org.galagosearch.tupleflow
Interface Order<T>

Type Parameters:

T - The ordered class.

public interface Order<T>

An Order is a class that represents an ordering of a Galago Type. You won't usually implement this interface directly; instead, let Galago make the class for you with the TemplateTypeBuilder/TypeBuilderMojo tools.

Author:

trevor

Method Summary

java.lang.Class<T>	getOrderedClass()
java.lang.String[]	getOrderSpec() Returns a string representation of the fields ordered by this class.
java.util.Comparator<T>	greaterThan() lessThan().compare(a,b) = greaterThan().compare(b,a);
int	hash(T object) This is a hash function over an object that only uses ordered fields.
java.util.Comparator<T>	lessThan() Returns a comparator that applies this order to objects of type T.
ReaderSource<T>	orderedCombiner(java.util.Collection<TypeReader<T>> readers, boolean closeOnExit) Produces an OrderedCombiner object.
TypeReader<T>	orderedReader(ArrayInput input) Produces an OrderedReader object.
TypeReader<T>	orderedReader(ArrayInput input, int bufferSize) Produces an OrderedReader object.
Processor<T>	orderedWriter(ArrayOutput output) Produces an OrderedWriter object that can write objects of class T in this order.

Method Detail

getOrderedClass

java.lang.Class<T> getOrderedClass()

getOrderSpec

java.lang.String[] getOrderSpec()

Returns a string representation of the fields ordered by this class. For example:

{ "+document", "-score" }

means that this order orders first by the document number in ascending order, but breaks ties by the score in descending order.

lessThan

java.util.Comparator<T> lessThan()

Returns a comparator that applies this order to objects of type T. For example, if

getOrderSpec() == { "+document" }

and a.document = 5 and b.document = 7, then:

lessThan().compare(a, b) < 0

.

greaterThan

java.util.Comparator<T> greaterThan()

lessThan().compare(a,b) = greaterThan().compare(b,a);

hash

int hash(T object)

This is a hash function over an object that only uses ordered fields. For instance, if the order is

{ "+document", "-score" }

, this hash function incorporates data from the document and score fields, but no other fields.

Parameters:

object -

Returns:

orderedWriter

Processor<T> orderedWriter(ArrayOutput output)

Produces an OrderedWriter object that can write objects of class T in this order. This object assumes that its input is already correctly ordered. The OrderedWriter uses the ordering property to write the data in compressed form.

Parameters:

output -

Returns:

orderedReader

TypeReader<T> orderedReader(ArrayInput input)

Produces an OrderedReader object. This object can read objects that were written with an OrderedWriter object produced by the Order.orderedWriter method.

Parameters:

input -

Returns:

orderedReader

TypeReader<T> orderedReader(ArrayInput input,
                            int bufferSize)

Produces an OrderedReader object. This is just like the previous orderedReader method, except you can explicitly set a buffer size.

Parameters:

input -

bufferSize -

Returns:

orderedCombiner

ReaderSource<T> orderedCombiner(java.util.Collection<TypeReader<T>> readers,
                                boolean closeOnExit)

Produces an OrderedCombiner object. An ordered combiner merges objects from many OrderedReaders into a single ordered stream of objects.

Parameters:

readers -

closeOnExit -

Returns: