Android Open Source - MorseCode Code Mapping

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License

The source code is released under:

Custom License You are free to download and edit the source code for personal use but not for commercial app purposes. We are going to use this code to create an app in the future.

Java Source Code

package com.csc.morsecode.data;
//from   w  ww . j  a v a 2s .c om
import java.text.StringCharacterIterator;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;

import android.util.Log;


/**
 * @author dpk3062
 * Abstracts out how we transcribe text to morse code and morse code to text.
 */
public class CodeMapping {
  
  /**
   * Keys are lowercased by the helper methods.
   */
  private final HashMap<String, Encoding> textToCode = new HashMap<String, Encoding>();
  private final HashMap<String, String> codeToText = new HashMap<String, String>();
  
  public CodeMapping() {
    loadDefaults();  //TODO load these from a file
  }
  
  //--------------------------------------------------------------------------
  
  private boolean contains(String key) {
    key = key.toLowerCase();
    return textToCode.get(key) != null;
  }
  
  private boolean contains(Encoding codes) {
    return codeToText.get(codes.toString()) != null;
  }
  
  private Encoding get(String key) {
    key = key.toLowerCase();
    return textToCode.get(key);
  }
  
  //TODO get the iterator working so we can turn this private again
  public String get(Encoding codes) {
    Log.e("CM", "Checking: " + codes + ", " + codeToText.get(codes.toString()));
    return codeToText.get(codes.toString());
  }
  
  public void putBoth(String key, Encoding codes) {
    key = key.toLowerCase();
    textToCode.put(key, codes);
    codeToText.put(codes.toString(), key);
  }
  
  //--------------------------------------------------------------------------
  
  public void loadDefaults() {
    //International Morse Code   //TODO what about the other versions?
    //http://en.wikipedia.org/wiki/File:International_Morse_Code.svg  //TODO the space between letters is three units
    if ( textToCode.size() > 0) {
      return;  //TODO we'll probably want to remove this or double check if we need it at some point
    }
    textToCode.clear();
    codeToText.clear();
    putBoth("a", new Encoding(new Code[] {Code.dot, Code.unit, Code.dash}));
    putBoth("b", new Encoding(new Code[] {Code.dash, Code.unit, Code.dot, Code.unit, Code.dot, Code.unit, Code.dot}));
    putBoth("c", new Encoding(new Code[] {Code.dash, Code.unit, Code.dot, Code.unit, Code.dash, Code.unit, Code.dot}));
    putBoth("d", new Encoding(new Code[] {Code.dash, Code.unit, Code.dot, Code.unit, Code.dot}));
    putBoth("e", new Encoding(new Code[] {Code.dot}));
    putBoth("f", new Encoding(new Code[] {Code.dot, Code.unit, Code.dot, Code.unit, Code.dash, Code.unit, Code.dot}));
    putBoth("g", new Encoding(new Code[] {Code.dash, Code.unit, Code.dash, Code.unit, Code.dot}));
    putBoth("h", new Encoding(new Code[] {Code.dot, Code.unit, Code.dot, Code.unit, Code.dot, Code.unit, Code.dot}));
    putBoth("i", new Encoding(new Code[] {Code.dot, Code.unit, Code.dot}));
    putBoth("j", new Encoding(new Code[] {Code.dot, Code.unit, Code.dash, Code.unit, Code.dash, Code.unit, Code.dash}));
    putBoth("k", new Encoding(new Code[] {Code.dash, Code.unit, Code.dot, Code.unit, Code.dash}));
    putBoth("l", new Encoding(new Code[] {Code.dot, Code.unit, Code.dash, Code.unit, Code.dot, Code.unit, Code.dot}));
    putBoth("m", new Encoding(new Code[] {Code.dash, Code.unit, Code.dash}));
    putBoth("n", new Encoding(new Code[] {Code.dash, Code.unit, Code.dot}));
    putBoth("o", new Encoding(new Code[] {Code.dash, Code.unit, Code.dash, Code.unit, Code.dash}));
    putBoth("p", new Encoding(new Code[] {Code.dot, Code.unit, Code.dash, Code.unit, Code.dash, Code.unit, Code.dot}));
    putBoth("q", new Encoding(new Code[] {Code.dash, Code.unit, Code.dash, Code.unit, Code.dot, Code.unit, Code.dash}));
    putBoth("r", new Encoding(new Code[] {Code.dot, Code.unit, Code.dash, Code.unit, Code.dot}));
    putBoth("s", new Encoding(new Code[] {Code.dot, Code.unit, Code.dot, Code.unit, Code.dot}));
    putBoth("t", new Encoding(new Code[] {Code.dash}));
    putBoth("u", new Encoding(new Code[] {Code.dot, Code.unit, Code.dot, Code.unit, Code.dash}));
    putBoth("v", new Encoding(new Code[] {Code.dot, Code.unit, Code.dot, Code.unit, Code.dot, Code.unit, Code.dash}));
    putBoth("w", new Encoding(new Code[] {Code.dot, Code.unit, Code.dash, Code.unit, Code.dash}));
    putBoth("x", new Encoding(new Code[] {Code.dash, Code.unit, Code.dot, Code.unit, Code.dot, Code.unit, Code.dash}));
    putBoth("y", new Encoding(new Code[] {Code.dash, Code.unit, Code.dot, Code.unit, Code.dash, Code.unit, Code.dash}));
    putBoth("z", new Encoding(new Code[] {Code.dash, Code.unit, Code.dash, Code.unit, Code.dot, Code.unit, Code.dot}));
    
