Add expression and expressionBatch window

findbugs-exclude.xml

@@ -39,6 +39,14 @@
         <Class name="io.siddhi.core.event.stream.MetaStreamEvent"/>
         <Bug pattern="CN_IMPLEMENTS_CLONE_BUT_NOT_CLONEABLE"/>
     </Match>
+    <Match>
+        <Class name="io.siddhi.core.query.processor.stream.window.ExpressionWindowProcessor$MetaStreamEventWrapper"/>
+        <Bug pattern="CN_IMPLEMENTS_CLONE_BUT_NOT_CLONEABLE"/>
+    </Match>
+    <Match>
+        <Class name="io.siddhi.core.query.processor.stream.window.ExpressionBatchWindowProcessor$MetaStreamEventWrapper"/>
+        <Bug pattern="CN_IMPLEMENTS_CLONE_BUT_NOT_CLONEABLE"/>
+    </Match>
     <Match>
         <Class name="io.siddhi.query.api.definition.StreamDefinition"/>
         <Bug pattern="CN_IMPLEMENTS_CLONE_BUT_NOT_CLONEABLE"/>

modules/siddhi-core/src/main/java/io/siddhi/core/aggregation/AggregationRuntime.java

@@ -161,7 +161,7 @@ private static void initMetaStreamEvent(MetaStreamEvent metaStreamEvent, Abstrac
                                             String inputReferenceId) {
         metaStreamEvent.addInputDefinition(inputDefinition);
         metaStreamEvent.setInputReferenceId(inputReferenceId);
-        metaStreamEvent.initializeAfterWindowData();
+        metaStreamEvent.initializeOnAfterWindowData();
         inputDefinition.getAttributeList().forEach(metaStreamEvent::addData);
     }
 

modules/siddhi-core/src/main/java/io/siddhi/core/event/stream/MetaStreamEvent.java

@@ -62,6 +62,13 @@ public List<Attribute> getOutputData() {
         }
     }
 
+    public void initializeOnAfterWindowData() {
+        if (onAfterWindowData == null) {
+            onAfterWindowData = new ArrayList<Attribute>();
+        }
+    }
+
+    @Deprecated
     public void initializeAfterWindowData() {
         if (onAfterWindowData == null) {
             onAfterWindowData = new ArrayList<Attribute>();

modules/siddhi-core/src/main/java/io/siddhi/core/event/stream/StreamEventCloner.java

@@ -47,7 +47,9 @@ public StreamEventCloner(MetaStreamEvent metaStreamEvent, StreamEventFactory eve
      */
     public StreamEvent copyStreamEvent(StreamEvent streamEvent) {
         StreamEvent newEvent = eventFactory.newInstance();
-        if (beforeWindowDataSize > 0) {
+        if (streamEvent.getBeforeWindowData() == null) {
+            newEvent.setBeforeWindowData(null);
+        } else if (beforeWindowDataSize > 0) {
             System.arraycopy(streamEvent.getBeforeWindowData(), 0, newEvent.getBeforeWindowData(), 0,
                     beforeWindowDataSize);
         }

modules/siddhi-core/src/main/java/io/siddhi/core/executor/EventVariableFunctionExecutor.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2019, 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 io.siddhi.core.executor;
+
+import io.siddhi.core.config.SiddhiQueryContext;
+import io.siddhi.core.event.ComplexEvent;
+import io.siddhi.core.event.state.StateEvent;
+import io.siddhi.core.executor.function.FunctionExecutor;
+import io.siddhi.core.util.config.ConfigReader;
+import io.siddhi.core.util.snapshot.state.State;
+import io.siddhi.core.util.snapshot.state.StateFactory;
+import io.siddhi.query.api.definition.Attribute;
+
+import static io.siddhi.core.util.SiddhiConstants.STREAM_EVENT_CHAIN_INDEX;
+import static io.siddhi.core.util.SiddhiConstants.STREAM_EVENT_INDEX_IN_CHAIN;
+import static io.siddhi.core.util.SiddhiConstants.UNKNOWN_STATE;
+
+/**
+ * Executor class for Siddhi that extracts events.
+ */
+public class EventVariableFunctionExecutor extends FunctionExecutor {
+
+    private int[] position = new int[]{UNKNOWN_STATE, UNKNOWN_STATE};
+
+    public EventVariableFunctionExecutor(int streamEventChainIndex, int streamEventIndexInChain) {
+        position[STREAM_EVENT_CHAIN_INDEX] = streamEventChainIndex;
+        position[STREAM_EVENT_INDEX_IN_CHAIN] = streamEventIndexInChain;
+    }
+
+    @Override
+    protected StateFactory init(ExpressionExecutor[] attributeExpressionExecutors, ConfigReader configReader,
+                                SiddhiQueryContext siddhiQueryContext) {
+        return null;
+    }
+
+    @Override
+    public Attribute.Type getReturnType() {
+        return Attribute.Type.OBJECT;
+    }
+
+    @Override
+    protected Object execute(Object[] data, State state) {
+        //will not occur
+        return null;
+    }
+
+    @Override
+    protected Object execute(Object data, State state) {
+        //will not occur
+        return null;
+    }
+
+    public Object execute(ComplexEvent event) {
+        return ((StateEvent) event).getStreamEvent(position);
+    }
+
+}

