compass关联其他类为什么为空值？

package org.pis.model;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import org.compass.annotations.Searchable;
import org.compass.annotations.SearchableComponent;
import org.compass.annotations.SearchableId;
import org.compass.annotations.SearchableProperty;
import org.pis.security.model.User;
@Searchable(alias = "product")
public class Product {
	@SearchableId
	private Integer id;
			
	private Brand brand;
	
	private Catena catena;

	
	@SearchableComponent(refAlias="brand")
	public Brand getBrand() {
		return brand;
	}

	public void setBrand(Brand brand) {
		this.brand = brand;
	}
		
}


package org.pis.model;

import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;

import org.compass.annotations.Searchable;
import org.compass.annotations.SearchableId;
import org.compass.annotations.SearchableProperty;

@Searchable(root=false,alias = "brand" )
public class Brand implements Serializable {
	/**
	 * 
	 */
	private static final long serialVersionUID = -4756673952507926744L;

	// 品牌
	
	private Integer id;

         @SearchableProperty(name="brdname")
	private String name;

         public Integer getId() {
		return id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	
	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}}

只写了关联属性，，请各位。。。

如果要搜索 key 是 brdname的记录，不知道queryString怎么写?
search("brdname:"+keyWords)好象不得

没人知道 compass 的 SearchableComponent 怎么搜索吗？