src/main/java/org/apache/commons/codec/language/Nysiis.java - commons-codec - Git at Google

 /*
  * 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;

 import java.util.regex.Pattern;

 import org.apache.commons.codec.EncoderException;
 import org.apache.commons.codec.StringEncoder;

 /**
  * Encodes a string into a NYSIIS value. NYSIIS is an encoding used to relate similar names, but can also be used as a
  * general purpose scheme to find word with similar phonemes.
  * <p>
  * NYSIIS features an accuracy increase of 2.7% over the traditional Soundex algorithm.
  * <p>
  * Algorithm description:
  * <pre>
  * 1. Transcode first characters of name
  *   1a. MAC -&gt;   MCC
  *   1b. KN  -&gt;   NN
  *   1c. K   -&gt;   C
  *   1d. PH  -&gt;   FF
  *   1e. PF  -&gt;   FF
  *   1f. SCH -&gt;   SSS
  * 2. Transcode last characters of name
  *   2a. EE, IE          -&gt;   Y
  *   2b. DT,RT,RD,NT,ND  -&gt;   D
  * 3. First character of key = first character of name
  * 4. Transcode remaining characters by following these rules, incrementing by one character each time
  *   4a. EV  -&gt;   AF  else A,E,I,O,U -&gt; A
  *   4b. Q   -&gt;   G
  *   4c. Z   -&gt;   S
  *   4d. M   -&gt;   N
  *   4e. KN  -&gt;   N   else K -&gt; C
  *   4f. SCH -&gt;   SSS
  *   4g. PH  -&gt;   FF
  *   4h. H   -&gt;   If previous or next is nonvowel, previous
  *   4i. W   -&gt;   If previous is vowel, previous
  *   4j. Add current to key if current != last key character
  * 5. If last character is S, remove it
  * 6. If last characters are AY, replace with Y
  * 7. If last character is A, remove it
  * 8. Collapse all strings of repeated characters
  * 9. Add original first character of name as first character of key
  * </pre>
  * <p>
  * This class is immutable and thread-safe.
  *
  * @see <a href="http://en.wikipedia.org/wiki/NYSIIS">NYSIIS on Wikipedia</a>
  * @see <a href="http://www.dropby.com/NYSIIS.html">NYSIIS on dropby.com</a>
  * @see Soundex
  * @since 1.7
  */
 public class Nysiis implements StringEncoder {

     private static final char[] CHARS_A   = new char[] { 'A' };
     private static final char[] CHARS_AF  = new char[] { 'A', 'F' };
     private static final char[] CHARS_C   = new char[] { 'C' };
     private static final char[] CHARS_FF  = new char[] { 'F', 'F' };
     private static final char[] CHARS_G   = new char[] { 'G' };
     private static final char[] CHARS_N   = new char[] { 'N' };
     private static final char[] CHARS_NN  = new char[] { 'N', 'N' };
     private static final char[] CHARS_S   = new char[] { 'S' };
     private static final char[] CHARS_SSS = new char[] { 'S', 'S', 'S' };

     private static final Pattern PAT_MAC    = Pattern.compile("^MAC");
     private static final Pattern PAT_KN     = Pattern.compile("^KN");
     private static final Pattern PAT_K      = Pattern.compile("^K");
     private static final Pattern PAT_PH_PF  = Pattern.compile("^(PH|PF)");
     private static final Pattern PAT_SCH    = Pattern.compile("^SCH");
     private static final Pattern PAT_EE_IE  = Pattern.compile("(EE|IE)$");
     private static final Pattern PAT_DT_ETC = Pattern.compile("(DT|RT|RD|NT|ND)$");

     private static final char SPACE = ' ';
     private static final int TRUE_LENGTH = 6;

     /**
      * Tests if the given character is a vowel.
      *
      * @param c
      *            the character to test
      * @return <code>true</code> if the character is a vowel, <code>false</code> otherwise
      */
     private static boolean isVowel(final char c) {
         return c == 'A' || c == 'E' || c == 'I' || c == 'O' || c == 'U';
     }

