org.roda.core.common.RodaURIFileResolver.java Source code

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Here is the source code for org.roda.core.common.RodaURIFileResolver.java

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/**
 * The contents of this file are subject to the license and copyright
 * detailed in the LICENSE file at the root of the source
 * tree and available online at
 *
 * https://github.com/keeps/roda
 */
package org.roda.core.common;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;

import javax.xml.transform.Source;
import javax.xml.transform.TransformerException;
import javax.xml.transform.URIResolver;
import javax.xml.transform.stream.StreamSource;

import org.apache.commons.io.IOUtils;
import org.roda.core.RodaCoreFactory;
import org.roda.core.data.common.RodaConstants;
import org.roda.core.data.exceptions.NotFoundException;

import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;

public class RodaURIFileResolver implements URIResolver {

    private static CacheLoader<String, byte[]> loader = new CacheLoader<String, byte[]>() {

        @Override
        public byte[] load(String href) throws Exception {
            String filePath = RodaConstants.CROSSWALKS_DISSEMINATION_OTHER_PATH + href;

            try (InputStream in = RodaCoreFactory.getConfigurationFileAsStream(filePath);
                    ByteArrayOutputStream out = new ByteArrayOutputStream()) {
                if (in == null) {
                    throw new NotFoundException(filePath);
                }

                IOUtils.copy(in, out);
                return out.toByteArray();
            }
        }

    };
    private static LoadingCache<String, byte[]> cache = CacheBuilder.newBuilder()
            .expireAfterWrite(1, TimeUnit.MINUTES).build(loader);

    @Override
    public Source resolve(String href, String base) throws TransformerException {
        try {
            byte[] in = cache.get(href);
            return new StreamSource(new ByteArrayInputStream(in));
        } catch (ExecutionException e) {
            throw new TransformerException("Could not load URI: " + href, e);
        }
    }
}