Merge code for XStream JSON processing article

xstream/pom.xml

@@ -14,6 +14,12 @@
             <version>1.4.5</version>
         </dependency>
 
+        <dependency>
+            <groupId>org.codehaus.jettison</groupId>
+            <artifactId>jettison</artifactId>
+            <version>1.3.7</version>
+        </dependency>
+
         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>

xstream/src/main/java/com/baeldung/initializer/SimpleXstreamInitializer.java

@@ -1,19 +1,23 @@
 package com.baeldung.initializer;
 
 import com.thoughtworks.xstream.XStream;
+import com.thoughtworks.xstream.io.json.JettisonMappedXmlDriver;
+import com.thoughtworks.xstream.io.json.JsonHierarchicalStreamDriver;
 
 public class SimpleXstreamInitializer {
 
-    private XStream xtreamInstance;
-
     public XStream getXstreamInstance() {
-        if (xtreamInstance == null) {
-            synchronized (SimpleXstreamInitializer.class) {
-                if (xtreamInstance == null) {
-                    xtreamInstance = new XStream();
-                }
-            }
-        }
+        XStream xtreamInstance = new XStream();
         return xtreamInstance;
     }
+
+    public XStream getXstreamJettisonMappedInstance() {
+        XStream xstreamInstance = new XStream(new JettisonMappedXmlDriver());
+        return xstreamInstance;
+    }
+
+    public XStream getXstreamJsonHierarchicalInstance() {
+        XStream xstreamInstance = new XStream(new JsonHierarchicalStreamDriver());
+        return xstreamInstance;
+    }
 }

xstream/src/main/resources/log4j.properties

@@ -1,12 +1,10 @@
 # Root logger option
 log4j.rootLogger=DEBUG, file
-
 # Redirect log messages to console
 # log4j.appender.stdout=org.apache.log4j.ConsoleAppender
 # log4j.appender.stdout.Target=System.out
 # log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
 # log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
-
 # Redirect log messages to a log file, support file rolling.
 log4j.appender.file=org.apache.log4j.RollingFileAppender
 log4j.appender.file.File=D:\\Test\\xstream-application.log

xstream/src/test/java/com/baeldung/test/XStreamJettisonTest.java

@@ -0,0 +1,47 @@
+package com.baeldung.test;
+
+import com.baeldung.initializer.SimpleXstreamInitializer;
+import com.baeldung.pojo.ContactDetails;
+import com.baeldung.pojo.Customer;
+import com.baeldung.utility.SimpleDataGeneration;
+import com.thoughtworks.xstream.XStream;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+public class XStreamJettisonTest {
+
+    private Customer customer = null;
+
+    private String dataJson = null;
+
+    private XStream xstream = null;
+
+    @Before
+    public void dataSetup() {
+        SimpleXstreamInitializer simpleXstreamInitializer = new SimpleXstreamInitializer();
+        xstream = simpleXstreamInitializer.getXstreamJettisonMappedInstance();
+        xstream.processAnnotations(Customer.class);
+    }
+
+    @Test
+    public void convertObjectToJson() {
+        customer = SimpleDataGeneration.generateData();
+        xstream.alias("customer", Customer.class);
+        xstream.alias("contactDetails", ContactDetails.class);
+        xstream.aliasField("fn", Customer.class, "firstName");
+        dataJson = xstream.toXML(customer);
+        System.out.println(dataJson);
+        Assert.assertNotNull(dataJson);
+    }
+
+    @Test
+    public void convertJsonToObject() {
+        customer = SimpleDataGeneration.generateData();
+        dataJson = xstream.toXML(customer);
+        customer = (Customer) xstream.fromXML(dataJson);
+        System.out.println(customer);
+        Assert.assertNotNull(customer);
+    }
+
+}

xstream/src/test/java/com/baeldung/test/XStreamJsonHierarchicalTest.java

@@ -0,0 +1,44 @@
+package com.baeldung.test;
+
+import com.baeldung.initializer.SimpleXstreamInitializer;
+import com.baeldung.pojo.ContactDetails;
+import com.baeldung.pojo.Customer;
+import com.baeldung.utility.SimpleDataGeneration;
+import com.thoughtworks.xstream.XStream;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+public class XStreamJsonHierarchicalTest {
+
+    private Customer customer = null;
+    private String dataJson = null;
+    private XStream xstream = null;
+
+    @Before
+    public void dataSetup() {
+        SimpleXstreamInitializer simpleXstreamInitializer = new SimpleXstreamInitializer();
+        xstream = simpleXstreamInitializer.getXstreamJsonHierarchicalInstance();
+        xstream.processAnnotations(Customer.class);
+    }
+
+    @Test
+    public void convertObjectToJson() {
+        customer = SimpleDataGeneration.generateData();
+        xstream.alias("customer", Customer.class);
+        xstream.alias("contactDetails", ContactDetails.class);
+        xstream.aliasField("fn", Customer.class, "firstName");
+        dataJson = xstream.toXML(customer);
+        System.out.println(dataJson);
+        Assert.assertNotNull(dataJson);
+    }
+
+    @Test(expected = UnsupportedOperationException.class)
+    public void convertJsonToObject() {
+        customer = SimpleDataGeneration.generateData();
+        dataJson = xstream.toXML(customer);
+        customer = (Customer) xstream.fromXML(dataJson);
+        Assert.assertNotNull(customer);
+    }
+
+}