org.aesh.io.scanner.ZipFileIterator Maven / Gradle / Ivy
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* JBoss, Home of Professional Open Source
* Copyright 2014 Red Hat Inc. and/or its affiliates and other contributors
* as indicated by the @authors tag. All rights reserved.
* See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* 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.aesh.io.scanner;
import java.io.IOException;
import java.io.InputStream;
import java.util.Enumeration;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
/**
* {@code ZipFileIterator} is used to iterate over all entries in a given {@code zip} or
* {@code jar} file and returning the {@link InputStream} of these entries.
*
* It is possible to specify an (optional) entry name filter.
*
* The most efficient way of iterating is used, see benchmark in test classes.
* @author Ståle W. Pedersen
*
*/
final class ZipFileIterator {
private final ZipFile zipFile;
private final String[] entryNameFilter;
private final Enumeration entries;
private ZipEntry current;
/**
* Create a new {@code ZipFileIterator} instance.
*
* @param zipFile The ZIP file used to iterate over all entries
* @param entryNameFilter (optional) file name filter. Only entry names starting with
* one of the specified names in the filter are returned
*/
ZipFileIterator(final ZipFile zipFile, final String[] entryNameFilter) throws IOException {
this.zipFile = zipFile;
this.entryNameFilter = entryNameFilter;
this.entries = zipFile.entries();
}
public ZipEntry getEntry() {
return current;
}
@SuppressWarnings("emptyblock")
public InputStream next() throws IOException {
while (entries.hasMoreElements()) {
current = entries.nextElement();
if (accept(current)) {
return zipFile.getInputStream(current);
}
}
// no more entries in this ZipFile, so close ZipFile
try {
// zipFile is never null here
zipFile.close();
} catch (IOException ex) {
// suppress IOException, otherwise close() is called twice
}
return null;
}
private boolean accept(final ZipEntry entry) {
if (entry.isDirectory()) {
return false;
}
if (entryNameFilter == null) {
return true;
}
for (final String filter : entryNameFilter) {
if (entry.getName().startsWith(filter)) {
return true;
}
}
return false;
}
}