rubikscube

PatternTable.java

(2160B)

 import java.io.*;
 
 /**
  * Stores a mapping of a key to a value in a file.
  * Stores in the format: key:value
  */
 public class PatternTable {
 
     /** The file that contains the pattern table. */
     private String file;
 
     /**
      * Creates a pattern table in a specified file.
      * @param file The file to save the pattern table.
      */
     public PatternTable(String file) {
         this.file = file;
     }
 
     /**
      * Updates the pattern table with a new key and value.
      * @param state The hashed state.
      * @param heuristic Heuristic of state.
      */
     public void updateTable(int state, byte heuristic) {
         try {
             BufferedWriter out =
                     new BufferedWriter(new FileWriter(file,true));
             out.write(state+":"+
                     Short.toString(heuristic)+"\n");
             out.close();
         } catch (IOException e) {
             System.err.println("Error: " + e.getMessage());
             e.printStackTrace();
         }
     }
 
     /**
      * Reads the pattern table.
      * @returns Byte array of byte[key] = value.
      */
     public byte[] readTable() {
         // 88mil is the max for corner states in rubik's cube
         byte[] result = new byte[88179840];
 
         try {
             BufferedReader in =
                     new BufferedReader(new FileReader(file));
             String str;
             while ((str = in.readLine()) != null) {
                 String[] parts = str.trim().split(":");
                 result[Integer.valueOf(parts[0])] = Byte.valueOf(parts[1]);
             }
             in.close();
         } catch (IOException e) {
             System.err.println("Error: " + e.getMessage());
             e.printStackTrace();
         }
         return result;
     }
 
     /**
      * Clears or empties the entire target file.
      */
     public void clearTable() {
         try {
             BufferedWriter out =
                     new BufferedWriter(new FileWriter(file));
             out.write("");
             out.close();
         } catch (IOException e) {
             System.err.println("Error: " + e.getMessage());
             e.printStackTrace();
         }
     }
 
 
 }