com.github.ljtfreitas.restify.http.spring.client.call.exec.DeferredResultEndpointCallExecutableFactory.java Source code

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/*******************************************************************************
 *
 * MIT License
 *
 * Copyright (c) 2016 Tiago de Freitas Lima
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 *******************************************************************************/
package com.github.ljtfreitas.restify.http.spring.client.call.exec;

import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;

import org.springframework.web.context.request.async.DeferredResult;

import com.github.ljtfreitas.restify.http.client.call.EndpointCall;
import com.github.ljtfreitas.restify.http.client.call.exec.EndpointCallExecutable;
import com.github.ljtfreitas.restify.http.client.call.exec.EndpointCallExecutableDecoratorFactory;
import com.github.ljtfreitas.restify.http.contract.metadata.EndpointMethod;
import com.github.ljtfreitas.restify.http.contract.metadata.reflection.JavaType;

public class DeferredResultEndpointCallExecutableFactory<T, O>
        implements EndpointCallExecutableDecoratorFactory<DeferredResult<T>, T, O> {

    private final Long timeout;
    private final Executor executor;

    public DeferredResultEndpointCallExecutableFactory() {
        this(Executors.newSingleThreadExecutor());
    }

    public DeferredResultEndpointCallExecutableFactory(Executor executor) {
        this(null, executor);
    }

    public DeferredResultEndpointCallExecutableFactory(Long timeout) {
        this(timeout, Executors.newSingleThreadExecutor());
    }

    public DeferredResultEndpointCallExecutableFactory(Long timeout, Executor executor) {
        this.timeout = timeout;
        this.executor = executor;
    }

    @Override
    public boolean supports(EndpointMethod endpointMethod) {
        return endpointMethod.returnType().is(DeferredResult.class);
    }

    @Override
    public JavaType returnType(EndpointMethod endpointMethod) {
        return JavaType.of(unwrap(endpointMethod.returnType()));
    }

    private Type unwrap(JavaType declaredReturnType) {
        return declaredReturnType.parameterized()
                ? declaredReturnType.as(ParameterizedType.class).getActualTypeArguments()[0]
                : Object.class;
    }

    @Override
    public EndpointCallExecutable<DeferredResult<T>, O> create(EndpointMethod endpointMethod,
            EndpointCallExecutable<T, O> executable) {
        return new DeferredResultEndpointCallExecutable(executable);
    }

    private class DeferredResultEndpointCallExecutable implements EndpointCallExecutable<DeferredResult<T>, O> {

        private final EndpointCallExecutable<T, O> delegate;

        public DeferredResultEndpointCallExecutable(EndpointCallExecutable<T, O> executable) {
            this.delegate = executable;
        }

        @Override
        public JavaType returnType() {
            return delegate.returnType();
        }

        @Override
        public DeferredResult<T> execute(EndpointCall<O> call, Object[] args) {
            DeferredResult<T> deferredResult = new DeferredResult<>(timeout);

            CompletableFuture.supplyAsync(() -> delegate.execute(call, args), executor).whenComplete((r, ex) -> {
                if (r != null) {
                    deferredResult.setResult(r);
                } else if (ex != null) {
                    deferredResult.setErrorResult(ex);
                }
            });

            return deferredResult;
        }
    }
}