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  • Programmatically implementing an interface that combines some instances of the same interface in var

    - by namin
    What is the best way to implement an interface that combines some instances of the same interface in various specified ways? I need to do this for multiple interfaces and I want to minimize the boilerplate and still achieve good efficiency, because I need this for a critical production system. Here is a sketch of the problem. Abstractly, I have a generic combiner class which takes the instances and specify the various combinators: class Combiner<I> { I[] instances; <T> T combineSomeWay(InstanceMethod<I,T> method) { // ... method.call(instances[i]) ... combined in some way ... } // more combinators } Now, let's say I want to implement the following interface among many others: Interface Foo { String bar(int baz); } I want to end up with code like this: class FooCombiner implements Foo { Combiner<Foo> combiner; @Override public String bar(final int baz) { return combiner.combineSomeWay(new InstanceMethod<Foo, String> { @Override public call(Foo instance) { return instance.bar(baz); } }); } } Now, this can quickly get long and winded if the interfaces have lots of methods. I know I could use a dynamic proxy from the Java reflection API to implement such interfaces, but method access via reflection is hundred times slower. So what are the alternatives to boilerplate and reflection in this case?

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  • How to display the image in the web view using html code?

    - by Madan Mohan
    Hi Guys, I am getting the data form Parser, In that I am getting a set of urls. Using these urls can I make image url by appending any data values getting from the parser. http://musicbrainz.org/ws/1/artist/f27ec8db-af05-4f36-916e-3d57f91ecf5e?type=xml&inc=url-rels+artist-rels using these url i get data and set of urls.They are not providing image url or thumbnail. So, Is it possible to get or form an image url from parser (http://musicbrainz.org/ws/1/artist/f27ec8db-af05-4f36-916e-3d57f91ecf5e?type=xml&inc=url-rels+artist-rels) and display in the web view. Please help me from this problem. Thank You, Madan Mohan.

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  • Techniques for modeling a dynamic dataflow with Java concurrency API

    - by Maian
    Is there an elegant way to model a dynamic dataflow in Java? By dataflow, I mean there are various types of tasks, and these tasks can be "connected" arbitrarily, such that when a task finishes, successor tasks are executed in parallel using the finished tasks output as input, or when multiple tasks finish, their output is aggregated in a successor task (see flow-based programming). By dynamic, I mean that the type and number of successors tasks when a task finishes depends on the output of that finished task, so for example, task A may spawn task B if it has a certain output, but may spawn task C if has a different output. Another way of putting it is that each task (or set of tasks) is responsible for determining what the next tasks are. Sample dataflow for rendering a webpage: I have as task types: file downloader, HTML/CSS renderer, HTML parser/DOM builder, image renderer, JavaScript parser, JavaScript interpreter. File downloader task for HTML file HTML parser/DOM builder task File downloader task for each embedded file/link If image, image renderer If external JavaScript, JavaScript parser JavaScript interpreter Otherwise, just store in some var/field in HTML parser task JavaScript parser for each embedded script JavaScript interpreter Wait for above tasks to finish, then HTML/CSS renderer (obviously not optimal or perfectly correct, but this is simple) I'm not saying the solution needs to be some comprehensive framework (in fact, the closer to the JDK API, the better), and I absolutely don't want something as heavyweight is say Spring Web Flow or some declarative markup or other DSL. To be more specific, I'm trying to think of a good way to model this in Java with Callables, Executors, ExecutorCompletionServices, and perhaps various synchronizer classes (like Semaphore or CountDownLatch). There are a couple use cases and requirements: Don't make any assumptions on what executor(s) the tasks will run on. In fact, to simplify, just assume there's only one executor. It can be a fixed thread pool executor, so a naive implementation can result in deadlocks (e.g. imagine a task that submits another task and then blocks until that subtask is finished, and now imagine several of these tasks using up all the threads). To simplify, assume that the data is not streamed between tasks (task output-succeeding task input) - the finishing task and succeeding task won't exist together, so the input data to the succeeding task will not be changed by the preceeding task (since it's already done). There are only a couple operations that the dataflow "engine" should be able to handle: A mechanism where a task can queue more tasks A mechanism whereby a successor task is not queued until all the required input tasks are finished A mechanism whereby the main thread (or other threads not managed by the executor) blocks until the flow is finished A mechanism whereby the main thread (or other threads not managed by the executor) blocks until certain tasks have finished Since the dataflow is dynamic (depends on input/state of the task), the activation of these mechanisms should occur within the task code, e.g. the code in a Callable is itself responsible for queueing more Callables. The dataflow "internals" should not be exposed to the tasks (Callables) themselves - only the operations listed above should be available to the task. Note that the type of the data is not necessarily the same for all tasks, e.g. a file download task may accept a File as input but will output a String. If a task throws an uncaught exception (indicating some fatal error requiring all dataflow processing to stop), it must propagate up to the thread that initiated the dataflow as quickly as possible and cancel all tasks (or something fancier like a fatal error handler). Tasks should be launched as soon as possible. This along with the previous requirement should preclude simple Future polling + Thread.sleep(). As a bonus, I would like to dataflow engine itself to perform some action (like logging) every time task is finished or when no has finished in X time since last task has finished. Something like: ExecutorCompletionService<T> ecs; while (hasTasks()) { Future<T> future = ecs.poll(1 minute); some_action_like_logging(); if (future != null) { future.get() ... } ... } Are there straightforward ways to do all this with Java concurrency API? Or if it's going to complex no matter what with what's available in the JDK, is there a lightweight library that satisfies the requirements? I already have a partial solution that fits my particular use case (it cheats in a way, since I'm using two executors, and just so you know, it's not related at all to the web browser example I gave above), but I'd like to see a more general purpose and elegant solution.

