Over a million developers have joined DZone.
{{announcement.body}}
{{announcement.title}}

A Comparison of Two Large CSV Files in MuleSoft

DZone's Guide to

A Comparison of Two Large CSV Files in MuleSoft

One file is 5 MB and the other is 1 MB. How can we deal with such large files without setting aside a huge amount of time?

· Integration Zone
Free Resource

Today’s data climate is fast-paced and it’s not slowing down. Here’s why your current integration solution is not enough. Brought to you in partnership with Liaison Technologies.

In this scenario, we have two CSV files. The requirement is to replace the fourth field J_D with I_D in File 1 if first three fields in both the files are the same.

File 1: JDEFile

J_A,J_B,J_C,J_D
82301,8179613,20161219,555
82301,8179613,20161226,1155
82301,8179613,20170102,954
82301,8179613,20170109,668
82301,8179613,20170116,968
82301,8179613,20170123,602
82301,8179613,20170130,782
82301,8179613,20170206,815
82301,8179613,20170213,632

File 2: IL File

I_A,I_B,I_C,I_D
82301,8179613,20170213,632
82301,8179613,20170220,632
82301,8179613,20170206,810
82301,8179613,20170123,6021

Approach 1

<mulerequester:requestresource="file://D:/LOC/JDE_UPLOAD_REPORT.csv?autoDelete=false"doc:name="JD_File"/>
        <set-variable variableName="jdeFile" value="#[payload]"mimeType="application/csv" doc:name="JDEFile"/>
        <mulerequester:requestresource="file://D:/LOC/UK_EU_DSFCST_IL.csv?autoDelete=false"doc:name="IL_File"/>
        <set-variable variableName="ilFile" value="#[payload]"doc:name="ILFile" mimeType="application/csv"/>
        <dw:transform-message metadata:id="bb792c8d-6ebf-4343-a470-81746b5b1873" doc:name="FilterMap">
            <dw:input-variable mimeType="application/csv"variableName="jdeFile"/>
            <dw:input-variable mimeType="application/csv"variableName="ilFile"/>
            <dw:set-payload><![CDATA[
%dw 1.0
%output application/csv
%var D = null
%function checkPresence(A,B,C) flowVars.ilFile[?($[0] == A and $[1] ==B and $[2] == C)][0][3]  
---
flowVars.jdeFile map ((jdeFile , indexOfJdeFile) -> {
      R_A: jdeFile[0],
      R_B: jdeFile[1],
      R_C: jdeFile[2],
      R_D: checkPresence(jdeFile[0],jdeFile[1],jdeFile[2]) default 
             jdeFile[2]
})
]]></dw:set-payload>
</dw:transform-message>

Well, Approach 1 was not efficient for dealing with larger files. It takes more than 30 minutes to scan and compare. Let's move on to Approach 2.

Approach 2

File 1: JDEFile (size 5 MB).

File 2: IL File (size 1 MB).

XML flow.

The highlighted code shows the usage of a Java code inside a DataWeave script.

  • Read JD_File and store it in a flow variable named jdeFile as a string. Headers are explicitly added as the first line gets omitted in the responses of the DataWeave scripts.

  • Read IL_File and transform it into an ArrayList of HashMaps. 

  • Java code is used to add the elements of all the HashMaps in the ArrayList to one single HashMap. Refer to the file CreateHashMap.java. 

