example.customers.integration.StoreIntegration.java Source code

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Here is the source code for example.customers.integration.StoreIntegration.java

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/*
 * Copyright 2014 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License 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 example.customers.integration;

import java.net.URI;

import lombok.Getter;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.env.Environment;
import org.springframework.hateoas.Link;
import org.springframework.hateoas.MediaTypes;
import org.springframework.hateoas.client.Traverson;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;
import org.springframework.web.client.RestClientException;
import org.springframework.web.client.RestTemplate;

/**
 * @author Oliver Gierke
 */
@Component
@RequiredArgsConstructor(onConstructor = @__(@Autowired))
@Slf4j
public class StoreIntegration {

    private final Environment env;

    private @Getter Link storesByLocationLink;

    @Scheduled(fixedDelay = 5000)
    public void checkStoresAvailability() {

        if (storesByLocationLink != null) {
            verify(storesByLocationLink);
        } else {
            discoverByLocationLink();
        }
    }

    private void verify(Link link) {

        try {
            log.info("Verifying stores-nearby link pointing to {}", storesByLocationLink);
            new RestTemplate().headForHeaders(link.expand().getHref());
            log.info("Successfully verified link!");
        } catch (RestClientException o_O) {

            log.info("Verification failed, marking as outdated!");
            this.storesByLocationLink = null;
        }
    }

    private void discoverByLocationLink() {

        try {
            URI storesUri = URI.create(env.getProperty("integration.stores.uri"));
            log.info("Trying to access the stores system at {}", storesUri);

            Traverson traverson = new Traverson(storesUri, MediaTypes.HAL_JSON);
            this.storesByLocationLink = traverson.follow("stores", "search", "by-location").asLink();

            log.info("Found stores-by-location link pointing to {}.", storesByLocationLink.getHref());

        } catch (RuntimeException o_O) {
            this.storesByLocationLink = null;
            log.info("Stores system unavailable. Got: ", o_O.getMessage());
        }
    }

    public boolean isStoresAvailable() {
        return storesByLocationLink != null;
    }
}