19. జావా అబ్‌స్ట్రాక్ట్ క్లాసెస్, ఇంటర్‌ఫేసెస్ & డిఫాల్ట్ మెథడ్స్ (Abstract Classes & Interfaces)

public class AbstractClassTemplatePatternDemo {

    // Base Abstract Pipeline Class
    public static abstract class DataProcessingPipeline {
        private final String pipelineName;

        public DataProcessingPipeline(String name) {
            this.pipelineName = name;
        }

        // Concrete Steps (Common to all pipelines)
        private void connectSource() {
            System.out.println("  1. Connected to source storage stream.");
        }

        private void closeSource() {
            System.out.println("  4. Closed data stream successfully.");
        }

        // Abstract Steps (To be customized by each specific pipeline)
        protected abstract void parseData();
        protected abstract void transformAndEnrich();

        // The Template Method (final so child classes cannot alter the master workflow order)
        public final void executePipeline() {
            System.out.println("🚀 Executing Pipeline: " + pipelineName);
            connectSource();
            parseData();
            transformAndEnrich();
            closeSource();
            System.out.println("✅ Pipeline completed.
");
        }
    }

    // Concrete Pipeline 1: CSV Financial Parser
    public static class CsvFinancialPipeline extends DataProcessingPipeline {
        public CsvFinancialPipeline() {
            super("CSV-Financial-Batch-Loader");
        }

        @Override
        protected void parseData() {
            System.out.println("  2. [Custom] Parsing comma-separated financial rows into ledger objects.");
        }

        @Override
        protected void transformAndEnrich() {
            System.out.println("  3. [Custom] Calculating currency exchange rates and adding GST tags.");
        }
    }

    // Concrete Pipeline 2: JSON Sensor Event Parser
    public static class JsonSensorPipeline extends DataProcessingPipeline {
        public JsonSensorPipeline() {
            super("JSON-IoT-Stream-Loader");
        }

        @Override
        protected void parseData() {
            System.out.println("  2. [Custom] Deserializing UTF-8 JSON sensor payload buffers.");
        }

        @Override
        protected void transformAndEnrich() {
            System.out.println("  3. [Custom] Computing rolling temperature anomaly thresholds.");
        }
    }

    public static void main(String[] args) {
        System.out.println("=================================================");
        System.out.println("🏭 ABSTRACT TEMPLATE METHOD DESIGN PATTERN DEMO");
        System.out.println("=================================================
");

        DataProcessingPipeline p1 = new CsvFinancialPipeline();
        p1.executePipeline();

        DataProcessingPipeline p2 = new JsonSensorPipeline();
        p2.executePipeline();

        System.out.println("=================================================");
    }
}

public class MultipleInterfacesAndDefaultMethodsDemo {

    // Interface 1: Deployable Contract
    public interface Deployable {
        void deployToCluster(String clusterId);

        // Java 8 Default Method (Free standard implementation)
        default void runHealthCheck() {
            System.out.println("  🩺 [Default HealthCheck] Ping probe returned 200 OK.");
        }

        // Java 8 Static Helper Method
        static String getDeploymentStandard() {
            return "OCI-Container-v1.4";
        }
    }

    // Interface 2: Auditable Contract
    public interface SecurityAuditable {
        void auditCompliance();
    }

    // Concrete Microservice implementing MULTIPLE Interfaces
    public static class PaymentGatewayService implements Deployable, SecurityAuditable {
        private final String serviceName;

        public PaymentGatewayService(String name) {
            this.serviceName = name;
        }

        @Override
        public void deployToCluster(String clusterId) {
            System.out.printf("🚀 Deploying '%s' to Kubernetes Cluster [%s]%n", serviceName, clusterId);
        }

        @Override
        public void auditCompliance() {
            System.out.printf("🔒 Auditing '%s': PCI-DSS Level 1 & ISO 27001 Passed%n", serviceName);
        }

        // Optionally overriding the default method for customized behavior
        @Override
        public void runHealthCheck() {
            System.out.printf("  🩺 [Custom HealthCheck for %s] Deep DB Socket + Vault Tokens Valid.%n", serviceName);
        }
    }

    public static void main(String[] args) {
        System.out.println("=================================================");
        System.out.println("🌐 MULTIPLE INTERFACES & DEFAULT METHODS DEMO");
        System.out.println("=================================================
");