<?xml version="1.0" encoding="UTF-8"?>
<mule xmlns:cluster="
      . . . . . .
      . . . . . .
 http://www.mulesoft.org/schema/mule/http http://www.mulesoft.org/schema/mule/http/current/mule-http.xsd">
 <file:connector name="File" autoDelete="false"  streaming="false" validateConnections="true" doc:name="File"/>
 <configuration doc:name="Configuration">
  <expression-language>
               <global-functions>
                def getKey(value) {
                return payload.get(value)
                }
               </global-functions>
  </expression-language>
 </configuration>
    <flow name="filesrbFlow">
        <poll doc:name="Poll">
            <fixed-frequency-scheduler frequency="1000" timeUnit="DAYS"/>
            <logger message="****************************Started*****************************8" level="INFO" doc:name="Logger"/>
        </poll>
        <mulerequester:request resource="file://D:/Accounts/POC/JDE_UPLOAD_REPORT.csv?autoDelete=false" doc:name="JD_File"/>
        <set-variable variableName="jdeFile" value="J_A,J_B,J_C,J_D#['\n']#[message.payloadAs(java.lang.String)]" mimeType="application/csv" doc:name="JDEFile"/>
        <mulerequester:request resource="file://D:/Accounts/POC/UK_EU_DSFCST_IL.csv?autoDelete=false" doc:name="IL_File"/>
        <set-payload value="I_A,I_B,I_C,I_D#['\n']#[message.payloadAs(java.lang.String)]" mimeType="application/csv" doc:name="Set Payload"/>
        <dw:transform-message metadata:id="af17dc95-43d6-4749-b97e-f7d4c8ef58b0" doc:name="IL_File_Map">
            <dw:input-payload mimeType="application/csv"/>
            <dw:input-variable mimeType="application/csv" variableName="jdeFile"/>
            <dw:set-payload><![CDATA[%dw 1.0
%output application/java
---
payload map ((payload01 , indexOfPayload01) -> {
      ABC: payload01[0] ++ payload01[1] ++ payload01[2],
      D: payload01[3]
})]]></dw:set-payload>

        </dw:transform-message>
        <logger message="*********************Starting FlowStep - Transforming File Now****************************" level="INFO" doc:name="Logger"/>
        <component class="filesrb.utils.CreateHashMap" doc:name="Java"/>
        <dw:transform-message metadata:id="bb792c8d-6ebf-4343-a470-81746b5b1873" doc:name="SwapCreate">
            <dw:input-variable mimeType="application/csv" variableName="jdeFile"/>
            <dw:set-payload><![CDATA[%dw 1.0
%output application/csv header=false, separator = ","
---
flowVars.jdeFile map ((jdeFile , indexOfJdeFile) -> {
      A: jdeFile[0],
      B: jdeFile[1],
      C: jdeFile[2],
      D: getKey(jdeFile[0] ++ jdeFile[1] ++ jdeFile[2]) default jdeFile[3]
     }
)]]></dw:set-payload>
        </dw:transform-message>
        <logger message="*********************Writing File Now****************************" level="INFO" doc:name="Logger"/>
        <file:outbound-endpoint path="D:\Accounts\RB\POC" outputPattern="RESPONSE.csv" connector-ref="File" responseTimeout="10000" doc:name="File"/>
        <logger message="*********************End Transforming &amp; Writing ****************************" level="INFO" doc:name="Logger"/>
    </flow>
</mule>

Java Code

package filesrb.utils;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.mule.api.MuleEventContext;
import org.mule.api.lifecycle.Callable;

      public class CreateHashMap implements Callable {
      public void run() {       
      }

      @SuppressWarnings("unchecked")
      @Override
      public Object onCall(MuleEventContext eventContext) throws Exception {
            // TODO Auto-generated method stub
            Map<String, String> ilfilemap  = new HashMap<String, String>();
            List<Map<String, String>> list = (ArrayList<Map<String, String>>) eventContext.getMessage().getPayload();
            for (Map<String, String> entry : list) {
                  String keyValue[] = new String[2];
                  int ctr=0;
                for (String key : entry.keySet()) {
                    String value = entry.get(key);
                    keyValue[ctr] = value;
                    ctr = ctr + 1;
                }
                ilfilemap.put(keyValue[0], keyValue[1]);
            }
            return ilfilemap;
      }
}

The above task can be done without using Java code. 

In this flow, we are adding values to a flowVariable in form of a HashMap using a Groovy script embedded inside the DataWeave script. Further, the same variable is used to get the value based on the key.