     /**
      * Transcodes the remaining parts of the String. The method operates on a sliding window, looking at 4 characters at
      * a time: [i-1, i, i+1, i+2].
      *
      * @param prev
      *            the previous character
      * @param curr
      *            the current character
      * @param next
      *            the next character
      * @param aNext
      *            the after next character
      * @return a transcoded array of characters, starting from the current position
      */
     private static char[] transcodeRemaining(final char prev, final char curr, final char next, final char aNext) {
         // 1. EV -> AF
         if (curr == 'E' && next == 'V') {
             return CHARS_AF;
         }

         // A, E, I, O, U -> A
         if (isVowel(curr)) {
             return CHARS_A;
         }

         // 2. Q -> G, Z -> S, M -> N
         if (curr == 'Q') {
             return CHARS_G;
         } else if (curr == 'Z') {
             return CHARS_S;
         } else if (curr == 'M') {
             return CHARS_N;
         }

         // 3. KN -> NN else K -> C
         if (curr == 'K') {
             if (next == 'N') {
                 return CHARS_NN;
             }
             return CHARS_C;
         }

         // 4. SCH -> SSS
         if (curr == 'S' && next == 'C' && aNext == 'H') {
             return CHARS_SSS;
         }

         // PH -> FF
         if (curr == 'P' && next == 'H') {
             return CHARS_FF;
         }

         // 5. H -> If previous or next is a non vowel, previous.
         if (curr == 'H' && (!isVowel(prev) || !isVowel(next))) {
             return new char[] { prev };
         }

         // 6. W -> If previous is vowel, previous.
         if (curr == 'W' && isVowel(prev)) {
             return new char[] { prev };
         }

         return new char[] { curr };
     }

     /** Indicates the strict mode. */
     private final boolean strict;

     /**
      * Creates an instance of the {@link Nysiis} encoder with strict mode (original form),
      * i.e. encoded strings have a maximum length of 6.
      */
     public Nysiis() {
         this(true);
     }

     /**
      * Create an instance of the {@link Nysiis} encoder with the specified strict mode:
      *
      * <ul>
      *  <li><code>true</code>: encoded strings have a maximum length of 6</li>
      *  <li><code>false</code>: encoded strings may have arbitrary length</li>
      * </ul>
      *
      * @param strict
      *            the strict mode
      */
     public Nysiis(final boolean strict) {
         this.strict = strict;
     }

     /**
      * Encodes an Object using the NYSIIS algorithm. This method is provided in order to satisfy the requirements of the
      * Encoder interface, and will throw an {@link EncoderException} if the supplied object is not of type
      * {@link String}.
      *
      * @param obj
      *            Object to encode
      * @return An object (or a {@link String}) containing the NYSIIS code which corresponds to the given String.
      * @throws EncoderException
      *            if the parameter supplied is not of a {@link String}
      * @throws IllegalArgumentException
      *            if a character is not mapped
      */
     @Override
     public Object encode(final Object obj) throws EncoderException {
         if (!(obj instanceof String)) {
             throw new EncoderException("Parameter supplied to Nysiis encode is not of type java.lang.String");
         }
         return this.nysiis((String) obj);
     }

     /**
      * Encodes a String using the NYSIIS algorithm.
      *
      * @param str
      *            A String object to encode
      * @return A Nysiis code corresponding to the String supplied
      * @throws IllegalArgumentException
      *            if a character is not mapped
      */
     @Override
     public String encode(final String str) {
         return this.nysiis(str);
     }

     /**
      * Indicates the strict mode for this {@link Nysiis} encoder.
      *
      * @return <code>true</code> if the encoder is configured for strict mode, <code>false</code> otherwise
      */
     public boolean isStrict() {
         return this.strict;
     }

     /**
      * Retrieves the NYSIIS code for a given String object.
      *
      * @param str
      *            String to encode using the NYSIIS algorithm
      * @return A NYSIIS code for the String supplied
      */
     public String nysiis(String str) {
         if (str == null) {
             return null;
         }