        System.out.println("Static Interface Standard: " + Deployable.getDeploymentStandard() + "
");

        PaymentGatewayService service = new PaymentGatewayService("PaymentGateway-Core");
        service.deployToCluster("k8s-prod-us-east-1");
        service.runHealthCheck();
        service.auditCompliance();

        System.out.println("
=================================================");
        System.out.println("✅ Multiple inheritance of type achieved cleanly!");
        System.out.println("=================================================");
    }
}

public class MultiCloudInfrastructureProvisionerEngine {

    // Interface 1: Cost Management
    public interface CostTrackable {
        double calculateMonthlyCostUsd();

        default void printCostBreakdown() {
            System.out.printf("   💵 Monthly Estimated Spend: $%,.2f USD%n", calculateMonthlyCostUsd());
        }
    }

    // Interface 2: Disaster Recovery
    public interface DisasterRecoverable {
        void replicateToFailoverZone(String targetZone);
    }

    // Base Abstract Compute Instance
    public static abstract class CloudComputeInstance implements CostTrackable, DisasterRecoverable {
        private final String instanceId;
        private final int cpuCores;
        private final int ramGigabytes;
        private boolean isRunning;

        public CloudComputeInstance(String id, int cpu, int ram) {
            this.instanceId = id;
            this.cpuCores = cpu;
            this.ramGigabytes = ram;
            this.isRunning = false;
        }

        public void startInstance() {
            this.isRunning = true;
            System.out.printf("🟢 Instance [%s] Booted with %d vCPUs & %d GB RAM%n",
                    instanceId, cpuCores, ramGigabytes);
        }

        public abstract String getCloudProvider();
        public abstract void attachStorageVolume(int gigabytes);

        public String getInstanceId() { return instanceId; }
        public boolean isRunning() { return isRunning; }
    }

    // Implementation 1: AWS EC2 Instance
    public static class AwsEc2Instance extends CloudComputeInstance {
        public AwsEc2Instance(String id, int cpu, int ram) {
            super(id, cpu, ram);
        }

        @Override public String getCloudProvider() { return "Amazon Web Services (AWS)"; }

        @Override
        public void attachStorageVolume(int gb) {
            System.out.println("  💾 [AWS EBS] Provisioning gp3 IOPS Volume: " + gb + " GB");
        }

        @Override
        public double calculateMonthlyCostUsd() { return 145.50; }

        @Override
        public void replicateToFailoverZone(String zone) {
            System.out.println("  🛡️ [AWS Cross-Region] Snapshot synced to " + zone);
        }
    }

    // Implementation 2: Azure Virtual Machine
    public static class AzureVmInstance extends CloudComputeInstance {
        public AzureVmInstance(String id, int cpu, int ram) {
            super(id, cpu, ram);
        }

        @Override public String getCloudProvider() { return "Microsoft Azure"; }

        @Override
        public void attachStorageVolume(int gb) {
            System.out.println("  💾 [Azure Managed Disk] Attaching Premium SSD v2: " + gb + " GB");
        }

        @Override
        public double calculateMonthlyCostUsd() { return 138.20; }

        @Override
        public void replicateToFailoverZone(String zone) {
            System.out.println("  🛡️ [Azure Site Recovery] Failover vault replicated to " + zone);
        }
    }

    public static void main(String[] args) {
        System.out.println("=================================================");
        System.out.println("☁️ MULTI-CLOUD DEVOPS PROVISIONER PIPELINE");
        System.out.println("=================================================
");

        CloudComputeInstance[] cloudFleet = {
            new AwsEc2Instance("i-08a9f2bc", 8, 32),
            new AzureVmInstance("vm-eastus-prod", 8, 32)
        };

        double totalMonthlySpend = 0;

        for (CloudComputeInstance node : cloudFleet) {
            System.out.println("Provider: " + node.getCloudProvider());
            node.startInstance();
            node.attachStorageVolume(500);
            node.replicateToFailoverZone("ap-southeast-1 (Singapore)");
            node.printCostBreakdown(); // Calling interface default method!
            totalMonthlySpend += node.calculateMonthlyCostUsd();
            System.out.println("-------------------------------------------------");
        }

        System.out.printf("💰 TOTAL FLEET MONTHLY RUN-RATE: $%,.2f USD%n", totalMonthlySpend);
        System.out.println("=================================================");
    }
}