    putBoth(" ", new Encoding(new Code[] {Code.unit, Code.unit, Code.unit, Code.unit, Code.unit, Code.unit, Code.unit}));
    
    putBoth("1", new Encoding(new Code[] {Code.dot, Code.unit, Code.dash, Code.unit, Code.dash, Code.unit, Code.dash, Code.unit, Code.dash}));
    putBoth("2", new Encoding(new Code[] {Code.dot, Code.unit, Code.dot, Code.unit, Code.dash, Code.unit, Code.dash, Code.unit, Code.dash}));
    putBoth("3", new Encoding(new Code[] {Code.dot, Code.unit, Code.dot, Code.unit, Code.dot, Code.unit, Code.dash, Code.unit, Code.dash}));
    putBoth("4", new Encoding(new Code[] {Code.dot, Code.unit, Code.dot, Code.unit, Code.dot, Code.unit, Code.dot, Code.unit, Code.dash}));
    putBoth("5", new Encoding(new Code[] {Code.dot, Code.unit, Code.dot, Code.unit, Code.dot, Code.unit, Code.dot, Code.unit, Code.dot}));
    putBoth("6", new Encoding(new Code[] {Code.dash, Code.unit, Code.dot, Code.unit, Code.dot, Code.unit, Code.dot, Code.unit, Code.dot}));
    putBoth("7", new Encoding(new Code[] {Code.dash, Code.unit, Code.dash, Code.unit, Code.dot, Code.unit, Code.dot, Code.unit, Code.dot}));
    putBoth("8", new Encoding(new Code[] {Code.dash, Code.unit, Code.dash, Code.unit, Code.dash, Code.unit, Code.dot, Code.unit, Code.dot}));
    putBoth("9", new Encoding(new Code[] {Code.dash, Code.unit, Code.dash, Code.unit, Code.dash, Code.unit, Code.dash, Code.unit, Code.dot}));
    putBoth("0", new Encoding(new Code[] {Code.dash, Code.unit, Code.dash, Code.unit, Code.dash, Code.unit, Code.dash, Code.unit, Code.dash}));
    //TODO what about whitespace and other characters?
  }
  
  //--------------------------------------------------------------------------  
  
  /**
   * Creates a new iterator that returns Code arrays indicating the next largest matching sequence (a Code array could match a string longer than one character).
   * @param reader
   * @return
   * @throws IllegalArgumentException If the giver reader is null
   */
  public Iterator<Encoding> sToEIterator(StringCharacterIterator reader) throws IllegalArgumentException {
    if(reader == null) {
      throw new IllegalArgumentException("The character iterator cannot be null");
    }
    
    return new TextToCodeIterator(reader);
  }
  
  
  /**
   * @author dpk3062
   * Moves over the given reader returning Code textToCode for the largest possible character sequence.
   */
  private class TextToCodeIterator implements Iterator<Encoding> {
    
    private final StringCharacterIterator reader;
    
    public TextToCodeIterator(StringCharacterIterator reader) {
      this.reader = reader;
    }
    
    @Override
    public boolean hasNext() {
      return reader.getIndex() < reader.getEndIndex();
    }
    
    @Override
    public Encoding next() {
      String key = "";
      Code[] code = new Code[0];
      
      //TODO this loop only matches the first Char.  Change it to keep looping through until it doesn't match, then backup and return the last matching key
      while(hasNext()) {
        key += reader.current();
        reader.next();
        
        if( contains(key) ) {
          return get(key);
        }
      }
      Log.w("code-mapping", "Left over characters without a code mapping: " + key);
      
      return new Encoding(code);
    }
    
    @Override
    public void remove() throws UnsupportedOperationException {
      throw new UnsupportedOperationException("Remove not supported");
    }
  }
  
  //--------------------------------------------------------------------------
  
  public Iterator<String> eToSIterator(Encoding encoding) throws IllegalArgumentException {
    if(encoding == null) {
      throw new IllegalArgumentException("The encoding iterator cannot be null");
    }
    
    return new CodeToTextIterator(encoding);
  }
  
  //TODO this needs testing
  /**
   * @author dpk3062
   *
   */
  private class CodeToTextIterator implements Iterator<String> {
    
    private final Encoding encoding;
    private int index = 0;
    
    public CodeToTextIterator(Encoding encoding) {
      this.encoding = encoding;
    }
    
    public boolean hasNext() {
      return index < encoding.get.length;
    }
    
    public String next() {
      String value = "";
      
      //TODO this loop only matches the first encoding.  Change it to keep looping through until it matches the longest matchable encoding.
      ArrayList<Code> codes = new ArrayList<Code>();
      Encoding e;
      while(hasNext()) {
        codes.add(encoding.get[index]);
        ++index;
        
        e = new Encoding(codes.toArray(new Code[0]));
        if(contains(e)) {
          return get(e);
        }
      }
      
      return value;
    }
    
    public void remove() throws UnsupportedOperationException {
      throw new UnsupportedOperationException("Remove not supported");
    }
  }
  
}

Java Source Code List

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