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Search found 112 results on 5 pages for 'comparator'.

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  • C# .NET: Ascending comparison of a SortedDictionary?

    - by Rosarch
    I'm want a IDictionary<float, foo> that returns the larges values of the key first. private IDictionary<float, foo> layers = new SortedDictionary<float, foo>(new AscendingComparer<float>()); class AscendingComparer<T> : IComparer<T> where T : IComparable<T> { public int Compare(T x, T y) { return -y.CompareTo(x); } } However, this returns values in order of the smallest first. I feel like I'm making a stupid mistake here. Just to see what would happen, I removed the - sign from the comparator: public int Compare(T x, T y) { return y.CompareTo(x); } But I got the same result. This reinforces my intuition that I'm making a stupid error.

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  • Problem with implementing removeAll for List of custom object

    - by Jay
    Hello everyone, I have a scenario in my code where I need to compare two Lists and remove from the first list, objects which are present in the second list. Akin to how the "removeAll" object works for List. Since my List is created on a custom object, the removeAll method won't work for me. I have tried various methods to make this work: - implemented equals() and hashCode for the custom object comprising the list - implemented the Comparable Interface for the custom object - implemented the Comparator Interface for the custom object I've even tried using the Apache Common's CollectionUtils and ListUtils methods (subtract, intersect, removeAll). None seem to work. I understand I will perhaps need to write some custom removal code. But not sure how to go about doing that. Any pointers helping me move in the right direction will be really appreciated. Thanks, Jay

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  • php SimpleCassie Cassandra TimeUUID

    - by chnet
    I created a column family Users using following command: create column family Users with comparator=TimeUUIDType and default_validation_class=UTF8Type; Then I insert a column into Users. It shows as follows. RowKey: jsmith =>(column=66829930-515b-11e0-8443-0f82b246fa40, value=hello, timestamp=1300451382) I want to access it using SimpleCassie. The command is: $data = $cassie->keyspace('Keyspace1')->cf('Users')->key('jsmith')->column('66829930-515b-11e0-8443-0f82b246fa40')->value(); (I also tried: $data = $cassie->keyspace('Keyspace1')->cf('Users')->key('jsmith')->column($cassie->uuid('66829930-515b-11e0-8443-0f82b246fa40')->__toString())->value();) However, They do not work. It always return NULL. How can I get the column value (hello) I want?

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  • MyClass cannot be cast to java.lang.Comparable: java.lang.ClassCastException

    - by user2234225
    I am doing a java project and I got this problem and don't know how to fix it. The classes in my project (simplified): public class Item { private String itemID; private Integer price; public Integer getPrice() { return this.price; } } public class Store { private String storeID; private String address; } public class Stock { private Item item; private Store store; private Integer itemCount; public Integer getInventoryValue() { return this.item.getPrice() * this.itemCount; } } Then I try to sort an ArrayList of Stock so I create another class called CompareByValue public class CompareByValue implements Comparator<Stock> { @Override public int compare(Stock stock1, Stock stock2) { return (stock1.getInventoryValue() - stock2.getInventoryValue()); } } When I try to run the program, it gives the error: Exception in thread "main" java.lang.ClassCastException: Stock cannot be cast to java.lang.Comparable Anyone know what's wrong?

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  • C++ min heap with user-defined type.

    - by bsg
    Hi, I am trying to implement a min heap in c++ for a struct type that I created. I created a vector of the type, but it crashed when I used make_heap on it, which is understandable because it doesn't know how to compare the items in the heap. How do I create a min-heap (that is, the top element is always the smallest one in the heap) for a struct type? The struct is below: struct DOC{ int docid; double rank; }; I want to compare the DOC structures using the rank member. How would I do this? I tried using a priority queue with a comparator class, but that also crashed, and it also seems silly to use a data structure which uses a heap as its underlying basis when what I really need is a heap anyway. Thank you very much, bsg

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  • C++: set of C-strings

    - by Nicholas
    I want to create one so that I could check whether a certain word is in the set using set::find However, C-strings are pointers, so the set would compare them by the pointer values by default. To function correctly, it would have to dereference them and compare the strings. I could just pass the constructor a pointer to the strcmp() function as a comparator, but this is not exactly how I want it to work. The word I might want to check could be part of a longer string, and I don't want to create a new string due to performance concerns. If there weren't for the set, I would use strncmp(a1, a2, 3) to check the first 3 letters. In fact, 3 is probably the longest it could go, so I'm fine with having the third argument constant. Is there a way to construct a set that would compare its elements by calling strncmp()? Code samples would be greatly appreciated.

