Subversion Repositories SmartDukaan

package in.shop2020.serving.services;

import in.shop2020.serving.utils.Utils;

import java.io.File;

import java.util.ArrayList;

import java.util.HashSet;

import java.util.List;

import java.util.Map;

import java.util.Set;

import org.apache.commons.io.FileUtils;

import org.apache.log4j.Logger;

import com.google.gson.Gson;

import com.google.gson.reflect.TypeToken;

/**

 * 

 * @author rajveer

 * 

 * Auto suggest service will help user to search some term. This is based on turnary search tree. 

 */

public class AutoSuggestService

{

	private Node root;

	private static Logger log = Logger.getLogger(AutoSuggestService.class);

	private static AutoSuggestService autoSuggestService;

	static{

		synchronized(AutoSuggestService.class){

			autoSuggestService = new AutoSuggestService();

			autoSuggestService.initialize();

		}

	}

	private void initialize() {

		log.info("Starting instance of Autosuggest service");

		try {

			Set<String> titleSet = new HashSet<String>();

			Gson g = new Gson();

			java.lang.reflect.Type typeOfT = new TypeToken<Map<Long, List<String>>>(){}.getType();

			Map<Long, List<String>> synonyms = g.fromJson(FileUtils.readFileToString(new File(Utils.EXPORT_JAVASCRIPT_CONTENT_PATH + "autosuggest.json")), typeOfT);

			if(synonyms != null){

				for(List<String> entry : synonyms.values()){

					for(String title : entry){

						titleSet.add(title);

					}

				}

				List<String> titlelist = new ArrayList<String>(titleSet);

				java.util.Collections.sort(titlelist);

				for(String title : titlelist){

					addItemName(title);

				}

			}

		} catch (Exception e) {

			log.error("", e);

		}

		log.info("Done with starting Autosuggest service");

	}

	public static AutoSuggestService getAutoSuggestServiceInstance(){

		return autoSuggestService;

	}

	private Node addChars(char[] s, int position, Node node, String string)

    {

        if (node == null) { 

        	node = new Node(s[position], null); 

        }

        if (s[position] < node.storedChar) {

        	node.left = addChars(s, position, node.left, string); 

        }

        else if (s[position] > node.storedChar) {

        	node.right = addChars(s, position, node.right, string); 

        }

        else {

        	if (position + 1 == s.length) {

        		node.addItem(string);

        	}

        	else {

        		node.center =  addChars(s, position + 1, node.center, string);

        	}

        }

        return node;

    }

    public void addStringPart(String part, String string)

    {

        if (part == null || part == "") return;

        root = addChars(part.toCharArray(), 0, root, string);

    }

    /**

     * Add String to the tree

     * @param string

     */

    private void addItemName(String string) {

        if (string == null || string == "") return;

        String[] parts = string.trim().toLowerCase().split("\\s+");

        for(String part : parts){

        	addStringPart(part, string);

        }

    }

    /**

     * Get list of matching product names.

     * @param str

     * @param resultCount

     * @return

     */

    public List<String> getMatchingQueries(String str, int resultCount){

    	Set<String> totalSet = new HashSet<String>();

    	String[] parts = str.trim().toLowerCase().split("\\s+");

        for(String part : parts){

        	Node node = getPartialMatchNode(part);

        	Set<String> set = new HashSet<String>();

        	getChildElements(node, set, part);

        	if(totalSet.isEmpty()){

        		totalSet.addAll(set);	

        	}else{

        		totalSet.retainAll(set);

        	}

        }

        List<String> items = new ArrayList<String>(totalSet);

        if(items.size() > resultCount){

        	return items.subList(0, resultCount-1);

        }else{

        	return items;	

        }

    }

    /**

     * Return the node till which we are able to match the word.

     * @param str

     * @return

     */

    private Node getPartialMatchNode(String str){

	    char[] s = str.toCharArray();

	    int pos = 0;

	    Node node = root;

	    while (node != null)

	    {

	        if (s[pos] < node.storedChar) { node = node.left; }

	        else if (s[pos] > node.storedChar) { node = node.right; }

	        else

	        {

	            if (++pos == s.length){

	            	return node;

	            }

	            node = node.center;

	        }

	    }

	    return node;

    }

    private void getChildElements(Node node, Set<String>  set, String str){

    	if(node == null){

    		return;

    	}

    	if(node.itemSet != null && !node.itemSet.isEmpty()){

    		for(String item_name : node.itemSet) {

    			String ignore_item_name = item_name.toLowerCase();

    			if(ignore_item_name.indexOf(str) != -1){

    				set.add(item_name);

    			}

    		}

    	}

    	getChildElements(node.center, set, str);	

    	getChildElements(node.left, set, str);

    	getChildElements(node.right, set, str);

    }

	@Override

	public String toString() {

		return "AutoSuggest [root=" + root + "]";

	}

	public static void main(String[] args) throws Exception {

		AutoSuggestService as = new AutoSuggestService();

		as.addItemName("Nokia N8");

		as.addItemName("Nokia C5-00");

		as.addItemName("Nokia C3-00");

		as.addItemName("Nokia X2-01");

		as.addItemName("Samsung Galaxy Pro");

		as.addItemName("Samsung Galaxy Pop");

		as.addItemName("Samsung Galaxy 551 I5510");

		System.out.println(as.getMatchingQueries("noki", 10));

		System.out.println(as.getMatchingQueries("nok", 10));

		System.out.println(as.getMatchingQueries("n8", 10));

		System.out.println(as.getMatchingQueries("po gala", 10));

	}

}

class Node

{

	char storedChar;

    Node left, center, right;

    Set<String> itemSet;

    public void addItem(String itemName){

    	if(itemSet == null || itemSet.isEmpty()){

    		itemSet = new HashSet<String>();

    	}

    	itemSet.add(itemName);

    }

    public Node(char ch, String itemName)

    {

        this.storedChar = ch;

        if(itemName != null){

        	itemSet = new HashSet<String>();

        	itemSet.add(itemName);

        }

    }

	@Override

	public String toString() {

		return "Node [storedChar=" + storedChar + ", left=" + left

				+ ", center=" + center + ", right=" + right + ", itemSet="

				+ itemSet + "]";

	}   

}