LINQ for Java: Quaere

Examples To import the DSL into any Java class, simply add the following import to the class: import static org.quaere.DSL.*;

Below is an example of a simple query that selects the numbers less than five from an array of integers:

Integer[] numbers = {5, 4, 1, 3, 9, 8, 6, 7, 2, 0};
Iterable lowNums = from("n").in(numbers)
    .where(lt("n", 5))
    .select("n");

This query uses a projection expression to select the names of all products in the array:

List products = Arrays.asList(Product.getAllProducts());
Iterable productNames = from("p")
   .in(products)
   .select("p.getProductName()");

The following query creates a sequence anonymous class instances with two properties containing the upper and lower case versions of the words in an array. The classes in the upperLowerWords collection will have two strongly typed JavaBean properties:

String[] words = {"aPPLE", "BlUeBeRrY", "cHeRry"};
Iterable upperLowerWords = from("w")
   .in(words)
   .select( create( property("upper", "w.toUpperCase()"),
        property("lower", "w.toLowerCase()") ) );

With all the current talk of DSLs and concurrency, what I find lacking is discussions about how to combine the two. Of course, domain specific languages are incredibly important - they create a logical separation between the implementors of the business logic, and the people implementing the actual implementation of the DSL. Does it seem like a strange idea to want many DSLs to be able to run parallel to each other? I would imagine that in most cases a DSL that describes business rules and business logic is sequential in the particulars, but that there are also larger concurrency possibilities. This should be totally invisible for the business rule implementor in most cases - the runtime system should be able to run everything as efficient as possible.

Nice!

Awesome although it has a lame name

Groovy equivalent

Integer[] numbers = [5, 4, 1, 3, 9, 8, 6, 7, 2, 0]
def lowNums = numbers.findAll { it < 5 }

List products = Arrays.asList(Product.getAllProducts())
def productNames = products.collect { it.productName }

String[] words = ["aPPLE", "BlUeBeRrY", "cHeRry"];
def upperLowerWords = words.collect { 
  def val = new Expando() 
  val.upper = it.toUpperCase()
  val.lower = it.toLowerCase()
  val
}

Considered response

Saffron

John's Perforce server - Farrago, Mondrian etc

Re: Considered response

joSQL

Saw it at JavaZone 2007

Re: joSQL

Quaere: alternative syntax

String[] cities = new String[]{"Auckland", "Oslo"};
Alias<String> city = alias(cities);
List<String> places = from(city)
    .where(city.length().isBigger(5))
    .orderBy(city.desc())
    .select(city);
Customer c = db.alias(Customer.class);
List<Customer> list = db.from(c)
  .where(c.city.is("London"))
  .orderBy(c.name.asc(), c.city.desc())
  .select();
public class Customer {
    public Column<Integer> id;
    public Column<String> name;
    public Column<String> city;
}

Customer c = db.alias(Customer.class);
List<Customer> list = db.from(c)
  .where(equal(c.city, "London"))
  .orderBy(c.name, desc(c.id))
  .select();
public class Customer {
    public Integer id;
    public String name;
    public String city;
}

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