io.telicent.smart.cache.sources.file.gzip.GZipEventReaderWriter Maven / Gradle / Ivy

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/**
 * Copyright (C) Telicent Ltd
 *
 * 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 io.telicent.smart.cache.sources.file.gzip;

import io.telicent.smart.cache.sources.Event;
import io.telicent.smart.cache.sources.file.FileEventAccessMode;
import io.telicent.smart.cache.sources.file.FileEventReaderWriter;

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

/**
 * A GZip decorator around an event reader/writer that compresses and decompresses the output with GZip
 *
 * @param    Key type
 * @param  Value type
 */
public class GZipEventReaderWriter implements FileEventReaderWriter {

    private final FileEventReaderWriter readerWriter;


    /**
     * Creates a new GZipped reader/writer
     *
     * @param readerWriter Underlying reader/writer
     */
    public GZipEventReaderWriter(FileEventReaderWriter readerWriter) {
        Objects.requireNonNull(readerWriter, "Event reader/writer cannot be null");
        this.readerWriter = readerWriter;
    }

    @Override
    public final Event read(File f) throws IOException {
        try (FileInputStream input = new FileInputStream(f)) {
            try (GZIPInputStream gzipInput = new GZIPInputStream(input)) {
                return read(gzipInput);
            }
        }
    }

    @Override
    public final Event read(InputStream input) throws IOException {
        if (!(input instanceof GZIPInputStream)) {
            input = new GZIPInputStream(input);
        }
        return this.readerWriter.read(input);
    }

    @Override
    public final void write(Event event, File f) throws IOException {
        try (FileOutputStream output = new FileOutputStream(f)) {
            try (GZIPOutputStream gzipOutput = new GZIPOutputStream(output)) {
                this.write(event, gzipOutput);
            }
        }
    }

    @Override
    public final void write(Event event, OutputStream output) throws IOException {
        if (!(output instanceof GZIPOutputStream)) {
            output = new GZIPOutputStream(output);
        }
        this.readerWriter.write(event, output);
    }

    @Override
    public FileEventAccessMode getMode() {
        return this.readerWriter.getMode();
    }
}