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  • What is the proper way to use a Logger in a Serializable Java class?

    - by Tim Visher
    I have the following (doctored) class in a system I'm working on and Findbugs is generating a SE_BAD_FIELD warning and I'm trying to understand why it would say that before I fix it in the way that I thought I would. The reason I'm confused is because the description would seem to indicate that I had used no other non-serializable instance fields in the class but bar.model.Foo is also not serializable and used in the exact same way (as far as I can tell) but Findbugs generates no warning for it. import bar.model.Foo; import java.io.File; import java.io.Serializable; import java.util.List; import org.slf4j.Logger; import org.slf4j.LoggerFactory; public class Demo implements Serializable { private final Logger logger = LoggerFactory.getLogger(this.getClass()); private final File file; private final List<Foo> originalFoos; private Integer count; private int primitive = 0; public Demo() { for (Foo foo : originalFoos) { this.logger.debug(...); } } ... } My initial blush at a solution is to get a logger reference from the factory right as I use it: public DispositionFile() { Logger logger = LoggerFactory.getLogger(this.getClass()); for (Foo foo : originalFoos) { this.logger.debug(...); } } That doesn't seem particularly efficient, though. Thoughts?

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  • Is it safe to silently catch ClassCastException when searching for a specific value?

    - by finnw
    Suppose I am implementing a sorted collection (simple example - a Set based on a sorted array.) Consider this (incomplete) implementation: import java.util.*; public class SortedArraySet<E> extends AbstractSet<E> { @SuppressWarnings("unchecked") public SortedArraySet(Collection<E> source, Comparator<E> comparator) { this.comparator = (Comparator<Object>) comparator; this.array = source.toArray(); Collections.sort(Arrays.asList(array), this.comparator); } @Override public boolean contains(Object key) { return Collections.binarySearch(Arrays.asList(array), key, comparator) >= 0; } private final Object[] array; private final Comparator<Object> comparator; } Now let's create a set of integers Set<Integer> s = new SortedArraySet<Integer>(Arrays.asList(1, 2, 3), null); And test whether it contains some specific values: System.out.println(s.contains(2)); System.out.println(s.contains(42)); System.out.println(s.contains("42")); The third line above will throw a ClassCastException. Not what I want. I would prefer it to return false (as HashSet does.) I can get this behaviour by catching the exception and returning false: @Override public boolean contains(Object key) { try { return Collections.binarySearch(Arrays.asList(array), key, comparator) >= 0; } catch (ClassCastException e) { return false; } } Assuming the source collection is correctly typed, what could go wrong if I do this?

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  • Java HashMap containsKey always false

    - by Dennis
    I have the funny situation, that I store a Coordinate into a HashMap<Coordinate, GUIGameField>. Now, the strange thing about it is, that I have a fragment of code, which should guard, that no coordinate should be used twice. But if I debug this code: if (mapForLevel.containsKey(coord)) { throw new IllegalStateException("This coordinate is already used!"); } else { ...do stuff... } ... the containsKey always returns false, although I stored a coordinate with a hashcode of 9731 into the map and the current coord also has the hashcode 9731. After that, the mapForLevel.entrySet() looks like: (java.util.HashMap$EntrySet) [(270,90)=gui.GUIGameField@29e357, (270,90)=gui.GUIGameField@ca470] What could I have possibly done wrong? I ran out of ideas. Thanks for any help! public class Coordinate { int xCoord; int yCoord; public Coordinate(int x, int y) { ...store params in attributes... } ...getters & setters... @Override public int hashCode() { int hash = 1; hash = hash * 41 + this.xCoord; hash = hash * 31 + this.yCoord; return hash; } }

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  • How can I go through a Set in JSP? (Hibernate Associations)

    - by Parris
    Hi All, So I am pretty new to JSP. I have tried this a few ways. Ways that would make sense in PHP or automagicy frameworks... I am probably thinking too much in fact... I have a hibernate one to many association. That is class x has many of class y. In class x's view.jsp. I would like to grab all of class y, where the foreign key of y matches the primary key of x and display them. It seems that hibernate properly puts this stuff into a set. Now, the question is how can I iterate through this set and then output it's contents... I am kind of stumped here. I tried to write a scriptlet, <% java.util.Iterator iter = aBean.getYs().iter(); // aBeans is the bean name // getYs would return the set and iter would return an iterator for the set while(iter.hasNext) { model.X a = new iter.next() %> <h1><%=a.getTitle()%></h1> <% } %> It would seem that that sort of thing should work? Hmmmmmm

