com.sazneo.export.file.FileProcessor.java Source code

Introduction

Here is the source code for com.sazneo.export.file.FileProcessor.java

Source

/*
 * Copyright 2012 Sazneo.
 *
 * 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.sazneo.export.file;

import com.sazneo.export.file.util.Encoding;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import java.io.*;
import java.text.MessageFormat;

/**
 * @author Jamie Atkinson
 */
public class FileProcessor {

    Log logger = LogFactory.getLog(FileProcessor.class);

    private File exportFile = null;
    private File outputDir = null;

    //----------------------------------------------------------------------------------------------- Constructors

    /**
     * Hide default constructor
     */
    private FileProcessor() {
        super();
    }

    /**
     * Initialise a new <code>FileProcessor</code> object
     * @param exportFile <code>File</code> referencing the exported XML file from Sazneo
     * @param outputDir <code>File</code> referencing the output dir to export files to
     */
    public FileProcessor(File exportFile, File outputDir) {
        logger.debug(MessageFormat.format("Exporting files from: {0}", exportFile.getAbsolutePath()));
        this.exportFile = exportFile;
        logger.debug(MessageFormat.format("Setting output dir to: {0}", outputDir.getAbsolutePath()));
        this.outputDir = outputDir;
    }

    //----------------------------------------------------------------------------------------------- Public Methods

    /**
     * Process the XML file
     */
    public void process() {
        try {
            Reader reader = new FileReader(exportFile);
            XMLInputFactory xmlFactory = XMLInputFactory.newInstance();
            XMLStreamReader xmlStreamReader = xmlFactory.createXMLStreamReader(reader);
            boolean fileTag = false;
            String fileName = null;
            Integer fileSize = null;
            while (xmlStreamReader.hasNext()) {
                xmlStreamReader.next();

                if (xmlStreamReader.getEventType() == XMLStreamReader.START_ELEMENT) {
                    if ("file".equals(xmlStreamReader.getLocalName())) {
                        fileTag = true;
                        fileName = MessageFormat.format("{0}_{1}", xmlStreamReader.getAttributeValue(null, "id"),
                                xmlStreamReader.getAttributeValue(null, "filename"));
                        fileSize = Integer.parseInt(xmlStreamReader.getAttributeValue(null, "size"));
                        logger.debug(MessageFormat.format("XML contains file with name: {0} and size {1} bytes",
                                fileName, fileSize));
                    }
                }

                if (fileTag) {
                    if (xmlStreamReader.getEventType() == XMLStreamReader.CHARACTERS) {
                        exportFile(xmlStreamReader.getText(), fileName, fileSize);
                    }

                    if (xmlStreamReader.getEventType() == XMLStreamReader.END_ELEMENT) {
                        fileSize = null;
                        fileName = null;
                        fileTag = false;
                    }
                }
            }
        } catch (FileNotFoundException e) {
            logger.error(MessageFormat.format("Could not find export file:-\n{0}", e));
        } catch (XMLStreamException e) {
            logger.error(MessageFormat.format("Could not parse xml export file:-\n{0}", e));
        }
    }

    /**
     * Decodes the file content from the export XML and then saves it to the output directory
     * @param encodedContent Base64 encoded text
     * @param fileName The name of the file to create
     * @param fileSize The size of the file as reported in the export XML
     */
    private void exportFile(String encodedContent, String fileName, Integer fileSize) {
        try {
            File file = new File(outputDir.getAbsolutePath(), fileName);
            byte[] decoded = Encoding.decode(encodedContent).getBytes();
            logger.info(MessageFormat.format("Writing file: {0}", fileName));
            FileOutputStream fileOutputStream = new FileOutputStream(file);
            fileOutputStream.write(decoded);
            assert (decoded.length == file.length() && fileSize == decoded.length);
        } catch (IOException e) {
            logger.error(MessageFormat.format("Error writing file: {0}:-\n{1}", fileName, e));
        }
    }
}