java GridGain模板搜索

Question

有人知道是否有可能使用GridGain对存储在内存数据网格中的对象执行模板搜索吗？让我们考虑下面的问题。您有以下课程：

class Employee{
 private Long id;
 private String name;
 private Address address;
 private Account account;
}

class Account{
 private Long id;
 private String accountNr;
}

class Address{
 private String street;
 private String postcode;
 private String city;
 private Country country;
}

然后您就有了这样一个搜索模板：

Address address = new Address(null, null, "New York", null);
Employee template = new Employee(null, null,address, null);
grid.read(template); 

• 这将找到所有居住在纽约的员工。是否有可能在GridGain中实现此功能？如果是的话，你能告诉我怎么做吗？ 我正在考虑使用sql连接来执行此操作，但是我需要在运行时创建这样一个查询，并且在Where子句之后始终使用不同数量的参数。。。我无法解决这个问题

我将感谢任何帮助/提示

彼得

Answer 1

您可以使用以下内容：

public class Address {
    @GridCacheQuerySqlField(unique = true)
    private long id;
    @GridCacheQuerySqlField
    private String street;
    @GridCacheQuerySqlField
    private String postcode;
    @GridCacheQuerySqlField
    private String city;
    @GridCacheQuerySqlField
    private Country country;
}

public class Employee {
    @GridCacheQuerySqlField(unique=true)
    private long id;

    @GridCacheQuerySqlField
    private long addressId; // Address ID.

    // Not indexed.
    private String name;
}

然后执行查询：

GridCacheQuery<Map.Entry<Long, Employee>> qry = cache.queries().createSqlQuery(Employee.class,
    "from Employee, Address where Employee.addressId = Address.id " +
        "and Address.name = ?");
// Query all nodes to find all cached CompanyZ employees in New York
qry.execute("CompanyZ","New York");