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  • PHP coding a price comparaison tool

    - by Tristan
    Hello, it's the first time I developp such tool you all know (the possibility to compare articles according to price and/or options) Since I never did that i want to tell me what do you think of the way i see that : On the database we would have : offer / price / option 1 / option 2 / option 3 / IDseller / IDoffer best buy / 15$ / full FTP / web hosting / php.ini / 10 / 1 .../..../.... And the request made by the client : "SELECT * FROM offers WHERE price <= 20 AND option1 = fullFTP"; I don't know if it seems OK to you. Plus i was wondering, how to avoid multiples entries for the same seller. Imagine you have multiple offers with a price <= 20 with the option FullFTP for the same seller, i don't want him to be shown 5 times on the comparator. If you have any advices ;) Thanks

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  • controlling the order of submitted futures

    - by mac
    In this example, i am submitting a few files to my comparator object. It all works fine, except that i noticed that order in which files are submitted is not always teh same order in which they are returned. Any suggestions on how i can better control this? ExecutorService pool = Executors.newFixedThreadPool(5); CompletionService<Properties> completion = new ExecutorCompletionService<Properties>(pool); for (String target : p.getTargetFiles()) { completion.submit(new PropertiesLoader(target, p)); } for (@SuppressWarnings("unused") String target : p.getTargetFiles()) { Properties r = null; try { r = completion.take().get(); } catch (InterruptedException e) { e.printStackTrace(); } catch (ExecutionException e) { e.printStackTrace(); } p.addTargetFilesProperties(r); } pool.shutdown();

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  • Neo4j+Gremlin : Trouble with T.gte and floating point node attributes

    - by letronje
    For a type of nodes in my graph, attribute values for an attribute(named 'some_count') is either missing or an integer or a float. I'm trying to write gremlin to filter these nodes based on minimum value for this attribute. I first verified that the values are indeed present by firing the following gremlin g.v(XXX)._().in('category').hasNot('some_count', T.eq, null).back(1).some_count Next, I tried filtering by exact value and that works and show me the matching nodes or gives an empty array if there is no match g.v(XXX)._().in('category').hasNot('some_count', T.eq, null).back(1).has('some_count', T.eq, 120000.0d) But the following query that uses the 'greater than or equal to' comparator doesn't work. g.v(XXX)._().in('category').hasNot('some_count', T.eq, null).back(1).has('some_count', T.gte, 1.0d) this returns nil (I'm querying via ruby/rails using Neo4j AR Adapter ) Instead of returning an empty array for no match, it returns a nil, which tells me something could be wrong with the query itself. I'm running neo4j community server 1.8. Is there a way I can ask Neo4j to log errors/queries, to see what could be going wrong ?

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  • Sorting a 2D numpy array by multiple axes

    - by perimosocordiae
    I have a 2D numpy array of shape (N,2) which is holding N points (x and y coordinates). For example: array([[3, 2], [6, 2], [3, 6], [3, 4], [5, 3]]) I'd like to sort it such that my points are ordered by x-coordinate, and then by y in cases where the x coordinate is the same. So the array above should look like this: array([[3, 2], [3, 4], [3, 6], [5, 3], [6, 2]]) If this was a normal Python list, I would simply define a comparator to do what I want, but as far as I can tell, numpy's sort function doesn't accept user-defined comparators. Any ideas?

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  • Filtering SQLAlchemy query on attribute_mapped_collection field of relationship

    - by bsa
    I have two classes, Tag and Hardware, defined with a simple parent-child relationship (see the full definition at the end). Now I want to filter a query on Tag using the version field in Hardware through an attribute_mapped_collection, eg: def get_tags(order_code=None, hardware_filters=None): session = Session() query = session.query(Tag) if order_code: query = query.filter(Tag.order_code == order_code) if hardware_filters: for k, v in hardware_filters.iteritems(): query = query.filter(getattr(Tag.hardware, k).version == v) return query.all() But I get: AttributeError: Neither 'InstrumentedAttribute' object nor 'Comparator' object associated with Tag.hardware has an attribute 'baseband The same thing happens if I strip it back by hard-coding the attribute, eg: query.filter(Tag.hardware.baseband.version == v) I can do it this way: query = query.filter(Tag.hardware.any(artefact=k, version=v)) But why can't I filter directly through the attribute? Class definitions class Tag(Base): __tablename__ = 'tag' tag_id = Column(Integer, primary_key=True) order_code = Column(String, nullable=False) version = Column(String, nullable=False) status = Column(String, nullable=False) comments = Column(String) hardware = relationship( "Hardware", backref="tag", collection_class=attribute_mapped_collection('artefact'), ) __table_args__ = ( UniqueConstraint('order_code', 'version'), ) class Hardware(Base): __tablename__ = 'hardware' hardware_id = Column(Integer, primary_key=True) tag_id = Column(String, ForeignKey('tag.tag_id')) product_id = Column(String, nullable=True) artefact = Column(String, nullable=False) version = Column(String, nullable=False)

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  • Ubuntu 13.XX unable to mount USB HDD. Tried everything. I/O error boot sector/file system

    - by XaviGG
    I know that there are many posts related but none of them helped me. I will jump to the last test because it is the one that should work, but it does not. An external HDD with single partition slow NTFS formatted in Windows, empty and clean. Checked for errors, it tells that not errors where found. Moving to Ubutnu 13.04... Gparted throws the first error when trying to read the disk: Input/output error It appears as unknown the content of the disk. Unable to create partition table or format it, getting the same error when trying. If I try to mount it in the terminal it tells me the same, specifying that also there is an I/O error reading the boot sector. I have this problem since I upgraded (always with fresh install) to 13.04. I thought it will be solved by the 13.10 but it has the same behavior. I tried with two different HDD (HD and SSHD) that work perfectly in Windows 7. In 13.04 at least I got a trying of mounting where the icon of the drive started showing and disappearing until finally it disappeared. But now it doesn't even try. Possible causes: -The HDD was my old main HDD, so it had WIN,RECOVERY,SYSTEM,UBU,SWAP partitions. Maybe the way or place where the partition table is defined is not the best for an external HDD but I don't know a lot in that topic. I would appreciate a lot if someone can give me a guideline to convert one of these HDD in a working external HDD. No files to recover, nothing to care about. Just format completely the disk and be able to use it for storing backups without having to move the files first to the windows partition, load windows and then copy them to the external HDD. Because I want to use a file comparator for the backups. Thanks a lot Edit 1: I found an option in Windows to convert it to a dynamic HDD that warns me that I wont be able to run O.S. after changing. I suppose that is what I need because in the current mode I cannot safely extract it. But it tells me an error that it couldn't change the mode.

