com.netflix.exhibitor.core.index.IndexMetaData.java Source code

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Here is the source code for com.netflix.exhibitor.core.index.IndexMetaData.java

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/*
 * Copyright 2012 Netflix, 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.netflix.exhibitor.core.index;

import com.google.common.io.Closeables;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.text.DateFormat;
import java.util.Date;
import java.util.Properties;

public class IndexMetaData {
    private final Date from;
    private final Date to;
    private final int entryCount;

    private static final String META_DATA_FILE_EXTENSION = ".properties";

    private static final int VERSION = 1;

    private static final String PROPERTY_FROM = "from";
    private static final String PROPERTY_TO = "to";
    private static final String PROPERTY_COUNT = "count";
    private static final String PROPERTY_VERSION = "version";

    public static boolean isValid(File indexDirectory) {
        return indexDirectory.exists() && indexDirectory.isDirectory();
    }

    public static File getMetaDataFile(File indexDirectory) {
        return new File(indexDirectory.getPath() + IndexMetaData.META_DATA_FILE_EXTENSION);
    }

    public static void write(IndexMetaData meta, File to) throws Exception {
        DateFormat format = DateFormat.getDateTimeInstance();

        Properties properties = new Properties();
        properties.setProperty(PROPERTY_FROM, format.format(meta.from));
        properties.setProperty(PROPERTY_TO, format.format(meta.to));
        properties.setProperty(PROPERTY_VERSION, Integer.toString(VERSION));
        properties.setProperty(PROPERTY_COUNT, Integer.toString(meta.entryCount));

        OutputStream out = new BufferedOutputStream(new FileOutputStream(to));
        try {
            properties.store(out, "Auto-generated by Exhibitor");
        } finally {
            Closeables.closeQuietly(out);
        }
    }

    public static IndexMetaData read(File from) throws Exception {
        DateFormat format = DateFormat.getDateTimeInstance();

        Properties properties = new Properties();
        InputStream in = new BufferedInputStream(new FileInputStream(from));
        try {
            properties.load(in);
        } finally {
            Closeables.closeQuietly(in);
        }

        String version = properties.getProperty(PROPERTY_VERSION, "0");
        if (!version.equals(Integer.toString(VERSION))) {
            throw new Exception("Unknown version: " + version);
        }

        return new IndexMetaData(format.parse(properties.getProperty(PROPERTY_FROM)),
                format.parse(properties.getProperty(PROPERTY_TO)),
                Integer.parseInt(properties.getProperty(PROPERTY_COUNT)));
    }

    public IndexMetaData(Date from, Date to, int entryCount) {
        this.from = from;
        this.to = to;
        this.entryCount = entryCount;
    }

    public Date getFrom() {
        return from;
    }

    public Date getTo() {
        return to;
    }

    public int getEntryCount() {
        return entryCount;
    }
}