Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
SequenceBuilder |
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| 0.0;0 |
1 | /* | |
2 | * Copyright 2007 Sun Microsystems, Inc. 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. Sun designates this | |
8 | * particular file as subject to the "Classpath" exception as provided | |
9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
22 | * CA 95054 USA or visit www.sun.com if you need additional information or | |
23 | * have any questions. | |
24 | */ | |
25 | ||
26 | package com.sun.javafx.runtime.sequence; | |
27 | ||
28 | import com.sun.javafx.runtime.Util; | |
29 | ||
30 | /** | |
31 | * Helper classes for building sequences, much like StringBuilder assists in building Strings. SequenceBuilder | |
32 | * stores the sequence building built in an array, which is automatically resized as needed. It can be converted | |
33 | * to a Sequence by calling toSequence(). | |
34 | * | |
35 | * @author Brian Goetz | |
36 | */ | |
37 | public class SequenceBuilder<T> { | |
38 | private final static int DEFAULT_SIZE = 16; | |
39 | ||
40 | private final Class clazz; | |
41 | private T[] array; | |
42 | private int size; | |
43 | ||
44 | /** Create a SequenceBuilder for a Sequence of type T */ | |
45 | public SequenceBuilder(Class clazz) { | |
46 | 2901 | this(clazz, DEFAULT_SIZE); |
47 | 2901 | } |
48 | ||
49 | /** Create a SequenceBuilder for a Sequence of type T, ensuring that there is initially room for at least | |
50 | * initialSize elements. */ | |
51 | 4378 | public SequenceBuilder(Class clazz, int initialSize) { |
52 | 4378 | this.clazz = clazz; |
53 | 4378 | array = Util.<T>newObjectArray(Util.powerOfTwo(1, initialSize)); |
54 | 4378 | } |
55 | ||
56 | private void ensureSize(int newSize) { | |
57 | 13131 | if (array.length < newSize) { |
58 | 171 | int newCapacity = Util.powerOfTwo(array.length, newSize); |
59 | 171 | T[] newArray = Util.<T>newObjectArray(newCapacity); |
60 | 171 | System.arraycopy(array, 0, newArray, 0, size); |
61 | 171 | array = newArray; |
62 | } | |
63 | 13131 | } |
64 | ||
65 | /** Add a single element to the sequence */ | |
66 | public void add(T element) { | |
67 | 11092 | if (element != null) { |
68 | 11090 | ensureSize(size + 1); |
69 | 11090 | array[size++] = element; |
70 | } | |
71 | 11092 | } |
72 | ||
73 | /** Add the contents of an existing sequence to the sequence */ | |
74 | public void add(Sequence<? extends T> elements) { | |
75 | 2041 | ensureSize(size + elements.size()); |
76 | 2041 | elements.toArray(array, size); |
77 | 2041 | size += elements.size(); |
78 | 2041 | } |
79 | ||
80 | /** Get the current size of the sequence being constructed */ | |
81 | public int size() { | |
82 | 0 | return size; |
83 | } | |
84 | ||
85 | /** Get the nth element of the sequence being constructed, returning the null sequence value if n is out of range */ | |
86 | public T get(int n) { | |
87 | 0 | if (n < 0 || n >= size) |
88 | 0 | throw new IndexOutOfBoundsException(Integer.toString(n)); |
89 | else | |
90 | 0 | return array[n]; |
91 | } | |
92 | ||
93 | /** Erase the current contents of the SequenceBuilder */ | |
94 | public void clear() { | |
95 | 0 | array = Util.<T>newObjectArray(Util.powerOfTwo(1, DEFAULT_SIZE)); |
96 | 0 | size = 0; |
97 | 0 | } |
98 | ||
99 | /** Convert the SequenceBuilder to a Sequence. The elements will be copied to a new sequence, and will remain | |
100 | * in the SequenceBuilder, so it can continue to be used to make more sequences */ | |
101 | public Sequence<T> toSequence() { | |
102 | // OPT: This causes the array to be copied; we can do the same trick as in StringBuilder to transfer | |
103 | // ownership of the array instead and avoid the copy | |
104 | 4378 | return Sequences.make(clazz, array, size); |
105 | } | |
106 | } |