XML Flow

<?xml version="1.0" encoding="UTF-8"?>
<mule xmlns:cluster=" 
    . . . . . .
    . . . . . . ">
    <file:connector name="File" autoDelete="false"  streaming="false" validateConnections="true" doc:name="File"/>
    <configuration doc:name="Configuration">
<expression-language>
               <global-functions>
                def getKey(value) {
                return flowVars.ilFile.get(value)
                }
                def putKeyValue(key,value) {
                  flowVars.ilFile.put(key,value)           
                }
               </global-functions>
            </expression-language>
 </configuration>
    <flow name="filesrbFlow">
        <poll doc:name="Poll">
            <fixed-frequency-scheduler frequency="1000" timeUnit="DAYS"/>
            <logger message="****************************Started*****************************8" level="INFO" doc:name="Logger"/>
        </poll>
        <mulerequester:request resource="file://D:/Accounts/POC/JDE_UPLOAD_REPORT.csv?autoDelete=false" doc:name="JD_File_Read"/>
        <set-variable variableName="jdeFile" value="J_A,J_B,J_C,J_D#['\n']#[message.payloadAs(java.lang.String)]" mimeType="application/csv" doc:name="JDE_File_Var"/>
        <mulerequester:request resource="file://D:/Accounts/POC/UK_EU_DSFCST_IL.csv?autoDelete=false" doc:name="IL_File_Read"/>
        <set-variable variableName="ilFile" value="#[new java.util.HashMap()]" doc:name="IL_File_Var"/>
        <set-payload value="I_A,I_B,I_C,I_D#['\n']#[message.payloadAs(java.lang.String)]" mimeType="application/csv" doc:name="Set Payload"/>
        <dw:transform-message metadata:id="af17dc95-43d6-4749-b97e-f7d4c8ef58b0" doc:name="IL_File_Map">
            <dw:input-payload mimeType="application/csv"/>
            <dw:input-variable mimeType="application/csv" variableName="jdeFile"/>
            <dw:set-payload><![CDATA[%dw 1.0
%output application/java
---
payload map ((payload01 , indexOfPayload01) -> {
      ABC: putKeyValue(payload01[0] ++ payload01[1] ++ payload01[2], payload01[3])
})]]></dw:set-payload>

        </dw:transform-message>
        <logger message="*********************Starting FlowStep - Transforming File Now****************************" level="INFO" doc:name="Logger"/>

        <dw:transform-message metadata:id="bb792c8d-6ebf-4343-a470-81746b5b1873" doc:name="SwapCreate">
            <dw:input-variable mimeType="application/csv" variableName="jdeFile"/>
            <dw:set-payload><![CDATA[%dw 1.0
%output application/csv header=false, separator = ","
---
flowVars.jdeFile map ((jdeFile , indexOfJdeFile) -> {
      A: jdeFile[0],
      B: jdeFile[1],
      C: jdeFile[2],
      D: getKey(jdeFile[0] ++ jdeFile[1] ++ jdeFile[2]) default jdeFile[3]

      }
)]]></dw:set-payload>
        </dw:transform-message>

        <logger message="*********************Writing File Now****************************" level="INFO" doc:name="Logger"/>
        <file:outbound-endpoint path="D:\Accounts\RB\POC" outputPattern="RESPONSE.csv" connector-ref="File" responseTimeout="10000" doc:name="File"/>
        <logger message="*********************End Transforming &amp; Writing ****************************" level="INFO" doc:name="Logger"/>
    </flow>
</mule>

Is iPaaS solving the right problems? Not knowing the fundamental difference between iPaaS and iPaaS+ could cost you down the road. Brought to you in partnership with Liaison Technologies.

Topics:
dataweave ,csv ,mulesoft ,integration

Opinions expressed by DZone contributors are their own.

THE DZONE NEWSLETTER

Dev Resources & Solutions Straight to Your Inbox

Thanks for subscribing!

Awesome! Check your inbox to verify your email so you can start receiving the latest in tech news and resources.

X

{{ parent.title || parent.header.title}}

{{ parent.tldr }}

{{ parent.urlSource.name }}