Android example source code file (MorseCodeConverter.java)

This example Android source code file (MorseCodeConverter.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

a, dash, dot, error_gap, letter_gap, letters, morsecodeconverter, numbers, speed_base, word_gap, z

The MorseCodeConverter.java Android example source code

/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.android.apis.os;

/** Class that implements the text to morse code coversion */
class MorseCodeConverter {
    private static final long SPEED_BASE = 100;
    static final long DOT = SPEED_BASE;
    static final long DASH = SPEED_BASE * 3;
    static final long GAP = SPEED_BASE;
    static final long LETTER_GAP = SPEED_BASE * 3;
    static final long WORD_GAP = SPEED_BASE * 7;

    /** The characters from 'A' to 'Z' */
    private static final long[][] LETTERS = new long[][] {
        /* A */ new long[] { DOT, GAP, DASH },
        /* B */ new long[] { DASH, GAP, DOT, GAP, DOT, GAP, DOT },
        /* C */ new long[] { DASH, GAP, DOT, GAP, DASH, GAP, DOT },
        /* D */ new long[] { DASH, GAP, DOT, GAP, DOT },
        /* E */ new long[] { DOT },
        /* F */ new long[] { DOT, GAP, DOT, GAP, DASH, GAP, DOT },
        /* G */ new long[] { DASH, GAP, DASH, GAP, DOT },
        /* H */ new long[] { DOT, GAP, DOT, GAP, DOT, GAP, DOT },
        /* I */ new long[] { DOT, GAP, DOT },
        /* J */ new long[] { DOT, GAP, DASH, GAP, DASH, GAP, DASH },
        /* K */ new long[] { DASH, GAP, DOT, GAP, DASH },
        /* L */ new long[] { DOT, GAP, DASH, GAP, DOT, GAP, DOT },
        /* M */ new long[] { DASH, GAP, DASH },
        /* N */ new long[] { DASH, GAP, DOT },
        /* O */ new long[] { DASH, GAP, DASH, GAP, DASH },
        /* P */ new long[] { DOT, GAP, DASH, GAP, DASH, GAP, DOT },
        /* Q */ new long[] { DASH, GAP, DASH, GAP, DOT, GAP, DASH },
        /* R */ new long[] { DOT, GAP, DASH, GAP, DOT },
        /* S */ new long[] { DOT, GAP, DOT, GAP, DOT },
        /* T */ new long[] { DASH },
        /* U */ new long[] { DOT, GAP, DOT, GAP, DASH },
        /* V */ new long[] { DOT, GAP, DOT, GAP, DASH },
        /* W */ new long[] { DOT, GAP, DASH, GAP, DASH },
        /* X */ new long[] { DASH, GAP, DOT, GAP, DOT, GAP, DASH },
        /* Y */ new long[] { DASH, GAP, DOT, GAP, DASH, GAP, DASH },
        /* Z */ new long[] { DASH, GAP, DASH, GAP, DOT, GAP, DOT },
    };

    /** The characters from '0' to '9' */
    private static final long[][] NUMBERS = new long[][] {
        /* 0 */ new long[] { DASH, GAP, DASH, GAP, DASH, GAP, DASH, GAP, DASH },
        /* 1 */ new long[] { DOT, GAP, DASH, GAP, DASH, GAP, DASH, GAP, DASH },
        /* 2 */ new long[] { DOT, GAP, DOT, GAP, DASH, GAP, DASH, GAP, DASH },
        /* 3 */ new long[] { DOT, GAP, DOT, GAP, DOT, GAP, DASH, GAP, DASH },
        /* 4 */ new long[] { DOT, GAP, DOT, GAP, DOT, GAP, DOT, GAP, DASH },
        /* 5 */ new long[] { DOT, GAP, DOT, GAP, DOT, GAP, DOT, GAP, DOT },
        /* 6 */ new long[] { DASH, GAP, DOT, GAP, DOT, GAP, DOT, GAP, DOT },
        /* 7 */ new long[] { DASH, GAP, DASH, GAP, DOT, GAP, DOT, GAP, DOT },
        /* 8 */ new long[] { DASH, GAP, DASH, GAP, DASH, GAP, DOT, GAP, DOT },
        /* 9 */ new long[] { DASH, GAP, DASH, GAP, DASH, GAP, DASH, GAP, DOT },
    };

    private static final long[] ERROR_GAP = new long[] { GAP };

    /** Return the pattern data for a given character */
    static long[] pattern(char c) {
        if (c >= 'A' && c <= 'Z') {
            return LETTERS[c - 'A'];
        }
        if (c >= 'a' && c <= 'z') {
            return LETTERS[c - 'a'];
        }
        else if (c >= '0' && c <= '9') {
            return NUMBERS[c - '0'];
        }
        else {
            return ERROR_GAP;
        }
    }

    static long[] pattern(String str) {
        boolean lastWasWhitespace;
        int strlen = str.length();

        // Calculate how long our array needs to be.
        int len = 1;
        lastWasWhitespace = true;
        for (int i=0; i<strlen; i++) {
            char c = str.charAt(i);
            if (Character.isWhitespace(c)) {
                if (!lastWasWhitespace) {
                    len++;
                    lastWasWhitespace = true;
                }
            } else {
                if (!lastWasWhitespace) {
                    len++;
                }
                lastWasWhitespace = false;
                len += pattern(c).length;
            }
        }

        // Generate the pattern array.  Note that we put an extra element of 0
        // in at the beginning, because the pattern always starts with the pause,
        // not with the vibration.
        long[] result = new long[len+1];
        result[0] = 0;
        int pos = 1;
        lastWasWhitespace = true;
        for (int i=0; i<strlen; i++) {
            char c = str.charAt(i);
            if (Character.isWhitespace(c)) {
                if (!lastWasWhitespace) {
                    result[pos] = WORD_GAP;
                    pos++;
                    lastWasWhitespace = true;
                }
            } else {
                if (!lastWasWhitespace) {
                    result[pos] = LETTER_GAP;
                    pos++;
                }
                lastWasWhitespace = false;
                long[] letter = pattern(c);
                System.arraycopy(letter, 0, result, pos, letter.length);
                pos += letter.length;
            }
        }
        return result;
    }
}