com.kolich.havalo.io.stores.MetaObjectStore.java Source code

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Here is the source code for com.kolich.havalo.io.stores.MetaObjectStore.java

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/**
 * Copyright (c) 2015 Mark S. Kolich
 * http://mark.koli.ch
 *
 * 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.kolich.havalo.io.stores;

import com.kolich.havalo.entities.StoreableEntity;
import com.kolich.havalo.exceptions.objects.ObjectFlushException;
import com.kolich.havalo.exceptions.objects.ObjectLoadException;
import com.kolich.havalo.io.MetaStore;

import java.io.*;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

import static com.kolich.common.DefaultCharacterEncoding.UTF_8;
import static java.util.zip.Deflater.BEST_COMPRESSION;
import static org.apache.commons.io.FileUtils.deleteQuietly;
import static org.apache.commons.io.IOUtils.closeQuietly;

public abstract class MetaObjectStore extends ObjectStore implements MetaStore {

    protected static final String JSON_EXTENSION = ".json";

    public MetaObjectStore(final File storeDir) {
        super(storeDir);
    }

    /**
     * The caller is most definitely responsible for closing the
     * returned {@link InputStream} when finished with it.
     * @param index
     * @return
     */
    @Override
    public InputStream getInputStream(final String index) {
        InputStream is = null;
        try {
            is = new GZIPInputStream(new FileInputStream(getCanonicalFile(index, false)));
        } catch (Exception e) {
            throw new ObjectLoadException("Failed to read entity: " + index, e);
        }
        return is;
    }

    @Override
    public void save(final StoreableEntity entity) {
        FileOutputStream fos = null;
        GZIPOutputStream gos = null;
        Writer writer = null;
        try {
            fos = new FileOutputStream(getCanonicalFile(entity));
            gos = new GZIPOutputStream(fos) {
                // Ugly anonymous constructor hack to set the compression
                // level on the underlying Deflater to "max compression".
                {
                    def.setLevel(BEST_COMPRESSION);
                }
            };
            writer = new OutputStreamWriter(gos, UTF_8);
            // Call the entity to write itself to the output stream.
            entity.toWriter(writer);
            writer.flush(); // Muy importante
            gos.finish(); // Muy importante mucho!
        } catch (Exception e) {
            throw new ObjectFlushException("Failed to save entity: " + entity.getKey(), e);
        } finally {
            closeQuietly(writer);
            closeQuietly(gos);
            closeQuietly(fos);
        }
    }

    @Override
    public void delete(final String index) {
        try {
            // Actually attempt to delete it, or report failure.
            if (!deleteQuietly(getCanonicalFile(index, false))) {
                throw new IOException("Deletion of index " + index + " failed.");
            }
        } catch (Exception e) {
            throw new ObjectFlushException("Failed to delete entity: " + index, e);
        }
    }

    private File getCanonicalFile(final StoreableEntity entity) {
        return getCanonicalFile(entity.getKey(), true);
    }

    private File getCanonicalFile(final String index, final boolean create) {
        return getCanonicalObject(storeDir_, index + JSON_EXTENSION, create).getFile();
    }

}