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  • Sampling SQL server batch activity

    - by extended_events
    Recently I was troubleshooting a performance issue on an internal tracking workload and needed to collect some very low level events over a period of 3-4 hours.  During analysis of the data I found that a common pattern I was using was to find a batch with a duration that was longer than average and follow all the events it produced.  This pattern got me thinking that I was discarding a substantial amount of event data that had been collected, and that it would be great to be able to reduce the collection overhead on the server if I could still get all activity from some batches. In the past I’ve used a sampling technique based on the counter predicate to build a baseline of overall activity (see Mikes post here).  This isn’t exactly what I want though as there would certainly be events from a particular batch that wouldn’t pass the predicate.  What I need is a way to identify streams of work and select say one in ten of them to watch, and sql server provides just such a mechanism: session_id.  Session_id is a server assigned integer that is bound to a connection at login and lasts until logout.  So by combining the session_id predicate source and the divides_by_uint64 predicate comparator we can limit collection, and still get all the events in batches for investigation. CREATE EVENT SESSION session_10_percent ON SERVER ADD EVENT sqlserver.sql_statement_starting(     WHERE (package0.divides_by_uint64(sqlserver.session_id,10))), ADD EVENT sqlos.wait_info (        WHERE (package0.divides_by_uint64(sqlserver.session_id,10))), ADD EVENT sqlos.wait_info_external (        WHERE (package0.divides_by_uint64(sqlserver.session_id,10))), ADD EVENT sqlserver.sql_statement_completed(     WHERE (package0.divides_by_uint64(sqlserver.session_id,10))) ADD TARGET ring_buffer WITH (MAX_DISPATCH_LATENCY=30 SECONDS,TRACK_CAUSALITY=ON) GO   There we go; event collection is reduced while still providing enough information to find the root of the problem.  By the way the performance issue turned out to be an IO issue, and the session definition above was more than enough to show long waits on PAGEIOLATCH*.        

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  • Questions related to writing your own file downloader using multiple threads java