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  • XML::LibXML Line Ending (whitespace) Problem.

    - by Gilbeg
    HI, I am parsing an XML file using LibXML in Perl. The problem that I have is the ending characters (whitespace) is treated as a text node. For instance, given an input like the following abc 123 The parser thinks that the number of child of node "books" is 3, they are: - text node (containing the char between and - element node of "book" - text node (containing the char between and Question is how do I tell LibXML to ignore whitespaces? I tried with no_blanks (that is $parser = XML::LibXML-new(no_blanks = 1) when construction the parser) but it seems that it has no effect. Thanks in advance

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  • XML::LibXML: How to write a xpath with qualified name?

    - by sid_com
    I've found this on http://www.perlmonks.org/?node_id=606909 looking by qualified name ... In this case you can call findnodes method on any node, you don't need the XML::LibXML::XPathContext with its prefix = namespace mapping: $doc-findnodes('///info/fooTransaction/transactionDetail/[name() = "histFile:transactionSummary"]/*'); In which way I have to edit my xpath to get my script working without XPathContext? #!/usr/bin/env perl use warnings; use strict; use 5.012; use XML::LibXML; my $parser = XML::LibXML->new; $parser->recover_silently( 1 ); my $doc = $parser->parse_file( 'http://www.heise.de/' ); my $xc = XML::LibXML::XPathContext->new( $doc->getDocumentElement ); $xc->registerNs( 'xmlns', 'http://www.w3.org/1999/xhtml' ); my $nodes = $xc->findnodes( '//xmlns:h2/xmlns:a' ); for my $node ( $nodes->get_nodelist ) { say $_->getName, '=', $_->getValue for $node->attributes; }

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  • Is there a Django template tag that lets me set a context variable?

    - by hekevintran
    I want to be able to set variables in a template to string values. I wrote a tag, but it doesn't seem to change the context. The intended use is: {% define my_var as "a string" %} class DefineNode(Node): def __init__(self, value, variable_name, nodelist): self.value = value self.variable_name = variable_name self.nodelist = nodelist def __repr__(self): return "<DefineNode>" def render(self, context): context[self.variable_name] = self.value return '' @register.tag def define(parser, token): bits = list(token.split_contents()) if len(bits) != 4: raise TemplateSyntaxError("%r expected format is 'value as variable'" % bits[0]) if bits[1][0] in ('"', "'") and bits[1][-1] == bits[1][0]: value = bits[1][1:-1] nodelist = parser.parse(('enddefine',)) parser.delete_first_token() return DefineNode(value, bits[3], nodelist) I

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  • I'm getting this exception : Unresolved compilation problems

    - by Stephan
    I get this exception after i removed from my project the jars (pdfbox ,bouncycastle etc) and moved them to another folder but i included them in the build path ... at the first line eclipse shows this error( the constructor PDFParser(InputStream) refers to missing type InputStream) -altought FileInputStream is extended from InputStream- and i don't know why? FileInputStream in = new FileInputStream(path); PDFParser parser = new PDFParser(in); PDFTextStripper textStripper = new PDFTextStripper(); parser.parse(); String text = textStripper.getText(new PDDocument(parser.getDocument())); any ideas? ** Exception in thread "AWT-EventQueue-0" java.lang.Error: Unresolved compilation problems: The constructor PDFParser(InputStream) refers to the missing type InputStream The constructor PDFTextStripper() refers to the missing type IOException The method parse() from the type PDFParser refers to the missing type IOException The method getText(PDDocument) from the type PDFTextStripper refers to the missing type IOException The method getDocument() from the type PDFParser refers to the missing type IOException The method getDocument() from the type PDFParser refers to the missing type IOException The method close() from the type COSDocument refers to the missing type IOException **