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  • Searching in an Arraylist

    - by Puchatek
    Currently I have two classes. A Classroom class and a School class. I would like to write a method in the School class public void showClassRoomDetails which would find the classroom details by only using the teacherName. e.g. teacherName = Daniel className = Science teacherName = Bob className = Maths so when I input Bob, it would print out Bob and Maths many, thanks public class Classroom { private String classRoomName; private String teacherName; public void setClassRoomName(String newClassRoomName) { classRoomName = newClassRoomName; } public String returnClassRoomName() { return classRoomName; } public void setTeacherName(String newTeacherName) { teacherName = newTeacherName; } public String returnTeacherName() { return teacherName; } } import java.util.ArrayList; public class School { private ArrayList<Classroom> classrooms; private String classRoomName; private String teacherName; public School() { classrooms = new ArrayList<Classroom>(); } public void addClassRoom(Classroom newClassRoom, String theClassRoomName) { classrooms.add(newClassRoom); classRoomName = theClassRoomName; } public void addTeacherToClassRoom(int classroomId, String TeacherName) { if (classroomId < classrooms.size() ) { classrooms.get(classroomId).setTeacherName(TeacherName); } } public void showClassRoomDetails { //loop System.out.println(returnClassRoomName); System.out.println(returnTeacherName); } }

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  • Why do Scala maps have poor performance relative to Java?

    - by Mike Hanafey
    I am working on a Scala app that consumes large amounts of CPU time, so performance matters. The prototype of the system was written in Python, and performance was unacceptable. The application does a lot with inserting and manipulating data in maps. Rex Kerr's Thyme was used to look at the performance of updating and retrieving data from maps. Basically "n" random Ints were stored in maps, and retrieved from the maps, with the time relative to java.util.HashMap used as a reference. The full results for a range of "n" are here. Sample (n=100,000) performance relative to java, smaller is worse: Update Read Mutable 16.06% 76.51% Immutable 31.30% 20.68% I do not understand why the scala immutable map beats the scala mutable map in update performance. Using the sizeHint on the mutable map does not help (it appears to be ignored in the tested implementation, 2.10.3). Even more surprisingly the immutable read performance is worse than the mutable read performance, more significantly so with larger maps. The update performance of the scala mutable map is surprisingly bad, relative to both scala immutable and plain Java. What is the explanation?

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  • Help with Java Generics: Cannot use "Object" as argument for "? extends Object"

    - by AniDev
    Hello, I have the following code: import java.util.*; public class SellTransaction extends Transaction { private Map<String,? extends Object> origValueMap; public SellTransaction(Map<String,? extends Object> valueMap) { super(Transaction.Type.Sell); assignValues(valueMap); this.origValueMap=valueMap; } public SellTransaction[] splitTransaction(double splitAtQuantity) { Map<String,? extends Object> valueMapPart1=origValueMap; valueMapPart1.put(nameMappings[3],(Object)new Double(splitAtQuantity)); Map<String,? extends Object> valueMapPart2=origValueMap; valueMapPart2.put(nameMappings[3],((Double)origValueMap.get(nameMappings[3]))-splitAtQuantity); return new SellTransaction[] {new SellTransaction(valueMapPart1),new SellTransaction(valueMapPart2)}; } } The code fails to compile when I call valueMapPart1.put and valueMapPart2.put, with the error: The method put(String, capture#5-of ? extends Object) in the type Map is not applicable for the arguments (String, Object) I have read on the Internet about generics and wildcards and captures, but I still don't understand what is going wrong. My understanding is that the value of the Map's can be any class that extends Object, which I think might be redundant, because all classes extend Object. And I cannot change the generics to something like ? super Object, because the Map is supplied by some library. So why is this not compiling? Also, if I try to cast valueMap to Map<String,Object>, the compiler gives me that 'Unchecked conversion' warning. Thanks!

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  • Read quicktime movie from servlet in a webpage?

