1/*
2 * Copyright (c) 2009, 2013, 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.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package sun.nio.fs;
27
28import java.util.*;
29import java.nio.file.*;
30import java.nio.charset.Charset;
31import sun.security.action.GetPropertyAction;
32
33/**
34 * Utility methods
35 */
36
37class Util {
38    private Util() { }
39
40    private static final Charset jnuEncoding = Charset.forName(
41        GetPropertyAction.privilegedGetProperty("sun.jnu.encoding"));
42
43    /**
44     * Returns {@code Charset} corresponding to the sun.jnu.encoding property
45     */
46    static Charset jnuEncoding() {
47        return jnuEncoding;
48    }
49
50    /**
51     * Encodes the given String into a sequence of bytes using the {@code Charset}
52     * specified by the sun.jnu.encoding property.
53     */
54    static byte[] toBytes(String s) {
55        return s.getBytes(jnuEncoding);
56    }
57
58    /**
59     * Constructs a new String by decoding the specified array of bytes using the
60     * {@code Charset} specified by the sun.jnu.encoding property.
61     */
62    static String toString(byte[] bytes) {
63        return new String(bytes, jnuEncoding);
64    }
65
66
67    /**
68     * Splits a string around the given character. The array returned by this
69     * method contains each substring that is terminated by the character. Use
70     * for simple string spilting cases when needing to avoid loading regex.
71     */
72    static String[] split(String s, char c) {
73        int count = 0;
74        for (int i=0; i<s.length(); i++) {
75            if (s.charAt(i) == c)
76                count++;
77        }
78        String[] result = new String[count+1];
79        int n = 0;
80        int last = 0;
81        for (int i=0; i<s.length(); i++) {
82            if (s.charAt(i) == c) {
83                result[n++] = s.substring(last, i);
84                last = i + 1;
85            }
86        }
87        result[n] = s.substring(last, s.length());
88        return result;
89    }
90
91    /**
92     * Returns a Set containing the given elements.
93     */
94    @SafeVarargs
95    static <E> Set<E> newSet(E... elements) {
96        HashSet<E> set = new HashSet<>();
97        for (E e: elements) {
98            set.add(e);
99        }
100        return set;
101    }
102
103    /**
104     * Returns a Set containing all the elements of the given Set plus
105     * the given elements.
106     */
107    @SafeVarargs
108    static <E> Set<E> newSet(Set<E> other, E... elements) {
109        HashSet<E> set = new HashSet<>(other);
110        for (E e: elements) {
111            set.add(e);
112        }
113        return set;
114    }
115
116    /**
117     * Returns {@code true} if symbolic links should be followed
118     */
119    static boolean followLinks(LinkOption... options) {
120        boolean followLinks = true;
121        for (LinkOption option: options) {
122            if (option == LinkOption.NOFOLLOW_LINKS) {
123                followLinks = false;
124            } else if (option == null) {
125                throw new NullPointerException();
126            } else {
127                throw new AssertionError("Should not get here");
128            }
129        }
130        return followLinks;
131    }
132}
133