query Parser

package com.innovaatio.query.parser;

import java.util.ArrayList;
import java.util.List;

import com.innovation.model.Criteria;
import com.innovation.model.Field;
import com.innovation.model.Query;

public class QueryParser {

Query query = new Query();
public Query Parse(String strQuery){
final int selectIndex = (strQuery.indexOf("SELECT") != -1) ? strQuery.indexOf("SELECT") : strQuery.indexOf("select");
        final int fromIndex = (strQuery.indexOf("FROM") != -1) ? strQuery.indexOf("FROM") : strQuery.indexOf("from");;
        final int whereIndex = (strQuery.indexOf("WHERE") != -1) ? strQuery.indexOf("WHERE") : strQuery.indexOf("where");
        final int orderByIndex = (strQuery.indexOf("ORDERBY") != -1) ? strQuery.indexOf("ORDERBY") : strQuery.indexOf("orderby");
        if (selectIndex == -1){
        query.setSelect(false);
        return query;
        }
       
        if (fromIndex == -1){
        query.setParseMessage("Invalid SQL, missing the from clause");
        return query;
        }
        String tableName = strQuery.substring(fromIndex, whereIndex).trim().substring(4);
        query.setTableName(tableName);
        String criteriaStr = null;
        if(orderByIndex != -1){
        String orderByField =  strQuery.substring(orderByIndex).trim().substring(7).trim();
        criteriaStr = strQuery.substring(whereIndex, orderByIndex).trim().substring(5);
        query.setSortByFieldName(orderByField);
        }else{
        criteriaStr = strQuery.substring(whereIndex).trim();
        }
        query.setCriteriaList(parseCriteriaList(criteriaStr));
        return query;
}

private String getOperator(String condition){
if(condition.contains("=")){
return "=";
}else if(condition.contains("<")){
return "<";
}else if(condition.contains(">")){
return ">";
}else if(condition.contains("<>")){
return "<>";
}
return "";
}

private Criteria getCriteria(String criteria){
Criteria criteriaObj = null;
if(criteria.contains("=") || criteria.contains("<") || criteria.contains(">") || criteria.contains("<>")){
String[] fields = criteria.split(getOperator(criteria));
if(fields.length == 2){
criteriaObj = new Criteria(getOperator(criteria), new Field(fields[0],fields[1]));
}
}

return criteriaObj;
}

public List<Criteria> parseCriteriaList(String criteriaStr){
List<Criteria> criteriaList = new ArrayList<Criteria>();
if(criteriaStr.indexOf("AND") != -1 || criteriaStr.indexOf("and") != -1){
int andIndex = (criteriaStr.indexOf("AND") != -1) ? criteriaStr.indexOf("AND") : criteriaStr.indexOf("and");
if(andIndex != -1){
query.setLogicalOperator("AND");
String[] criteriaArr = (criteriaStr.split("AND").length == 2)?criteriaStr.split("AND"):criteriaStr.split("and");
for(String criteria: criteriaArr){
criteriaList.add(getCriteria(criteria));
}
}
}else if(criteriaStr.indexOf("OR") != -1 || criteriaStr.indexOf("or") != -1){
int orIndex = (criteriaStr.indexOf("OR") != -1) ? criteriaStr.indexOf("OR") : criteriaStr.indexOf("or");
if(orIndex != -1){
query.setLogicalOperator("OR");
String[] criteriaArr = (criteriaStr.split("OR").length == 2)?criteriaStr.split("OR"):criteriaStr.split("or");
for(String criteria: criteriaArr){
criteriaList.add(getCriteria(criteria));
}
}
}
return criteriaList;
}
}

package com.innovation.service;

import java.lang.reflect.Field;

import java.lang.reflect.InvocationTargetException;

import java.util.Arrays;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import com.innovation.model.Employee;

public class MappingService {

public static void main(String[] args) throws IllegalAccessException, IllegalArgumentException, InvocationTargetException, NoSuchFieldException, SecurityException, InstantiationException {

Employee emp = Employee.class.newInstance();

Class  aClass = Employee.class;

List<String> fieldList = Arrays.asList("firstName","lastName","empId","designation");

Map<String, Object> queryResult = new HashMap<String, Object>();

queryResult.put("firstName", "Amit");

queryResult.put("lastName", "Sharma");

queryResult.put("empId", 11380);

queryResult.put("designation", "Development Engineer");

for(String field:fieldList){

Field pvtField = aClass.getDeclaredField(field);

pvtField.setAccessible(true);

pvtField.set(emp,queryResult.get(field));

}

System.out.println("Employee::"+emp.toString());

}

}

package com.innovation.model;

import java.util.List;

public class Query {

private boolean isSelect;

private List<String> columns;

private String tableName;

private String sortByFieldName;

private String logicalOperator;

private List<Criteria> criteriaList;

private String parseMessage;

public List<Criteria> getCriteriaList() {

return criteriaList;

}

public void setCriteriaList(List<Criteria> criteriaList) {

this.criteriaList = criteriaList;

}

public boolean isSelect() {

return isSelect;

}

public void setSelect(boolean isSelect) {

this.isSelect = isSelect;

}

public List<String> getColumns() {

return columns;

}

public void setColumns(List<String> columns) {

this.columns = columns;

}

public String getTableName() {

return tableName;

}

public void setTableName(String tableName) {

this.tableName = tableName;

}

public String getSortByFieldName() {

return sortByFieldName;

}

public void setSortByFieldName(String sortByFieldName) {

this.sortByFieldName = sortByFieldName;

