1 package org.djutils.data;
2
3 import org.djutils.base.Identifiable;
4 import org.djutils.immutablecollections.ImmutableList;
5
6 /**
7 * Table with data stored in structured records.
8 * <p>
9 * Copyright (c) 2020-2022 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
10 * BSD-style license. See <a href="https://djutils.org/docs/current/djutils/licenses.html">DJUTILS License</a>.
11 * </p>
12 * @author <a href="https://www.tudelft.nl/averbraeck">Alexander Verbraeck</a>
13 * @author <a href="https://www.tudelft.nl/pknoppers">Peter Knoppers</a>
14 */
15 public interface DataTable extends Iterable<DataRecord>, Identifiable
16 {
17
18 /**
19 * Returns the description.
20 * @return description
21 */
22 String getDescription();
23
24 /**
25 * Returns the list of columns.
26 * @return list of columns
27 */
28 ImmutableList<DataColumn<?>> getColumns();
29
30 /**
31 * Returns the number of columns.
32 * @return number of columns
33 */
34 default int getNumberOfColumns()
35 {
36 return getColumns().size();
37 }
38
39 /**
40 * Returns whether the table is empty.
41 * @return whether the table is empty
42 */
43 boolean isEmpty();
44
45 /**
46 * Return the column ids as a String[].
47 * @return String[]; the column ids
48 */
49 default String[] getColumnIds()
50 {
51 String[] headers = new String[getNumberOfColumns()];
52 int index = 0;
53 for (DataColumn<?> column : getColumns())
54 {
55 headers[index++] = column.getId();
56 }
57 return headers;
58 }
59
60 /**
61 * Return the column descriptions as a String[].
62 * @return String[] the column headers
63 */
64 default String[] getColumnDescriptions()
65 {
66 String[] descriptions = new String[getNumberOfColumns()];
67 int index = 0;
68 for (DataColumn<?> column : getColumns())
69 {
70 descriptions[index++] = column.getDescription();
71 }
72 return descriptions;
73 }
74
75 /**
76 * Return the column data types as a Class<?>[].
77 * @return Class<?>[] the column data types
78 */
79 default Class<?>[] getColumnDataTypes()
80 {
81 Class<?>[] dataTypes = new Class[getNumberOfColumns()];
82 int index = 0;
83 for (DataColumn<?> column : getColumns())
84 {
85 dataTypes[index++] = column.getValueType();
86 }
87 return dataTypes;
88 }
89
90 /**
91 * Return the column data types as a String[]. Each data type is presented as the full class name or the primitive name. In
92 * case of an array, the result is preceded by an "[" for each dimension. After one or more "[" symbols, the class name is
93 * preceded by an "L" for a non-primitive class or interface, and by "I" for integer, "Z" for boolean, "B" for byte, "C" for
94 * char, "D" for double, "F" for float, "J" for long and "S" for short. So for a column with a double, "double" is returned.
95 * For a column with a "Double", "java.lang.Double" is returned, for an int[][], "[[I" is returned, and for a Long[],
96 * "[Ljava.lang.Long" is returned.
97 * @return String[] the column data types as an array of Strings
98 */
99 default String[] getColumnDataTypeStrings()
100 {
101 String[] dataTypes = new String[getNumberOfColumns()];
102 int index = 0;
103 for (DataColumn<?> column : getColumns())
104 {
105 dataTypes[index++] = column.getValueType().getName();
106 }
107 return dataTypes;
108 }
109
110 }