org.eclipse.gyrex.logback.config.internal.LogbackConfigGenerator.java Source code

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Here is the source code for org.eclipse.gyrex.logback.config.internal.LogbackConfigGenerator.java

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/**
 * Copyright (c) 2012 Gunnar Wagenknecht and others.
 * All rights reserved.
 *
 * This program and the accompanying materials are made available under the terms of the
 * Eclipse Public License v1.0 which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Gunnar Wagenknecht - initial API and implementation
 */
package org.eclipse.gyrex.logback.config.internal;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Arrays;
import java.util.Comparator;

import javax.xml.stream.XMLOutputFactory;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamWriter;

import org.eclipse.gyrex.logback.config.model.LogbackConfig;

import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;
import org.apache.commons.lang.CharEncoding;
import org.apache.commons.lang.exception.ExceptionUtils;
import org.apache.commons.lang.time.DateFormatUtils;

/**
 * Generated a Logback configuration file based on snippets.
 */
public class LogbackConfigGenerator {

    private final long lastModified;
    private final File parentFolder;
    private final LogbackConfig config;

    public LogbackConfigGenerator(final long lastModified, final File parentFolder, final LogbackConfig config) {
        this.lastModified = lastModified;
        this.parentFolder = parentFolder;
        this.config = config;
    }

    public File generateConfig() {
        // get state location
        if (!parentFolder.isDirectory() && !parentFolder.mkdirs()) {
            throw new IllegalStateException(
                    String.format("Unable to create configs directory (%s).", parentFolder));
        }

        // save file
        final File configFile = new File(parentFolder,
                String.format("logback.%s.xml", DateFormatUtils.format(lastModified, "yyyyMMdd-HHmmssSSS")));
        OutputStream outputStream = null;
        XMLStreamWriter xmlStreamWriter = null;
        try {
            outputStream = new BufferedOutputStream(FileUtils.openOutputStream(configFile));
            final XMLOutputFactory outputFactory = XMLOutputFactory.newInstance();
            xmlStreamWriter = outputFactory.createXMLStreamWriter(outputStream, CharEncoding.UTF_8);
            // try to format the output
            try {
                final Class<?> clazz = getClass().getClassLoader()
                        .loadClass("com.sun.xml.internal.txw2.output.IndentingXMLStreamWriter");
                xmlStreamWriter = (XMLStreamWriter) clazz.getConstructor(XMLStreamWriter.class)
                        .newInstance(xmlStreamWriter);
            } catch (final Exception e) {
                // ignore
            }
            config.toXml(xmlStreamWriter);
            xmlStreamWriter.flush();
        } catch (final IOException e) {
            throw new IllegalStateException(
                    String.format("Unable to create config file (%s).", ExceptionUtils.getRootCauseMessage(e)), e);
        } catch (final XMLStreamException e) {
            throw new IllegalStateException(
                    String.format("Error writing config (%s).", ExceptionUtils.getRootCauseMessage(e)), e);
        } finally {
            if (null != xmlStreamWriter) {
                try {
                    xmlStreamWriter.close();
                } catch (final Exception e) {
                    // ignore
                }
            }
            IOUtils.closeQuietly(outputStream);
        }

        // cleanup directory
        removeOldFiles(parentFolder);

        return configFile;
    }

    private void removeOldFiles(final File parentFolder) {
        // only keep last 5 files
        File[] files = parentFolder.listFiles();
        if (null != files) {
            // remove any directories
            for (final File file : files) {
                if (file.isDirectory()) {
                    FileUtils.deleteQuietly(file);
                }
            }

            // refresh
            files = parentFolder.listFiles();

            // remove old files
            if ((null != files) && (files.length > 5)) {
                // sort based on file name (reverse order)
                Arrays.sort(files, new Comparator<File>() {
                    @Override
                    public int compare(final File o1, final File o2) {
                        return o2.getName().compareTo(o1.getName());
                    }
                });

                for (int i = 5; i < files.length; i++) {
                    FileUtils.deleteQuietly(files[i]);
                }
            }
        }
    }

}