/*
* ModeShape (http://www.modeshape.org)
*
* 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 org.modeshape.jcr;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.zip.GZIPInputStream;
import org.infinispan.schematic.document.Document;
import org.infinispan.schematic.document.DocumentSequence;
import org.infinispan.schematic.document.Json;
import org.modeshape.common.annotation.NotThreadSafe;
import org.modeshape.common.collection.Problems;
import org.modeshape.common.util.CheckArg;
import org.modeshape.common.util.StringUtil;
/**
* A utility that writes {@link Document} instances to one or more sequential files in a backup directory.
*/
@NotThreadSafe
public final class BackupDocumentReader {
public static final String GZIP_EXTENSION = BackupDocumentWriter.GZIP_EXTENSION;
public static final String DOCUMENTS_EXTENSION = BackupDocumentWriter.DOCUMENTS_EXTENSION;
private final File parentDirectory;
private final String filenamePrefix;
private final Problems problems;
protected InputStream stream;
protected DocumentSequence documents;
protected long fileCount = 0L;
private File currentFile;
public BackupDocumentReader( File parentDirectory,
String filenamePrefix,
Problems problems ) {
CheckArg.isNotNull(parentDirectory, "parentDirectory");
CheckArg.isNotEmpty(filenamePrefix, "filenamePrefix");
this.parentDirectory = parentDirectory;
this.filenamePrefix = filenamePrefix;
this.problems = problems;
}
/**
* Read the next document from the files.
*
* @return the document, or null if there are no more documents
*/
public Document read() {
try {
do {
if (stream == null) {
// Open the stream to the next file ...
stream = openNextFile();
if (stream == null) {
// No more files to read ...
return null;
}
documents = Json.readMultiple(stream);
}
try {
Document doc = documents.nextDocument();
if (doc != null) return doc;
} catch (IOException e) {
// We'll just continue ...
}
// Close the stream and try opening the next stream ...
close(stream);
stream = null;
} while (true);
} catch (IOException e) {
problems.addError(JcrI18n.problemsWritingDocumentToBackup, currentFile.getAbsolutePath(), e.getMessage());
return null;
}
}
protected InputStream openNextFile() throws IOException {
// Open the stream to the next file ...
++fileCount;
String suffix = StringUtil.justifyRight(Long.toString(fileCount), BackupService.NUM_CHARS_IN_FILENAME_SUFFIX, '0');
String filename = filenamePrefix + "_" + suffix + DOCUMENTS_EXTENSION + GZIP_EXTENSION;
currentFile = new File(parentDirectory, filename);
boolean compressed = true;
if (!currentFile.exists()) {
// Try the uncompressed form ...
filename = filenamePrefix + "_" + suffix + DOCUMENTS_EXTENSION;
currentFile = new File(parentDirectory, filename);
if (!currentFile.exists()) return null;
compressed = false;
}
if (!currentFile.canRead() || !currentFile.isFile()) return null;
InputStream fileStream = new FileInputStream(currentFile);
if (compressed) fileStream = new GZIPInputStream(fileStream);
return new BufferedInputStream(fileStream);
}
protected void close( InputStream stream ) {
if (stream != null) {
try {
stream.close();
} catch (IOException e) {
problems.addError(JcrI18n.problemsClosingBackupFiles, parentDirectory.getAbsolutePath(), e.getMessage());
} finally {
stream = null;
}
}
}
/**
* Close this writer, which flushes and closes any currently-open streams. Even after this is called, additional documents can
* be written to additional files.
*/
public void close() {
close(stream);
}
}