Restore JSONEventLayout class

README.md

@@ -113,12 +113,12 @@ Originally the layout class was called `JSONEventLayout`. This was originally wr
 - `@version`
 - `@timestamp` (optional - will be inferred from event receipt time
 
-Because of this, when adding support for the new format, `JSONEventLayoutV1` was used to allow backwards compatibility. As of `1.6` of the jsonevent-layout library, we've now gone to fully versioned appenders. There is no longer a `JSONEventLayout`. Instead there is:
+Because of this, when adding support for the new format, `JSONEventLayoutV1` was used to allow backwards compatibility. As of `1.6` of the jsonevent-layout library, we've now gone to fully versioned appenders. Always use either:
 
 - `JSONEventLayoutV0`
 - `JSONEventLayoutV1`
 
-Work has stopped on V0 but it won't be removed. No new features are added to V0 (custom UserFields for instance).
+Work has stopped on V0 but it won't be removed. No new features are added to V0 (custom UserFields for instance). For convenience, `JSONEventLayout` is an alias to `JSONEventLayoutV0` but its use is discouraged.
 
 # Custom User Fields
 As of version 1.6, you can now add your own metadata to the event in the form of comma-separated key:value pairs. This can be set in either the log4jconfig OR set on the java command-line:

src/main/java/net/logstash/log4j/JSONEventLayout.java

@@ -0,0 +1,18 @@
+package net.logstash.log4j;
+
+import net.logstash.log4j.JSONEventLayoutV0;
+import org.apache.log4j.helpers.LogLog;
+
+public class JSONEventLayout extends JSONEventLayoutV0 {
+
+    public JSONEventLayout() {
+        this(true);
+    }
+
+    public JSONEventLayout(boolean locationInfo) {
+        super(locationInfo);
+        String whoami = this.getClass().getSimpleName();
+        LogLog.warn("["+whoami+"] JSONEventLayout use is discouraged, use JSONEventLayoutV0 instead");
+    }
+
+}

src/test/java/net/logstash/log4j/JSONEventLayoutTest.java

@@ -0,0 +1,60 @@
+package net.logstash.log4j;
+
+import junit.framework.Assert;
+import net.minidev.json.JSONObject;
+import net.minidev.json.JSONValue;
+import org.apache.log4j.Level;
+import org.apache.log4j.Logger;
+import org.apache.log4j.NDC;
+import org.apache.log4j.MDC;
+import org.junit.After;
+import org.junit.BeforeClass;
+import org.junit.Ignore;
+import org.junit.Test;
+
+public class JSONEventLayoutTest {
+    static Logger logger;
+    static MockAppender appender;
+    static final String[] logstashFields = new String[]{
+            "@message",
+            "@source_host",
+            "@fields",
+            "@timestamp"
+    };
+
+    @BeforeClass
+    public static void setupTestAppender() {
+        appender = new MockAppender(new JSONEventLayout());
+        logger = Logger.getRootLogger();
+        appender.setThreshold(Level.TRACE);
+        appender.setName("mockappender");
+        appender.activateOptions();
+        logger.addAppender(appender);
+    }
+
+    @After
+    public void clearTestAppender() {
+        NDC.clear();
+        appender.clear();
+        appender.close();
+    }
+
+    @Test
+    public void testJSONEventLayoutIsJSON() {
+        logger.info("this is an info message");
+        String message = appender.getMessages()[0];
+        Assert.assertTrue("Event is not valid JSON", JSONValue.isValidJsonStrict(message));
+    }
+
+    @Test
+    public void testJSONEventLayoutHasKeys() {
+        logger.info("this is a test message");
+        String message = appender.getMessages()[0];
+        Object obj = JSONValue.parse(message);
+        JSONObject jsonObject = (JSONObject) obj;
+
+        for (String fieldName : logstashFields) {
+            Assert.assertTrue("Event does not contain field: " + fieldName, jsonObject.containsKey(fieldName));
+        }
+    }
+}

src/test/java/net/logstash/log4j/JSONEventLayoutV0Test.java

@@ -34,7 +34,7 @@ public static void setupTestAppender() {
         appender = new MockAppenderV0(new JSONEventLayoutV0());
         logger = Logger.getRootLogger();
         appender.setThreshold(Level.TRACE);
-        appender.setName("mockappender");
+        appender.setName("mockappenderv0");
         appender.activateOptions();
         logger.addAppender(appender);
     }

src/test/java/net/logstash/log4j/MockAppender.java

@@ -0,0 +1,37 @@
+package net.logstash.log4j;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.log4j.AppenderSkeleton;
+import org.apache.log4j.spi.LoggingEvent;
+import org.apache.log4j.Layout;
+
+public class MockAppender extends AppenderSkeleton {
+
+    private static List messages = new ArrayList();
+
+    public MockAppender(Layout layout){
+        this.layout = layout;
+    }
+    @Override
+    protected void append(LoggingEvent event){
+        messages.add(layout.format(event));
+    }
+
+    public void close(){
+        messages.clear();
+    }
+
+    public boolean requiresLayout(){
+        return true;
+    }
+
+    public static String[] getMessages() {
+        return (String[]) messages.toArray(new String[messages.size()]);
+    }
+
+    public void clear() {
+        messages.clear();
+    }
+}