SPRING BATCH : commit interval changing according to data in input file

问题

Currently my batch has a static commit-interval (1000). We asked me to change it in order to commit once a data in my flat file get changed. So I should have a reader which reads lines from flat file, once it notice that this data has changed, it should process the read lines and writes in database.

I tried with completionPolicy as follows:

1. ReceptionCompletionPolicy.java:

   public class ReceptionCompletionPolicy extends SingleItemPeekableItemReader<ReceptionLineFieldHelper> implements CompletionPolicy{
   
       private ReceptionLineFieldHelper current;
   
       public boolean isComplete(RepeatContext context) {
           return ((ReaderRepeatContext) context).isComplete();
       }
   
   
       public boolean isComplete(RepeatContext context, RepeatStatus result) {
           return ((ReaderRepeatContext) context).isComplete();
       }
   
   
       public RepeatContext start(RepeatContext parent) {
           /*
            * Set first item of the chunk for later comparison.
            */
           this.current = invokePeek();
           return new ReaderRepeatContext(parent);
       }
   
   
       public void update(RepeatContext context) {
           /*
            * Check if the step should finish.
            * In this case when there are no more records to process.
            */
           if (current == null) {
               context.setCompleteOnly();
           }
       }
   
       private ReceptionLineFieldHelper invokePeek() {
           ReceptionLineFieldHelper peeked = null;
           try {
               peeked = peek();
           } catch (Exception e) {
               e.printStackTrace();
           }
           return peeked;
       }
   
       //custom RepeatContext
       protected class ReaderRepeatContext extends RepeatContextSupport{
   
           public ReaderRepeatContext(RepeatContext parent) {
               super(parent);
           }
   
           public boolean isComplete() {
               ReceptionLineFieldHelper next = null;
               next = invokePeek();
   
               if (next == null || !(next.getCode().equals(current.getCode()))) {
                   current = next;
                   return true;
               }
               return false;
           }               
       }
   }
   

2. ReceptionReader.java:

   public class ReceptionReader implements ItemReader {
   
       public Object read() {
           return this.filterFile(inputFile);
       }
   }
   

3. reception.xml:

   <?xml version="1.0" encoding="UTF-8"?>
   <beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:batch="http://www.springframework.org/schema/batch"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
           http://www.springframework.org/schema/aop
       http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
       http://www.springframework.org/schema/batch
       http://www.springframework.org/schema/batch/spring-batch-2.1.xsd">
   
       <!-- import config Spring générale -->
       <import
           resource="classpath*:spring/batch-spring.xml" />
   
       <batch:job id="reception" parent="simpleJob"
           job-repository="jobRepository">
   
   
           <!-- Déclaration step T01 -->
           <batch:step id="t01" parent="simpleStep">
               <batch:tasklet transaction-manager="transactionManager">
                   <batch:chunk reader="receptionReader"
                       writer="receptionProcessor"
                       chunk-completion-policy="receptionCompletionPolicy" />
               </batch:tasklet>
           </batch:step>
       </batch:job>
   
       <!-- 
           *****************
           *   ETAPE T01   *
           *****************   -->
       <!-- reader -->
       <bean id="receptionReader"
           class="com.reception.reader.ReceptionReader">
       </bean>
   
       <!-- writer -->
       <bean id="receptionProcessor"
           class="com.reception.processor.ReceptionProcessor">
       </bean>
   
       <!-- completionPolicy -->
       <bean id="receptionCompletionPolicy"
           class="com.reception.completionPolicy.ReceptionCompletionPolicy">
       </bean>
   </beans>
   

Apparently I have problem with completionPolicy at invokePeek() method. Does any one have an idea?

If there is an other way to reach my goal it will be welcome too.

来源：https://stackoverflow.com/questions/37922390/spring-batch-commit-interval-changing-according-to-data-in-input-file