writable

问题 Error: Can't clobber writable file : //file name// Solution: When you try to sync a file, perforce expects your files in workspace will have read-only permissions. But if a file is not checkout,(by p4 edit)but has write permission then it will throw the above error. Changing the file to read-only and syncing again will solve the issue. or try removing the workspace and get the latest revision again. 回答1: The "can't clobber writable" file error happens because Perforce is very cautious about

问题 Error: Can't clobber writable file : //file name// Solution: When you try to sync a file, perforce expects your files in workspace will have read-only permissions. But if a file is not checkout,(by p4 edit)but has write permission then it will throw the above error. Changing the file to read-only and syncing again will solve the issue. or try removing the workspace and get the latest revision again. 回答1: The "can't clobber writable" file error happens because Perforce is very cautious about

问题 I need to move complicated value (implements Writable) from output of 1st map-reduce job to input of other map-reduce job. Results of 1st job saved to file. File can store Text data or BytesWritable (with default output \ input formats). So I need some simple way to convert my Writable to Text or To BytesWritable and from it. Does it exists? Any alternative way to do this? Thanks a lot 回答1: User irW is correct, use SequenceFileOutputFormat. SequenceFile solves this exact problem, without

问题 I'm trying to get an output from an ArrayWritable in a simple MapReduce-Task. I found a few questions with a similar problem, but I can't solve the problem in my own code. So I'm looking forward to your help. Thanks :)! Input: Textfile with some sentence. Output should be: <Word, <length, number of same words in Textfile>> Example: Hello 5 2 The output that I get in my Job is: hello WordLength_V01$IntArrayWritable@221cf05 test WordLength_V01$IntArrayWritable@799e525a I think the problem is in

问题 I want to make folders in my sdcard and I have used the code below: public class Screen extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.welcome); operateOnFirstUsage(); } private void operateOnFirstUsage() { String state = Environment.getExternalStorageState(); Log.d("Media State", state); if (Environment.MEDIA_MOUNTED.equals(state)) { File appDirectory = new File( Environment

问题 Why should a Writable datatype be Mutable? What are the advantages of using Text (vs String) as a datatype for Key/Value in Map, Combine, Shuffle or Reduce processes? Thanks & Regards, Raja 回答1: You can't choose, these datatypes must be mutable. The reason is the serialization mechanism. Let's look at the code: // version 1.x MapRunner#run() K1 key = input.createKey(); V1 value = input.createValue(); while (input.next(key, value)) { // map pair to output mapper.map(key, value, output,

问题 Answers (please read them below, their respective authors provided valuable insights): "writable: false" prevents assigning a new value, but Object.defineProperty is not an assignement operation and therefore ignores the value of "writable" property attributes are inherited, therefore a property will remain non writable on every subclasses/instances until one subclass (or instance of subclass) changes the value of "writable" back to true for itself Question : MDN documentation concerning the

问题 I am emitting two 2D double arrays as key and value. I am constructing WritableComparable class. public class MF implements WritableComparable<MF>{ /** * @param args */ private double[][] value; public MF() { // TODO Auto-generated constructor stub } public MF(double[][] value) { // TODO Auto-generated constructor stub this.value = new double[value.length][value[0].length]; // System.out.println("in matrix"); } public void set(double[][] value) { this.value = value; } public double[][]

问题 I have a simple map-reduce program in which my map and reduce primitives look like this map(K,V) = (Text, OutputAggregator) reduce(Text, OutputAggregator) = (Text,Text) The important point is that from my map function I emit an object of type OutputAggregator which is my own class that implements the Writable interface. However, my reduce fails with the following exception. More specifically, the readFieds() function is throwing an exception. Any clue why ? I use hadoop 0.18.3 10/09/19 04:04

问题 I have asked a very resemblant question in a previous thread Hadoop: How can i have an array of doubles as a value in a key-value pair? . My problem is that i want to pass a double array as value from map to reduce phase. The answer i got was to serialize, convert to Text, pass it to the reducer and deserialize. This is a fine solution but its like serializing and deserializing it twice. ArrayWritable only accepts types that implement Writable like FloatWritable for example. So another