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the base moudle of ibankapp series

There is a newer version: 1.0.0-beta.6

/*
 * iBankApp
 *
 * License : Apache License,Version 2.0, January 2004
 *
 * See the LICENSE file in English or LICENSE.zh_CN in chinese
 * in the root directory or .
 */

package org.ibankapp.base.persistence.domain;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import javax.persistence.metamodel.EntityType;
import javax.persistence.metamodel.IdentifiableType;
import javax.persistence.metamodel.ManagedType;
import javax.persistence.metamodel.Metamodel;
import javax.persistence.metamodel.SingularAttribute;

/**
 * 实体信息类，通过此类的方法可获得实体类的一些静态信息
 *
 * @param  实体类
 * @author ibankapp
 * @author codelder
 * @since 1.0.0
 */
public class EntityInformation {

  private final IdMetadata idMetadata;
  private String entityName;

  /**
   * 构造函数.
   *
   * @param domainClass 实体类CLASS
   * @param metamodel 模型元数据,可从jpa的实体管理器EntityManage获取
   */
  public EntityInformation(Class domainClass, Metamodel metamodel) {

    ManagedType type = metamodel.managedType(domainClass);

    this.entityName = ((EntityType) type).getName();

    IdentifiableType identifiableType = (IdentifiableType) type;

    this.idMetadata = new IdMetadata(identifiableType);
  }

  /**
   * 获取实体类的名称.
   *
   * @return 实体类名称
   */
  public String getEntityName() {
    return entityName;
  }

  /**
   * 获取实体类的id属性列表.
   *
   * @return id属性列表
   */
  public Iterable getIdAttributeNames() {

    List attributeNames = new ArrayList(idMetadata.attributes.size());

    for (SingularAttribute attribute : idMetadata.attributes) {
      attributeNames.add(attribute.getName());
    }

    return attributeNames;
  }

  /**
   * Id元数据内部类.
   */
  private static class IdMetadata {

    /**
     * id所包含的属性字段.
     */
    private final Set> attributes;


    /**
     * 构造函数.
     *
     * @param source id类型
     */
    @SuppressWarnings("unchecked")
    IdMetadata(IdentifiableType source) {

      this.attributes = (Set>) (source.hasSingleIdAttribute()
          ? Collections.singleton(source.getId(source.getIdType().getJavaType()))
          : source.getIdClassAttributes());
    }
  }
}