1 /*
2 * Copyright 2007 Kasper B. Graversen
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16 package org.supercsv.encoder;
17
18 import java.util.HashSet;
19 import java.util.Set;
20
21 import org.supercsv.prefs.CsvPreference;
22 import org.supercsv.util.CsvContext;
23
24 /**
25 * A selective CsvEncoder implementation - only the desired column numbers (if any) are encoded. Use with caution -
26 * disabling encoding may increase performance but at the risk of invalid CSV.
27 *
28 * @author James Bassett
29 * @since 2.1.0
30 */
31 public class SelectiveCsvEncoder extends DefaultCsvEncoder {
32
33 private final Set<Integer> columnNumbers = new HashSet<Integer>();
34
35 /**
36 * Constructs a new <tt>SelectiveCsvEncoder</tt> that encodes columns by column number. If no column numbers are
37 * supplied (i.e. no parameters) then no columns will be encoded.
38 *
39 * @param columnsToEncode
40 * the column numbers to encode
41 */
42 public SelectiveCsvEncoder(final int... columnsToEncode) {
43 if( columnsToEncode == null ) {
44 throw new NullPointerException("columnsToEncode should not be null");
45 }
46 for( final Integer columnToEncode : columnsToEncode ) {
47 columnNumbers.add(columnToEncode);
48 }
49 }
50
51 /**
52 * Constructs a new <tt>SelectiveCsvEncoder</tt> that encodes columns if the element representing that column in the
53 * supplied array is true.
54 *
55 * @param columnsToEncode
56 * boolean array representing columns to encode (true indicates a column should be encoded).
57 */
58 public SelectiveCsvEncoder(final boolean[] columnsToEncode) {
59 if( columnsToEncode == null ) {
60 throw new NullPointerException("columnsToEncode should not be null");
61 }
62 for( int i = 0; i < columnsToEncode.length; i++ ) {
63 if( columnsToEncode[i] ) {
64 columnNumbers.add(i + 1); // column numbers start at 1
65 }
66 }
67 }
68
69 /**
70 * {@inheritDoc}
71 */
72 public String encode(final String input, final CsvContext context, final CsvPreference preference) {
73 return columnNumbers.contains(context.getColumnNumber()) ? super.encode(input, context, preference) : input;
74
75 }
76
77 }