Page Comparison

from StockExchangeStream[price >= 20] 
select symbol, custom:std(pricepizzaOrder#window.length(20)
select custom:count(orderNo) as stdPricetotalOrders
insert into StockQuoteorderCount;

/*
 * Copyright (c) 2015, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
 *
 * Licensed 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 * *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
 * limitations under the License.
 */

package org.wso2.siddhi.core.query.selector.attribute.aggregatorextension.customAggregateFunction;

import org.wso2.siddhi.core.config.ExecutionPlanContext;
import org.wso2.siddhi.core.exceptionexecutor.OperationNotSupportedExceptionExpressionExecutor;
import org.wso2.siddhi.core.executor.ExpressionExecutorquery.selector.attribute.aggregator.AttributeAggregator;
import org.wso2.siddhi.query.api.definition.Attribute;

/**
 * Custom Count Extension which 
import java.util.Arrays;
returns event count as a long
 */
public class StrandedDeviationAggregateFunctionCountAggregateFunction extends AttributeAggregator {
     private finalstatic Attribute.Type type = Attribute.Type.DOUBLELONG;
    private double mean, oldMean, stdDeviation, sum;
    private int countlong value = 00l;

    /**
     * The initialisationinitialization method for FunctionExecutorCountAggregateFunction
     *
     * @param attributeExpressionExecutors are the executors of each attributes in the function
     * @param executionPlanContext         Execution plan runtime context
     */
    @Override
    protected void init(ExpressionExecutor[] attributeExpressionExecutors, ExecutionPlanContext executionPlanContext) {
		//Implement class specific initialization
    if}
(attributeExpressionExecutors.length
!= 1) {  /**
     * The process add method throwof new OperationNotSupportedException("Stddev aggregator has to have exactly 1 parameter, currently " +the CountAggregateFunction, used when zero or one function parameter is provided
     *
     * @param data null if the function parameter count is attributeExpressionExecutors.lengthzero +or "runtime parameters provided");
   data value of the function parameter
    } * @return the count }value
       */
 @Override     public Attribute.Type getReturnType() { return type; }

    @Override
    public Object processAdd(Object data) {
        countvalue++;
        doublereturn value;
=  (Double) data; }

    /**
  if (count == 1)* {The process add method of the CountAggregateFunction, used when more than one function sumparameters =are meanprovided
= oldMean = value;  *
     * @param data the data stdDeviationvalues = 0.0;
 for the function parameters
     * }@return elsethe {count value
     */
    @Override
oldMean = mean;  public Object processAdd(Object[] data) {
      sum += value++;
            mean = sum / countreturn value;
    }

    /**
 stdDeviation += (value - oldMean)*(value -The mean);process remove method of the CountAggregateFunction, used when zero }or one function parameter is provided
    if (count*
< 2) {   * @param data null if the function parameter count is return 0.0;
        }zero or runtime data value of the function parameter
     * @return the count value
return Math.sqrt(stdDeviation / count);  */
  }      @Override
    public Object processRemove(Object data) {
        countvalue--;
        doublereturn value = (Double) data;

        if (count == 0) {
            sum = mean = 0;
            stdDeviation = 0;
        }
else
{    /**
     * The process oldMeanremove =method mean;of the CountAggregateFunction, used when more than one function parameters are provided
 sum -= value;  *
     * @param data the data meanvalues =for sumthe /function count;parameters
            stdDeviation -= (value - oldMean)*(value -@return mean);
        }

        if (count < 2) {
            return 0.0;
        }
        return Math.sqrt(stdDeviation / count);
    }

    the count value
     */
    @Override
    public Object resetprocessRemove(Object[] data) {
        sum = mean = oldMean = 0.0;
        stdDeviation = 0.0;
        count = 0value--;
        return 0value;
    }

    @Override/**
    public Object processAdd(Object[] data) {* Reset count value
     *
  return new IllegalStateException("Stddev cannot* process@return datareset array,value
but found " + Arrays.deepToString(data));
    } */
     @Override
    public Object processRemovereset(Object[] data) {
        return new IllegalStateException("Stddev cannot process data array, but found " + Arrays.deepToString(data))value = 0l;
        return value;
    }

    /**
     * This will be called only once and this can be used to acquire
     * required resources for the processing element.
     * This will be called after initializing the system and before
     * starting to process the events.
     */
    @Override
    public void start() {
        //Implement start logic to acquire relevant resources
    }

    /**
     * This will be called only once and this can be used to release
     * the acquired resources for processing.
     * This will be called before shutting down the system.
     */
    @Override
    public void stop() {
        //Implement stop logic to release the acquired resources
    }

    /**
     * Used to collect the serialisableserializable state of the processing element, that need to be
     * persisted for the reconstructing the element to the same state on a different point of time
     *
     * @return stateful objects of the processing element as an array
     */
    @Override
    public Object[] currentState() {
        return new Object[] {sum, mean, oldMean, stdDeviation, count{value};
     }

    /**
     * Used to restore serialisedserialized state of the processing element, for reconstructing
     * the element to the same state as if was on a previous point of time.
     *
     * @param state the stateful objects of the element as an array on
     *              the same order provided by currentState().
     */
    @Override
    public void restoreState(Object[] state) {
        sumvalue = (DoubleLong) state[0];
    }

  mean = (Double) state[1]  public Attribute.Type getReturnType() {
        return type;
    }
}

 oldMean = (Double) state[2];
        stdDeviation = (Double) state[3];
        count = (Integer) state[4];
    }
}