    - by Shekhar
    Hello In my current company, i am doing a PoC on how we can write a file downloader utility. We have to use socket programming(TCP/IP) for downloading the files. One of the requirements of the client is that a file(which will be large in size) should be transfered in chunks for example if we have a file of 5Mb size then we can have 5 threads which transfer 1 Mb each. I have written a small application which downloads a file. You can download the eclipe project from http://www.fileflyer.com/view/QM1JSC0 A brief explanation of my classes FileSender.java This class provides the bytes of file. It has a method called sendBytesOfFile(long start,long end, long sequenceNo) which gives the number of bytes. import java.io.File; import java.io.IOException; import java.util.zip.CRC32; import org.apache.commons.io.FileUtils; public class FileSender { private static final String FILE_NAME = "C:\\shared\\test.pdf"; public ByteArrayWrapper sendBytesOfFile(long start,long end, long sequenceNo){ try { File file = new File(FILE_NAME); byte[] fileBytes = FileUtils.readFileToByteArray(file); System.out.println("Size of file is " +fileBytes.length); System.out.println(); System.out.println("Start "+start +" end "+end); byte[] bytes = getByteArray(fileBytes, start, end); ByteArrayWrapper wrapper = new ByteArrayWrapper(bytes, sequenceNo); return wrapper; } catch (IOException e) { throw new RuntimeException(e); } } private byte[] getByteArray(byte[] bytes, long start, long end){ long arrayLength = end-start; System.out.println("Start : "+start +" end : "+end + " Arraylength : "+arrayLength +" length of source array : "+bytes.length); byte[] arr = new byte[(int)arrayLength]; for(int i = (int)start, j =0; i < end;i++,j++){ arr[j] = bytes[i]; } return arr; } public static long fileSize(){ File file = new File(FILE_NAME); return file.length(); } } Second Class is FileReceiver.java - This class receives the file. Small Explanation what this file does This class finds the size of the file to be fetched from Sender Depending upon the size of the file it finds the start and end position till the bytes needs to be read. It starts n number of threads giving each thread start,end, sequence number and a list which all the threads share. Each thread reads the number of bytes and creates a ByteArrayWrapper. ByteArrayWrapper objects are added to the list Then i have while loop which basically make sure that all threads have done their work finally it sorts the list based on the sequence number. then the bytes are joined, and a complete byte array is formed which is converted to a file. Code of File Receiver package com.filedownloader; import java.io.File; import java.io.IOException; import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; import java.util.List; import java.util.zip.CRC32; import org.apache.commons.io.FileUtils; public class FileReceiver { public static void main(String[] args) { FileReceiver receiver = new FileReceiver(); receiver.receiveFile(); } public void receiveFile(){ long startTime = System.currentTimeMillis(); long numberOfThreads = 10; long filesize = FileSender.fileSize(); System.out.println("File size received "+filesize); long start = filesize/numberOfThreads; List<ByteArrayWrapper> list = new ArrayList<ByteArrayWrapper>(); for(long threadCount =0; threadCount<numberOfThreads ;threadCount++){ FileDownloaderTask task = new FileDownloaderTask(threadCount*start,(threadCount+1)*start,threadCount,list); new Thread(task).start(); } while(list.size() != numberOfThreads){ // this is done so that all the threads should complete their work before processing further. //System.out.println("Waiting for threads to complete. List size "+list.size()); } if(list.size() == numberOfThreads){ System.out.println("All bytes received "+list); Collections.sort(list, new Comparator<ByteArrayWrapper>() { @Override public int compare(ByteArrayWrapper o1, ByteArrayWrapper o2) { long sequence1 = o1.getSequence(); long sequence2 = o2.getSequence(); if(sequence1 < sequence2){ return -1; }else if(sequence1 > sequence2){ return 1; } else{ return 0; } } }); byte[] totalBytes = list.get(0).getBytes(); byte[] firstArr = null; byte[] secondArr = null; for(int i = 1;i<list.size();i++){ firstArr = totalBytes; secondArr = list.get(i).getBytes(); totalBytes = concat(firstArr, secondArr); } System.out.println(totalBytes.length); convertToFile(totalBytes,"c:\\tmp\\test.pdf"); long endTime = System.currentTimeMillis(); System.out.println("Total time taken with "+numberOfThreads +" threads is "+(endTime-startTime)+" ms" ); } } private byte[] concat(byte[] A, byte[] B) { byte[] C= new byte[A.length+B.length]; System.arraycopy(A, 0, C, 0, A.length); System.arraycopy(B, 0, C, A.length, B.length); return C; } private void convertToFile(byte[] totalBytes,String name) { try { FileUtils.writeByteArrayToFile(new File(name), totalBytes); } catch (IOException e) { throw new RuntimeException(e); } } } Code of ByteArrayWrapper package com.filedownloader; import java.io.Serializable; public class ByteArrayWrapper implements Serializable{ private static final long serialVersionUID = 3499562855188457886L; private byte[] bytes; private long sequence; public ByteArrayWrapper(byte[] bytes, long sequenceNo) { this.bytes = bytes; this.sequence = sequenceNo; } public byte[] getBytes() { return bytes; } public long getSequence() { return sequence; } } Code of FileDownloaderTask import java.util.List; public class FileDownloaderTask implements Runnable { private List<ByteArrayWrapper> list; private long start; private long end; private long sequenceNo; public FileDownloaderTask(long start,long end,long sequenceNo,List<ByteArrayWrapper> list) { this.list = list; this.start = start; this.end = end; this.sequenceNo = sequenceNo; } @Override public void run() { ByteArrayWrapper wrapper = new FileSender().sendBytesOfFile(start, end, sequenceNo); list.add(wrapper); } } Questions related to this code 1) Does file downloading becomes fast when multiple threads is used? In this code i am not able to see the benefit. 2) How should i decide how many threads should i create ? 3) Are their any opensource libraries which does that 4) The file which file receiver receives is valid and not corrupted but checksum (i used FileUtils of common-io) does not match. Whats the problem? 5) This code gives out of memory when used with large file(above 100 Mb) i.e. because byte array which is created. How can i avoid? I know this is a very bad code but i have to write this in one day -:). Please suggest any other good way to do this? Thanks Shekhar

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  • Sorting and Re-arranging List of HashMaps

