com.esri.geoportal.harvester.sink.SinkFile.java Source code

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Here is the source code for com.esri.geoportal.harvester.sink.SinkFile.java

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/*
 * Copyright 2016 Esri, Inc.
 *
 * 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.esri.geoportal.harvester.sink;

import com.esri.geoportal.harvester.api.base.SimpleDataReference;
import com.esri.geoportal.commons.constants.MimeType;
import com.esri.geoportal.commons.constants.MimeTypeUtils;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.URISyntaxException;
import java.nio.file.FileSystemException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Date;
import org.apache.commons.io.IOUtils;

/**
 * Sink file.
 */
/*package*/ class SinkFile {
    private final SinkContext ctx;
    private final SinkBroker broker;
    private final Path file;

    /**
     * Creates instance of Sink file.
     * @param broker broker
     * @param file file
     */
    public SinkFile(SinkContext ctx, SinkBroker broker, Path file) {
        this.ctx = ctx;
        this.broker = broker;
        this.file = file;
    }

    /**
     * Reads content.
     * @return content reference
     * @throws IOException if reading content fails
     * @throws URISyntaxException if file url is an invalid URI
     */
    public SimpleDataReference readContent() throws IOException, URISyntaxException {
        Date lastModifiedDate = readLastModifiedDate();
        MimeType contentType = readContentType();
        try (InputStream input = attemptToOpenStream(ctx.attemptCount, ctx.attemptDelay);) {
            SimpleDataReference ref = new SimpleDataReference(broker.getBrokerUri(),
                    broker.getEntityDefinition().getLabel(), file.toAbsolutePath().toString(), lastModifiedDate,
                    file.toUri(), broker.td.getSource().getRef(), broker.td.getRef());
            ref.addContext(contentType, IOUtils.toByteArray(input));
            return ref;
        } finally {
            // once file is read, delete it
            attemptToDeleteFile(ctx.attemptCount, ctx.attemptDelay);
        }
    }

    /**
     * Attempts to open a file
     * @param attempts number of attempts
     * @param mills delay between consecutive attempts
     * @return input stream
     * @throws IOException if all attempts fail
     */
    private InputStream attemptToOpenStream(int attempts, long mills) throws IOException {
        while (true) {
            attempts--;
            try {
                // it should be open at the first attempt
                return new FileInputStream(file.toFile());
            } catch (FileNotFoundException ex) {
                // if not check if maximum number of attempts has been exhausted...
                if (attempts <= 0) {
                    // ...then throw exceptiion
                    throw ex;
                }
                // otherwise wait and try again latter
                try {
                    Thread.sleep(mills);
                } catch (InterruptedException e) {
                    // ignore
                }
            }
        }
    }

    /**
     * Attempts to delete file
     * @param attempts number of attempts
     * @param mills delay between consecutive attempts
     * @throws IOException if all attempts fail
     */
    private void attemptToDeleteFile(int attempts, long mills) throws IOException {
        while (true) {
            attempts--;
            try {
                Files.delete(file);
                return;
            } catch (FileSystemException ex) {
                // if not check if maximum number of attempts has been exhausted...
                if (attempts <= 0) {
                    // ...then throw exceptiion
                    throw ex;
                }
                // otherwise wait and try again latter
                try {
                    Thread.sleep(mills);
                } catch (InterruptedException e) {
                    // ignore
                }
            }
        }
    }

    /**
     * Reads last modified date.
     * @return last modified date
     */
    private Date readLastModifiedDate() throws IOException {
        return new Date(Files.getLastModifiedTime(file).toMillis());
    }

    /**
     * Reads content type.
     * @return content type or <code>null</code> if unable to read content type
     */
    private MimeType readContentType() {
        try {
            String strFileUrl = file.toAbsolutePath().toString();
            int lastDotIndex = strFileUrl.lastIndexOf(".");
            String ext = lastDotIndex >= 0 ? strFileUrl.substring(lastDotIndex + 1) : "";
            return MimeTypeUtils.mapExtension(ext);
        } catch (Exception ex) {
            return null;
        }
    }

    @Override
    public String toString() {
        return file.toString();
    }
}