io.github.ascopes.jct.workspaces.impl.JarFactoryImpl Maven / Gradle / Ivy
/*
* Copyright (C) 2022 - 2024, the original author or authors.
*
* 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 io.github.ascopes.jct.workspaces.impl;
import java.io.BufferedOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.jar.JarOutputStream;
import java.util.stream.Collectors;
import java.util.stream.StreamSupport;
import java.util.zip.ZipEntry;
/**
* A special singleton factory class that is used to create JAR files in memory on the fly.
*
* @author Ashley Scopes
* @since 0.3.0
*/
public final class JarFactoryImpl {
private static final JarFactoryImpl INSTANCE = new JarFactoryImpl();
/**
* Get an instance of this factory.
*
* @return the instance.
*/
public static JarFactoryImpl getInstance() {
return INSTANCE;
}
private JarFactoryImpl() {
// Do nothing.
}
/**
* Create a JAR in the given output file from everything recursively in the given source
* directory.
*
* This JAR will not be compressed in a special way.
*
* @param outputFile the output file to write to.
* @param sourceDirectory the source directory to read from recursively.
* @throws IOException if an IO exception occurs anywhere.
*/
public void createJarFrom(Path outputFile, Path sourceDirectory) throws IOException {
try (var outputStream = new BufferedOutputStream(Files.newOutputStream(outputFile))) {
createJarFrom(outputStream, sourceDirectory);
}
}
/**
* Create a JAR and stream it into the given output stream, using a given source directory.
*
*
This JAR will not be compressed in a special way.
*
* @param outputStream the output stream to write to.
* @param sourceDirectory the source directory to read from recursively.
* @throws IOException if an IO exception occurs anywhere.
*/
public void createJarFrom(OutputStream outputStream, Path sourceDirectory) throws IOException {
try (var jarStream = new JarOutputStream(outputStream)) {
Files.walkFileTree(sourceDirectory, new SimpleFileVisitor<>() {
@Override
public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
// File names should be forward-slash delimited in ZIP files.
var fileName = StreamSupport
.stream(sourceDirectory.relativize(file).spliterator(), false)
.map(Path::getFileName)
.map(Path::toString)
.collect(Collectors.joining("/"));
jarStream.putNextEntry(new ZipEntry(fileName));
jarStream.write(Files.readAllBytes(file));
jarStream.closeEntry();
return FileVisitResult.CONTINUE;
}
});
jarStream.finish();
}
}
}