         // Use the same clean rules as Soundex
         str = SoundexUtils.clean(str);

         if (str.length() == 0) {
             return str;
         }

         // Translate first characters of name:
         // MAC -> MCC, KN -> NN, K -> C, PH | PF -> FF, SCH -> SSS
         str = PAT_MAC.matcher(str).replaceFirst("MCC");
         str = PAT_KN.matcher(str).replaceFirst("NN");
         str = PAT_K.matcher(str).replaceFirst("C");
         str = PAT_PH_PF.matcher(str).replaceFirst("FF");
         str = PAT_SCH.matcher(str).replaceFirst("SSS");

         // Translate last characters of name:
         // EE -> Y, IE -> Y, DT | RT | RD | NT | ND -> D
         str = PAT_EE_IE.matcher(str).replaceFirst("Y");
         str = PAT_DT_ETC.matcher(str).replaceFirst("D");

         // First character of key = first character of name.
         final StringBuilder key = new StringBuilder(str.length());
         key.append(str.charAt(0));

         // Transcode remaining characters, incrementing by one character each time
         final char[] chars = str.toCharArray();
         final int len = chars.length;

         for (int i = 1; i < len; i++) {
             final char next = i < len - 1 ? chars[i + 1] : SPACE;
             final char aNext = i < len - 2 ? chars[i + 2] : SPACE;
             final char[] transcoded = transcodeRemaining(chars[i - 1], chars[i], next, aNext);
             System.arraycopy(transcoded, 0, chars, i, transcoded.length);

             // only append the current char to the key if it is different from the last one
             if (chars[i] != chars[i - 1]) {
                 key.append(chars[i]);
             }
         }

         if (key.length() > 1) {
             char lastChar = key.charAt(key.length() - 1);

             // If last character is S, remove it.
             if (lastChar == 'S') {
                 key.deleteCharAt(key.length() - 1);
                 lastChar = key.charAt(key.length() - 1);
             }

             if (key.length() > 2) {
                 final char last2Char = key.charAt(key.length() - 2);
                 // If last characters are AY, replace with Y.
                 if (last2Char == 'A' && lastChar == 'Y') {
                     key.deleteCharAt(key.length() - 2);
                 }
             }

             // If last character is A, remove it.
             if (lastChar == 'A') {
                 key.deleteCharAt(key.length() - 1);
             }
         }

         final String string = key.toString();
         return this.isStrict() ? string.substring(0, Math.min(TRUE_LENGTH, string.length())) : string;
     }

 }
	/*
	* 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;

	import java.util.regex.Pattern;

	import org.apache.commons.codec.EncoderException;
	import org.apache.commons.codec.StringEncoder;

	/**
	* Encodes a string into a NYSIIS value. NYSIIS is an encoding used to relate similar names, but can also be used as a
	* general purpose scheme to find word with similar phonemes.
	* <p>
	* NYSIIS features an accuracy increase of 2.7% over the traditional Soundex algorithm.
	* <p>
	* Algorithm description:
	* <pre>
	* 1. Transcode first characters of name
	* 1a. MAC -> MCC
	* 1b. KN -> NN
	* 1c. K -> C
	* 1d. PH -> FF
	* 1e. PF -> FF
	* 1f. SCH -> SSS
	* 2. Transcode last characters of name
	* 2a. EE, IE -> Y
	* 2b. DT,RT,RD,NT,ND -> D
	* 3. First character of key = first character of name
	* 4. Transcode remaining characters by following these rules, incrementing by one character each time
	* 4a. EV -> AF else A,E,I,O,U -> A
	* 4b. Q -> G
	* 4c. Z -> S
	* 4d. M -> N
	* 4e. KN -> N else K -> C
	* 4f. SCH -> SSS
	* 4g. PH -> FF
	* 4h. H -> If previous or next is nonvowel, previous
	* 4i. W -> If previous is vowel, previous
	* 4j. Add current to key if current != last key character
	* 5. If last character is S, remove it
	* 6. If last characters are AY, replace with Y
	* 7. If last character is A, remove it
	* 8. Collapse all strings of repeated characters
	* 9. Add original first character of name as first character of key
	* </pre>
	* <p>
	* This class is immutable and thread-safe.
	*
	* @see <a href="http://en.wikipedia.org/wiki/NYSIIS">NYSIIS on Wikipedia</a>
	* @see <a href="http://www.dropby.com/NYSIIS.html">NYSIIS on dropby.com</a>
	* @see Soundex
	* @since 1.7
	*/
	public class Nysiis implements StringEncoder {

