Intro to JDO Queries 2/2 article (#2871)

* ADD 
MyApp.java class
ProductItem.java class

modify:
package.jdo to add a named query
pom.xml to add datanucleus-jdo-query.jar

* remove sys.out statements

libraries/pom.xml

@@ -105,6 +105,13 @@
                 </executions>
             </plugin>
             <!-- /Neuroph -->
+            <plugin>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>1.8</source>
+                    <target>1.8</target>
+                </configuration>
+            </plugin>
         </plugins>
     </build>
     <dependencies>
@@ -326,6 +333,11 @@
             <artifactId>datanucleus-xml</artifactId>
             <version>5.0.0-release</version>
         </dependency>
+        <dependency>
+            <groupId>org.datanucleus</groupId>
+            <artifactId>datanucleus-jdo-query</artifactId>
+            <version>5.0.2</version>
+        </dependency>
         <dependency>
             <groupId>net.openhft</groupId>
             <artifactId>chronicle</artifactId>

libraries/src/main/java/com/baeldung/jdo/query/MyApp.java

@@ -0,0 +1,104 @@
+package com.baeldung.jdo.query;
+
+import java.util.List;
+
+import javax.jdo.JDOQLTypedQuery;
+import javax.jdo.PersistenceManager;
+import javax.jdo.PersistenceManagerFactory;
+import javax.jdo.Query;
+
+import org.datanucleus.api.jdo.JDOPersistenceManagerFactory;
+import org.datanucleus.metadata.PersistenceUnitMetaData;
+
+public class MyApp {
+
+    private static PersistenceManagerFactory pmf;
+    private static PersistenceManager pm;
+
+    public static void main(String[] args) {
+
+        defineDynamicPersistentUnit();
+        createTestData();
+        queryUsingJDOQL();
+        queryUsingTypedJDOQL();
+        queryUsingSQL();
+        queryUsingJPQL();
+
+    }
+
+    public static void createTestData(){
+        ProductItem item1 = new ProductItem("supportedItem", "price less than 10", "SoldOut",5);
+        ProductItem item2 = new ProductItem("pro2", "price less than 10","InStock", 8);
+        ProductItem item3 = new ProductItem("pro3", "price more than 10","SoldOut", 15);
+
+        if( pm != null ){
+            pm.makePersistent(item1);
+            pm.makePersistent(item2);
+            pm.makePersistent(item3); 
+        }
+    }
+
+    public static void defineDynamicPersistentUnit(){
+
+        PersistenceUnitMetaData pumd = new PersistenceUnitMetaData("dynamic-unit", "RESOURCE_LOCAL", null);
+        pumd.addProperty("javax.jdo.option.ConnectionURL", "jdbc:mysql://localhost:3306/jdo_db");
+        pumd.addProperty("javax.jdo.option.ConnectionUserName", "root");
+        pumd.addProperty("javax.jdo.option.ConnectionPassword", "admin");
+        pumd.addProperty("javax.jdo.option.ConnectionDriverName", "com.mysql.jdbc.Driver");
+        pumd.addProperty("datanucleus.schema.autoCreateAll", "true");
+
+        pmf = new JDOPersistenceManagerFactory(pumd, null);
+        pm = pmf.getPersistenceManager();
+    }
+
+    public static void queryUsingJDOQL(){
+
+        Query query = pm.newQuery("SELECT FROM com.baeldung.jdo.query.ProductItem "
+                + "WHERE price < threshold PARAMETERS double threshold");
+        List<ProductItem> explicitParamResults = (List<ProductItem>)query.execute(10);
+
+        query = pm.newQuery("SELECT FROM "
+                + "com.baeldung.jdo.query.ProductItem WHERE price < :threshold");
+        query.setParameters("double threshold");
+        List<ProductItem> explicitParamResults2 = (List<ProductItem>)query.execute(10);
+
+        query = pm.newQuery("SELECT FROM "
+                + "com.baeldung.jdo.query.ProductItem WHERE price < :threshold");
+        List<ProductItem> implicitParamResults = (List<ProductItem>)query.execute(10);
+
+    }
+
+    public static void queryUsingTypedJDOQL(){
+
+        JDOQLTypedQuery<ProductItem> tq = pm.newJDOQLTypedQuery(ProductItem.class);
+        QProductItem cand = QProductItem.candidate();
+        tq=tq.filter(cand.price.lt(10).and(cand.name.startsWith("pro")));
+        List<ProductItem> results = tq.executeList();
+
+    }
+
+    public static void queryUsingSQL(){
+
+        Query query = pm.newQuery("javax.jdo.query.SQL","select * from "
+                + "product_item where price < ? and status = ?");
+        query.setClass(ProductItem.class);
+        query.setParameters(10,"InStock");
+        List<ProductItem> results = query.executeList();
+
+    }
+
+    public static void queryUsingJPQL(){
+        Query query = pm.newQuery("JPQL","select i from "
+                + "com.baeldung.jdo.query.ProductItem i where i.price < 10"
+                + " and i.status = 'InStock'");
+        List<ProductItem> results = (List<ProductItem>) query.execute();
+
+    }
+
+    public static void namedQuery(){
+        Query<ProductItem> query = pm.newNamedQuery(
+                ProductItem.class, "PriceBelow10");
+        List<ProductItem> results = query.executeList();
+
+    }
+}

libraries/src/main/java/com/baeldung/jdo/query/ProductItem.java

@@ -0,0 +1,68 @@
+package com.baeldung.jdo.query;
+
+import javax.jdo.annotations.IdGeneratorStrategy;
+import javax.jdo.annotations.PersistenceAware;
+import javax.jdo.annotations.PersistenceCapable;
+import javax.jdo.annotations.Persistent;
+import javax.jdo.annotations.PrimaryKey;
+
+@PersistenceCapable(table = "product_item")
+public class ProductItem {
+
+    @PrimaryKey
+    @Persistent(valueStrategy=IdGeneratorStrategy.INCREMENT)
+    int id;
+    String name;
+    String description;
+    String status;
+    double price;
+
+    public ProductItem(){
+
+    }
+
+    public ProductItem(String name,String description,String status,double price){
+        this.name=name;
+        this.description = description;
+        this.status = status;
+        this.price = price;
+    }
+
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+    public void setName(String name) {
+        this.name = name;
+    }
+    public String getDescription() {
+        return description;
+    }
+    public void setDescription(String description) {
+        this.description = description;
+    }
+    public double getPrice() {
+        return price;
+    }
+    public void setPrice(double price) {
+        this.price = price;
+    }
+
+    public String getStatus() {
+        return status;
+    }
+
+    public void setStatus(String status) {
+        this.status = status;
+    }
+
+
+}

libraries/src/main/resources/META-INF/package.jdo

@@ -16,6 +16,14 @@
             </field>
         </class>
     </package>
+    <package name="com.baeldung.jdo.query">
+        <class name="ProductItem" detachable="true" table="product_item">
  
+            <query name="PriceBelow10" language="javax.jdo.query.SQL">
+            <![CDATA[SELECT * FROM PRODUCT_ITEM WHERE PRICE < 10
+            ]]></query>
+ 
+        </class>
+    </package>
 
 </jdo>