    - by khue
    Hi, I have a servlet that construct response to a media file request by reading the file from server: File uploadFile = new File("C:\\TEMP\\movie.mov"); FileInputStream in = new FileInputStream(uploadFile); Then write that stream to the response stream. My question is how do I play the media file in the webpage using embed or object tag to read the media stream from the response? Here is my code in the servlet: public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.getParameter("location"); uploadFile(response); } private void uploadFile(HttpServletResponse response) { File transferFile = new File("C:/TEMP/captured.mov"); FileInputStream in = null; try { in = new FileInputStream(transferFile); } catch (FileNotFoundException e) { System.out.println("File not found"); } try { System.out.println("in byes i s" + in.available()); } catch (IOException e) { } DataOutputStream responseStream = null; try { responseStream = new DataOutputStream(response.getOutputStream()); } catch (IOException e) { System.out.println("Io exception"); } try { Util.copyStream(in, responseStream); } catch (CopyStreamException e) { System.out.println("copy Stream exception"); } try { responseStream.flush(); } catch (IOException e) { } try { responseStream.close(); } catch (IOException e) { } } And here is html page as Ryan suggested: <embed SRC="http://localhost:7101/movies/transferservlet" WIDTH=100 HEIGHT=196 AUTOPLAY=true CONTROLLER=true LOOP=false PLUGINSPAGE="http://www.apple.com/quicktime/"> Any ideas?

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  • Problem painting JLabel class to another JPanel class

    - by jjpotter
    I have created a class that extends JLabel to use as my object moving around a JPanel for a game. import javax.swing.*; public class Head extends JLabel { int xpos; int ypos; int xvel; int yvel; ImageIcon chickie = new ImageIcon("C:\\Users\\jjpotter.MSDOM1\\Pictures\\clavalle.jpg"); JLabel myLabel = new JLabel(chickie); public Head(int xpos, int ypos, int xvel, int yvel){ this.xpos = xpos; this.ypos = ypos; this.xvel = xvel; this.yvel = yvel; } public void draw(){ myLabel.setLocation(xpos, ypos); } public double getXpos() { return xpos; } public double getYpos() { return ypos; } public int getXvel() { return xvel; } public int getYvel() { return yvel; } public void setPos(int x, int y){ xpos = x; ypos = y; } } I am then trying to add it onto my JPanel. From here I will randomly have it increment its x and y coordinates to float it around the screen. I can not get it to paint itself onto the JPanel. I know there is a key concept I am missing here that involves painting components on different panels. Here is what I have in my GamePanel class import java.awt.Dimension; import java.util.Random; import javax.swing.*; public class GamePanel extends JPanel { Random myRand = new Random(); Head head = new Head(20,20,0,0); public GamePanel(){ this.setSize(new Dimension(640, 480)); this.add(head); } } Any suggestions on how to get this to add to the JPanel? Also, is this a good way to go about having the picture float around the screen randomly for a game?

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  • Why does grails use hsqldb when I ask for mysql?

    - by John
    I'm following the racetrack example from Jason Rudolph's book at InfoQ, using grails-1.2.1. I got up to the part where I was to switch from hsqldb to mysql. I think I've deleted every reference to hsqldb in the DataSource.groovy file, but I get an exception and the stack trace shows it's still using hsqldb. DataSource.groovy dataSource { boolean pooled = true String driverClassName = "com.mysql.jdbc.Driver" String url = "jdbc:mysql://localhost/dfpc2" String dbCreate = "create" String username = "dfpc2" String password = "dfpc2" dialect = org.hibernate.dialect.MySQL5InnoDBDialect } hibernate { cache.use_second_level_cache=true cache.use_query_cache=true cache.provider_class='net.sf.ehcache.hibernate.EhCacheProvider' } // environment specific settings environments { development { } test { } production { } } When I grails run-app it all starts up with no errors. I can navigate to the home page. But when I click on one of the links, I get a stack trace: java.sql.SQLException: Table not found in statement [select this_.id as id0_0_, this_.version as version0_0_, this_.name as name0_0_, this_.variant as variant0_0_ from domainObject this_ limit ?] at org.hsqldb.jdbc.Util.throwError(Unknown Source) at org.hsqldb.jdbc.jdbcPreparedStatement.<init>(Unknown Source) at org.hsqldb.jdbc.jdbcConnection.prepareStatement(Unknown Source) at dfpc2.domainObjectController$_closure2.doCall(script1269434425504953491149.groovy:13) at dfpc2.domainObjectController$_closure2.doCall(script1269434425504953491149.groovy) at java.lang.Thread.run(Thread.java:619) My mysql database shows no tables created. (I don't think groovy's connected to mysql yet.) Things I've checked: mysql-connector-java-5.1.6.jar is in lib directory. I've tried grails clean I tried putting the dataSource info in the development environment (I haven't graduated to test or prod yet), but it seemed to make no difference. The stdout shows I'm using development env. I've googled for solutions, but the only solution I've found is when people don't change the test or production environments.

