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.io;
17
18 import java.io.IOException;
19 import java.util.List;
20
21 import org.supercsv.cellprocessor.ift.CellProcessor;
22 import org.supercsv.exception.SuperCsvConstraintViolationException;
23 import org.supercsv.exception.SuperCsvException;
24
25 /**
26 * Interface for readers that read into Lists.
27 *
28 * @author Kasper B. Graversen
29 * @author James Bassett
30 */
31 public interface ICsvListReader extends ICsvReader {
32
33 /**
34 * Reads a row of a CSV file and returns a List of Strings containing each column. If you are forced to use this
35 * method instead of {@link #read(CellProcessor...)} because your CSV file has a variable number of columns, then
36 * you can call the {@link #executeProcessors(CellProcessor...)} method after calling {@link #read()} to execute the
37 * cell processors manually (after determining the number of columns read in and which cell processors to use).
38 *
39 * @return the List of columns, or null if EOF
40 * @throws IOException
41 * if an I/O error occurred
42 * @throws SuperCsvException
43 * if there was a general exception while reading/processing
44 * @since 1.0
45 */
46 List<String> read() throws IOException;
47
48 /**
49 * Reads a row of a CSV file and returns a List of Objects containing each column. The data can be further processed
50 * by cell processors (each element in the processors array corresponds with a CSV column). A <tt>null</tt> entry in
51 * the processors array indicates no further processing is required (the unprocessed String value will be added to
52 * the List). Prior to version 2.0.0 this method returned a List of Strings.
53 *
54 * @param processors
55 * an array of CellProcessors used to further process data before it is added to the List (each element
56 * in the processors array corresponds with a CSV column - the number of processors should match the
57 * number of columns). A <tt>null</tt> entry indicates no further processing is required (the unprocessed
58 * String value will be added to the List).
59 * @return the List of columns, or null if EOF
60 * @throws IOException
61 * if an I/O error occurred
62 * @throws NullPointerException
63 * if processors is null
64 * @throws SuperCsvConstraintViolationException
65 * if a CellProcessor constraint failed
66 * @throws SuperCsvException
67 * if there was a general exception while reading/processing
68 * @since 1.0
69 */
70 List<Object> read(CellProcessor... processors) throws IOException;
71
72 /**
73 * Executes the supplied cell processors on the last row of CSV that was read. This should only be used when the
74 * number of CSV columns is unknown before the row is read, and you are forced to use {@link #read()} instead of
75 * {@link #read(CellProcessor...)}.
76 *
77 * @param processors
78 * an array of CellProcessors used to further process the last row of CSV data that was read (each
79 * element in the processors array corresponds with a CSV column - the number of processors should match
80 * the number of columns). A <tt>null</tt> entry indicates no further processing is required (the
81 * unprocessed String value will be added to the List).
82 * @return the List of processed columns
83 * @throws NullPointerException
84 * if processors is null
85 * @throws SuperCsvConstraintViolationException
86 * if a CellProcessor constraint failed
87 * @throws SuperCsvException
88 * if the wrong number of processors are supplied, or CellProcessor execution failed
89 * @since 2.1.0
90 */
91 List<Object> executeProcessors(CellProcessor... processors);
92 }