Adapter

/**
 * A simple adapter class that converts between input and output POJOs
 * All classes are contained within this single file for simplicity
 */
public class PojoAdapter {

    /**
     * Sample Input POJO representing user data from an external system
     */
    public static class InputPojo {
        private String firstName;
        private String lastName;
        private int age;
        private String emailAddress;
        private String phoneNumber;

        // Constructors
        public InputPojo() {}

        public InputPojo(String firstName, String lastName, int age, String emailAddress, String phoneNumber) {
            this.firstName = firstName;
            this.lastName = lastName;
            this.age = age;
            this.emailAddress = emailAddress;
            this.phoneNumber = phoneNumber;
        }

        // Getters and Setters
        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 getAge() { return age; }
        public void setAge(int age) { this.age = age; }

        public String getEmailAddress() { return emailAddress; }
        public void setEmailAddress(String emailAddress) { this.emailAddress = emailAddress; }

        public String getPhoneNumber() { return phoneNumber; }
        public void setPhoneNumber(String phoneNumber) { this.phoneNumber = phoneNumber; }

        @Override
        public String toString() {
            return "InputPojo{" +
                    "firstName='" + firstName + '\'' +
                    ", lastName='" + lastName + '\'' +
                    ", age=" + age +
                    ", emailAddress='" + emailAddress + '\'' +
                    ", phoneNumber='" + phoneNumber + '\'' +
                    '}';
        }
    }

    /**
     * Sample Output POJO representing user data for internal system
     */
    public static class OutputPojo {
        private String fullName;
        private String ageCategory;
        private String email;
        private String contact;
        private boolean isAdult;

        // Constructors
        public OutputPojo() {}

        public OutputPojo(String fullName, String ageCategory, String email, String contact, boolean isAdult) {
            this.fullName = fullName;
            this.ageCategory = ageCategory;
            this.email = email;
            this.contact = contact;
            this.isAdult = isAdult;
        }

        // Getters and Setters
        public String getFullName() { return fullName; }
        public void setFullName(String fullName) { this.fullName = fullName; }

        public String getAgeCategory() { return ageCategory; }
        public void setAgeCategory(String ageCategory) { this.ageCategory = ageCategory; }

        public String getEmail() { return email; }
        public void setEmail(String email) { this.email = email; }

        public String getContact() { return contact; }
        public void setContact(String contact) { this.contact = contact; }

        public boolean isAdult() { return isAdult; }
        public void setAdult(boolean adult) { isAdult = adult; }

        @Override
        public String toString() {
            return "OutputPojo{" +
                    "fullName='" + fullName + '\'' +
                    ", ageCategory='" + ageCategory + '\'' +
                    ", email='" + email + '\'' +
                    ", contact='" + contact + '\'' +
                    ", isAdult=" + isAdult +
                    '}';
        }
    }

    /**
     * Adapter method that converts InputPojo to OutputPojo
     * @param input The input POJO to convert
     * @return The converted output POJO
     */
    public static OutputPojo adaptInputToOutput(InputPojo input) {
        if (input == null) {
            return null;
        }

        OutputPojo output = new OutputPojo();

        // Combine first and last name into full name
        output.setFullName(input.getFirstName() + " " + input.getLastName());

        // Categorize age
        output.setAgeCategory(categorizeAge(input.getAge()));

        // Map email address to email
        output.setEmail(input.getEmailAddress());

        // Map phone number to contact
        output.setContact(input.getPhoneNumber());

        // Determine if adult (18 or older)
        output.setAdult(input.getAge() >= 18);

        return output;
    }

    /**
     * Helper method to categorize age into groups
     * @param age The age to categorize
     * @return The age category as a string
     */
    private static String categorizeAge(int age) {
        if (age < 13) {
            return "Child";
        } else if (age < 18) {
            return "Teenager";
        } else if (age < 65) {
            return "Adult";
        } else {
            return "Senior";
        }
    }

    /**
     * Reverse adapter method that converts OutputPojo back to InputPojo
     * Note: Some data loss may occur due to different field structures
     * @param output The output POJO to convert
     * @return The converted input POJO
     */
    public static InputPojo adaptOutputToInput(OutputPojo output) {
        if (output == null) {
            return null;
        }

        InputPojo input = new InputPojo();

        // Split full name back to first and last name (simple approach)
        String[] nameParts = output.getFullName().split(" ", 2);
        input.setFirstName(nameParts.length > 0 ? nameParts[0] : "");
        input.setLastName(nameParts.length > 1 ? nameParts[1] : "");

        // Age cannot be precisely determined from category, so we'll use defaults
        input.setAge(getDefaultAgeForCategory(output.getAgeCategory()));

        // Map email back to email address
        input.setEmailAddress(output.getEmail());

        // Map contact back to phone number
        input.setPhoneNumber(output.getContact());

        return input;
    }

    /**
     * Helper method to get a default age for an age category
     * @param category The age category
     * @return A default age for that category
     */
    private static int getDefaultAgeForCategory(String category) {
        switch (category) {
            case "Child": return 10;
            case "Teenager": return 16;
            case "Adult": return 30;
            case "Senior": return 70;
            default: return 25;
        }
    }

    /**
     * Main method to demonstrate the adapter functionality
     */
    public static void main(String[] args) {
        // Create a sample input POJO
        InputPojo input = new InputPojo("John", "Doe", 25, "[email protected]", "+1-555-123-4567");

        System.out.println("Original Input POJO:");
        System.out.println(input);
        System.out.println();

        // Adapt input to output
        OutputPojo output = adaptInputToOutput(input);

        System.out.println("Adapted Output POJO:");
        System.out.println(output);
        System.out.println();

        // Adapt output back to input (demonstrating reverse adaptation)
        InputPojo reversedInput = adaptOutputToInput(output);

        System.out.println("Reverse Adapted Input POJO:");
        System.out.println(reversedInput);
        System.out.println();

        // Test with different age categories
        System.out.println("Testing different age categories:");

        InputPojo child = new InputPojo("Alice", "Smith", 8, "[email protected]", "555-0001");
        System.out.println("Child: " + adaptInputToOutput(child));

        InputPojo teenager = new InputPojo("Bob", "Johnson", 16, "[email protected]", "555-0002");
        System.out.println("Teenager: " + adaptInputToOutput(teenager));

        InputPojo senior = new InputPojo("Carol", "Williams", 70, "[email protected]", "555-0003");
        System.out.println("Senior: " + adaptInputToOutput(senior));
    }
}