Merge pull request #87 from JeffinsonDarmawan/Fuzzy-Logic-2

Add Damerau-Levenshtein distance and fixed a bug on parser
AY2324S2-CS2113-T11-3 · Apr 2, 2024 · 5dd5baf · 5dd5baf
2 parents 9d992aa + ca1c508
commit 5dd5baf
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Showing 3 changed files with 56 additions and 29 deletions.
diff --git a/src/main/java/florizz/core/FuzzyLogic.java b/src/main/java/florizz/core/FuzzyLogic.java
@@ -57,11 +57,11 @@ public static String detectItem(String userInput) throws FlorizzException {
         Ui uiFuzzy = new Ui();
 
         // Iterate over predefined commands
-        for (String command : ITEMS.keySet()) {
-            int distance = computeLevenshteinDistance(command, userInput);
+        for (String item : ITEMS.keySet()) {
+            int distance = computeDLDistance(item, userInput);
             if (distance < bestDistance) {
                 bestDistance = distance;
-                bestMatch = command;
+                bestMatch = item;
             }
         }
 
@@ -79,19 +79,19 @@ public static String detectItem(String userInput) throws FlorizzException {
     }
 
     /**
-     * Computes the Levenshtein distance which is a metric used to measure the similarity between two strings.
+     * Computes the Damerau-Levenshtein distance which is a metric used to measure the similarity between two strings.
      * It calculates the minimum number of single-character edits required to change one string into another.
-     * These edits can be insertions, deletions, or substitutions of individual characters.
+     * These edits can be insertions, deletions, substitutions and transpositions of individual characters.
      *
-     * @param s1 The first string.
-     * @param s2 The second string.
-     * @return The Levenshtein distance between the two strings.
+     * @param item The first string.
+     * @param userInput The second string.
+     * @return The Damerau-Levenshtein distance between the two strings.
      */
-    private static int computeLevenshteinDistance(String s1, String s2) {
-        assert s1 != null && s2 != null : "Strings cannot be null";
+    private static int computeDLDistance(String item, String userInput) {
+        assert item != null && userInput != null : "Strings cannot be null";
 
-        int m = s1.length();
-        int n = s2.length();
+        int m = item.length();
+        int n = userInput.length();
 
         int[] previousRow = new int[n + 1];
         int[] currentRow = new int[n + 1];
@@ -101,16 +101,22 @@ private static int computeLevenshteinDistance(String s1, String s2) {
             previousRow[j] = j;
         }
 
-        // Calculate the Levenshtein distance
+        // Calculate the Damerau-Levenshtein distance
         for (int i = 1; i <= m; i++) {
             currentRow[0] = i;
 
             for (int j = 1; j <= n; j++) {
-                int substitutionCost = (s1.charAt(i - 1) == s2.charAt(j - 1)) ? 0 : 1;
+                int substitutionCost = (item.charAt(i - 1) == userInput.charAt(j - 1)) ? 0 : 1;
                 currentRow[j] = Math.min(Math.min(
                                 previousRow[j] + 1,             // deletion
                                 currentRow[j - 1] + 1),         // insertion
                         previousRow[j - 1] + substitutionCost); // substitution
+
+                // Check for transpositions
+                if (i > 1 && j > 1 && item.charAt(i - 1) == userInput.charAt(j - 2)
+                        && item.charAt(i - 2) == userInput.charAt(j - 1)) {
+                    currentRow[j] = Math.min(currentRow[j], previousRow[j - 2] + substitutionCost);
+                }
             }
 
             // Swap rows
@@ -119,7 +125,7 @@ private static int computeLevenshteinDistance(String s1, String s2) {
             currentRow = tempRow;
         }
 
-        // Return the Levenshtein distance
+        // Return the Damerau-Levenshtein distance
         assert previousRow[n] >= 0 : "Levenshtein distance cannot be negative";
         return previousRow[n];
     }

diff --git a/src/main/java/florizz/core/Parser.java b/src/main/java/florizz/core/Parser.java
@@ -84,26 +84,47 @@ public static Command parse (String input) throws FlorizzException {
 
 
     /**
-     * Splits input into command and arguments. Also handles capitalisation and space exceptions
+     * Splits input into command and arguments (if any). Handles capitalisation, whitespaces and small typos.
      *
      * @param input
-     * @return String[] output; output[0] = command ; output[1] arguments
+     * @return String[] output; output[0] = item ; output[1] = argument(s)
      */
+
     private static String[] commandHandler(String input) throws FlorizzException {
-        String[] output = new String[2];
-        String trimmedInput = input.trim();
-        int firstWhitespace = trimmedInput.indexOf(" ");
-        if (firstWhitespace != -1) {
-            // input have arguments
-            output[0] = FuzzyLogic.detectItem(trimmedInput.substring(0,firstWhitespace).toLowerCase());
-            output[1] = FuzzyLogic.detectItem(trimmedInput.substring(firstWhitespace).trim());
-        } else {
-            output[0] = FuzzyLogic.detectItem(trimmedInput.toLowerCase());
+        String[] outputs = new String[2];
+        try {
+            String trimmedInput = input.trim();
+            int firstWhitespace = trimmedInput.indexOf(" ");
+            if (firstWhitespace != -1) {
+                outputs[0] = FuzzyLogic.detectItem(trimmedInput.substring(0,firstWhitespace).toLowerCase());
+                switch (outputs[0]) {
+                case ("delete"): // Fallthrough
+                case ("new"):
+                    outputs[1] = trimmedInput.substring(firstWhitespace).trim();
+                    break;
+                case ("remove"): // Fallthrough
+                case ("add"):
+                    String[] arguments = new String[2];
+                    String trimmedArgument = trimmedInput.substring(firstWhitespace).trim();
+                    int secondWhitespace = trimmedArgument.indexOf(" ");
+                    arguments[0] = FuzzyLogic.detectItem(trimmedArgument.substring(0,secondWhitespace));
+                    arguments[1] = trimmedArgument.substring(secondWhitespace).trim();
+                    outputs[1] = arguments[0] + " " + arguments[1];
+                    break;
+                default:
+                    outputs[1] = FuzzyLogic.detectItem(trimmedInput.substring(firstWhitespace).trim());
+                    break;
+                }
+            } else {
+                outputs[0] = FuzzyLogic.detectItem(trimmedInput.toLowerCase());
+            }
+        } catch (FlorizzException ex) {
+            Logger.getLogger("CommandHandler").log(Level.SEVERE, "Exception occurred in commandHandler", ex);
+            throw ex;
         }
-        return output;
+        return outputs;
     }
 
-
     /**
      * remove prefix from an input string
      * e.g. "/to For Mom" -> " For Mom"

diff --git a/src/main/java/florizz/core/Ui.java b/src/main/java/florizz/core/Ui.java
@@ -66,7 +66,7 @@ public void printBouquetDeleted(Bouquet bouquetDeleted){
      * @param bouquetList The list of saved bouquets.
      */
     public void printAllBouquets(ArrayList<Bouquet> bouquetList){
-        System.out.println("Here are the list of your saved bouquets:");
+        System.out.println("Here is the list of your saved bouquets:");
         int i = 1;
         double totalPrice = 0;
         for (Bouquet bouquet : bouquetList){