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https://github.com/nileshkhaire/babycorn

Short and sweet strongly typed XML reader for JVM
https://github.com/nileshkhaire/babycorn

android commons-configuration2 graalvm groovy java java-field jaxb jaxb2 jvm jvm-languages strongly-typed xml xml-parser xmlreader xpath

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Short and sweet strongly typed XML reader for JVM

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# BabyCorn XML

Short and sweet strongly typed XML reader for JVM.



BabyCorn XML is a library to read XML data into Java data types using XPath selector. 



It could be a good configuration library because of in-built features like validator and preprocessor. 



## Adding BabyCorn XML to your build:



There are multiple options. Select one of the following:



### Download from GitHub releases:



[GitHub Releases](https://github.com/nileshkhaire/BabyCorn/releases)



### To add a dependency using Maven, use the following:



```xml



  com.fervort.babycorn

  babycorn-xml

  1.0.0



```



### To add a dependency using Gradle:



```gradle

implementation 'com.fervort.babycorn:babycorn-xml:1.0.0'

```



## How to use : 



In 3 quick steps: 



1. Add BabyCorn XML jar to your build as specified in above options.

2. Create a Java class with fields and annotate it using XPath as per your XML file.

3. Create an object of a java field class you have created in the last step and pass it to BabyCornXML constructor. All values will be set to field class you have created. That's All!



## Example :



### Your XML :

```xml



	

		Foo Bar

		11

		A

		78.77

		yes

		922337203685477

		63.9873333

		


		

			Singing

			Reading

			Yoga

		

		

			

			

			

		

		

			Painting

			calligraphy

		

	

	

```



### Create a Java class with fields and annotate it using XPath :



```java

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;



import com.fervort.babycorn.xml.annotation.BabyCornXMLField;



public class Students {



	@BabyCornXMLField(xPath = "students/student/name")

	String name;



	@BabyCornXMLField(xPath = "students/student/rollno")

	int rollNumber;

	

	@BabyCornXMLField(xPath = "students/student/division")

	char division;

	

	@BabyCornXMLField(xPath = "students/student/lastYearGrade")

	float lastYearGradeofStudent;

	

	@BabyCornXMLField(xPath = "students/student/inTopTen")

	boolean isStudentInTop10;

	

	@BabyCornXMLField(xPath = "students/student/secretKeyNumber")

	long secretKeyNumber;

	

	@BabyCornXMLField(xPath = "students/student/studentWeight")

	double weight;

	

	@BabyCornXMLField(xPath = "students/student/hobbies/hobby" ,listValue = "text()")

	List hobbies = new ArrayList();

	

	@BabyCornXMLField(xPath = "students/student/subjects/subject" ,mapKey = "@name",mapValue = "@teacherName")

	Map subjects = new HashMap();

}

```



### Create an object of a java field class you have created in the last step and pass it to BabyCornXML constructor :



```java



public class StudentTest {



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

		

		Students students = new Students();

		

		BabyCornXML babyCornXML = new BabyCornXML("Students.xml",students);

		

		System.out.println("Name: "+students.name);

		

		System.out.println("Roll Number "+students.rollNumber);

		

		System.out.println("Division "+students.division);

		

		System.out.println("In Top 10 "+students.isStudentInTop10);

		

		System.out.println("last year grade "+students.lastYearGradeofStudent);

		

		System.out.println("Weight "+students.weight);

	

		System.out.println("SecretKey "+students.secretKeyNumber);



		System.out.println("Hobbies "+students.hobbies);

		

		System.out.println("Subjects "+students.subjects);



	}



}



```



### Output :



```bash

Name: Foo Bar

Roll Number 11

Division A

In Top 10 true

last year grade 78.77

Weight 63.9873333

SecretKey 922337203685477

Hobbies [Singing, Reading, Yoga]

Subjects {English=Def Xyz, Science=Abc Pqr, Mathematics=Lmn Opq}

```



## Handling multiple nodes :

If there are multiple nodes/records in the XML, you can create 2 classes, 1 for holding list of records and other one for holding fields. For example: 



### XML with multiple nodes:

```xml



	

		Abc

		101

		Art

	

	

		Pqr

		102

		Science

	

	

		Xyz

		103

		Commerce

	



