DirectoryCrawler.java
/* Copyright 2002-2022 CS GROUP
* Licensed to CS GROUP (CS) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* CS 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.orekit.data;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.text.ParseException;
import java.util.Arrays;
import java.util.regex.Pattern;
import org.hipparchus.exception.DummyLocalizable;
import org.orekit.errors.OrekitException;
import org.orekit.errors.OrekitMessages;
/** Provider for data files stored in a directories tree on filesystem.
* <p>
* This class handles data files recursively starting from a root directories
* tree. The organization of files in the directories is free. There may be
* sub-directories to any level. All sub-directories are browsed and all terminal
* files are checked for loading.
* </p>
* <p>
* All {@link FiltersManager#addFilter(DataFilter) registered}
* {@link DataFilter filters} are applied.
* </p>
* <p>
* Zip archives entries are supported recursively.
* </p>
* <p>
* This is a simple application of the <code>visitor</code> design pattern for
* directory hierarchy crawling.
* </p>
* @see DataProvidersManager
* @author Luc Maisonobe
*/
public class DirectoryCrawler implements DataProvider {
/** Root directory. */
private final File root;
/** Build a data files crawler.
* @param root root of the directories tree (must be a directory)
*/
public DirectoryCrawler(final File root) {
if (!root.isDirectory()) {
throw new OrekitException(OrekitMessages.NOT_A_DIRECTORY, root.getAbsolutePath());
}
this.root = root;
}
/** {@inheritDoc} */
public boolean feed(final Pattern supported,
final DataLoader visitor,
final DataProvidersManager manager) {
try {
return feed(supported, visitor, manager, root);
} catch (IOException | ParseException ioe) {
throw new OrekitException(ioe, new DummyLocalizable(ioe.getMessage()));
}
}
/** Feed a data file loader by browsing a directory hierarchy.
* @param supported pattern for file names supported by the visitor
* @param visitor data file visitor to feed
* @param manager with the filters to apply.
* @param directory current directory
* @return true if something has been loaded
* @exception IOException if data cannot be read
* @exception ParseException if data cannot be read
*/
private boolean feed(final Pattern supported,
final DataLoader visitor,
final DataProvidersManager manager,
final File directory)
throws IOException, ParseException {
// search in current directory
final File[] list = directory.listFiles();
if (list == null) {
// notify about race condition if directory is removed by another program
throw new OrekitException(OrekitMessages.NOT_A_DIRECTORY, directory.getAbsolutePath());
}
Arrays.sort(list, File::compareTo);
OrekitException delayedException = null;
boolean loaded = false;
for (final File file : list) {
try {
if (visitor.stillAcceptsData()) {
if (file.isDirectory()) {
// recurse in the sub-directory
loaded = feed(supported, visitor, manager, file) || loaded;
} else if (ZIP_ARCHIVE_PATTERN.matcher(file.getName()).matches()) {
// browse inside the zip/jar file
final DataProvider zipProvider = new ZipJarCrawler(file);
loaded = zipProvider.feed(supported, visitor, manager) || loaded;
} else {
// apply all registered filters
DataSource data = new DataSource(file.getName(), () -> new FileInputStream(file));
data = manager.getFiltersManager().applyRelevantFilters(data);
if (supported.matcher(data.getName()).matches()) {
// visit the current file
try (InputStream input = data.getOpener().openStreamOnce()) {
visitor.loadData(input, file.getPath());
loaded = true;
}
}
}
}
} catch (OrekitException oe) {
delayedException = oe;
}
}
if (!loaded && delayedException != null) {
throw delayedException;
}
return loaded;
}
}