - by posfan12
    I'm trying to convert the following code (from Wikipedia) from Java to JavaScript: /* * 3 June 2003, [[:en:User:Cyp]]: * Maze, generated by my algorithm * 24 October 2006, [[:en:User:quin]]: * Source edited for clarity * 25 January 2009, [[:en:User:DebateG]]: * Source edited again for clarity and reusability * 1 June 2009, [[:en:User:Nandhp]]: * Source edited to produce SVG file when run from the command-line * * This program was originally written by [[:en:User:Cyp]], who * attached it to the image description page for an image generated by * it on en.wikipedia. The image was licensed under CC-BY-SA-3.0/GFDL. */ import java.awt.*; import java.applet.*; import java.util.Random; /* Define the bit masks */ class Constants { public static final int WALL_ABOVE = 1; public static final int WALL_BELOW = 2; public static final int WALL_LEFT = 4; public static final int WALL_RIGHT = 8; public static final int QUEUED = 16; public static final int IN_MAZE = 32; } public class Maze extends java.applet.Applet { /* The width and height (in cells) of the maze */ private int width; private int height; private int maze[][]; private static final Random rnd = new Random(); /* The width in pixels of each cell */ private int cell_width; /* Construct a Maze with the default width, height, and cell_width */ public Maze() { this(20,20,10); } /* Construct a Maze with specified width, height, and cell_width */ public Maze(int width, int height, int cell_width) { this.width = width; this.height = height; this.cell_width = cell_width; } /* Initialization method that will be called when the program is * run from the command-line. Maze will be written as SVG file. */ public static void main(String[] args) { Maze m = new Maze(); m.createMaze(); m.printSVG(); } /* Initialization method that will be called when the program is * run as an applet. Maze will be displayed on-screen. */ public void init() { createMaze(); } /* The maze generation algorithm. */ private void createMaze(){ int x, y, n, d; int dx[] = { 0, 0, -1, 1 }; int dy[] = { -1, 1, 0, 0 }; int todo[] = new int[height * width], todonum = 0; /* We want to create a maze on a grid. */ maze = new int[width][height]; /* We start with a grid full of walls. */ for (x = 0; x < width; ++x) { for (y = 0; y < height; ++y) { if (x == 0 || x == width - 1 || y == 0 || y == height - 1) { maze[x][y] = Constants.IN_MAZE; } else { maze[x][y] = 63; } } } /* Select any square of the grid, to start with. */ x = 1 + rnd.nextInt (width - 2); y = 1 + rnd.nextInt (height - 2); /* Mark this square as connected to the maze. */ maze[x][y] &= ~48; /* Remember the surrounding squares, as we will */ for (d = 0; d < 4; ++d) { if ((maze[][d][][d] & Constants.QUEUED) != 0) { /* want to connect them to the maze. */ todo[todonum++] = ((x + dx[d]) << Constants.QUEUED) | (y + dy[d]); maze[][d][][d] &= ~Constants.QUEUED; } } /* We won't be finished until all is connected. */ while (todonum > 0) { /* We select one of the squares next to the maze. */ n = rnd.nextInt (todonum); x = todo[n] >> 16; /* the top 2 bytes of the data */ y = todo[n] & 65535; /* the bottom 2 bytes of the data */ /* We will connect it, so remove it from the queue. */ todo[n] = todo[--todonum]; /* Select a direction, which leads to the maze. */ do { d = rnd.nextInt (4); } while ((maze[][d][][d] & Constants.IN_MAZE) != 0); /* Connect this square to the maze. */ maze[x][y] &= ~((1 << d) | Constants.IN_MAZE); maze[][d][][d] &= ~(1 << (d ^ 1)); /* Remember the surrounding squares, which aren't */ for (d = 0; d < 4; ++d) { if ((maze[][d][][d] & Constants.QUEUED) != 0) { /* connected to the maze, and aren't yet queued to be. */ todo[todonum++] = ((x + dx[d]) << Constants.QUEUED) | (y + dy[d]); maze[][d][][d] &= ~Constants.QUEUED; } } /* Repeat until finished. */ } /* Add an entrance and exit. */ maze[1][1] &= ~Constants.WALL_ABOVE; maze[width - 2][height - 2] &= ~Constants.WALL_BELOW; } /* Called by the applet infrastructure to display the maze on-screen. */ public void paint(Graphics g) { drawMaze(g); } /* Called to write the maze to an SVG file. */ public void printSVG() { System.out.format("<svg width=\"%d\" height=\"%d\" version=\"1.1\"" + " xmlns=\"http://www.w3.org/2000/svg\">\n", width*cell_width, height*cell_width); System.out.println(" <g stroke=\"black\" stroke-width=\"1\"" + " stroke-linecap=\"round\">"); drawMaze(null); System.out.println(" </g>\n</svg>"); } /* Main maze-drawing loop. */ public void drawMaze(Graphics g) { int x, y; for (x = 1; x < width - 1; ++x) { for (y = 1; y < height - 1; ++y) { if ((maze[x][y] & Constants.WALL_ABOVE) != 0) drawLine( x * cell_width, y * cell_width, (x + 1) * cell_width, y * cell_width, g); if ((maze[x][y] & Constants.WALL_BELOW) != 0) drawLine( x * cell_width, (y + 1) * cell_width, (x + 1) * cell_width, (y + 1) * cell_width, g); if ((maze[x][y] & Constants.WALL_LEFT) != 0) drawLine( x * cell_width, y * cell_width, x * cell_width, (y + 1) * cell_width, g); if ((maze[x][y] & Constants.WALL_RIGHT) != 0) drawLine((x + 1) * cell_width, y * cell_width, (x + 1) * cell_width, (y + 1) * cell_width, g); } } } /* Draw a line, either in the SVG file or on the screen. */ public void drawLine(int x1, int y1, int x2, int y2, Graphics g) { if ( g != null ) g.drawLine(x1, y1, x2, y2); else System.out.format(" <line x1=\"%d\" y1=\"%d\"" + " x2=\"%d\" y2=\"%d\" />\n", x1, y1, x2, y2); } } Anyway, I was chugging along fairly quickly when I came to a bit that I just don't understand: /* Remember the surrounding squares, as we will */ for (var d = 0; d < 4; ++d) { if ((maze[][d][][d] & Constants.QUEUED) != 0) { /* want to connect them to the maze. */ todo[todonum++] = ((x + dx[d]) << Constants.QUEUED) | (y + dy[d]); maze[][d][][d] &= ~Constants.QUEUED; } } What I don't get is why there are four sets of brackets following the "maze" parameter instead of just two, since "maze" is a two dimensional array, not a four dimensional array. I'm sure there's a good reason for this. Problem is, I just don't get it. Thanks!

