Fix #216 Repository vs DAO

repository/src/main/java/com/iluwatar/repository/App.java

@@ -5,7 +5,6 @@ import java.util.List;
 import org.springframework.context.support.ClassPathXmlApplicationContext;
 
 /**
- * 
  * Repository pattern mediates between the domain and data mapping layers using a collection-like
  * interface for accessing domain objects. A system with complex domain model often benefits from a
  * layer that isolates domain objects from the details of the database access code and in such
@@ -16,9 +15,9 @@ import org.springframework.context.support.ClassPathXmlApplicationContext;
  * <p>
  * In this example we utilize Spring Data to automatically generate a repository for us from the
  * {@link Person} domain object. Using the {@link PersonRepository} we perform CRUD operations on
- * the entity. Underneath we have configured in-memory H2 database for which schema is created and
- * dropped on each run.
- *
+ * the entity, moreover, the query by {@link org.springframework.data.jpa.domain.Specification} are
+ * also performed. Underneath we have configured in-memory H2 database for which schema is created
+ * and dropped on each run.
  */
 public class App {
 
@@ -28,16 +27,21 @@ public class App {
    * @param args command line args
    */
   public static void main(String[] args) {
+
     ClassPathXmlApplicationContext context =
         new ClassPathXmlApplicationContext("applicationContext.xml");
     PersonRepository repository = context.getBean(PersonRepository.class);
 
-    Person peter = new Person("Peter", "Sagan");
-    Person nasta = new Person("Nasta", "Kuzminova");
+    Person peter = new Person("Peter", "Sagan", 17);
+    Person nasta = new Person("Nasta", "Kuzminova", 25);
+    Person john = new Person("John", "lawrence", 35);
+    Person terry = new Person("Terry", "Law", 36);
 
     // Add new Person records
     repository.save(peter);
     repository.save(nasta);
+    repository.save(john);
+    repository.save(terry);
 
     // Count Person records
     System.out.println("Count Person records: " + repository.count());
@@ -48,9 +52,6 @@ public class App {
       System.out.println(person);
     }
 
-    // Find Person by surname
-    System.out.println("Find by surname 'Sagan': " + repository.findBySurname("Sagan"));
-
     // Update Person
     nasta.setName("Barbora");
     nasta.setSurname("Spotakova");
@@ -61,9 +62,22 @@ public class App {
     // Remove record from Person
     repository.delete(2L);
 
-    // And finally count records
+    // count records
     System.out.println("Count Person records: " + repository.count());
 
+    // find by name
+    Person p = repository.findOne(new PersonSpecifications.NameEqualSpec("John"));
+    System.out.println("Find by John is " + p);
+
+    // find by age
+    persons = repository.findAll(new PersonSpecifications.AgeBetweenSpec(20, 40));
+
+    System.out.println("Find Person with age between 20,40: ");
+    for (Person person : persons) {
+      System.out.println(person);
+    }
+
     context.close();
+
   }
 }

repository/src/main/java/com/iluwatar/repository/Person.java

@@ -18,11 +18,14 @@ public class Person {
   private String name;
   private String surname;
 
+  private int age;
+
   public Person() {}
 
-  public Person(String name, String surname) {
+  public Person(String name, String surname, int age) {
     this.name = name;
     this.surname = surname;
+    this.age = age;
   }
 
   public Long getId() {
@@ -49,8 +52,59 @@ public class Person {
     this.surname = surname;
   }
 
+
+  public int getAge() {
+    return age;
+  }
+
+  public void setAge(int age) {
+    this.age = age;
+  }
+
   @Override
   public String toString() {
-    return "Person [id=" + id + ", name=" + name + ", surname=" + surname + "]";
+    return "Person [id=" + id + ", name=" + name + ", surname=" + surname + ", age=" + age + "]";
   }
+
+  @Override
+  public int hashCode() {
+
+    final int prime = 31;
+    int result = 1;
+    result = prime * result + age;
+    result = prime * result + ((id == null) ? 0 : id.hashCode());
+    result = prime * result + ((name == null) ? 0 : name.hashCode());
+    result = prime * result + ((surname == null) ? 0 : surname.hashCode());
+    return result;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj)
+      return true;
+    if (obj == null)
+      return false;
+    if (getClass() != obj.getClass())
+      return false;
+    Person other = (Person) obj;
+    if (age != other.age)
+      return false;
+    if (id == null) {
+      if (other.id != null)
+        return false;
+    } else if (!id.equals(other.id))
+      return false;
+    if (name == null) {
+      if (other.name != null)
+        return false;
+    } else if (!name.equals(other.name))
+      return false;
+    if (surname == null) {
+      if (other.surname != null)
+        return false;
+    } else if (!surname.equals(other.surname))
+      return false;
+    return true;
+  }
+
 }

repository/src/main/java/com/iluwatar/repository/PersonRepository.java

@@ -1,7 +1,6 @@
 package com.iluwatar.repository;
 
-import java.util.List;
-
+import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
 import org.springframework.data.repository.CrudRepository;
 import org.springframework.stereotype.Repository;
 
@@ -11,7 +10,8 @@ import org.springframework.stereotype.Repository;
  *
  */
 @Repository
-public interface PersonRepository extends CrudRepository<Person, Long> {
+public interface PersonRepository
+    extends CrudRepository<Person, Long>, JpaSpecificationExecutor<Person> {
 
-  public List<Person> findBySurname(String surname);
+  public Person findByName(String name);
 }

repository/src/main/java/com/iluwatar/repository/PersonSpecifications.java

@@ -0,0 +1,50 @@
+package com.iluwatar.repository;
+
+import javax.persistence.criteria.CriteriaBuilder;
+import javax.persistence.criteria.CriteriaQuery;
+import javax.persistence.criteria.Predicate;
+import javax.persistence.criteria.Root;
+
+import org.springframework.data.jpa.domain.Specification;
+
+/**
+ * Helper class, includes vary Specification as the abstraction of sql query criteria
+ */
+public class PersonSpecifications {
+
+  public static class AgeBetweenSpec implements Specification<Person> {
+
+    private int from;
+
+    private int to;
+
+    public AgeBetweenSpec(int from, int to) {
+      this.from = from;
+      this.to = to;
+    }
+
+    @Override
+    public Predicate toPredicate(Root<Person> root, CriteriaQuery<?> query, CriteriaBuilder cb) {
+
+      return cb.between(root.get("age"), from, to);
+
+    }
+
+  }
+  public static class NameEqualSpec implements Specification<Person> {
+
+    public String name;
+
+    public NameEqualSpec(String name) {
+      this.name = name;
+    }
+
+    public Predicate toPredicate(Root<Person> root, CriteriaQuery<?> query, CriteriaBuilder cb) {
+
+      return cb.equal(root.get("name"), this.name);
+
+    }
+  }
+
+}
+

repository/src/main/resources/applicationContext.xml

@@ -6,10 +6,10 @@
 	xmlns:jpa="http://www.springframework.org/schema/data/jpa"
 	xsi:schemaLocation="
 				http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
-				http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.0.xsd">
-
-	<jpa:repositories base-package="com.iluwatar" />
+				http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa.xsd">
 
+	<jpa:repositories base-package="com.iluwatar"  base-class="org.springframework.data.jpa.repository.support.SimpleJpaRepository" />
+ 
 	<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
 		<property name="entityManagerFactory" ref="entityManagerFactory" />
 	</bean>