}

public String getParseMessage() {

return parseMessage;

}

public void setParseMessage(String parseMessage) {

this.parseMessage = parseMessage;

}

public String getLogicalOperator() {

return logicalOperator;

}

public void setLogicalOperator(String logicalOperator) {

this.logicalOperator = logicalOperator;

}

}

package com.innovation.model;

public class Employee {

private String firstName;

private String lastName;

private int empId;

private String designation;

public String getFirstName() {

return firstName;

}

public void setFirstName(String firstName) {

this.firstName = firstName;

}

public String getLastName() {

return lastName;

}

public void setLastName(String lastName) {

this.lastName = lastName;

}

public int getEmpId() {

return empId;

}

public void setEmpId(int empId) {

this.empId = empId;

}

public String getDesignation() {

return designation;

}

public void setDesignation(String designation) {

this.designation = designation;

}

@Override

public String toString() {

return "FirstName:" + firstName + "\nLastName:" + lastName + "\nEmpId:"

+ empId + "\nDesignation:" + designation;

}

}

package com.innovation.model;

public class Field {

private String name;

private String value;

public Field(){}

public Field(String name, String value){

this.name = name;

this.value = value;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getValue() {

return value;

}

public void setValue(String value) {

this.value = value;

}

}

package com.innovation.model;

public class Criteria {

private String operator;

private Field field;

public Criteria(){}

public Criteria(String operator, Field field){

this.operator = operator;

this.field = field;

}

public Field getField() {

return field;

}

public void setField(Field field) {

this.field = field;

}

public String getOperator() {

return operator;

}

public void setOperator(String operator) {

this.operator = operator;

}

}

Reverse a linked list

java code to create single linked list
 
//This is linked list node structure
class LinkedList{
    public int data;
    public LinkedList link;
    public LinkedList(int data) {
        this.data = data;
    }
}

public class LinkedListReverse {
    LinkedList node,start = null, end = null;
    public static void main(String[] args) throws InterruptedException {
        LinkedListReverse linkedListReverse = new LinkedListReverse();
        linkedListReverse.insert(50);
        linkedListReverse.insert(40);
        linkedListReverse.insert(56);
        linkedListReverse.insert(53);
        linkedListReverse.insert(23);
        linkedListReverse.insert(11);
        linkedListReverse.traverse();
        System.out.println("Reverse Linked List");
        linkedListReverse.reversePrint(linkedListReverse.getFirstNode());
        linkedListReverse.reverseLinkedList(linkedListReverse.getFirstNode());
        System.out.println("**********************");
        linkedListReverse.traverse();
    }
   
// This method insert new node to existing linkedlist
private void insert(int record){
        node = new LinkedList(record);
        if(start == null){
            node.link = start;
            start =node;
        }
        else{
            end.link= node;
        }
        end =node;
}

 /*Prints the linkedlist in reverse order using recursion but there is no change in binding of node */
private void reversePrint(LinkedList linkedList) throws InterruptedException{
        if(linkedList.link != null){
            reversePrint(linkedList.link);
        }
        System.out.println(linkedList.data);
    }



// reverse the linked list in reverse order. This method changes the binding of node.
LinkedList preStart = null;
private void reverseLinkedList(LinkedList linkedList){
        if(linkedList.link.link != null)
            reverseLinkedList(linkedList.link);
        else if(linkedList.link.link == null){
            preStart = getFirstNode();
            start = linkedList.link;
            start.link = null;
        }
        linkedList.link.link = linkedList;
        if(linkedList == preStart)
            linkedList.link = null;
    }

Online PF Transfer Procedure

Hi Friends,

This is my first non-technical blogs.

We need to transfer our PF account as we switch our job. Many of you might be familiar that we can transfer our PF account online now.

Here is simple steps to start online PF transfer process
1. Goto http://memberclaims.epfoservices.in/ and login to the portal. For first time user, register first and then login.
2. Goto Claim -> Request For Transfer of Account
3. Fill up the form.
4. Select Claim attestation through as Previous Establishment to get your settlement done relatively soon.
5. Submit the form and take printout of document.
6. Submit printed document to CurrentEmployer/PreviousEmployer based on Claim attestation through field selection.

and your work is done. Your PF Account will be transferred within 15 working days.

You can visit http://members.epfoservices.in/ to know your PF balance. 

Remote Debugger

Find the steps below to start tomcat in debug mode from command line.

set two environment variables as...
    set JPDA_TRANSPORT=dt_socket
    set JPDA_ADDRESS=7777

After setting the environment, start the tomcat server using following command
    catalina.bat jpda start

To debug application using IDE Eclipse you need to connect your IDE to tomcat listening port.

Goto debug Configuration, 
Select Remote Java Application, Click New Launch Configuration icon to create new configuration.
Enter Project Name, Host(Remote Tomcat Server running in debug mode IP Address) and Port(JPDA_ADDRESS before starting tomcat in debug mode)

Click Debug and start debugging your application.

Creating Reusable Directive in AngularJS

Code snippet for creating Reusable directive in AngularJS

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html lang="en" ng-app="APP">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Custom Tag Example</title>
</head>
<body>
<name first="Amit" last="Sharma"></name>
<script src="script/angular.min.js"></script>
<script>
var APP=angular.module('APP',[]);
APP.directive('name',function(){
return{
restrict:'E',
link:function(scope,e,a){
scope.fullname = a.first+' '+a.last
},
replace:true,
template:"<h1>{{fullname}}</h1>"
}
});
</script>
</body>
</html>