com.kajj.tools.logviewer.LogRepository.java Source code

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Here is the source code for com.kajj.tools.logviewer.LogRepository.java

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/*
 * Copyright 2014 Andrew Tytula.
 *
 * 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.kajj.tools.logviewer;

import java.io.File;
import java.io.IOException;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;
import org.apache.commons.io.input.ReversedLinesFileReader;
import org.springframework.stereotype.Repository;

/**
 * A repository for retrieving logs from a file.
 *
 * @author Andrew Tytula
 */
@Repository
public class LogRepository {

    private static final File LOG_DIRECTORY = new File("../logs/");

    /**
     * Returns the last <code>numberOfLines</code> lines from the log file.
     *
     * @param fileName the name of the log file.
     * @param numberOfLines the number of lines to return.
     * @return The last <code>numberOfLines</code> lines in the log file.
     * @throws IOException if an I/O exception occurs reading the log file.
     */
    public List<String> getTailLog(final String fileName, final int numberOfLines) throws IOException {
        final File logFile = new File(LOG_DIRECTORY, fileName);
        final ReversedLinesFileReader reader = new ReversedLinesFileReader(logFile);
        final LinkedList<String> logs = new LinkedList<>();
        for (int i = 0; i < numberOfLines; i++) {
            final String line = reader.readLine();
            if (line == null) {
                break;
            }

            logs.addFirst(line);
        }

        return logs;
    }

    /**
     * Returns a list of file names that can be accessed by the repository.
     *
     * @return the list of file names
     */
    public List<String> getLogFileNames() {
        return Arrays.asList(LOG_DIRECTORY.list());
    }
}