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1 | /* |
2 | * Licensed to the Apache Software Foundation (ASF) under one or more | |
3 | * contributor license agreements. See the NOTICE file distributed with | |
4 | * this work for additional information regarding copyright ownership. | |
5 | * The ASF licenses this file to You under the Apache License, Version 2.0 | |
6 | * (the "License"); you may not use this file except in compliance with | |
7 | * the License. You may obtain a copy of the License at | |
8 | * | |
9 | * http://www.apache.org/licenses/LICENSE-2.0 | |
10 | * | |
11 | * Unless required by applicable law or agreed to in writing, software | |
12 | * distributed under the License is distributed on an "AS IS" BASIS, | |
13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
14 | * See the License for the specific language governing permissions and | |
15 | * limitations under the License. | |
16 | */ | |
17 | ||
18 | package org.apache.arrow.vector; | |
19 | ||
20 | import org.apache.arrow.memory.BufferAllocator; | |
21 | import org.apache.arrow.memory.util.ArrowBufPointer; | |
22 | import org.apache.arrow.memory.util.hash.ArrowBufHasher; | |
23 | import org.apache.arrow.vector.types.pojo.Field; | |
24 | import org.apache.arrow.vector.types.pojo.FieldType; | |
25 | import org.apache.arrow.vector.util.CallBack; | |
26 | import org.apache.arrow.vector.util.TransferPair; | |
27 | ||
28 | /** | |
29 | * A zero length vector of any type. | |
30 | */ | |
31 | public final class ZeroVector extends NullVector { | |
32 | public static final ZeroVector INSTANCE = new ZeroVector(); | |
33 | ||
34 | /** | |
35 | * Instantiate a ZeroVector. | |
36 | * | |
37 | * @param name name of the vector | |
38 | */ | |
39 | public ZeroVector(String name) { | |
40 | super(name); | |
41 | } | |
42 | ||
43 | /** | |
44 | * Instantiate a ZeroVector. | |
45 | * | |
46 | * @param name name of the vector | |
47 | * @param fieldType type of Field materialized by this vector. | |
48 | */ | |
49 | public ZeroVector(String name, FieldType fieldType) { | |
50 | super(name, fieldType); | |
51 | } | |
52 | ||
53 | /** | |
54 | * Instantiate a ZeroVector. | |
55 | * | |
56 | * @param field field materialized by this vector. | |
57 | */ | |
58 | public ZeroVector(Field field) { | |
59 | super(field); | |
60 | } | |
61 | ||
62 | @Deprecated | |
63 | public ZeroVector() { | |
64 | } | |
65 | ||
66 | @Override | |
67 | public int getValueCount() { | |
68 | return 0; | |
69 | } | |
70 | ||
71 | @Override | |
72 | public void setValueCount(int valueCount) { | |
73 | } | |
74 | ||
75 | @Override | |
76 | public int getNullCount() { | |
77 | return 0; | |
78 | } | |
79 | ||
80 | @Override | |
81 | public boolean isNull(int index) { | |
82 | throw new IndexOutOfBoundsException(); | |
83 | } | |
84 | ||
85 | @Override | |
86 | public int hashCode(int index) { | |
87 | return 0; | |
88 | } | |
89 | ||
90 | @Override | |
91 | public int hashCode(int index, ArrowBufHasher hasher) { | |
92 | return ArrowBufPointer.NULL_HASH_CODE; | |
93 | } | |
94 | ||
95 | @Override | |
96 | public int getValueCapacity() { | |
97 | return 0; | |
98 | } | |
99 | ||
100 | @Override | |
101 | public TransferPair getTransferPair(BufferAllocator allocator) { | |
102 | return defaultPair; | |
103 | } | |
104 | ||
105 | @Override | |
106 | public TransferPair getTransferPair(String ref, BufferAllocator allocator) { | |
107 | return defaultPair; | |
108 | } | |
109 | ||
110 | @Override | |
111 | public TransferPair getTransferPair(String ref, BufferAllocator allocator, CallBack callBack) { | |
112 | return defaultPair; | |
113 | } | |
114 | ||
115 | @Override | |
116 | public TransferPair makeTransferPair(ValueVector target) { | |
117 | return defaultPair; | |
118 | } | |
119 | ||
120 | private final TransferPair defaultPair = new TransferPair() { | |
121 | @Override | |
122 | public void transfer() { | |
123 | } | |
124 | ||
125 | @Override | |
126 | public void splitAndTransfer(int startIndex, int length) { | |
127 | } | |
128 | ||
129 | @Override | |
130 | public ValueVector getTo() { | |
131 | return ZeroVector.this; | |
132 | } | |
133 | ||
134 | @Override | |
135 | public void copyValueSafe(int from, int to) { | |
136 | } | |
137 | }; | |
138 | } |