com.amazon.ask.mvc.annotation.condition.WhenDialogState Maven / Gradle / Ivy

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The Alexa Skills Kit MVC Framework extends the existing ASK SDK, adding features for mapping requests to methods and rendering responses via view scripts and templates such as Nashorn Javascript and Freemarker. It also integrates with the ASK SDK Interaction Model Mapper framework to create a single environment where both the interaction model and business logic of skills can be managed as code packages.

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/*
    Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.

    Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file
    except in compliance with the License. A copy of the License is located at

        http://aws.amazon.com/apache2.0/

    or in the "license" file accompanying this file. This file is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for
    the specific language governing permissions and limitations under the License.
 */

package com.amazon.ask.mvc.annotation.condition;

import com.amazon.ask.dispatcher.request.handler.HandlerInput;
import com.amazon.ask.model.DialogState;
import com.amazon.ask.model.IntentRequest;
import com.amazon.ask.model.Request;
import com.amazon.ask.mvc.annotation.plugin.AutoPredicate;
import com.amazon.ask.mvc.mapper.AnnotationContext;

import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import java.util.Arrays;
import java.util.List;
import java.util.Set;
import java.util.function.Predicate;
import java.util.stream.Collectors;

import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * When added to a handler method, the method will only be invoked if the dialog's
 * state is in one of the provided values.
 */
@Target(value = METHOD)
@Retention(value = RUNTIME)
@AutoPredicate(WhenDialogState.Plugin.class)
public @interface WhenDialogState {
    /**
     * @return allowed dialog state values.
     */
    DialogState[] value() default {};

    /**
     * @return allowed dialog state values.
     */
    DialogState[] states() default {};

    class Plugin implements AutoPredicate.Plugin {
        @Override
        public Predicate apply(AnnotationContext entity, WhenDialogState annotation) {
            List annotationValues = Arrays.asList(annotation.states().length == 0
                ? annotation.value()
                : annotation.states());

            Set values = annotationValues.stream()
                .map(DialogState::toString)
                .collect(Collectors.toSet());

            return input -> {
                Request request = input.getRequestEnvelope().getRequest();

                return request instanceof IntentRequest &&
                    ((IntentRequest)request).getDialogState() != null &&
                    values.contains(((IntentRequest)request).getDialogState().toString());
            };
        }
    }
}