com.instaclustr.operations.OperationBindings Maven / Gradle / Ivy

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Common classes and utilities integrated with various projects
There is a newer version: 2.0.0
package com.instaclustr.operations;

import com.google.inject.Binder;
import com.google.inject.TypeLiteral;
import com.google.inject.assistedinject.FactoryModuleBuilder;
import com.google.inject.multibindings.MapBinder;
import com.google.inject.util.Types;

public final class OperationBindings {
    private OperationBindings() {
    }

    /**
     * Install the various bindings and AssistedInject {@link OperationFactory}s for
     * a {@link Operation} and its associated {@link OperationRequest} type.
     * 
     * This allows for automatic JSON serialization/deserialization (via {@link MapBackedTypeIdResolver}),
     * and creation of Operations from their Requests.

     * @param binder binder to use
     * @param typeId id of type
     * @param requestClass request class
     * @param operationClass operation class
     * @param  type of request
     * @param  type of operation
     */
    public static >
    void installOperationBindings(final Binder binder,
                                  final String typeId,
                                  final Class requestClass,
                                  final Class operationClass) {

        @SuppressWarnings("unchecked") final TypeLiteral> operationFactoryType =
                (TypeLiteral>) TypeLiteral.get(
                        Types.newParameterizedType(OperationFactory.class, requestClass)
                );

        final TypeLiteral> operationRequestClassType = new TypeLiteral>() {
        };
        final TypeLiteral> operationClassType = new TypeLiteral>() {
        };

        // get Guice to create the AssistedInject OperationFactory implementation for the Operation class
        // to allow creation Operations from their OperationRequests
        binder.install(new FactoryModuleBuilder()
                               .implement(Operation.class, operationClass)
                               .build(operationFactoryType));

        // add an entry to the Map, OperationFactory> for the factory created above
        MapBinder.newMapBinder(binder, operationRequestClassType, TypeLiteral.get(OperationFactory.class))
                .addBinding(requestClass).to(operationFactoryType);

        // add an entry to the Map> for the typeId.
        // this allows OperationRequest.TypeIdResolver to lookup the Class for a given typeId (and vice versa)
        MapBinder.newMapBinder(binder, TypeLiteral.get(String.class), operationRequestClassType)
                .addBinding(typeId).toInstance(requestClass);

        // add an entry to the Map> for the typeId.
        // this allows Operation.TypeIdResolver to lookup the Class for a given typeId (and vice versa)
        MapBinder.newMapBinder(binder, TypeLiteral.get(String.class), operationClassType)
                .addBinding(typeId).toInstance(operationClass);
    }
}