[Metamodel Wiki] Update of "examples/PojoDataContext" by KasperSorensen

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The "examples/PojoDataContext" page has been changed by KasperSorensen:
https://wiki.apache.org/metamodel/examples/PojoDataContext

Comment:
Converted 'POJO datastores - Query your Java objects!' page to wiki format

New page:
= POJO datastores - Query your Java objects! =

With the MetaModel-pojo module of MetaModel you can use MetaModel's query engine to fire queries on a collection of regular Java objects (Java beans, Maps or arrays).

Assume we have a Person class:

{{{#!java
public class Person {
  private String name;
  private int age;
  
  // getters and setters
}
}}}
And some list of persons:
{{{#!java
List<Person> persons = ...
}}}
You can easily wrap this collection in a PojoDataContext and query it like a database, for instance to get all the adult names:
{{{#!java
TableDataProvider<Person> provider = new ObjectTableDataProvider<Person>("persons",Person.class,persons);
DataContext dc = new PojoDataContext(provider);

DataSet ds = dc.query().from("persons").select("name").where("age").greaterThan(18).execute();
while (ds.next()) {
  Row row = ds.getRow();
  String name = (String) row.getValue(0);
  System.out.println(name);
}
ds.close();
}}}

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CategoryExamples