README.md

Diff Objects

This project helps you to build functionalities that needs to show the differences between two objects. You can use this project in two ways:

• using the annotations @DiffMappings, @DiffMapping and @DiffProperty;
• using the DiffBuilder to map the properties of a class;

Installation

<dependency>
    <groupId>com.github.jonpereiradev</groupId>
    <artifactId>diff-objects</artifactId>
    <version>1.3.0</version>
</dependency>

DiffBuilder

The DiffBuilder provides an API to map an object without the use of annotations:

Example

public class User {
    
    private final String login;
    private final String password;
    private final LocalDate birthday;
    private final Boolean active;
    private final List<Email> emails;
    
    // getters and constructor ommited ...
}

public class Email {
    
    private final String description;
    private final Boolean active;
    
    // getters and constructor ommited ...
}

import com.github.jonpereiradev.diffobjects.DiffConfig;

public class Main {

    public static void main(String[] args) {
        User u1 = new User("user1", "123456", LocalDate.now().minusDays(1), true);
        User u2 = new User("user2", "12345678", LocalDate.now(), true);

        u1.getEmails().add(new Email("[email protected]", true));
        u2.getEmails().add(new Email("[email protected]", false));

        DiffConfig configuration = DiffBuilder
                .map(User.class)
                .mapping("login")
                .mapping("password")
                .mapping("emails", "description")
                .configuration();

        List<DiffResult> diffs = DiffObjects.forClass(User.class).diff(u1, u2, configuration);

        for (DiffResult diff : diffs) {
            if (!diff.isEquals()) {
                System.out.println("Field: " + diff.getProperties().get("field"));
                System.out.println("Before: " + diff.getBefore());
                System.out.println("After: " + diff.getAfter());
            }
        }
    }
}

Annotations

The annotations provided by the diff objects are:

• DiffMappings: to map multiple properties of an object relationship;
• DiffMapping: to map a method of an object;
• DiffProperty: to add properties that will be on the diff result for access;

Example

public class User {
    
    // fields and constructor ommited ...
    
    @DiffMapping
    public String getLogin() {
        return login;
    }
    
    @DiffMapping
    public String getPassword() {
        return password;
    }
    
    @DiffMapping
    public LocalDate getBirthday() {
        return birthday;
    }
    
    @DiffMapping
    public Boolean getActive() {
        return active;
    }
    
    @DiffMapping(value = "description")
    public List<Email> getEmails() {
        return emails;
    }
}

public class Main {
    
    public static void main(String[] args) {
        User u1 = new User("user1", "123456", LocalDate.now().minusDays(1), true);
        User u2 = new User("user2", "12345678", LocalDate.now(), true);
        
        u1.getEmails().add(new Email("[email protected]", true));
        u2.getEmails().add(new Email("[email protected]", false));
        
        List<DiffResult> diffs = (DiffObjects).forClass(User.class).diff(u1, u2);
        
        for (DiffResult diff : diffs) {
            if (!diff.isEquals()) {
                System.out.println("Field: " + diff.getProperties().get("field"));
                System.out.println("Before: " + diff.getBefore());
                System.out.println("After: " + diff.getAfter());
            }
        }
    }
}

@DiffProperty

This annotations is used to provide information in the DiffResult about the field. All objects already have the property "field" with the field name as value.

@DiffProperty(key = "field", value = "{{fieldName}}")

Example

public class User {
    
    // code ommited ...
    
    @DiffMapping(value = "description", properties = {
        @DiffProperty(key = "id", value = "E-mail:"),
        @DiffProperty(key = "maxlength", value = "50")
    })
    public List<Email> getEmails() {
        return emails;
    }
}

public class Main {
    
    public static void main(String[] args) {
        // code omitted ...
        
        List<DiffResult> diffs = DiffObjects.diff(u1, u2);
        
        for (DiffResult diff : diffs) {
            if (diff.getProperties().containsKey("id")) {
                String id = diff.getProperties().get("id");
                String maxlength = diff.getProperties().get("maxlength");
            
                System.out.println("Id: " + id);
                System.out.println("Maxlength: " + maxlength);
                System.out.println("Field: " + diff.getProperties().get("field"));
                System.out.println("Before: " + diff.getBefore());
                System.out.println("After: " + diff.getAfter());
            }
        }
    }
}

License

Diff-Objects is available under the MIT license.