kishankg

// State interface
interface TrafficLightState {
    void display();
}

// Concrete State: RedLightState
class RedLightState implements TrafficLightState {
    @Override
    public void display() {
        System.out.println("Red Light - Stop");

kishankg

// Abstraction: BankAccount
abstract class BankAccount {
    protected TransactionProcessor transactionProcessor;

    BankAccount(TransactionProcessor transactionProcessor) {
        this.transactionProcessor = transactionProcessor;
    }

    abstract void processTransaction(double amount);
}

kishankg

// Subject: Image interface
interface Image {
    void display();
}

// RealSubject: RealImage class (Actual heavy object)
class RealImage implements Image {
    private String filename;

    RealImage(String filename) {

kishankg

import java.util.Stack;

// Receiver: TextEditor
class TextEditor {
    private StringBuilder text = new StringBuilder();

    void insertText(String insertedText) {
        text.append(insertedText);
    }

kishankg

// Abstract Product: Button
interface Button {
    void click();
}

// Concrete Products: WindowsButton and MacOSButton
class WindowsButton implements Button {
    @Override
    public void click() {
        System.out.println("Windows button clicked");

kishankg

// Product Interface: DatabaseConnection
interface DatabaseConnection {
    void connect();
    void disconnect();
}

// Concrete Products: MySqlConnection and PostgreSqlConnection
class MySqlConnection implements DatabaseConnection {
    @Override
    public void connect() {

kishankg

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

// Observer interface
interface Observer {
    void update(String weather);
}

// Subject interface
interface Subject {

kishankg

public class ClientWrapper {
    int connectionState, requestingThreads; //-1 null, 1 init done, 2 closed
    Lock lock;
    Condition awaitRequest, awaitClose;

    ClientWrapper2(){
        //constructor
        connectionState = -1;
        requestingThreads = 0;
        lock = new ReentrantLock();