Apache Commons Codec library provides implementations of common encoders and decoders such as Base64, Hex, Phonetic and URLs.

Apache Commons Codec Source Code files are provided in both binary packge (commons-codec-3.15-bin.zip) and source package (commons-codec-3.15-src.zip). You can download them at Apache Commons Codec Website.

Apache Commons Codec Source Code has no dependencies. You can compile it to generate your own version of Apache Commons Codec JAR file.

The source code of Apache Commons Codec 1.15 is provided below:

⏎ org/apache/commons/codec/language/Caverphone2.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.commons.codec.language;

/**
 * Encodes a string into a Caverphone 2.0 value.
 *
 * This is an algorithm created by the Caversham Project at the University of Otago. It implements the Caverphone 2.0
 * algorithm:
 *
 * @see <a href="http://en.wikipedia.org/wiki/Caverphone">Wikipedia - Caverphone</a>
 * @see <a href="http://caversham.otago.ac.nz/files/working/ctp150804.pdf">Caverphone 2.0 specification</a>
 * @since 1.5
 *
 * <p>This class is immutable and thread-safe.</p>
 */
public class Caverphone2 extends AbstractCaverphone {

    private static final String TEN_1 = "1111111111";

    /**
     * Encodes the given String into a Caverphone 2.0 value.
     *
     * @param source
     *            String the source string
     * @return A caverphone code for the given String
     */
    @Override
    public String encode(final String source) {
        String txt = source;
        if (txt == null || txt.length() == 0) {
            return TEN_1;
        }

        // 1. Convert to lowercase
        txt = txt.toLowerCase(java.util.Locale.ENGLISH);

        // 2. Remove anything not A-Z
        txt = txt.replaceAll("[^a-z]", "");

        // 2.5. Remove final e
        txt = txt.replaceAll("e$", ""); // 2.0 only

        // 3. Handle various start options
        txt = txt.replaceAll("^cough", "cou2f");
        txt = txt.replaceAll("^rough", "rou2f");
        txt = txt.replaceAll("^tough", "tou2f");
        txt = txt.replaceAll("^enough", "enou2f"); // 2.0 only
        txt = txt.replaceAll("^trough", "trou2f"); // 2.0 only
                                                   // note the spec says ^enough here again, c+p error I assume
        txt = txt.replaceAll("^gn", "2n");

        // End
        txt = txt.replaceAll("mb$", "m2");

        // 4. Handle replacements
        txt = txt.replaceAll("cq", "2q");
        txt = txt.replaceAll("ci", "si");
        txt = txt.replaceAll("ce", "se");
        txt = txt.replaceAll("cy", "sy");
        txt = txt.replaceAll("tch", "2ch");
        txt = txt.replaceAll("c", "k");
        txt = txt.replaceAll("q", "k");
        txt = txt.replaceAll("x", "k");
        txt = txt.replaceAll("v", "f");
        txt = txt.replaceAll("dg", "2g");
        txt = txt.replaceAll("tio", "sio");
        txt = txt.replaceAll("tia", "sia");
        txt = txt.replaceAll("d", "t");
        txt = txt.replaceAll("ph", "fh");
        txt = txt.replaceAll("b", "p");
        txt = txt.replaceAll("sh", "s2");
        txt = txt.replaceAll("z", "s");
        txt = txt.replaceAll("^[aeiou]", "A");
        txt = txt.replaceAll("[aeiou]", "3");
        txt = txt.replaceAll("j", "y"); // 2.0 only
        txt = txt.replaceAll("^y3", "Y3"); // 2.0 only
        txt = txt.replaceAll("^y", "A"); // 2.0 only
        txt = txt.replaceAll("y", "3"); // 2.0 only
        txt = txt.replaceAll("3gh3", "3kh3");
        txt = txt.replaceAll("gh", "22");
        txt = txt.replaceAll("g", "k");
        txt = txt.replaceAll("s+", "S");
        txt = txt.replaceAll("t+", "T");
        txt = txt.replaceAll("p+", "P");
        txt = txt.replaceAll("k+", "K");
        txt = txt.replaceAll("f+", "F");
        txt = txt.replaceAll("m+", "M");
        txt = txt.replaceAll("n+", "N");
        txt = txt.replaceAll("w3", "W3");
        txt = txt.replaceAll("wh3", "Wh3");
        txt = txt.replaceAll("w$", "3"); // 2.0 only
        txt = txt.replaceAll("w", "2");
        txt = txt.replaceAll("^h", "A");
        txt = txt.replaceAll("h", "2");
        txt = txt.replaceAll("r3", "R3");
        txt = txt.replaceAll("r$", "3"); // 2.0 only
        txt = txt.replaceAll("r", "2");
        txt = txt.replaceAll("l3", "L3");
        txt = txt.replaceAll("l$", "3"); // 2.0 only
        txt = txt.replaceAll("l", "2");

        // 5. Handle removals
        txt = txt.replaceAll("2", "");
        txt = txt.replaceAll("3$", "A"); // 2.0 only
        txt = txt.replaceAll("3", "");

        // 6. put ten 1s on the end
        txt = txt + TEN_1;

        // 7. take the first ten characters as the code
        return txt.substring(0, TEN_1.length());
    }

}

⏎ org/apache/commons/codec/language/Caverphone2.java

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File name: commons-codec-1.15-sources.jar
File size: 364441 bytes
Release date: 2020-09-01
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