ch.ivyteam.ivy.maven.util.ClasspathJar.java Source code

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Here is the source code for ch.ivyteam.ivy.maven.util.ClasspathJar.java

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/*
 * Copyright (C) 2016 AXON IVY AG
 *
 * 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 ch.ivyteam.ivy.maven.util;

import java.io.EOFException;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.jar.Attributes;
import java.util.jar.Manifest;
import java.util.stream.Collectors;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
import java.util.zip.ZipOutputStream;

import org.apache.commons.lang3.StringUtils;

/**
 * Jar with only a Manifest.MF that defines the classpath.
 * 
 * @author Reguel Wermelinger
 * @since 6.0.2
 */
public class ClasspathJar {
    private static final String MANIFEST_MF = "META-INF/MANIFEST.MF";
    private final File jar;
    private String mainClass;

    public ClasspathJar(File jar) {
        this.jar = jar;
    }

    public void setMainClass(String fqClassName) {
        this.mainClass = fqClassName;
    }

    public void create(List<String> classpathEntries) throws IOException {
        jar.getParentFile().mkdir();
        try (ZipOutputStream zipStream = new ZipOutputStream(new FileOutputStream(jar))) {
            String name = StringUtils.substringBeforeLast(jar.getName(), ".");
            writeManifest(name, zipStream, classpathEntries);
        }
    }

    public void createFileEntries(Collection<File> classpathEntries) throws IOException {
        create(getClassPathUris(classpathEntries));
    }

    private void writeManifest(String name, ZipOutputStream jarStream, List<String> classpathEntries)
            throws IOException {
        Manifest manifest = new Manifest();
        manifest.getMainAttributes().put(Attributes.Name.MANIFEST_VERSION, "1.0");
        manifest.getMainAttributes().putValue("Name", name);
        if (mainClass != null) {
            manifest.getMainAttributes().put(Attributes.Name.MAIN_CLASS, mainClass);
        }
        if (!classpathEntries.isEmpty()) {
            manifest.getMainAttributes().put(Attributes.Name.CLASS_PATH, StringUtils.join(classpathEntries, " "));
        }
        jarStream.putNextEntry(new ZipEntry(MANIFEST_MF));
        manifest.write(jarStream);
    }

    private static List<String> getClassPathUris(Collection<File> classpathEntries) {
        return classpathEntries.stream().map(file -> file.toURI().toASCIIString()).collect(Collectors.toList());
    }

    public List<File> getFiles() {
        String urlClasspath = getClasspathUrlEntries();
        if (StringUtils.isBlank(urlClasspath)) {
            return Collections.emptyList();
        }

        List<File> files = new ArrayList<>();
        for (String entry : urlClasspath.split(" ")) {
            files.add(new File(uriToAbsoluteFilePath(entry)));
        }
        return files;
    }

    public String getClasspathFiles() {
        return StringUtils.join(getFiles(), ",");
    }

    private static String uriToAbsoluteFilePath(String entry) {
        try {
            return new URI(entry).getSchemeSpecificPart();
        } catch (URISyntaxException ex) {
            return entry;
        }
    }

    public String getClasspathUrlEntries() {
        try (ZipInputStream is = new ZipInputStream(new FileInputStream(jar))) {
            Manifest manifest = new Manifest(getInputStream(is, MANIFEST_MF));
            return manifest.getMainAttributes().getValue(Attributes.Name.CLASS_PATH);
        } catch (IOException ex) {
            return null;
        }
    }

    private static InputStream getInputStream(ZipInputStream zin, String entry) throws IOException {
        for (ZipEntry e; (e = zin.getNextEntry()) != null;) {
            if (e.getName().equals(entry)) {
                return zin;
            }
        }
        throw new EOFException("Cannot find " + entry);
    }
}