Add siddhi extension to Get json array form given list of arguments

pom.xml

@@ -48,8 +48,8 @@
             <artifactId>json</artifactId>
         </dependency>
         <dependency>
-            <groupId>junit</groupId>
+            <groupId>org.testng</groupId>
-            <artifactId>junit</artifactId>
+            <artifactId>testng</artifactId>
             <scope>test</scope>
         </dependency>
     </dependencies>

src/main/java/org/wso2/extension/siddhi/execution/json/GetArrayFunctionExtension.java

@@ -0,0 +1,96 @@
+/*
+ * Copyright (c)  2017, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
+ *
+ * WSO2 Inc. licenses this file to you under the Apache License,
+ * Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.wso2.extension.siddhi.execution.json;
+
+import org.json.JSONArray;
+import org.wso2.siddhi.core.config.ExecutionPlanContext;
+import org.wso2.siddhi.core.executor.ExpressionExecutor;
+import org.wso2.siddhi.core.executor.function.FunctionExecutor;
+import org.wso2.siddhi.query.api.definition.Attribute;
+import org.wso2.siddhi.query.api.exception.ExecutionPlanValidationException;
+
+/**
+ * getArray(elements..)
+ * Returns json array of elements as a string
+ * Accept Type(s): (STRING|INT|DOUBLE|FLOAT|OBJECT ..)
+ * Return Type(s): (STRING)
+ */
+public class GetArrayFunctionExtension extends FunctionExecutor {
+
+    private Attribute.Type returnType = Attribute.Type.STRING;
+
+    @Override
+    protected void init(ExpressionExecutor[] attributeExpressionExecutors,
+                        ExecutionPlanContext executionPlanContext) {
+        if (attributeExpressionExecutors.length <= 0) {
+            throw new ExecutionPlanValidationException(
+                    "Invalid no of arguments passed to json:getArray() function," + " required one or more, but found "
+                    + attributeExpressionExecutors.length);
+        }
+        Attribute.Type inputType = attributeExpressionExecutors[0].getReturnType();
+        for (int i = 1; i < attributeExpressionExecutors.length; i++) {
+            if (attributeExpressionExecutors[0].getReturnType() != inputType) {
+                throw new ExecutionPlanValidationException(
+                        "Parameter types are inconsistent. All parameters should be same");
+            }
+        }
+    }
+
+    @Override
+    protected Object execute(Object[] data) {
+
+        JSONArray jsonArray = new JSONArray();
+        for (Object obj : data) {
+            jsonArray.put(obj);
+        }
+        return jsonArray.toString();
+    }
+
+    @Override
+    protected Object execute(Object data) {
+        return execute(new Object[]{data});
+    }
+
+    @Override
+    public void start() {
+        //Nothing to start
+    }
+
+    @Override
+    public void stop() {
+        //Nothing to stop
+    }
+
+    @Override
+    public Attribute.Type getReturnType() {
+        return returnType;
+    }
+
+    @Override
+    public Object[] currentState() {
+        return null;    //No need to maintain a state.
+    }
+
+    @Override
+    public void restoreState(Object[] state) {
+        //Since there's no need to maintain a state, nothing needs to be done here.
+    }
+}
+
+

src/main/resources/json.siddhiext

@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2016, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
+# Copyright (c) 2017, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
 #
 # WSO2 Inc. licenses this file to you under the Apache License,
 # Version 2.0 (the "License"); you may not use this file except
@@ -17,3 +17,4 @@
 #
 
 getProperty=org.wso2.extension.siddhi.execution.json.GetPropertyFunctionExtension
+getArray=org.wso2.extension.siddhi.execution.json.GetArrayFunctionExtension

src/test/java/org/wso2/extension/siddhi/execution/json/ExtensionTestCase.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c)  2016, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
+ * Copyright (c)  2017, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
  *
  * WSO2 Inc. licenses this file to you under the Apache License,
  * Version 2.0 (the "License"); you may not use this file except
@@ -18,10 +18,10 @@
 
 package org.wso2.extension.siddhi.execution.json;
 
-import junit.framework.Assert;
 import org.apache.log4j.Logger;
-import org.junit.Before;
+import org.testng.Assert;
-import org.junit.Test;
+import org.testng.annotations.BeforeClass;
+import org.testng.annotations.Test;
 import org.wso2.siddhi.core.ExecutionPlanRuntime;
 import org.wso2.siddhi.core.SiddhiManager;
 import org.wso2.siddhi.core.event.Event;
@@ -32,12 +32,12 @@ import org.wso2.extension.siddhi.execution.json.test.util.SiddhiTestHelper;
 
 import java.util.concurrent.atomic.AtomicInteger;
 
-public class getPropertyFunctionTestCase {
+public class ExtensionTestCase {
-    static final Logger log = Logger.getLogger(getPropertyFunctionTestCase.class);
+    static final Logger log = Logger.getLogger(ExtensionTestCase.class);
     private AtomicInteger count = new AtomicInteger(0);
     private volatile boolean eventArrived;
 
-    @Before
+    @BeforeClass
     public void init() {
         count.set(0);
         eventArrived = false;
@@ -85,4 +85,39 @@ public class getPropertyFunctionTestCase {
         Assert.assertTrue(eventArrived);
         executionPlanRuntime.shutdown();
     }
+
+    @Test(dependsOnMethods = {"testGetPropertyFunctionExtension"})
+    public void testGetArrayFunctionExtension() throws InterruptedException {
+        count.set(0);
+        eventArrived = false;
+        log.info("GetArrayFunctionExtension TestCase");
+        SiddhiManager siddhiManager = new SiddhiManager();
+
+        String inStreamDefinition = "define stream inputStream (arg1 string, arg2 string);";
+        String query = ("@info(name = 'query1') from inputStream select json:getArray(arg1, arg2) "
+                        + "as array insert into outputStream;");
+
+        ExecutionPlanRuntime executionPlanRuntime = siddhiManager.createExecutionPlanRuntime(inStreamDefinition + query);
+
+        executionPlanRuntime.addCallback("query1", new QueryCallback() {
+            @Override
+            public void receive(long timeStamp, Event[] inEvents, Event[] removeEvents) {
+                EventPrinter.print(timeStamp, inEvents, removeEvents);
+                for (Event event : inEvents) {
+                    count.incrementAndGet();
+                    if (count.get() == 1) {
+                        eventArrived = true;
+                    }
+                }
+            }
+        });
+
+        InputHandler inputHandler = executionPlanRuntime.getInputHandler("inputStream");
+        executionPlanRuntime.start();
+        inputHandler.send(new Object[]{"Arg1","Arg2"});
+        SiddhiTestHelper.waitForEvents(100, 1, count, 60000);
+        Assert.assertEquals(1, count.get());
+        Assert.assertTrue(eventArrived);
+        executionPlanRuntime.shutdown();
+    }
 }