    - by HonorGod
    I have a List which is straight forward representation of a database table. I am trying to sort and apply some magic after the data is loaded into List of HashMaps. In my case this is the only hard and fast way of doing it becoz I have a rules engine that actually updates the values in the HashMap after several computations. Here is a sample data representation of the HashMap (List of HashMap) - {fromDate=Wed Mar 17 10:54:12 EDT 2010, eventId=21, toDate=Tue Mar 23 10:54:12 EDT 2010, actionId=1234} {fromDate=Wed Mar 17 10:54:12 EDT 2010, eventId=11, toDate=Wed Mar 17 10:54:12 EDT 2010, actionId=456} {fromDate=Sat Mar 20 10:54:12 EDT 2010, eventId=20, toDate=Thu Apr 01 10:54:12 EDT 2010, actionId=1234} {fromDate=Wed Mar 24 10:54:12 EDT 2010, eventId=22, toDate=Sat Mar 27 10:54:12 EDT 2010, actionId=1234} {fromDate=Wed Mar 17 10:54:12 EDT 2010, eventId=11, toDate=Fri Mar 26 10:54:12 EDT 2010, actionId=1234} {fromDate=Sat Mar 20 10:54:12 EDT 2010, eventId=11, toDate=Wed Mar 31 10:54:12 EDT 2010, actionId=1234} {fromDate=Mon Mar 15 10:54:12 EDT 2010, eventId=12, toDate=Wed Mar 17 10:54:12 EDT 2010, actionId=567} I am trying to achieve couple of things - 1) Sort the list by actionId and eventId after which the data would look like - {fromDate=Wed Mar 17 10:54:12 EDT 2010, eventId=11, toDate=Wed Mar 17 10:54:12 EDT 2010, actionId=456} {fromDate=Mon Mar 15 10:54:12 EDT 2010, eventId=12, toDate=Wed Mar 17 10:54:12 EDT 2010, actionId=567} {fromDate=Wed Mar 24 10:54:12 EDT 2010, eventId=22, toDate=Sat Mar 27 10:54:12 EDT 2010, actionId=1234} {fromDate=Wed Mar 17 10:54:12 EDT 2010, eventId=21, toDate=Tue Mar 23 10:54:12 EDT 2010, actionId=1234} {fromDate=Sat Mar 20 10:54:12 EDT 2010, eventId=20, toDate=Thu Apr 01 10:54:12 EDT 2010, actionId=1234} {fromDate=Wed Mar 17 10:54:12 EDT 2010, eventId=11, toDate=Fri Mar 26 10:54:12 EDT 2010, actionId=1234} {fromDate=Sat Mar 20 10:54:12 EDT 2010, eventId=11, toDate=Wed Mar 31 10:54:12 EDT 2010, actionId=1234} 2) If we group the above list by actionId they would be resolved into 3 groups - actionId=1234, actionId=567 and actionId=456. Now here is my question - For each group having the same eventId, I need to update the records so that they have wider fromDate to toDate. Meaning, if you consider the last two rows they have same actionId = 1234 and same eventId = 11. Now we can to pick the least fromDate from those 2 records which is Wed Mar 17 10:54:12 and farther toDate which is Wed Mar 31 10:54:12 and update those 2 record's fromDate and toDate to Wed Mar 17 10:54:12 and Wed Mar 31 10:54:12 respectively. Any ideas? PS: I already have some pseudo code to start with. import java.util.ArrayList; import java.util.Calendar; import java.util.Collections; import java.util.Comparator; import java.util.Date; import java.util.HashMap; import java.util.List; import org.apache.commons.lang.builder.CompareToBuilder; public class Tester { boolean ascending = true ; boolean sortInstrumentIdAsc = true ; boolean sortEventTypeIdAsc = true ; public static void main(String args[]) { Tester tester = new Tester() ; tester.printValues() ; } public void printValues () { List<HashMap<String,Object>> list = new ArrayList<HashMap<String,Object>>() ; HashMap<String,Object> map = new HashMap<String,Object>(); map.put("actionId", new Integer(1234)) ; map.put("eventId", new Integer(21)) ; map.put("fromDate", getDate(1) ) ; map.put("toDate", getDate(7) ) ; list.add(map); map = new HashMap<String,Object>(); map.put("actionId", new Integer(456)) ; map.put("eventId", new Integer(11)) ; map.put("fromDate", getDate(1)) ; map.put("toDate", getDate(1) ) ; list.add(map); map = new HashMap<String,Object>(); map.put("actionId", new Integer(1234)) ; map.put("eventId", new Integer(20)) ; map.put("fromDate", getDate(4) ) ; map.put("toDate", getDate(16) ) ; list.add(map); map = new HashMap<String,Object>(); map.put("actionId", new Integer(1234)) ; map.put("eventId", new Integer(22)) ; map.put("fromDate",getDate(8) ) ; map.put("toDate", getDate(11)) ; list.add(map); map = new HashMap<String,Object>(); map.put("actionId", new Integer(1234)) ; map.put("eventId", new Integer(11)) ; map.put("fromDate",getDate(1) ) ; map.put("toDate", getDate(10) ) ; list.add(map); map = new HashMap<String,Object>(); map.put("actionId", new Integer(1234)) ; map.put("eventId", new Integer(11)) ; map.put("fromDate",getDate(4) ) ; map.put("toDate", getDate(15) ) ; list.add(map); map = new HashMap<String,Object>(); map.put("actionId", new Integer(567)) ; map.put("eventId", new Integer(12)) ; map.put("fromDate", getDate(-1) ) ; map.put("toDate",getDate(1)) ; list.add(map); System.out.println("\n Before Sorting \n "); for(int j = 0 ; j < list.size() ; j ++ ) System.out.println(list.get(j)); Collections.sort ( list , new HashMapComparator2 () ) ; System.out.println("\n After Sorting \n "); for(int j = 0 ; j < list.size() ; j ++ ) System.out.println(list.get(j)); } public static Date getDate(int days) { Calendar cal = Calendar.getInstance(); cal.setTime(new Date()); cal.add(Calendar.DATE, days); return cal.getTime() ; } public class HashMapComparator2 implements Comparator { public int compare ( Object object1 , Object object2 ) { if ( ascending == true ) { return new CompareToBuilder() .append(( ( HashMap ) object1 ).get ( "actionId" ), ( ( HashMap ) object2 ).get ( "actionId" )) .append(( ( HashMap ) object2 ).get ( "eventId" ), ( ( HashMap ) object1 ).get ( "eventId" )) .toComparison(); } else { return new CompareToBuilder() .append(( ( HashMap ) object2 ).get ( "actionId" ), ( ( HashMap ) object1 ).get ( "actionId" )) .append(( ( HashMap ) object2 ).get ( "eventId" ), ( ( HashMap ) object1 ).get ( "eventId" )) .toComparison(); } } } }

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  • Why am I getting an IndexOutOfBoundsException here?