```



### Class to hold list of teachers:

```java

public class Teachers {



	// Note Xpath, it is teachers/teacher

	@BabyCornXMLField(xPath = "teachers/teacher")

	List teacherList = new ArrayList();

}

```

### Class to hold teacher fields:

```java

public class Teacher {



	// Note Xpath, it is only name, excluding teachers/teacher

	@BabyCornXMLField(xPath = "name")

	public String name;

	

	@BabyCornXMLField(xPath = "tid")

	public int tid;

	

	@BabyCornXMLField(xPath = "department")

	public String department;

}

```

### Get list of teachers and fields:

```java

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



	Teachers teachers = new Teachers();

	BabyCornXML babyCornXML = new BabyCornXML("Teachers.xml",teachers);

	

	// Iterate through each teacher

	for(Teacher teacher: teachers.teacherList)

	{

		System.out.println("name: "+teacher.name);

		System.out.println("teacher id: "+teacher.tid);

		System.out.println("department: "+teacher.department);

		System.out.println("");

	}

```

### Output :



```bash

name: Abc

teacher id: 101

department: Art



name: Pqr

teacher id: 102

department: Science



name: Xyz

teacher id: 103

department: Commerce

```



## Validator & Pre processor :

Anything can be written in a XML file that can cause a program failure. To avoid such scenarios, validator can be used. You can write your own validator or use built in validators.



### Writing custom validator:

You can write your own validators. Here are simple steps:

1. Add `@BabyCornXMLValidation(validationMethod = "validateEmployeeName")` annotation on the field. Here `validateEmployeeName` is a java method, where validation code will be written.

```java

public class Employees {

	

	@BabyCornXMLValidation(validationMethod = "validateEmployeeName")

	@BabyCornXMLField(xPath = "employees/employee/name")

	public String name;



}



```

2. Write a validation method `validateEmployeeName` in class Emplyees. Method should have 2 parameters as written below.

```java

public ValidationResult validateEmployeeName(Field field, Object object)

{

	String nameFromXML = (String)object;

	ValidationResult result = new ValidationResult(true);

	if(nameFromXML.trim().isEmpty())

	{

		result = new ValidationResult(false);

		result.setIfInvalidMessage("Name in XML is empty");

		result.setSeverity(ValidationResult.SEVERITY.STOP);

		// You can use SEVERITY.CONTINUE to continue with the execution

		//result.setSeverity(ValidationResult.SEVERITY.CONTINUE);

		

	}

	return result;

}

```

3. You can get result of validation using BabyCorn XML APIs

```java

	Employees employees = new Employees();

	BabyCornXML babyCornXML = new BabyCornXML("Employees.xml",employees);

	Validator validator =babyCornXML.getValidator();

	validator.getValidationList();

	System.out.println("validation list "+validator);

```

Check complete example here [Employees.java](https://github.com/nileshkhaire/BabyCorn/blob/main/Source/baby-corn/babycorn-xml/src/test/java/com/fervort/babycorn/xml/validator/Employees.java)



> Note : For field type `String,Char,Boolean` 2nd method parameter `object` could be cast to `String` and for `Double,float,Long` parameters `object` could be cast to `Double` before using. Return value `setIfInvalidValue(returnValue)` should be same as type of the field.



### Validator to pre process the field values:

Validator can be used to pre process the value. For example: In Employees.java example, if department is not a `IT,Finance or Manufacturing` then `UNKNOWN_DEPARTMENT` will be set on the field.

```java

public ValidationResult validateDepartment(Field field, Object object)

{

	String[] departments = {"IT","Finance","Manufacturing"};

	

	String departmentFromXML = (String)object;

	ValidationResult result = new ValidationResult(true);

	if(!Arrays.asList(departments).contains(departmentFromXML))

	{

		result = new ValidationResult(false);

		result.setIfInvalidValue("UNKNOWN_DEPARTMENT");

	}

	return result;

} 

```

## BabyCorn XML APIs:

BabyCorn XML can also be used as XML DOM APIs



```java

public void testAPIs() throws Exception

{

	BabyCornXML babyCornXML = new BabyCornXML("D:\Nilesh\Students.xml");

		

	Document doc= babyCornXML.getDocumentRoot();

		

	NodeList nodeList = doc.getElementsByTagName("lastYearGrade");  

		

	Node node = nodeList.item(0);  

	

	System.out.println("lastYearGrade:" + node.getTextContent());

} 

```