	private static final char[] CHARS_A = new char[] { 'A' };
	private static final char[] CHARS_AF = new char[] { 'A', 'F' };
	private static final char[] CHARS_C = new char[] { 'C' };
	private static final char[] CHARS_FF = new char[] { 'F', 'F' };
	private static final char[] CHARS_G = new char[] { 'G' };
	private static final char[] CHARS_N = new char[] { 'N' };
	private static final char[] CHARS_NN = new char[] { 'N', 'N' };
	private static final char[] CHARS_S = new char[] { 'S' };
	private static final char[] CHARS_SSS = new char[] { 'S', 'S', 'S' };

	private static final Pattern PAT_MAC = Pattern.compile("^MAC");
	private static final Pattern PAT_KN = Pattern.compile("^KN");
	private static final Pattern PAT_K = Pattern.compile("^K");
	private static final Pattern PAT_PH_PF = Pattern.compile("^(PH\|PF)");
	private static final Pattern PAT_SCH = Pattern.compile("^SCH");
	private static final Pattern PAT_EE_IE = Pattern.compile("(EE\|IE)$");
	private static final Pattern PAT_DT_ETC = Pattern.compile("(DT\|RT\|RD\|NT\|ND)$");

	private static final char SPACE = ' ';
	private static final int TRUE_LENGTH = 6;

	/**
	* Tests if the given character is a vowel.
	*
	* @param c
	* the character to test
	* @return <code>true</code> if the character is a vowel, <code>false</code> otherwise
	*/
	private static boolean isVowel(final char c) {
	return c == 'A' \|\| c == 'E' \|\| c == 'I' \|\| c == 'O' \|\| c == 'U';
	}

	/**
	* Transcodes the remaining parts of the String. The method operates on a sliding window, looking at 4 characters at
	* a time: [i-1, i, i+1, i+2].
	*
	* @param prev
	* the previous character
	* @param curr
	* the current character
	* @param next
	* the next character
	* @param aNext
	* the after next character
	* @return a transcoded array of characters, starting from the current position
	*/
	private static char[] transcodeRemaining(final char prev, final char curr, final char next, final char aNext) {
	// 1. EV -> AF
	if (curr == 'E' && next == 'V') {
	return CHARS_AF;
	}

	// A, E, I, O, U -> A
	if (isVowel(curr)) {
	return CHARS_A;
	}

	// 2. Q -> G, Z -> S, M -> N
	if (curr == 'Q') {
	return CHARS_G;
	} else if (curr == 'Z') {
	return CHARS_S;
	} else if (curr == 'M') {
	return CHARS_N;
	}

	// 3. KN -> NN else K -> C
	if (curr == 'K') {
	if (next == 'N') {
	return CHARS_NN;
	}
	return CHARS_C;
	}

	// 4. SCH -> SSS
	if (curr == 'S' && next == 'C' && aNext == 'H') {
	return CHARS_SSS;
	}

	// PH -> FF
	if (curr == 'P' && next == 'H') {
	return CHARS_FF;
	}

	// 5. H -> If previous or next is a non vowel, previous.
	if (curr == 'H' && (!isVowel(prev) \|\| !isVowel(next))) {
	return new char[] { prev };
	}

	// 6. W -> If previous is vowel, previous.
	if (curr == 'W' && isVowel(prev)) {
	return new char[] { prev };
	}

	return new char[] { curr };
	}

	/** Indicates the strict mode. */
	private final boolean strict;

	/**
	* Creates an instance of the {@link Nysiis} encoder with strict mode (original form),
	* i.e. encoded strings have a maximum length of 6.
	*/
	public Nysiis() {
	this(true);
	}

	/**
	* Create an instance of the {@link Nysiis} encoder with the specified strict mode:
	*
	* <ul>
	* <li><code>true</code>: encoded strings have a maximum length of 6</li>
	* <li><code>false</code>: encoded strings may have arbitrary length</li>
	* </ul>
	*
	* @param strict
	* the strict mode
	*/
	public Nysiis(final boolean strict) {
	this.strict = strict;
	}