    - by Berzerker
    I'm getting an index out of bounds exception thrown and I don't know why, within my replaceValue method below. [null, (10,4), (52,3), (39,9), (78,7), (63,8), (42,2), (50,411)] replacement value test:411 size=7 [null, (10,4), (52,3), (39,9), (78,7), (63,8), (42,2), (50,101)] removal test of :(10,4) [null, (39,9), (52,3), (42,2), (78,7), (63,8), (50,101)] size=6 I try to replace the value again here and get an error... package heappriorityqueue; import java.util.*; public class HeapPriorityQueue<K,V> { protected ArrayList<Entry<K,V>> heap; protected Comparator<K> comp; int size = 0; protected static class MyEntry<K,V> implements Entry<K,V> { protected K key; protected V value; protected int loc; public MyEntry(K k, V v,int i) {key = k; value = v;loc =i;} public K getKey() {return key;} public V getValue() {return value;} public int getLoc(){return loc;} public String toString() {return "(" + key + "," + value + ")";} void setKey(K k1) {key = k1;} void setValue(V v1) {value = v1;} public void setLoc(int i) {loc = i;} } public HeapPriorityQueue() { heap = new ArrayList<Entry<K,V>>(); heap.add(0,null); comp = new DefaultComparator<K>(); } public HeapPriorityQueue(Comparator<K> c) { heap = new ArrayList<Entry<K,V>>(); heap.add(0,null); comp = c; } public int size() {return size;} public boolean isEmpty() {return size == 0; } public Entry<K,V> min() throws EmptyPriorityQueueException { if (isEmpty()) throw new EmptyPriorityQueueException("Priority Queue is Empty"); return heap.get(1); } public Entry<K,V> insert(K k, V v) { size++; Entry<K,V> entry = new MyEntry<K,V>(k,v,size); heap.add(size,entry); upHeap(size); return entry; } public Entry<K,V> removeMin() throws EmptyPriorityQueueException { if (isEmpty()) throw new EmptyPriorityQueueException("Priority Queue is Empty"); if (size == 1) return heap.remove(1); Entry<K,V> min = heap.get(1); heap.set(1, heap.remove(size)); size--; downHeap(1); return min; } public V replaceValue(Entry<K,V> e, V v) throws InvalidEntryException, EmptyPriorityQueueException { // replace the value field of entry e in the priority // queue with the given value v, and return the old value This is where I am getting the IndexOutOfBounds exception, on heap.get(i); if (isEmpty()){ throw new EmptyPriorityQueueException("Priority Queue is Empty."); } checkEntry(e); int i = e.getLoc(); Entry<K,V> entry=heap.get(((i))); V oldVal = entry.getValue(); K key=entry.getKey(); Entry<K,V> insert = new MyEntry<K,V>(key,v,i); heap.set(i, insert); return oldVal; } public K replaceKey(Entry<K,V> e, K k) throws InvalidEntryException, EmptyPriorityQueueException, InvalidKeyException { // replace the key field of entry e in the priority // queue with the given key k, and return the old key if (isEmpty()){ throw new EmptyPriorityQueueException("Priority Queue is Empty."); } checkKey(k); checkEntry(e); K oldKey=e.getKey(); int i = e.getLoc(); Entry<K,V> entry = new MyEntry<K,V>(k,e.getValue(),i); heap.set(i,entry); downHeap(i); upHeap(i); return oldKey; } public Entry<K,V> remove(Entry<K,V> e) throws InvalidEntryException, EmptyPriorityQueueException{ // remove entry e from priority queue and return it if (isEmpty()){ throw new EmptyPriorityQueueException("Priority Queue is Empty."); } MyEntry<K,V> entry = checkEntry(e); if (size==1){ return heap.remove(size--); } int i = e.getLoc(); heap.set(i, heap.remove(size--)); downHeap(i); return entry; } protected void upHeap(int i) { while (i > 1) { if (comp.compare(heap.get(i/2).getKey(), heap.get(i).getKey()) <= 0) break; swap(i/2,i); i = i/2; } } protected void downHeap(int i) { int smallerChild; while (size >= 2*i) { smallerChild = 2*i; if ( size >= 2*i + 1) if (comp.compare(heap.get(2*i + 1).getKey(), heap.get(2*i).getKey()) < 0) smallerChild = 2*i+1; if (comp.compare(heap.get(i).getKey(), heap.get(smallerChild).getKey()) <= 0) break; swap(i, smallerChild); i = smallerChild; } } protected void swap(int j, int i) { heap.get(j).setLoc(i); heap.get(i).setLoc(j); Entry<K,V> temp; temp = heap.get(j); heap.set(j, heap.get(i)); heap.set(i, temp); } public String toString() { return heap.toString(); } protected MyEntry<K,V> checkEntry(Entry<K,V> ent) throws InvalidEntryException { if(ent == null || !(ent instanceof MyEntry)) throw new InvalidEntryException("Invalid entry."); return (MyEntry)ent; } protected void checkKey(K key) throws InvalidKeyException{ try{comp.compare(key,key);} catch(Exception e){throw new InvalidKeyException("Invalid key.");} } }

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  • qsort on an array of pointers to Objective-C objects

