1/*
2 * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24import javax.tools.JavaCompiler;
25import javax.tools.StandardJavaFileManager;
26import javax.tools.StandardLocation;
27import javax.tools.ToolProvider;
28import java.io.IOException;
29import java.nio.file.Files;
30import java.nio.file.Path;
31import java.util.Arrays;
32import java.util.Collections;
33import java.util.List;
34import java.util.stream.Collectors;
35
36/**
37 * This class consists exclusively of static utility methods for invoking the
38 * java compiler.
39 */
40
41public final class CompilerUtils {
42    private CompilerUtils() { }
43
44    /**
45     * Compile all the java sources in {@code <source>/**} to
46     * {@code <destination>/**}. The destination directory will be created if
47     * it doesn't exist.
48     *
49     * All warnings/errors emitted by the compiler are output to System.out/err.
50     *
51     * @return true if the compilation is successful
52     *
53     * @throws IOException
54     *         if there is an I/O error scanning the source tree or
55     *         creating the destination directory
56     * @throws UnsupportedOperationException
57     *         if there is no system java compiler
58     */
59    public static boolean compile(Path source, Path destination, String ... options)
60        throws IOException
61    {
62        JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
63        if (compiler == null) {
64            // no compiler available
65            throw new UnsupportedOperationException("Unable to get system java compiler. " +
66                "Perhaps, jdk.compiler module is not available.");
67        }
68        StandardJavaFileManager jfm = compiler.getStandardFileManager(null, null, null);
69
70        List<Path> sources
71            = Files.find(source, Integer.MAX_VALUE,
72                (file, attrs) -> (file.toString().endsWith(".java")))
73                .collect(Collectors.toList());
74
75        Files.createDirectories(destination);
76        jfm.setLocation(StandardLocation.CLASS_PATH, Collections.EMPTY_LIST);
77        jfm.setLocationFromPaths(StandardLocation.CLASS_OUTPUT,
78                                 Arrays.asList(destination));
79
80        List<String> opts = Arrays.asList(options);
81        JavaCompiler.CompilationTask task
82            = compiler.getTask(null, jfm, null, opts, null,
83                jfm.getJavaFileObjectsFromPaths(sources));
84
85        return task.call();
86    }
87}
88