GridGain模板搜索

Question

有没有人知道是否有可能用GridGain实现存储在内存数据网格中的对象的模板搜索？让我们考虑以下几点。你有这样的课程：

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;
}

然后就有了这样的搜索模板：

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

• 这会发现所有员工都住在纽约。是否有可能在GridGain中实现这一点？如果是的话，你能建议怎么做吗？我正在考虑使用sql联接来执行此操作，但是我需要在运行时创建这样的查询，并且在Where子句之后始终使用不同数量的参数.我解决不了这个问题。

我将感谢任何帮助/暗示。

彼得

Answer 1

你可以使用这样的东西：

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;
}

然后执行以下查询：

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");