    - by ElBueno
    I have an array of pointers to Objective-C objects. These objects have a sort key associated with them. I'm trying to use qsort to sort the array of pointers to these objects. However, the first time my comparator is called, the first argument points to the first element in my array, but the second argument points to garbage, giving me an EXC_BAD_ACCESS when I try to access its sort key. Here is my code (paraphrased): - (void)foo:(int)numThingies { Thingie **array; array = malloc(sizeof(deck[0])*numThingies); for(int i = 0; i < numThingies; i++) { array[i] = [[Thingie alloc] initWithSortKey:(float)random()/RAND_MAX]; } qsort(array[0], numThingies, sizeof(array[0]), thingieCmp); } int thingieCmp(const void *a, const void *b) { const Thingie *ia = (const Thingie *)a; const Thingie *ib = (const Thingie *)b; if (ia.sortKey > ib.sortKey) return 1; //ib point to garbage, so ib.sortKey produces the EXC_BAD_ACCESS else return -1; } Any ideas why this is happening?

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  • Store comparison in variable (or execute comparison when it's given as an string)

    - by BorrajaX
    Hello everyone. I'd like to know if the super-powerful python allows to store a comparison in a variable or, if not, if it's possible calling/executing a comparison when given as an string ("==" or "!=") I want to allow the users of my program the chance of giving a comparison in an string. For instance, let's say I have a list of... "products" and the user wants to select the products whose manufacturer is "foo". He could would input something like: Product.manufacturer == "foo" and if the user wants the products whose manufacturer is not "bar" he would input Product.manufacturer != "bar" If the user inputs that line as an string, I create a tree with an structure like: != / \ manufacturer bar I'd like to allow that comparison to run properly, but I don't know how to make it happen if != is an string. The "manufacturer" field is a property, so I can properly get it from the Product class and store it (as a property) in the leaf, and well... "bar" is just an string. I'd like to know if I can something similar to what I do with "manufacturer": storing it with a 'callable" (kind of) thing: the property with the comparator: != I have tried with "eval" and it may work, but the comparisons are going to be actually used to query a MySQL database (using sqlalchemy) and I'm a bit concerned about the security of that... Any idea will be deeply appreciated. Thank you! PS: The idea of all this is being able to generate a sqlalchemy query, so if the user inputs the string: Product.manufacturer != "foo" || Product.manufacturer != "bar" ... my tree thing can generate the following: sqlalchemy.or_(Product.manufacturer !="foo", Product.manufacturer !="bar") Since sqlalchemy.or_ is callable, I can also store it in one of the leaves... I only see a problem with the "!="

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  • XML Comparison?

    - by CrazyNick
    I got a books.xml file from http://msdn.microsoft.com/en-us/library/ms762271(VS.85).aspx and just saved it with two different names, removed few lines from the second file and tried to compare the files using the below powershell code: clear-host $xml = New-Object XML $xml = [xml](Get-Content D:\SharePoint\Powershell\Comparator\Comparator_Config.xml) $xml.config.compare | ForEach-Object { $strFile1 = get-Content $.source; $strFile2 = get-Content $.destination; $diff  = Compare-Object $strFile1 $strFile2; $result1 = $diff | where {$.SideIndicator -eq "<=" } | select InputObject; $result2 = $diff | where {$.SideIndicator -eq "=" } | select InputObject; Write-host "nEntries are differ in First web.config filen"; $result1 | ForEach-Object {write-host $.InputObject}; Write-host "nEntries are differ in Second web.config filen" ;$result2 | ForEach-Object {write-host $.InputObject}; $.parameters | ForEach-Object { write-host $.parameter } } and it is working perfectly and giving me the below results: Entries are differ in First web.config file < price36.95< /price < descriptionMicrosoft Visual Studio 7 is explored in depth, looking at how Visual Basic, Visual C++, C#, and ASP+ are integrated into a comprehensive development environment.< /description Entries are differ in Second web.config file < price< /price < description< /description however I wan to know the root node of the above mentioned nodes, is that possible to find? if so, how?

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  • Template with constant expression: error C2975 with VC++2008

    - by Arman
    Hello, I am trying to use elements of meta programming, but hit the wall with the first trial. I would like to have a comparator structure which can be used as following: intersect_by<ID>(L1.data, L2.data, "By ID: "); intersect_by<IDf>(L1.data, L2.data, "By IDf: "); Where: struct ID{};// Tag used for original IDs struct IDf{};// Tag used for the file position //following Boost.MultiIndex examples template<typename Tag,typename MultiIndexContainer> void intersect_by( const MultiIndexContainer& L1,const MultiIndexContainer& L2,std::string msg, Tag* =0 /* fixes a MSVC++ 6.0 bug with implicit template function parms / ) { / obtain a reference to the index tagged by Tag */ const typename boost::multi_index::index<MultiIndexContainer,Tag>::type& L1_ID_index= get<Tag>(L1); const typename boost::multi_index::index<MultiIndexContainer,Tag>::type& L2_ID_index= get<Tag>(L2); std::set_intersection( L1_ID_index.begin(), L1_ID_index.end(), L2_ID_index.begin(), L2_ID_index.end(), std::inserter(s, s.begin()), strComparator() // Here I get the C2975 error ); } template<int N> struct strComparator; template<> struct strComparator<0>{ bool operator () (const particleID& id1, const particleID& id2) const { return id1.ID struct strComparator<1{ bool operator () (const particleID& id1, const particleID& id2) const { return id1.IDf }; What I am missing? kind regards Arman.