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  • Download a file from one ASP.NET web application to other (given the credentials)

    - by Tom S.
    Hi everybody! Im working on a asp.net 3.5 web application (C#), where i have a file with some information that is updated frequently, and only few accounts can access to it (the application is using the asp.net authentication system, stored in a SQL database). My task is to parse that file, so i made a small parser (another web app) a to show the information in a more friendly way. However, everytime i want to parse it, i need to enter in the application with one of those accounts, download the file, put in the parser's folder. Is there any way to, given the username and password, download the file directly from the parser application and use that one? Thanks in advance

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  • How to resolve Android class issues: android.Manifest$permission and android.R?

    - by Maxood
    I have updated software and ADT in my Eclipse a number of times. I am unable to run projects above than 1.5.I have the following errors showing up in my console window after i create a HelloWorld project with API Level 4 (1.6): [2010-04-04 22:21:53 - Framework Resource Parser] Collect resource IDs failed, class android.R not found in E:\Android\android-sdk_r04-windows\android-sdk-windows\platforms\android-1.6\android.jar [2010-04-04 22:21:53 - Framework Resource Parser] Collect permissions failed, class android.Manifest$permission not found in E:\Android\android-sdk_r04-windows\android-sdk-windows\platforms\android-1.6\android.jar [2010-04-04 22:21:54 - Android Framework Parser] failed to collect preference classes How to resolve this issue?

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  • why egrep's stdout did not go through pipe?

    - by ccfenix
    Hi, i got a weird problem regarding egrep and pipe I tried to filter a stream containing some lines who start with a topic name, such as "TICK:this is a tick message\n" When I try to use egrep to filter it : ./stream_generator | egrep 'TICK' | ./topic_processor It seems that the topic_processor never receives any messages However, when i use the following python script: ./stream_generator | python filter.py --topics TICK | ./topic_processor everything looks to be fine. I guess there need to be a 'flush' mechanism for egrep as well, is this correct? Can anyone here give me a clue? Thanks a million import sys from optparse import OptionParser if __name__ == '__main__': parser = OptionParser() parser.add_option("-m", "--topics", action="store", type="string", dest="topics") (opts, args) = parser.parse_args() topics = opts.topics.split(':') while True: s = sys.stdin.readline() for each in topics: if s[0:4] == each: sys.stdout.write(s) sys.stdout.flush()

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  • Haskell parsec parsing a string of items

    - by Chris
    I have a list that I need to parse where the all but the last element needs to be parsed by one parser, and the last element needs to be parsed by another parser. a = "p1 p1b ... p2" or a = "p2" Originally I tried parser = do parse1 <- many parser1 parse2 <- parser2 return AParse parse1 parse2 The problem is that parse1 can consume a parse2 input. So parse1 always consumes the entire list, and leave parse2 with nothing. Is there a way to say to apply parse1 to everything besides the last element in a string, and then apply parse2?

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  • How to ignore CDATA tags?

    - by Petre
    I'm trying to make an html parser, but when I load the html I get warnings like this Warning: DOMDocument::loadHTML() [domdocument.loadhtml]: Invalid char in CDATA 0x1C in Entity, line: 1302 Here is the code I use class Parser { public $url=null; public $html=null; public $tidy=null; public $head=null; public $head_xpath=null; function __construct($url){ $this->url=$url; $this->html=file_get_contents($this->url); $this->tidy=tidy_parse_string($this->html); $this->head=new DOMDocument(); $this->head->loadHTML($this->tidy->head()); $this->head_xpath= new DOMXPath($this->head); } } $x=new Parser("http://www.guardian.co.uk/politics/2012/mar/24/vince-cable-coalition-banking-row"); I searched around and found the LIBXML_NOCDATA constant, but I don't know how to set it. So how could i completely ignore CDATA?