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  • Lightning effect in opengl es

    - by sad_panda
    Is there a way to create a lightning effect on the iPhone using opengl?(like this app) Right now I have modified the glpaint sample to draw random points around a line (between two points that the user touches) and then connecting them, but the result is a zigzag line that constantly jumps around and lags horribly on the actual device.

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  • How to get statistical distributions out of C++ Code?

    - by Bader
    I want some help in programming a random generator for different types of distribution using C++ language. for the following: Geometric distribution Hypergeometric distribution Weibull distribution Rayleigh distribution Erlang distribution Gamma distribution Poisson distribution Thanks.

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  • [PHP]RegEx help with a string

    - by Uffo
    So I have a random of strings and I need to parse them, let's take an example: This string - DeleteMe please and some other text So I want to find DDeleteMe please and some other text and remove it, because all I need is This string Best Regards,

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  • How to rate-limit a pipe under linux ?

    - by Frédéric Grosshans
    Is there a filter which I could use to rate-limit a pipe on linux? If this exists, let call it rate-limit, I want to be able to type in a terminal something like cat /dev/urandom | rate-limit 3 -k | foo in order to send a a stream of random bytes to foo's standard input at a rate (lower than) 3 kbytes/s.

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  • how did SO animate answer div

    - by c0mrade
    I am wondering for some time now, how did SO do this animation on answers when you click on link answer, answer divs color changes for some time and it reverts back, I'm sure this question has been asked before but I just couldn't find it. Or this random example : http://stackoverflow.com/questions/2706443/what-pitfalls-if-any-are-there-to-learning-c-c-as-a-first-language/2706531#2706531

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