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  • Defining < for STL sort algorithm - operator overload, functor or standalone function?

    - by Andy
    I have a stl::list containing Widget class objects. They need to be sorted according to two members in the Widget class. For the sorting to work, I need to define a less-than comparator comparing two Widget objects. There seems to be a myriad of ways to do it. From what I can gather, one can either: a. Define a comparison operator overload in the class: bool Widget::operator< (const Widget &rhs) const b. Define a standalone function taking two Widgets: bool operator<(const Widget& lhs, const Widget& rhs); And then make the Widget class a friend of it: class Widget { // Various class definitions ... friend bool operator<(const Widget& lhs, const Widget& rhs); }; c. Define a functor and then include it as a parameter when calling the sort function: class Widget_Less : public binary_function<Widget, Widget, bool> { bool operator()(const Widget &lhs, const Widget& rhs) const; }; Does anybody know which method is better? In particular I am interested to know if I should do 1 or 2. I searched the book Effective STL by Scott Meyer but unfortunately it does not have anything to say about this. Thank you for your reply.

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  • Log 2 N generic comparison tree

    - by Morano88
    Hey! I'm working on an algorithm for Redundant Binary Representation (RBR) where every two bits represent a digit. I designed the comparator that takes 4 bits and gives out 2 bits. I want to make the comparison in log 2 n so If I have X and Y .. I compare every 2 bits of X with every 2 bits of Y. This is smooth if the number of bits of X or Y equals n where (n = 2^X) i.e n = 2,4,8,16,32,... etc. Like this : However, If my input let us say is 6 or 10 .. then it becomes not smooth and I have to take into account some odd situations like this : I have a shallow experience in algorithms .. is there a generic way to do it .. so at the end I get only 2 bits no matter what the input is ? I just need hints or pseudo-code. If my question is not appropriate here .. so feel free to flag it or tell me to remove it. I'm using VHDL by the way!

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  • Unable to change background colour for JOptionPane

    - by Sunil Kumar Sahoo
    Hi I have created sample progeam which will give same look and feel of a confirm dialog and set the background colour as red. But I donot know what is the problem that my background colour of option is displayed as the default colour but not red. also i need same look and feel of confirm dialog across all platforms. Here is the code that I have written. please help me to solve the issue public class JOptionPaneBackground { public static void main(String[] args) throws Exception { // UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName()); UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); UIDefaults uiDefaults = UIManager.getLookAndFeelDefaults(); List<Object> keys = new ArrayList<Object>(uiDefaults.keySet()); Collections.sort(keys, new Comparator<Object>() { public int compare(Object o1, Object o2) { return (o1.toString()).compareTo(o2.toString()); } }); for (Object key : keys) { System.out.println(String.format("%-40s = %s", key, uiDefaults.get(key))); } UIManager.put("OptionPane.background", Color.red); UIManager.put("Panel.background", Color.red); JOptionPane.showConfirmDialog(null, "Hello World!"); } }

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  • Poor performance using RMI-proxies with Swing components

    - by Patrick
    I'm having huge performance issues when I add RMI proxy references to a Java Swing JList-component. I'm retrieving a list of user Profiles with RMI from a server. The retrieval itself takes just a second or so, so that's acceptable under the circumstances. However, when I try to add these proxies to a JList, with the help of a custom ListModel and a CellRenderer, it takes between 30-60 seconds to add about 180 objects. Since it is a list of users' names, it's preferrable to present them alphabetically. The biggest performance hit is when I sort the elements as they get added to the ListModel. Since the list will always be sorted, I opted to use the built-in Collections.binarySearch() to find the correct position for the next element to be added, and the comparator uses two methods that are defined by the Profile interface, namely getFirstName() and getLastName(). Is there any way to speed this process up, or am I simply implementing it the wrong way? Or is this a "feature" of RMI? I'd really love to be able to cache some of the data of the remote objects locally, to minimize the remote method calls.

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  • Is this overly clever or unsafe?

    - by Liberalkid
    I was working on some code recently and decided to work on my operator overloading in c++, because I've never really implemented it before. So I overloaded the comparison operators for my matrix class using a compare function that returned 0 if LHS was less than RHS, 1 if LHS was greater than RHS and 2 if they were equal. Then I exploited the properties of logical not in c++ on integers, to get all of my compares in one line: inline bool Matrix::operator<(Matrix &RHS){ return ! (compare(*this,RHS)); } inline bool Matrix::operator>(Matrix &RHS){ return ! (compare((*this),RHS)-1); } inline bool Matrix::operator>=(Matrix &RHS){ return compare((*this),RHS); } inline bool Matrix::operator<=(Matrix &RHS){ return compare((*this),RHS)-1; } inline bool Matrix::operator!=(Matrix &RHS){ return compare((*this),RHS)-2; } inline bool Matrix::operator==(Matrix &RHS){ return !(compare((*this),RHS)-2); } Obviously I should be passing RHS as a const, I'm just probably not going to use this matrix class again and I didn't feel like writing another function that wasn't a reference to get the array index values solely for the comparator operation.

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