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  • How to get the compression ratio for a GZipped file ?

    - by Enigma
    Here is how I compressed the data: <%@ page import="javax.servlet.jsp.*,java.io.*,java.util.zip.*" %> <% String encodings = request.getHeader("Accept-Encoding"); PrintWriter outWriter = null; if ((encodings != null) && (encodings.indexOf("gzip") != -1)) { OutputStream outA = response.getOutputStream(); outWriter = new PrintWriter(new GZIPOutputStream(outA), false); response.setHeader("Content-Encoding", "gzip"); int a = response.getBufferSize(); System.out.println("ZIPPED VERSION BF:"+a); } else { System.out.println("UN-ZIPPED VERSION"); outWriter = new PrintWriter(response.getOutputStream(), false); } outWriter.println("<HTML><BODY>"); for(int i=0; i<1000; i++) { outWriter.println(" blah blah blah<br>"); } outWriter.println("</BODY></HTML>"); outWriter.close(); %>

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  • how to display values of an arraylist defined in servlet using ajax call

    - by veena123
    can anyone please help me with below code servlet: below servlet is for statically defining an array. import java.io.; import javax.servlet.; import javax.servlet.http.; import java.util.; public class SampleAjax extends HttpServlet{ public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException,IOException { response.setContentType("text/html"); string plociyno = "abd1234"; PrintWriter pw = response.getWriter(); if (policyno.equals("abc1234")) { List dataList= new ArrayList(); dataList.add("automated refund possible"); request.setAttribute("data",dataList); RequestDispatcher dispatcher = request.getRequestDispatcher("refund.jsp"); if (dispatcher != null){ dispatcher.forward(request, response); } } } and my jsp: jsp for displayng the values of the arraylist in a table.... i want to do the same thing but using ajax.... please help <html <body><table id= "table" border="0" width="303"> <tr> <td width="250"><b>Your Policy Refund Details is:</b></td> </tr> <%Iterator itr; %> <% ArrayList refund= (ArrayList)request.getAttribute("data"); if(refund != null){ for(itr=refund.iterator(); itr.hasNext();){ %> <tr> <td><%=itr.next()%></td> </tr> <%}}%> </table> </body> </html> how can i display this arraylist values using ajax??? please help

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  • JAVA MySql multiple word search

    - by user1703849
    i have a database in MySql that has a name column in it which contains several words(description). I am connected to database with java through eclipse. I have a search, that returns results if only name field contains one word. id: name: info: type: 1 balloon big red balloon big 2 house expensive beautiful luxury 3 chicken wings deep fried wings tasty these are just random words but as an example my search can only see ex. balloon and then show info, but if i type chicken wings, it does nothing. so it possible somehow to search from columns with multiple words? this is my search code below import java.io.*; import java.sql.*; import java.util.*; class Search { public static void main(String[] args) { Scanner inp``ut = new Scanner(System.in); try { Connection con = DriverManager.getConnection( "jdbc:mysql://example/mydb", "user", "password"); Statement stmt = (Statement) con.createStatement(); System.out.print("enter search: "); String name = input.next(); String SQL = "SELECT * FROM menu where name LIKE '" + name + "'"; ResultSet rs = stmt.executeQuery(SQL); while (rs.next()) { System.out.println("Name: " +rs.getString("name")); System.out.println("Description: " + rs.getString("info") ); System.out.println("Price: " + rs.getString("Price")); } } catch (Exception e) { System.out.println("ERROR: " + e.getMessage()); } } }

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  • Does everything after my try statement have to be encompassed in that try statement to access variab

    - by Mithrax
    I'm learning java and one thing I've found that I don't like, is generally when I have code like this: import java.util.*; import java.io.*; public class GraphProblem { public static void main(String[] args) { if (args.length < 2) { System.out.println("Error: Please specify a graph file!"); return; } FileReader in = new FileReader(args[1]); Scanner input = new Scanner(in); int size = input.nextInt(); WeightedGraph graph = new WeightedGraph(size); for(int i = 0; i < size; i++) { graph.setLabel(i,Character.toString((char)('A' + i))); } for(int i = 0; i < size; i++) { for(int j = 0; j < size; j++) { graph.addEdge(i, j, input.nextInt()); } } // .. lots more code } } I have an uncaught exception around my FileReader. So, I have to wrap it in a try-catch to catch that specific exception. My question is does that try { } have to encompass everything after that in my method that wants to use either my FileReader (in) or my Scanner (input)? If I don't wrap the whole remainder of the program in that try statement, then anything outside of it can't access the in/input because it may of not been initialized or has been initialized outside of its scope. So I can't isolate the try-catch to just say the portion that intializes the FileReader and close the try statement immediately after that. So, is it the "best practice" to have the try statement wrapping all portions of the code that are going to access variables initialized in it? Thanks!

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  • (JBoss) Problem with .war project on production, while test works

    - by ikky
    Hello. I have a java project (using Spring mvc) which i have built and deployed on my local computer. It runs on a JBoss application server, and works fine on the local machine. The next step i do, is to copy the deployed project.war from the local machine to the server which has the same development environment as the local machine. I stop the JBoss server, delete the cache, and run the JBoss server again. When i now try to run one of the pages(xx.xxx.xxx:8080/webservice/test.htm), i get this exception: exception org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.NullPointerException org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:583) root cause java.lang.NullPointerException com.project.db.DBCustomer.isCredentialsCorrect(DBCustomer.java:44) com.project.CreateHController.handleRequest(CreateHController.java:60) org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:48) org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:875) org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:807) org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:571) org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:501) javax.servlet.http.HttpServlet.service(HttpServlet.java:697) javax.servlet.http.HttpServlet.service(HttpServlet.java:810) org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:75) It seems like none of my classes are reachable. Does anyone have any idea of what is wrong? btw: as i said, the project works fine on the local machine.

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  • Dice Emulation - ImageView

    - by Michelle Harris
    I am trying to emulate dice using ImageView. When I click the button, nothing seems to happen. I have hard coded this example to replace the image with imageView4 for debugging purposes (I was making sure the random wasn't fail). Can anyone point out what I am doing wrong? I am new to Java, Eclipse and Android so I'm sure I've probably made more than one mistake. Java: import java.util.Random; import android.app.Activity; import android.os.Bundle; import android.view.View; import android.widget.ArrayAdapter; import android.widget.ImageView; import android.widget.Spinner; import android.widget.Toast; public class Yahtzee4Activity extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); Spinner s = (Spinner) findViewById(R.id.spinner); ArrayAdapter adapter = ArrayAdapter.createFromResource( this, R.array.score_types, android.R.layout.simple_spinner_dropdown_item); adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); s.setAdapter(adapter); } public void onMyButtonClick(View view) { ImageView imageView1 = new ImageView(this); Random rand = new Random(); int rndInt = 4; //rand.nextInt(6) + 1; // n = the number of images, that start at index 1 String imgName = "die" + rndInt; int id = getResources().getIdentifier(imgName, "drawable", getPackageName()); imageView1.setImageResource(id); } } XML for the button: <Button android:id="@+id/button_roll" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/roll" android:onClick="onMyButtonClick" />

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  • What's the best way of accessing a DRb object (e.g. Ruby Queue) from Scala (and Java)?

