Пояснение кода

Голову ломаю который час, надеюсь на вашу помощь

1.Хотелось бы понять что значит эта часть кода:
[code]String SearchContactKeywordCreteria = '%'+(SearchContactKeyword == null ? '' : SearchContactKeyword)+'%';[/code]
2.Никак не могу понять почему кнопка поиска не работает:
[code]<apex:page controller="ContactsManagerController">
    
    	<apex:pageBlock title="Contact">
            <apex:form>
               
            <apex:inputText value="{!SearchContactKeyword}" />
		<apex:commandButton value="Search" rerender="ContactTableBox" status="SearchStatus"/>
		<apex:actionStatus id="SearchStatus">
			<apex:facet name="start"><img src="/img/loading.gif" alt="" /></apex:facet>
			<apex:facet name="stop"></apex:facet>
		</apex:actionStatus>
                <apex:outputPanel layout="block" id="ContactTableBox">
			<apex:panelGrid columns="7">
				<apex:commandButton action="{!setCon.first}" status="PaginationStatus" reRender="ContactTableBox" value="|<" disabled="{!!setCon.hasPrevious}" title="First Page"/>
				<apex:commandButton action="{!setCon.previous}" status="PaginationStatus" reRender="ContactTableBox" value="<" disabled="{!!setCon.hasPrevious}" title="Previous Page"/>
				<apex:commandButton action="{!setCon.next}" status="PaginationStatus" reRender="ContactTableBox" value=">" disabled="{!!setCon.hasNext}" title="Next Page"/>
				<apex:commandButton action="{!setCon.last}" status="PaginationStatus" reRender="ContactTableBox" value=">|" disabled="{!!setCon.hasNext}" title="Last Page"/>
				<apex:outputText >{!(setCon.pageNumber * size)+1-size}-{!IF((setCon.pageNumber * size)>noOfRecords, noOfRecords,(setCon.pageNumber * size))} of {!noOfRecords}</apex:outputText>
				<apex:actionStatus id="PaginationStatus">
					<apex:facet name="start"><img src="/img/loading.gif" alt="" /></apex:facet>
					<apex:facet name="stop"></apex:facet>
				</apex:actionStatus>
			</apex:panelGrid>
    	
            <apex:pageBlockTable id="ContactTable" value="{!Contacts}" var="item">
                   
                <apex:column >
       <apex:outputLink title="" value="/{!item.id}/e?retURL=/apex/{!$CurrentPage.Name}" style="font-weight:bold">Edit</apex:outputLink>&nbsp;|&nbsp;
       <a href="javascript:if (window.confirm('Are you sure?')) DeleteAccount('{!item.Id}');" style="font-weight:bold">Del</a>
     </apex:column>
                <apex:column value="{!item.Name}"/>
                <apex:column value="{!item.Email}" />
                <apex:column value="{!item.Contact_Level__c}" />
                <apex:column headerValue="Account"  value="{!item.AccountId}" />
                <apex:column headerValue="Owner"  value="{!item.OwnerId}" />
                <apex:column value="{!item.CreatedById}" />
                <apex:column value="{!item.CreatedDate}" />
                
                
    
    
    
    </apex:pageBlockTable>
                </apex:outputPanel>
   </apex:form>
    	</apex:pageBlock>
</apex:page> [/code]
[code]public with sharing class ContactsManagerController {

    public String SearchContactKeyword { get; set; }
    public Integer noOfRecords{get; set;}
    public Integer size{get;set;}

    public List<Contact> Contacts { get{
        return (List<Contact>)setCon.getRecords();
    } set; }

    public ApexPages.StandardSetController setCon {
        get{
            if(setCon == null){
                size = 10;
                String SearchContactKeywordCreteria = '%'+(SearchContactKeyword == null ? '' : SearchContactKeyword)+'%';
                List<Contact> ContactList = [SELECT Id, Name, Email, Contact_Level__c, AccountId, OwnerId, CreatedById, CreatedDate
                                             FROM Contact 
                                             WHERE Name 
                                             LIKE :SearchContactKeywordCreteria 
                                             LIMIT 10000];
                setCon = new ApexPages.StandardSetController(ContactList);
                setCon.setPageSize(size);
                noOfRecords = setCon.getResultSize();
                
            }return setCon;
            
        }set;
    }

    public void SearchContacts() {
        setCon = null;
        setCon.setPageNumber(1);
    }

}[/code]