Examples

Author: lokeshgupta1981

src/main/java/com/howtodoinjava/concurrency/SharedSeedExample.java

@@ -0,0 +1,55 @@
+package com.howtodoinjava.concurrency;
+
+import java.security.SecureRandom;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.atomic.AtomicInteger;
+
+public class SharedSeedExample {
+
+  private static final int THREAD_COUNT = 5;
+  private static final int ITERATIONS_PER_THREAD = 10;
+  private static ExecutorService executorService = Executors.newFixedThreadPool(THREAD_COUNT);
+
+  private static final AtomicInteger sharedCounter = new AtomicInteger(0);
+
+  public static void main(String[] args) {
+    System.out.println("Using a shared Random instance:");
+    java.util.Random sharedRandom = new java.util.Random();
+
+    for (int i = 0; i < THREAD_COUNT; i++) {
+      executorService.submit(() -> {
+        for (int j = 0; j < ITERATIONS_PER_THREAD; j++) {
+          int randomNumber = sharedRandom.nextInt();
+          processRandomNumber(randomNumber);
+        }
+      });
+    }
+
+    System.out.println("\nUsing a shared SecureRandom instance:");
+    SecureRandom sharedSecureRandom = new SecureRandom();
+
+    for (int i = 0; i < THREAD_COUNT; i++) {
+      executorService.submit(() -> {
+        for (int j = 0; j < ITERATIONS_PER_THREAD; j++) {
+          int randomNumber = sharedSecureRandom.nextInt();
+          processRandomNumber(randomNumber);
+        }
+      });
+    }
+    shutdownExecutor(executorService);
+  }
+
+  private static void processRandomNumber(int randomNumber) {
+    // Simulate some processing of the random number
+    sharedCounter.incrementAndGet();
+  }
+
+  private static void shutdownExecutor(ExecutorService executorService) {
+    executorService.shutdown();
+    while (!executorService.isTerminated()) {
+      // Wait for all threads to finish
+    }
+    System.out.println(STR."The counter value: \{sharedCounter.get()}");
+  }
+}

src/main/java/com/howtodoinjava/core/datetime/GetQuarterInfo.java

@@ -4,6 +4,7 @@
 import java.time.format.DateTimeFormatter;
 import java.time.temporal.IsoFields;
 import java.time.temporal.TemporalAdjusters;
+import net.bytebuddy.asm.Advice.Local;
 
 public class GetQuarterInfo {
 
@@ -23,5 +24,9 @@ public static void main(String[] args) {
     LocalDate lastDay = firstDay.plusMonths(2).with(TemporalAdjusters.lastDayOfMonth());
     System.out.println(firstDay);
     System.out.println(lastDay);
+
+    //Quarter between two dates
+    long quarterCount = IsoFields.QUARTER_YEARS.between(firstDay, lastDay);
+    System.out.println(quarterCount);
   }
 }

src/main/java/com/howtodoinjava/core/datetime/WeeksBetweenDates.java

@@ -0,0 +1,19 @@
+package com.howtodoinjava.core.datetime;
+
+import java.time.LocalDate;
+import java.time.temporal.ChronoUnit;
+
+public class WeeksBetweenDates {
+
+  public static void main(String[] args) {
+    LocalDate startLd = LocalDate.of(2023, 8, 5);
+    LocalDate endLd = LocalDate.of(2023, 9, 5);
+    long numWeeks = ChronoUnit.WEEKS.between(startLd, endLd);
+    System.out.println(numWeeks);
+
+    long daysDifference = ChronoUnit.DAYS.between(startLd, endLd);  // 31
+    int extraDays = Long.valueOf(daysDifference % 7).intValue(); //3
+    System.out.println(extraDays);
+  }
+
+}

src/main/java/com/howtodoinjava/jaxb/Main.java

@@ -1,10 +1,15 @@
 package com.howtodoinjava.jaxb;
 
+import com.howtodoinjava.xml.model.Department;
+import com.howtodoinjava.xml.model.Employee;
+import java.io.File;
+import java.io.StringWriter;
 import java.util.HashMap;
 import java.util.Map;
 
 import javax.xml.bind.JAXBContext;
 import javax.xml.bind.JAXBException;
+import javax.xml.bind.Marshaller;
 import javax.xml.bind.annotation.XmlAccessType;
 import javax.xml.bind.annotation.XmlAccessorType;
 import javax.xml.bind.annotation.XmlRootElement;
@@ -24,6 +29,16 @@ public static void main(final String[] args) throws JAXBException {
         JAXBContext context6 = getJAXBContext(Book.class);
         JAXBContext context7 = getJAXBContext(Book.class);
         JAXBContext context8 = getJAXBContext(Book.class);
+
+        JAXBContext jaxbContext 	= JAXBContext.newInstance( Employee.class );
+        Marshaller jaxbMarshaller 	= jaxbContext.createMarshaller();
+
+        Employee employee = new Employee(1, "Lokesh", "Gupta", "India", new Department(101, "IT"));
+
+        //Overloaded methods to marshal to different outputs
+        jaxbMarshaller.marshal(employee, System.out);
+        jaxbMarshaller.marshal(employee, new File("output.xml"));
+        jaxbMarshaller.marshal(employee, new StringWriter());
     }
 
     @SuppressWarnings("rawtypes")

src/main/java/com/howtodoinjava/jaxb/MarshalListExample.java

@@ -0,0 +1,67 @@
+package com.howtodoinjava.jaxb;
+
+import com.howtodoinjava.xml.model.Employee;
+import jakarta.xml.bind.Unmarshaller;
+import java.io.File;
+import java.util.ArrayList;
+import java.util.List;
+import jakarta.xml.bind.JAXBContext;
+import jakarta.xml.bind.JAXBException;
+import jakarta.xml.bind.Marshaller;
+import jakarta.xml.bind.annotation.XmlAccessType;
+import jakarta.xml.bind.annotation.XmlAccessorType;
+import jakarta.xml.bind.annotation.XmlElement;
+import jakarta.xml.bind.annotation.XmlRootElement;
+
+public class MarshalListExample {
+
+  public static void main(String[] args) throws JAXBException {
+    Employees employees = new Employees();
+
+    //Add the employees in list
+    Employee emp1 = new Employee(1, "Lokesh", "Gupta", null, null);
+    Employee emp2 = new Employee(1, "John", "McLean", null, null);
+    employees.getEmployees().add(emp1);
+    employees.getEmployees().add(emp2);
+
+    //Write to XML
+    JAXBContext jaxbContext = JAXBContext.newInstance(Employees.class);
+    Marshaller jaxbMarshaller = jaxbContext.createMarshaller();
+
+    jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
+
+    //Marshal the employees list in console
+    jaxbMarshaller.marshal(employees, System.out);
+
+    //Marshal the employees list in file
+    jaxbMarshaller.marshal(employees, new File("out.xml"));
+
+    //unmarshal example
+    Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
+
+    //We had written this file in marshalling example
+    Employees emps = (Employees) jaxbUnmarshaller.unmarshal(new File("out.xml"));
+
+    for (Employee emp : emps.getEmployees()) {
+
+      System.out.println(emp.getId());
+      System.out.println(emp.getFirstName());
+    }
+  }
+}
+
+@XmlRootElement(name = "employees")
+@XmlAccessorType(XmlAccessType.FIELD)
+class Employees {
+
+  @XmlElement(name = "employee")
+  private List<Employee> employees = new ArrayList<>();
+
+  public List<Employee> getEmployees() {
+    return employees;
+  }
+
+  public void setEmployees(List<Employee> employees) {
+    this.employees = employees;
+  }
+}