Apex Batch Class Template

OpportunityBatchable.cls

/**
 * @File Name          : CreateMissingContactUserLinkController.cls
 * @Description        : 
 * @Author             : 
 * @Group              :
 * @Last Modified By   : 
 * @Last Modified On   : 2020-01-29 15:32:43
 * @Modification Log   :
 * @Param
 * @Return
 * Ver       Date            Author                  Modification
 * 1.0       2020-01-29      Srujan                   Initial Version
 **/
public class OpportunityBatchable implements Database.Batchable<sObject> {
	
	/**
	* <Explain Method Here>
	* @author 
	* @param       Database.BatchableContext batchableContext
	* @return      Database.QueryLocator
	* /
	public Database.QueryLocator start(Database.BatchableContext batchableContext) {
		  return Database.getQueryLocator(getQuery());
	}
    
     /**
    * <Explain Method Here>
    * @author 
    * @param       Database.BatchableContext batchableContext,List<Opportunity> opportunityList
    * @return      void
    * /
    public void execute(  Database.BatchableContext batchableContext
	                , List<Opportunity> opportunityList) {
	
          /***re-query the database***/
          opportunityList = Database.query(getQuery(opportunityList)); 

          if(!opportunityList.isEmpty()){
              //Buisness logic which updates the opportunity status
              //BusinessLogic.processOpportunities(opportunityList);
              system.debug(opportunityList);
          }
    }
    
     /**
    * <Explain Method Here>
    * @author 
    * @param       Database.BatchableContext batchableContext
    * @return      Database.QueryLocator
    * /
    private String getQuery(){
	    return getQuery(null);
    }
    
     /**
    * <Explain Method Here>
    * @author 
    * @param       List<SObject>
    * @return      String - Query
    * /
    private String getQuery(List<Opportunity> opportunityList){
	
        String query =   ' Select Id'
                        +' From  '+  Schema.SobjectType.Opportunity.Name
                        +' Where '+  Opportunity.Amount    +' > :TARGET_AMOUNT'
                        +'   AND '+  Opportunity.StageName +' IN :OPPORTUNITY_STAGE_OPEN';

        if(null!=opportunityList && !opportunityList.isEmpty()){
            query+= ' AND Id IN :opportunityList';
    	}
    
	    return query;
    }
    
    /**
    * <Explain Method Here>
    * @author 
    * @param       Database.BatchableContext batchableContext
    * @return      void
    * /
    public void finish(Database.BatchableContext batchableContext) {
                    
    }
}