modules/siddhi-core/src/main/java/io/siddhi/core/executor/function/EventTimestampFunctionExecutor.java

@@ -20,6 +20,7 @@
 
 import io.siddhi.annotation.Example;
 import io.siddhi.annotation.Extension;
+import io.siddhi.annotation.Parameter;
 import io.siddhi.annotation.ParameterOverload;
 import io.siddhi.annotation.ReturnAttribute;
 import io.siddhi.annotation.util.DataType;
@@ -30,7 +31,6 @@
 import io.siddhi.core.util.snapshot.state.State;
 import io.siddhi.core.util.snapshot.state.StateFactory;
 import io.siddhi.query.api.definition.Attribute;
-import io.siddhi.query.api.exception.SiddhiAppValidationException;
 
 /**
  * Executor class for Siddhi cast function. Converts the given parameter according to the castTo parameter.
@@ -39,38 +39,55 @@
 @Extension(
         name = "eventTimestamp",
         namespace = "",
-        description = "Returns the timestamp of the processed event.",
-        parameters = {},
+        description = "Returns the timestamp of the processed/passed event.",
+        parameters = {
+                @Parameter(name = "event",
+                        description = "Event reference.",
+                        type = {DataType.OBJECT},
+                        dynamic = true,
+                        optional = true,
+                        defaultValue = "Current Event")
+        },
         parameterOverloads = {
-                @ParameterOverload()
+                @ParameterOverload(),
+                @ParameterOverload(parameterNames = {"event"})
         },
         returnAttributes = @ReturnAttribute(
-                description = "timestamp of the event.",
+                description = "Timestamp of the event.",
                 type = DataType.LONG),
         examples = {
                 @Example(
-                        syntax = "from fooStream\n" +
+                        syntax = "from FooStream\n" +
                                 "select symbol as name, eventTimestamp() as eventTimestamp \n" +
-                                "insert into barStream;",
-                        description = "This will extract current events timestamp.")
+                                "insert into BarStream;",
+                        description = "Extracts current event's timestamp."),
+                @Example(
+                        syntax = "from FooStream as f join FooBarTable as fb\n" +
+                                "select fb.symbol as name, eventTimestamp(f) as eventTimestamp \n" +
+                                "insert into BarStream;",
+                        description = "Extracts FooStream event's timestamp.")
         }
 )
 public class EventTimestampFunctionExecutor extends FunctionExecutor {
 
+    private boolean expectEventObject;
+
     @Override
     protected StateFactory init(ExpressionExecutor[] attributeExpressionExecutors, ConfigReader configReader,
                                 SiddhiQueryContext siddhiQueryContext) {
-        if (attributeExpressionExecutors.length != 0) {
-            throw new SiddhiAppValidationException("Invalid no of arguments passed to eventTimestamp() function, " +
-                    "required 0 parameters, but found " +
-                    attributeExpressionExecutors.length);
+        if (attributeExpressionExecutors.length == 1) {
+            expectEventObject = true;
         }
         return null;
     }
 
     @Override
     public Object execute(ComplexEvent event) {
-        return event.getTimestamp();
+        if (expectEventObject) {
+            return ((ComplexEvent) attributeExpressionExecutors[0].execute(event)).getTimestamp();
+        } else {
+            return event.getTimestamp();
+        }
     }
 
     @Override

modules/siddhi-core/src/main/java/io/siddhi/core/query/processor/stream/window/BatchingWindowProcessor.java

@@ -71,6 +71,11 @@ protected void processEventChunk(ComplexEventChunk<StreamEvent> streamEventChunk
                                      StreamEventCloner streamEventCloner, ComplexEventPopulater complexEventPopulater,
                                      S state) {
         streamEventChunk.reset();
+        while (streamEventChunk.hasNext()) {
+            StreamEvent streamEvent = streamEventChunk.next();
+            streamEvent.setBeforeWindowData(null);
+        }
+        streamEventChunk.reset();
         process(streamEventChunk, nextProcessor, streamEventCloner, state);
     }