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  • python sax error "junk after document element"

    - by user293487
    Hi, I use python sax to parse xml file. The xml file is actually a combination of multiple xml files. It looks like as follows: <row name="abc" age="40" body="blalalala..." creationdate="03/10/10" /> <row name="bcd" age="50" body="blalalala..." creationdate="03/10/09" /> My python code is in the following. It show "junk after document element" error. Any good idea to solve this problem. Thanks. from xml.sax.handler import ContentHandler from xml.sax import make_parser,SAXException import sys class PostHandler (ContentHandler): def __init__(self): self.find = 0 self.buffer = '' self.mapping={} def startElement(self,name,attrs): if name == 'row': self.find = 1 self.body = attrs["body"] print attrs["body"] def character(self,data): if self.find==1: self.buffer+=data def endElement(self,name): if self.find == 1: self.mapping[self.body] = self.buffer print self.mapping parser = make_parser() handler = PostHandler() parser.setContentHandler(handler) try: parser.parse(open("2.xml")) except SAXException:

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  • Problem with Replacing special characters in a string

    - by Hossein
    Hi, I am trying to feed some text to a special pupose parser. The problem with this parser is that it is sensitive to ()[] characters and in my sentence in the text have quite a lot of these characters. The manual for the parser suggests that all the ()[] get replaced with \( \) \[ \]. So using str.replace i am using to attach \ to all of those charcaters. I use the code below: a = 'abcdef(1234)' a.replace('(','\(') however i get this as my output: 'abcdef\\(1234)' What is wrong with my code? can anyone provide me a solution to solve this for these characters?

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  • datetime command line argument in python 2.4

    - by Ike Walker
    I want to pass a datetime value into my python script on the command line. My first idea was to use optparse and pass the value in as a string, then use datetime.strptime to convert it to a datetime. This works fine on my machine (python 2.6), but I also need to run this script on machines that are running python 2.4, which doesn't have datetime.strptime. How can I pass the datetime value to the script in python 2.4? Here's the code I'm using in 2.6: parser = optparse.OptionParser() parser.add_option("-m", "--max_timestamp", dest="max_timestamp", help="only aggregate items older than MAX_TIMESTAMP", metavar="MAX_TIMESTAMP(YYYY-MM-DD HH24:MM)") options,args = parser.parse_args() if options.max_timestamp: # Try parsing the date argument try: max_timestamp = datetime.datetime.strptime(options.max_timestamp, "%Y-%m-%d %H:%M") except: print "Error parsing date input:",sys.exc_info() sys.exit(1)

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  • Can PMD be customized to fully support a new language?

    - by tinny
    Can PMD be customized to fully support a new language, in a reasonable amount of time. I mean I know that technically almost anything can be done, but im wondering if this can be done in a reasonable amount of time? E.g. < 2 weeks This page mentions how to write a CPD parser http://pmd.sourceforge.net/cpd-parser-howto.html But is this just for copy / paste detection? Does writing a CPD parser give me full support of PMD in terms of rile sets?

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  • Mockito upgrade causes null pointer problems

    - by Ann Addicks
    We upgraded from mockito-all-1.8.5.jar to mockito-all-1.9.0.jar and now see null pointers when using annotations for the classes being mocked. Here is an example: @Mock private static IAccountManager accountManager; @Mock private static IBusinessUnitManager businessUnitManager; private static Gson parser; @InjectMocks private static DownloadController downloadController; @BeforeClass public static void setUpBeforeClass() throws Exception { parser = new Gson(); downloadController = new DownloadController(accountManager, businessUnitManager, parser); } @Before public void setUp() throws Exception { MockitoAnnotations.initMocks(this); Mockito.reset(accountManager, businessUnitManager); } As soon as accountManager is referenced in the download controller, it throws a npe. This worked in 1.8.5.

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  • code throws std::bad_alloc, not enough memory or can it be a bug?

    - by Andreas
    I am parsing using a pretty large grammar (1.1 GB, it's data-oriented parsing). The parser I use (bitpar) is said to be optimized for highly ambiguous grammars. I'm getting this error: 1terminate called after throwing an instance of 'std::bad_alloc' what(): St9bad_alloc dotest.sh: line 11: 16686 Aborted bitpar -p -b 1 -s top -u unknownwordsm -w pos.dfsa /tmp/gsyntax.pcfg /tmp/gsyntax.lex arbobanko.test arbobanko.results Is there hope? Does it mean that it has ran out of memory? It uses about 15 GB before it crashes. The machine I'm using has 32 GB of RAM, plus swap as well. It crashes before outputting a single parse tree. The parser is an efficient CYK chart parser using bit vector representations; I presume it is already near the limit of memory efficiency. If it really requires too much memory I could sample from the grammar rules, but this will decrease parse accuracy of course.

