Java tutorial
/** * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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 org.apache.camel.processor.aggregate.tarfile; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import org.apache.camel.Exchange; import org.apache.camel.component.file.FileConsumer; import org.apache.camel.component.file.GenericFile; import org.apache.camel.component.file.GenericFileMessage; import org.apache.camel.component.file.GenericFileOperationFailedException; import org.apache.camel.processor.aggregate.AggregationStrategy; import org.apache.camel.spi.Synchronization; import org.apache.camel.util.FileUtil; import org.apache.camel.util.IOHelper; import org.apache.commons.compress.archivers.ArchiveEntry; import org.apache.commons.compress.archivers.ArchiveException; import org.apache.commons.compress.archivers.ArchiveStreamFactory; import org.apache.commons.compress.archivers.tar.TarArchiveEntry; import org.apache.commons.compress.archivers.tar.TarArchiveInputStream; import org.apache.commons.compress.archivers.tar.TarArchiveOutputStream; import org.apache.commons.compress.utils.IOUtils; /** * This aggregation strategy will aggregate all incoming messages into a TAR file. * <p>If the incoming exchanges contain {@link GenericFileMessage} file name will * be taken from the body otherwise the body content will be treated as a byte * array and the TAR entry will be named using the message id (unless the flag * useFilenameHeader is set to true.</p> * <p><b>Note:</b> Please note that this aggregation strategy requires eager * completion check to work properly.</p> * * TODO This implementation is very inefficient especially on big files since the tar * file is completely rewritten for each file that is added to it. Investigate if the * files can be collected and at completion stored to tar file. */ public class TarAggregationStrategy implements AggregationStrategy { private String filePrefix; private String fileSuffix = ".tar"; private boolean preserveFolderStructure; private boolean useFilenameHeader; public TarAggregationStrategy() { this(false, false); } /** * @param preserveFolderStructure if true, the folder structure is preserved when the source is * a type of {@link GenericFileMessage}. If used with a file, use recursive=true. */ public TarAggregationStrategy(boolean preserveFolderStructure) { this(preserveFolderStructure, false); } /** * @param preserveFolderStructure if true, the folder structure is preserved when the source is * a type of {@link GenericFileMessage}. If used with a file, use recursive=true. * @param useFilenameHeader if true, the filename header will be used to name aggregated byte arrays * within the TAR file. */ public TarAggregationStrategy(boolean preserveFolderStructure, boolean useFilenameHeader) { this.preserveFolderStructure = preserveFolderStructure; this.useFilenameHeader = useFilenameHeader; } /** * Gets the prefix used when creating the TAR file name. * @return the prefix */ public String getFilePrefix() { return filePrefix; } /** * Sets the prefix that will be used when creating the TAR filename. * @param filePrefix prefix to use on TAR file. */ public void setFilePrefix(String filePrefix) { this.filePrefix = filePrefix; } /** * Gets the suffix used when creating the TAR file name. * @return the suffix */ public String getFileSuffix() { return fileSuffix; } /** * Sets the suffix that will be used when creating the ZIP filename. * @param fileSuffix suffix to use on ZIP file. */ public void setFileSuffix(String fileSuffix) { this.fileSuffix = fileSuffix; } @Override public Exchange aggregate(Exchange oldExchange, Exchange newExchange) { File tarFile; Exchange answer = oldExchange; // Guard against empty new exchanges if (newExchange == null) { return oldExchange; } // First time for this aggregation if (oldExchange == null) { try { tarFile = FileUtil.createTempFile(this.filePrefix, this.fileSuffix, new File(System.getProperty("java.io.tmpdir"))); } catch (IOException e) { throw new GenericFileOperationFailedException(e.getMessage(), e); } answer = newExchange; answer.addOnCompletion(new DeleteTarFileOnCompletion(tarFile)); } else { tarFile = oldExchange.getIn().getBody(File.class); } // Handle GenericFileMessages if (GenericFileMessage.class.isAssignableFrom(newExchange.getIn().getClass())) { try { File appendFile = newExchange.getIn().getMandatoryBody(File.class); if (appendFile != null) { addFileToTar(tarFile, appendFile, this.preserveFolderStructure ? newExchange.getIn().toString() : null); GenericFile<File> genericFile = FileConsumer.asGenericFile(tarFile.getParent(), tarFile, null); // Do not set charset here, that will cause the tar file to be handled as ASCII later which breaks it.. genericFile.bindToExchange(answer); } } catch (Exception e) { throw new GenericFileOperationFailedException(e.getMessage(), e); } } else { // Handle all other messages try { byte[] buffer = newExchange.getIn().getMandatoryBody(byte[].class); String entryName = useFilenameHeader ? newExchange.getIn().getHeader(Exchange.FILE_NAME, String.class) : newExchange.getIn().getMessageId(); addEntryToTar(tarFile, entryName, buffer, buffer.length); GenericFile<File> genericFile = FileConsumer.asGenericFile(tarFile.getParent(), tarFile, null); genericFile.bindToExchange(answer); } catch (Exception e) { throw new GenericFileOperationFailedException(e.getMessage(), e); } } return answer; } private static void addFileToTar(File source, File file, String fileName) throws IOException, ArchiveException { File tmpTar = File.createTempFile(source.getName(), null); tmpTar.delete(); if (!source.renameTo(tmpTar)) { throw new IOException("Could not make temp file (" + source.getName() + ")"); } TarArchiveInputStream tin = (TarArchiveInputStream) new ArchiveStreamFactory() .createArchiveInputStream(ArchiveStreamFactory.TAR, new FileInputStream(tmpTar)); TarArchiveOutputStream tos = new TarArchiveOutputStream(new FileOutputStream(source)); tos.setLongFileMode(TarArchiveOutputStream.LONGFILE_POSIX); tos.setBigNumberMode(TarArchiveOutputStream.BIGNUMBER_POSIX); InputStream in = new FileInputStream(file); // copy the existing entries ArchiveEntry nextEntry; while ((nextEntry = tin.getNextEntry()) != null) { tos.putArchiveEntry(nextEntry); IOUtils.copy(tin, tos); tos.closeArchiveEntry(); } // Add the new entry TarArchiveEntry entry = new TarArchiveEntry(fileName == null ? file.getName() : fileName); entry.setSize(file.length()); tos.putArchiveEntry(entry); IOUtils.copy(in, tos); tos.closeArchiveEntry(); IOHelper.close(in); IOHelper.close(tin); IOHelper.close(tos); } private static void addEntryToTar(File source, String entryName, byte[] buffer, int length) throws IOException, ArchiveException { File tmpTar = File.createTempFile(source.getName(), null); tmpTar.delete(); if (!source.renameTo(tmpTar)) { throw new IOException("Cannot create temp file: " + source.getName()); } TarArchiveInputStream tin = (TarArchiveInputStream) new ArchiveStreamFactory() .createArchiveInputStream(ArchiveStreamFactory.TAR, new FileInputStream(tmpTar)); TarArchiveOutputStream tos = new TarArchiveOutputStream(new FileOutputStream(source)); tos.setLongFileMode(TarArchiveOutputStream.LONGFILE_POSIX); tos.setBigNumberMode(TarArchiveOutputStream.BIGNUMBER_POSIX); // copy the existing entries ArchiveEntry nextEntry; while ((nextEntry = tin.getNextEntry()) != null) { tos.putArchiveEntry(nextEntry); IOUtils.copy(tin, tos); tos.closeArchiveEntry(); } // Create new entry TarArchiveEntry entry = new TarArchiveEntry(entryName); entry.setSize(length); tos.putArchiveEntry(entry); tos.write(buffer, 0, length); tos.closeArchiveEntry(); IOHelper.close(tin); IOHelper.close(tos); } /** * This callback class is used to clean up the temporary TAR file once the exchange has completed. */ private class DeleteTarFileOnCompletion implements Synchronization { private final File fileToDelete; public DeleteTarFileOnCompletion(File fileToDelete) { this.fileToDelete = fileToDelete; } @Override public void onFailure(Exchange exchange) { // Keep the file if something gone a miss. } @Override public void onComplete(Exchange exchange) { FileUtil.deleteFile(this.fileToDelete); } } }