    - by Tom Morris
    I have built a variety of little scripts using Ruby's very simple Queue class, and share the Queue between Ruby and JRuby processes using DRb. It would be nice to be able to access these from Scala (and maybe Java) using JRuby. I've put together something Scala and the JSR-223 interface to access jruby-complete.jar. import javax.script._ class DRbQueue(host: String, port: Int) { private var engine = DRbQueue.factory.getEngineByName("jruby") private var invoker = engine.asInstanceOf[Invocable] engine.eval("require \"drb\" ") private var queue = engine.eval("DRbObject.new(nil, \"druby://" + host + ":" + port.toString + "\")") def isEmpty(): Boolean = invoker.invokeMethod(this.queue, "empty?").asInstanceOf[Boolean] def size(): Long = invoker.invokeMethod(this.queue, "length").asInstanceOf[Long] def threadsWaiting: Long = invoker.invokeMethod(this.queue, "num_waiting").asInstanceOf[Long] def offer(obj: Any) = invoker.invokeMethod(this.queue, "push", obj.asInstanceOf[java.lang.Object]) def poll(): Any = invoker.invokeMethod(this.queue, "pop") def clear(): Unit = { invoker.invokeMethod(this.queue, "clear") } } object DRbQueue { var factory = new ScriptEngineManager() } (It conforms roughly to java.util.Queue interface, but I haven't declared the interface because it doesn't implement the element and peek methods because the Ruby class doesn't offer them.) The problem with this is the type conversion. JRuby is fine with Scala's Strings - because they are Java strings. But if I give it a Scala Int or Long, or one of the other Scala types (List, Set, RichString, Array, Symbol) or some other custom type. This seems unnecessarily hacky: surely there has got to be a better way of doing RMI/DRb interop without having to use JSR-223 API. I could either make it so that the offer method serializes the object to, say, a JSON string and takes a structural type of only objects that have a toJson method. I could then write a Ruby wrapper class (or just monkeypatch Queue) to would parse the JSON. Is there any point in carrying on with trying to access DRb from Java/Scala? Might it just be easier to install a real message queue? (If so, any suggestions for a lightweight JVM-based MQ?)

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  • final transient fields and serialization

    - by doublep
    Is it possible to have final transient fields that are set to any non-default value after serialization in Java? My usecase is a cache variable — that's why it is transient. I also have a habit of making Map fields that won't be changed (i.e. contents of the map is changed, but object itself remains the same) final. However, these attributes seem to be contradictory — while compiler allows such a combination, I cannot have the field set to anything but null after unserialization. I tried the following, without success: simple field initialization (shown in the example): this is what I normally do, but the initialization doesn't seem to happen after unserialization; initialization in constructor (I believe this is semantically the same as above though); assigning the field in readObject() — cannot be done since the field is final. In the example cache is public only for testing. import java.io.*; import java.util.*; public class test { public static void main (String[] args) throws Exception { X x = new X (); System.out.println (x + " " + x.cache); ByteArrayOutputStream buffer = new ByteArrayOutputStream (); new ObjectOutputStream (buffer).writeObject (x); x = (X) new ObjectInputStream (new ByteArrayInputStream (buffer.toByteArray ())).readObject (); System.out.println (x + " " + x.cache); } public static class X implements Serializable { public final transient Map <Object, Object> cache = new HashMap <Object, Object> (); } } Output: test$X@1a46e30 {} test$X@190d11 null

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  • What i am doing wrong with Class Overview?

    - by RFM software
    This code not work. Anyone can helpme? .java package rfmsoftware.util.test1; import android.app.Activity; import android.os.Bundle; public class test1 extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); Button button = (Button)findViewById(R.id.Button01); <---- Error at this line !? } } .xml <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" > <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="@string/hello" /> <EditText android:id="@+id/EditText01" android:layout_width="wrap_content" android:layout_height="wrap_content" android:ems="10"></EditText> <Button android:id="@+id/Button01" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/Scan"></Button> <View android:id="@+id/View01" android:layout_width="wrap_content" android:layout_height="wrap_content"></View> </LinearLayout> .error Button cannot be resolved to a type (type Java problem) ???

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  • how to set Content-Type automatically when i download the data that i uploaded.

    - by zjm1126
    this is my code : import os from google.appengine.ext import webapp from google.appengine.ext.webapp import template from google.appengine.ext.webapp.util import run_wsgi_app from google.appengine.ext import db #from login import htmlPrefix,get_current_user class MyModel(db.Model): blob = db.BlobProperty() class BaseRequestHandler(webapp.RequestHandler): def render_template(self, filename, template_args=None): if not template_args: template_args = {} path = os.path.join(os.path.dirname(__file__), 'templates', filename) self.response.out.write(template.render(path, template_args)) class upload(BaseRequestHandler): def get(self): self.render_template('index.html',) def post(self): file=self.request.get('file') obj = MyModel() obj.blob = db.Blob(file.encode('utf8')) obj.put() self.response.out.write('upload ok') class download(BaseRequestHandler): def get(self): #id=self.request.get('id') o = MyModel.all().get() #self.response.out.write(''.join('%s: %s <br/>' % (a, getattr(o, a)) for a in dir(o))) self.response.out.write(o) application = webapp.WSGIApplication( [ ('/?', upload), ('/download',download), ], debug=True ) def main(): run_wsgi_app(application) if __name__ == "__main__": main() my index.html is : <form action="/" method="post"> <input type="file" name="file" /> <input type="submit" /> </form> and it show : <__main__.MyModel object at 0x02506830> but ,i don't want to see this , i want to download it , how to change my code to run, thanks updated it is ok now : class upload(BaseRequestHandler): def get(self): self.render_template('index.html',) def post(self): file=self.request.get('file') obj = MyModel() obj.blob = db.Blob(file) obj.put() self.response.out.write('upload ok') class download(BaseRequestHandler): def get(self): #id=self.request.get('id') o = MyModel.all().order('-').get() #self.response.out.write(''.join('%s: %s <br/>' % (a, getattr(o, a)) for a in dir(o))) self.response.headers['Content-Type'] = "image/png" self.response.out.write(o.blob) and new question is : if you upload a 'png' file ,it will show successful , but ,when i upload a rar file ,i will run error , so how to set Content-Type automatically , and what is the Content-Type of the 'rar' file thanks