	/**
	* Encodes an Object using the NYSIIS algorithm. This method is provided in order to satisfy the requirements of the
	* Encoder interface, and will throw an {@link EncoderException} if the supplied object is not of type
	* {@link String}.
	*
	* @param obj
	* Object to encode
	* @return An object (or a {@link String}) containing the NYSIIS code which corresponds to the given String.
	* @throws EncoderException
	* if the parameter supplied is not of a {@link String}
	* @throws IllegalArgumentException
	* if a character is not mapped
	*/
	@Override
	public Object encode(final Object obj) throws EncoderException {
	if (!(obj instanceof String)) {
	throw new EncoderException("Parameter supplied to Nysiis encode is not of type java.lang.String");
	}
	return this.nysiis((String) obj);
	}

	/**
	* Encodes a String using the NYSIIS algorithm.
	*
	* @param str
	* A String object to encode
	* @return A Nysiis code corresponding to the String supplied
	* @throws IllegalArgumentException
	* if a character is not mapped
	*/
	@Override
	public String encode(final String str) {
	return this.nysiis(str);
	}

	/**
	* Indicates the strict mode for this {@link Nysiis} encoder.
	*
	* @return <code>true</code> if the encoder is configured for strict mode, <code>false</code> otherwise
	*/
	public boolean isStrict() {
	return this.strict;
	}

	/**
	* Retrieves the NYSIIS code for a given String object.
	*
	* @param str
	* String to encode using the NYSIIS algorithm
	* @return A NYSIIS code for the String supplied
	*/
	public String nysiis(String str) {
	if (str == null) {
	return null;
	}

	// Use the same clean rules as Soundex
	str = SoundexUtils.clean(str);

	if (str.length() == 0) {
	return str;
	}

	// Translate first characters of name:
	// MAC -> MCC, KN -> NN, K -> C, PH \| PF -> FF, SCH -> SSS
	str = PAT_MAC.matcher(str).replaceFirst("MCC");
	str = PAT_KN.matcher(str).replaceFirst("NN");
	str = PAT_K.matcher(str).replaceFirst("C");
	str = PAT_PH_PF.matcher(str).replaceFirst("FF");
	str = PAT_SCH.matcher(str).replaceFirst("SSS");

	// Translate last characters of name:
	// EE -> Y, IE -> Y, DT \| RT \| RD \| NT \| ND -> D
	str = PAT_EE_IE.matcher(str).replaceFirst("Y");
	str = PAT_DT_ETC.matcher(str).replaceFirst("D");

	// First character of key = first character of name.
	final StringBuilder key = new StringBuilder(str.length());
	key.append(str.charAt(0));

	// Transcode remaining characters, incrementing by one character each time
	final char[] chars = str.toCharArray();
	final int len = chars.length;

	for (int i = 1; i < len; i++) {
	final char next = i < len - 1 ? chars[i + 1] : SPACE;
	final char aNext = i < len - 2 ? chars[i + 2] : SPACE;
	final char[] transcoded = transcodeRemaining(chars[i - 1], chars[i], next, aNext);
	System.arraycopy(transcoded, 0, chars, i, transcoded.length);

	// only append the current char to the key if it is different from the last one
	if (chars[i] != chars[i - 1]) {
	key.append(chars[i]);
	}
	}

	if (key.length() > 1) {
	char lastChar = key.charAt(key.length() - 1);

	// If last character is S, remove it.
	if (lastChar == 'S') {
	key.deleteCharAt(key.length() - 1);
	lastChar = key.charAt(key.length() - 1);
	}

	if (key.length() > 2) {
	final char last2Char = key.charAt(key.length() - 2);
	// If last characters are AY, replace with Y.
	if (last2Char == 'A' && lastChar == 'Y') {
	key.deleteCharAt(key.length() - 2);
	}
	}

	// If last character is A, remove it.
	if (lastChar == 'A') {
	key.deleteCharAt(key.length() - 1);
	}
	}

	final String string = key.toString();
	return this.isStrict() ? string.substring(0, Math.min(TRUE_LENGTH, string.length())) : string;
	}

	}