import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;

import javax.annotation.PostConstruct;
import javax.faces.bean.SessionScoped;
import javax.faces.bean.ViewScoped;
import javax.inject.Named;

@Named("test")
@SessionScoped
public class TestBean implements Serializable{

	private static final long serialVersionUID = 3310283369224800540L;
	
	private boolean collapced;
	private String test;
	
	@PostConstruct
	public void init(){
		
	}

	public boolean isCollapced() {
		return collapced;
	}

	public void setCollapced(boolean collapced) {
		this.collapced = collapced;
	}

	public String getTest() {
		return test;
	}

	public void setTest(String test) {
		this.test = test;
	}
	
	public List<String> auto(String query){
		List<String> result = new ArrayList<String>();
		result.add("test1");
		result.add("test2");
		result.add("test3");
		result.add("test4");
		result.add("test5");
		result.add("test6");
		result.add("test7");
		result.add("test8");
		result.add("test9");

		return result;
	}
	
	public void ajaxListener(){
		collapced = true;
	}
	
	public void toggbleListener(){
		collapced = false;
		test = null;
	}
	
	public void buttonListener(){
		collapced = !collapced;
	}

	
}

       <h:form id="test">
	<p:fieldset legend="TEST" toggleable="#{test.collapced}" collapsed="#{test.collapced}">
	<p:ajax event="toggle" update="test" listener="#{test.toggbleListener}"/>
	<p:autoComplete value="#{test.test}"
	completeMethod="#{test.auto}" id = "auto">
	<p:ajax event="itemSelect" update="test" listener="#{test.ajaxListener}"/>
	</p:autoComplete>
	</p:fieldset>
	
	<p:commandButton value="BUTTON" actionListener="#{test.buttonListener}" update="test"/>
	</h:form>