ai.grakn.graql.internal.pattern.property

Class PropertyExecutor

java.lang.Object

ai.grakn.graql.internal.pattern.property.PropertyExecutor

public abstract class PropertyExecutor
extends Object

A class describing an operation to perform using a VarProperty.

The behaviour is executed via a QueryOperationExecutor using execute(ai.grakn.graql.internal.query.QueryOperationExecutor). The class also report its requiredVars() before it can run and its producedVars(), that will be available to other PropertyExecutors after it has run.

For example:

         SubProperty property = SubProperty.of(y);
         PropertyExecutor executor = property.define(x);
         executor.requiredVars(); // returns `{y}`
         executor.producedVars(); // returns `{x}`

         // apply the `sub` property between `x` and `y`
         // because it requires `y`, it will call `queryOperationExecutor.get(y)`
         // because it produces `x`, it will call `queryOperationExecutor.builder(x)`
         executor.execute(queryOperationExecutor);
     

Author:

Felix Chapman

Constructor Summary

Constructors

Constructor and Description
PropertyExecutor()

Method Summary

Modifier and Type	Method and Description
static ai.grakn.graql.internal.pattern.property.PropertyExecutor.Builder	builder(ai.grakn.graql.internal.pattern.property.PropertyExecutor.Method executeMethod)
void	execute(QueryOperationExecutor executor) Apply the given property, if possible.
abstract com.google.common.collect.ImmutableSet<Var>	producedVars() Get all Vars whose Concept can only be created after this property is applied.
abstract com.google.common.collect.ImmutableSet<Var>	requiredVars() Get all Vars whose Concept must exist for the subject Var to be applied.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PropertyExecutor

public PropertyExecutor()

Method Detail

builder

public static ai.grakn.graql.internal.pattern.property.PropertyExecutor.Builder builder(ai.grakn.graql.internal.pattern.property.PropertyExecutor.Method executeMethod)

execute

public void execute(QueryOperationExecutor executor)

Apply the given property, if possible.

Parameters:

executor - a class providing a map of concepts that are accessible and methods to build new concepts.

This method can expect any key to be here that is returned from requiredVars(). The method may also build a concept provided that key is returned from producedVars().

requiredVars

public abstract com.google.common.collect.ImmutableSet<Var> requiredVars()

Get all Vars whose Concept must exist for the subject Var to be applied. For example, for IsaProperty the type must already be present before an instance can be created.

When calling execute(ai.grakn.graql.internal.query.QueryOperationExecutor), the method can expect any Var returned here to be available by calling QueryOperationExecutor.get(ai.grakn.graql.Var).

producedVars

public abstract com.google.common.collect.ImmutableSet<Var> producedVars()

Get all Vars whose Concept can only be created after this property is applied.

When calling execute(ai.grakn.graql.internal.query.QueryOperationExecutor), the method must help build a Concept for every Var returned from this method, using QueryOperationExecutor.builder(ai.grakn.graql.Var).