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

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

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  • How do I set streetView in my mapview

    - by John
    I an working on an android project whereby i need to set my map to zoom in and show a more detailed view of my map, like the streets of where i want my coordinates to triangulate. The problem is in Mapview class, setStreetView is deprecated, wat is the alternative? This is how setStreetView looks when i use it. package com.HelloMapView; import java.util.List; import com.google.android.maps.GeoPoint; import com.google.android.maps.MapActivity; import com.google.android.maps.MapController; import com.google.android.maps.MapView; import com.google.android.maps.Overlay; import com.google.android.maps.OverlayItem; import android.app.Activity; import android.graphics.drawable.Drawable; import android.os.Bundle; import android.widget.LinearLayout; public class HelloMapView extends MapActivity { MapView mapview; LinearLayout linearlayout; List<Overlay> mapOverlay; Drawable drawable; HelloItemizedOverlay itemizedOverlay; @SuppressWarnings("deprecation") @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); mapview=(MapView)findViewById(R.id.mapview); mapview.setBuiltInZoomControls(true); mapview.setStreetView(true); mapOverlay=mapview.getOverlays(); drawable=this.getResources().getDrawable(R.drawable.androidmarker); itemizedOverlay=new HelloItemizedOverlay(drawable); GeoPoint geoPoint=new GeoPoint(19240000,-99120000); OverlayItem overlayitem=new OverlayItem(geoPoint,"",""); itemizedOverlay.addoverlay(overlayitem); mapOverlay.add(itemizedOverlay); } @Override protected boolean isRouteDisplayed() { // TODO Auto-generated method stub return false; } } this does not work it only shows square boxes with no map at all

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  • Can JMX operations take interfaces as parameters?

    - by Thor84no
    I'm having problems with an MBean that takes a Map<String, Object> as a parameter. If I try to execute it via JMX using a proxy object, I get an Exception: Caused by: javax.management.ReflectionException at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:231) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:668) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) Caused by: java.lang.IllegalArgumentException: Unable to find operation updateProperties(java.util.HashMap) It appears that it attempts to use the actual implementation class rather than the interface, and doesn't check if this is a child of the required interface. The same thing happens for extended classes (for example declare HashMap, pass in LinkedHashMap). Does this mean it's impossible to use an interface for such methods? At the moment I'm getting around it by changing the method signature to accept a HashMap, but it seems odd that I wouldn't be able to use interfaces (or extended classes) in my MBeans. Edit: The proxy object is being created by an in-house utility class called JmxInvocationHandler. The (hopefully) relevant parts of it are as follows: public class JmxInvocationHandler implements InvocationHandler { ... public static <T> T createMBean(final Class<T> iface, SFSTestProperties properties, String mbean, int shHostID) { T newProxyInstance = (T) Proxy.newProxyInstance(iface.getClassLoader(), new Class[] { iface }, (InvocationHandler) new JmxInvocationHandler(properties, mbean, shHostID)); return newProxyInstance; } ... private JmxInvocationHandler(SFSTestProperties properties, String mbean, int shHostID) { this.mbeanName = mbean + MBEAN_SUFFIX + shHostID; msConfig = new MsConfiguration(properties.getHost(0), properties.getMSAdminPort(), properties.getMSUser(), properties.getMSPassword()); } ... public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { if (management == null) { management = ManagementClientStore.getInstance().getManagementClient(msConfig.getHost(), msConfig.getAdminPort(), msConfig.getUser(), msConfig.getPassword(), false); } final Object result = management.methodCall(mbeanName, method.getName(), args == null? new Object[] {} : args); return result; } }

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  • While loop not reading in the last item

    - by Gandalf StormCrow
    I'm trying to read in a multi line string then split it then print it .. here is the string : 1T1b5T!1T2b1T1b2T!1T1b1T2b2T!1T3b1T1b1T!3T3b1T!1T3b1T1b1T!5T1*1T 11X21b1X 4X1b1X When I split the string with ! I get this without the last line string : 1T1b5T 1T1b5T1T2b1T1b2T 1T2b1T1b2T1T1b1T2b2T 1T1b1T2b2T1T3b1T1b1T 1T3b1T1b1T3T3b1T 3T3b1T1T3b1T1b1T 1T3b1T1b1T5T1*1T 5T1*1T11X21b1X 11X21b1X Here is my code : import java.io.BufferedInputStream; import java.util.Scanner; public class Main { public static void main(String args[]) { Scanner stdin = new Scanner(new BufferedInputStream(System.in)); while (stdin.hasNext()) { for (String line : stdin.next().split("!")) { System.out.println(line); for (int i = 0; i < line.length(); i++) { System.out.print(line.charAt(i)); } } } } } Where did I make the mistake, why is not reading in the last line? After I read in all lines properly I should go trough each line if I encounter number I should print the next char the n times the number I just read, but that is long way ahead first I need help with this. Thank you UPDATE : Here is how the output should look like : 1T1b5T 1T2b1T1b2T 1T1b1T2b2T 1T3b1T1b1T 3T3b1T 1T3b1T1b1T 5T1*1T 11X21b1X 4X1b1X Here is a solution in C(my friend solved it not me), but I'd stil wanted to do it in JAVA : #include <stdio.h> int main (void) { char row[134]; for (;fgets (row,134,stdin)!=NULL;) { int i,j=0; for (i=0;row[i]!='\0';i++) { if (row[i]<='9'&&row[i]>='1') j+=(row[i]-'0'); else if ((row[i]<='Z'&&row[i]>='A')||row[i]=='*') for (;j;j--) printf ("%c",row[i]); else if (row[i]=='b') for (;j;j--) printf (" "); else if (row[i]=='!'||row[i]=='\n') printf ("\n"); } } return 0; }

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  • Cannot Find Symbol Method?

    - by Aaron
    In my driver program, This line gives me cannot find symbol error and I don't know why, the method is clearly defined in the SavingsAccount class, and I can refer to all other methods in my driver program but just not that one, I tried changing the type to double, and etc but still not working. Refer to ** Account acct2 = new SavingsAccount (name); acct2.calculateBalance(); SavingsAccount Class Inherited from Account Class: public class SavingsAccount extends Account { private final short minBalance = 0; private double overdraftFee; private double yearlyInterestRate = 0.02; private double interestAmount; public SavingsAccount (String name) { super(name); } public double withdraw (double amount) { if (accountBalance - amount >= minBalance) { accountBalance -= amount; System.out.print ("Withdraw Successful"); } else { accountBalance -= amount; overdraftFee = accountBalance * (0.10); accountBalance += overdraftFee; System.out.print ("Withdraw Succesful, however overdraft fee of 10% has been applied to your account"); } return accountBalance; } **public void calculateBalance () { interestAmount = (accountBalance * yearlyInterestRate); accountBalance += interestAmount; }** public String toString() { return super.toString() + " Interest Received: " + interestAmount; } } Account class, if needed import java.util.Random; import java.text.NumberFormat; public abstract class Account { protected double accountBalance; protected long accountNumber; protected String accountHolder; public Account (String name) { accountHolder = name; accountBalance = 0; Random accountNo = new Random(); accountNumber = accountNo.nextInt(100000); } public double deposit (double amount) { accountBalance += amount; return accountBalance; } public String toString() { NumberFormat accountBal = NumberFormat.getCurrencyInstance(); return "Account Balance: " + accountBal.format(accountBalance) + "\nAccount Number: " + accountNumber; } public String getAccountHolder() { return accountHolder; } public double getAccountBalance() { return accountBalance; } public abstract double withdraw (double amount); }

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