com.datazuul.iiif.presentation.backend.repository.impl.PresentationRepositoryImpl.java Source code

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Here is the source code for com.datazuul.iiif.presentation.backend.repository.impl.PresentationRepositoryImpl.java

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/*
 * 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 com.datazuul.iiif.presentation.backend.repository.impl;

import com.datazuul.iiif.presentation.api.model.Manifest;
import com.datazuul.iiif.presentation.backend.repository.PresentationRepository;
import com.datazuul.iiif.presentation.backend.repository.resolver.PresentationResolver;
import com.datazuul.iiif.presentation.model.NotFoundException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.util.List;
import org.apache.commons.io.IOUtils;
import org.apache.http.client.fluent.Executor;
import org.apache.http.client.fluent.Request;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.core.io.Resource;
import org.springframework.stereotype.Repository;

/**
 * Default implementation trying to get manifest.json from an resolved URI as String and returning
 * Manifest instance.
 *
 * @author Ralf Eichinger (ralf.eichinger at gmail.com)
 */
@Repository
public class PresentationRepositoryImpl implements PresentationRepository {

    private static final Logger LOGGER = LoggerFactory.getLogger(PresentationRepositoryImpl.class);

    @Autowired
    private ApplicationContext applicationContext;

    private final Cache<String, Manifest> httpCache;

    private final Executor httpExecutor;

    @Autowired
    private ObjectMapper objectMapper;

    @Autowired(required = true)
    List<PresentationResolver> resolvers;

    public PresentationRepositoryImpl() {
        this.httpExecutor = Executor.newInstance();
        httpCache = CacheBuilder.newBuilder().maximumSize(32).build();
    }

    @Override
    public Manifest getManifest(String identifier) throws NotFoundException {
        Manifest manifest = null;

        LOGGER.debug("Try to get manifest for: " + identifier);

        LOGGER.debug("START getManifest() for " + identifier);
        PresentationResolver resolver = getManifestResolver(identifier);
        URI manifestUri = resolver.getURI(identifier);

        String json;
        try {
            if (manifestUri.getScheme().equals("file")) {
                json = IOUtils.toString(manifestUri);
                manifest = objectMapper.readValue(json, Manifest.class);
            } else if (manifestUri.getScheme().equals("classpath")) {
                Resource resource = applicationContext.getResource(manifestUri.toString());
                InputStream is = resource.getInputStream();
                json = IOUtils.toString(is);
                manifest = objectMapper.readValue(json, Manifest.class);
            } else if (manifestUri.getScheme().startsWith("http")) {
                String cacheKey = getCacheKey(identifier);
                manifest = httpCache.getIfPresent(cacheKey);
                if (manifest == null) {
                    LOGGER.debug("HTTP Cache miss!");
                    json = httpExecutor.execute(Request.Get(manifestUri)).returnContent().asString();
                    manifest = objectMapper.readValue(json, Manifest.class);
                    httpCache.put(cacheKey, manifest);
                } else {
                    LOGGER.debug("HTTP Cache hit!");
                }
            }
        } catch (IOException e) {
            throw new NotFoundException(e);
        }
        LOGGER.debug("DONE getManifest() for " + identifier);

        if (manifest == null) {
            throw new NotFoundException("No manifest for identifier: " + identifier);
        }

        return manifest;
    }

    private PresentationResolver getManifestResolver(String identifier) throws NotFoundException {
        for (PresentationResolver resolver : resolvers) {
            if (resolver.isResolvable(identifier)) {
                String msg = identifier + " resolved with this resolver: " + resolver.getClass().getSimpleName();
                LOGGER.debug(msg);
                return resolver;
            }
        }
        String msg = "No resolver found for identifier '" + identifier + "'";
        throw new NotFoundException(msg);
    }

    private String getCacheKey(String identifier) {
        return String.format("iiif.manifest.%s", identifier);
    }
}