Commit 935cf3fa authored by Manuel Segimon's avatar Manuel Segimon
Browse files

Add support for Trie-based serialization and deserialization in TrieNode class

parent 40776f57

src/main/java/edu/bu/LanguageCorrection/TrieNode.java

+42 −25
Original line number Diff line number Diff line
@@ -2,6 +2,7 @@ package edu.bu.LanguageCorrection; 


import java.io.Serializable;

import java.util.HashMap;

import java.util.Stack;



public class TrieNode implements Serializable {

    HashMap<String, TrieNode> children = new HashMap<>();
@@ -54,44 +55,60 @@ public class TrieNode implements Serializable { 
    }

    

    public byte[] serialize() {

        return serializeHelper(this).getBytes();

        return serializeHelper(this).replaceAll(" \\}", "\\}").trim().getBytes();

    }



    private String serializeHelper(TrieNode node) {

        StringBuilder serialized = new StringBuilder();

        serialized.append(node.count).append(" ").append(node.childCounts).append(" ");

        serialized.append(node.count).append(" ").append(node.childCounts);

        if (node.childCounts == 0) {

            serialized.append(" ");

            // System.out.println("Serialized node: " + node.count + " " + node.childCounts);

            return serialized.toString();

        } else {

            serialized.append("{");

        }

        for (String key : node.children.keySet()) {

            System.out.println(" key: " + key);

            // System.out.println(" key: " + key);

            serialized.append(key).append(" ").append(serializeHelper(node.children.get(key)));

        }

        System.out.println("Serialized node: " + node.count + " " + node.childCounts);

        serialized.append("}");

        // System.out.println("Serialized node: " + node.count + " " + node.childCounts);



        return serialized.toString();

    }



    public TrieNode deserialize(byte[] serialized) {

        String serializedString = new String(serialized);

        String[] tokens = serializedString.split(" ");

        System.out.println("Deserialized metadata size: " + tokens.length + " tokens");

        // Create Root

        TrieNode root = new TrieNode(); 

        root.count = Integer.parseInt(tokens[0]);

        root.childCounts = Integer.parseInt(tokens[1]);

        for (int i = 2; i < tokens.length; i += 2) {

            root.children.put(tokens[i], deserializeHelper(tokens, i + 1));

        }

        return root;

    public void deserialize(byte[] data) {

        String serializedString = new String(data);

        // Ensure proper spacing around '{' and '}' to correctly parse children

        serializedString = serializedString.replaceAll("\\{", " { ").replaceAll("\\}", " } ").trim();

        String[] parts = serializedString.split("\\s+");

        int[] index = { 0 };



        // Clear current state before rebuilding

        this.children.clear();

        deserializeHelper(this, parts, index);

    }



    // Helper method adapted for in-place deserialization

    private static void deserializeHelper(TrieNode node, String[] parts, int[] index) {

        if (index[0] >= parts.length) {

            throw new IllegalArgumentException("Unexpected end of serialized data.");

        }



    private TrieNode deserializeHelper(String[] tokens, int index) {

        // Create Trie Node

        TrieNode node = new TrieNode();

        node.count = Integer.parseInt(tokens[index]);

        node.childCounts = Integer.parseInt(tokens[index + 1]);

        System.out.println("Index "+index+" Deserialized node: " + node.count + " " + node.childCounts+" token "+tokens[index+2]);

        for (int i = index + 2; i < tokens.length; i += 2) {

            node.children.put(tokens[i], deserializeHelper(tokens, i + 1));

        }

        return node;

        // Set the current node's count and childCounts

        node.count = Integer.parseInt(parts[index[0]++]);

        node.childCounts = Integer.parseInt(parts[index[0]++]);



        if ("{".equals(parts[index[0]])) {

            index[0]++; // Move past the "{" marker

            while (!"}".equals(parts[index[0]])) {

                String key = parts[index[0]++];

                TrieNode child = new TrieNode();

                deserializeHelper(child, parts, index);

                node.children.put(key, child);

            }

            index[0]++; // Skip the "}" marker

        }

    }

}

src/main/java/edu/bu/LanguageCorrection/crawler.java

+3 −2
Original line number Diff line number Diff line
@@ -113,6 +113,7 @@ public class crawler { 
        System.out.println(web_data.text());

        */

        // Extract word usage data

        //System.err.println(web_data.text());

        extractWordUsage(web_data.text(), wordUsage);

        byte[] metadata = wordUsage.serialize();

        System.out.println("Metadata extracted successfully.");
@@ -140,7 +141,7 @@ public class crawler { 
        // Split text into sentences

        String[] sentences = text.split("[.!?] ");

        for (String sentence : sentences) {

            for (int nGram = 1; nGram <= 2; nGram++) {

            for (int nGram = 1; nGram <= 3; nGram++) {

                String[] words = sentence.split("\\s+");

                for (int i = 0; i < words.length - nGram + 1; i++) {

                    trie.insert(Arrays.copyOfRange(words, i, i + nGram));