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  • Objective C Object Functioning & Passing Arrays

    - by Patrick
    I apologise if this has been asked before but I can't find the info I need. Basically I want a UITableView to be populated using info from a server, similar to the SeismicXML example. I have the parser as a separate object, is it correct to alloc, init an instance of that parser & then tell RootViewController to make it's table data source a copy of the parser's array. I can't include code because I haven't written anything yet, I'm just trying to get the design right before I start. Perhaps something like: xmlParser = [[XMLParser alloc] init]; [xmlParser getXMLData]; // Assuming xmlParser stores results in an array called returnedArray self.tableDataSource = xmlParser.returnedArray Is this the best way of doing it?

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  • What is the standard way to parse floats at runtime in C?

    - by Joel J. Adamson
    Hello, I have a scientific application for which I want to input initial values at runtime. I have an option to get them from the command line, or to get them from an input file. Either of these options are input to a generic parser that uses strtod to return a linked list of initial values for each simulation run. I either use the command-line argument or getline() to read the values. The question is, should I be rolling my own parser, or should I be using a parser-generator or some library? What is the standard method? This is the only data I will read at runtime, and everything else is set at compile time (except for output files and a few other totally simple things). Thanks, Joel

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  • A better way to do XML in Java

    - by jboyd
    There are a lot of questions that ask the best XML parser, I am more interested in what is the XML parser that is the most like Groovy for Java? I want: SomeApiDefinedObject o = parseXml( xml ); for( SomeApiDefinedObject it : o.getChildren() ) { System.out.println( it.getAttributes() ); } The most important things are that I don't want to create an object for every type of filed, I'd rather just deal with them all as strings, and that building the XML doesn't require any converters or anything, just a simple object that is already defined If you have used the Groovy XML parser, you will know what I'm talking about Alternatively, would it be better for me to just use Groovy from Java?

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  • C++ option/long option implementation

    - by K Hein
    I am working on a parser for meta programming language using C++ on Linux platform. Right now, I need to implement option/long option for the parser to provide some additional features. Basically, if the user pass in some additional option, the parser needs to store statistics while parsing the text files. I can think of two ways to implement it. One way is to user global to store options entered by users. Another way is to create a singleton class to store options. So I would like to know if there is any other way to implement it. What is the best/most recommended way of implementing it? Thanks in advance. Regards, K.Hein

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  • Incorrect emacs indentation in a C++ class with DLL export specification

    - by Michael Daum
    I often write classes with a DLL export/import specification, but this seems to confuse emacs' syntax parser. I end up with something like: class myDllSpec Foo { public: Foo( void ); }; Notice that the "public:" access spec is indented incorrectly, as well as everything that follows it. When I ask emacs to describe the syntax at the beginning of the line containing public, I get a return of: ((label 352)) If I remove the myDllSpec, the indentation is correct, and emacs tells me that the syntax there is: ((inclass 352) (access-label 352)) Which seems correct and reasonable. So I conclude that the syntax parser is not able to handle the DLL export spec, and that this is what's causing my indentation trouble. Unfortunately, I don't know how to teach the parser about my labels. Seems that this is pretty common practice, so I'm hoping there's a way around it.

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  • Scala's lazy arguments: How do they work?

    - by python dude
    In the file Parsers.scala (Scala 2.9.1) from the parser combinators library I seem to have come across a lesser known Scala feature called "lazy arguments". Here's an example: def ~ [U](q: => Parser[U]): Parser[~[T, U]] = { lazy val p = q // lazy argument (for(a <- this; b <- p) yield new ~(a,b)).named("~") } Apparently, there's something going on here with the assignment of the call-by-name argument q to the lazy val p. So far I have not been able to work out what this does and why it's useful. Can anyone help?

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  • Is this time related process accounting stats gathering appropriate?

    - by Ceko Cakata
    Based on sys/acct.h (V1, not V3) I need to gather some user usage statistics based on a parser that parser the acct file line by line. The parser will run and parse the entire file every N seconds and I need to gather user statistics accumulated since the last run (N seconds back). I'm not sure what will be the most appropriate way to do it based on the info provided by sys/acct.h. Maybe something like this: if ((ac_btime + ac_etime) < (current_time - N)) { gather; } Also comp_t is said to be "floating-point value consisting of a 3-bit, base-8 exponent, and a 13-bit mantissa", but I think u_int16_t is just a unsigned short int. Should I be converting it to long it with the provided formula or not?

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