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The Apache Commons CSV library provides a simple interface for reading and writing
CSV files of various types.
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.csv;
import java.io.Serializable;
import java.util.Arrays;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Objects;
/**
* A CSV record parsed from a CSV file.
*
*
* Note: Support for {@link Serializable} is scheduled to be removed in version 2.0.
* In version 1.8 the mapping between the column header and the column index was
* removed from the serialised state. The class maintains serialization compatibility
* with versions pre-1.8 for the record values; these must be accessed by index
* following deserialization. There will be loss of any functionally linked to the header
* mapping when transferring serialised forms pre-1.8 to 1.8 and vice versa.
*
*/
public final class CSVRecord implements Serializable, Iterable {
private static final String[] EMPTY_STRING_ARRAY = new String[0];
private static final long serialVersionUID = 1L;
private final long characterPosition;
/** The accumulated comments (if any) */
private final String comment;
/** The record number. */
private final long recordNumber;
/** The values of the record */
private final String[] values;
/** The parser that originates this record. This is not serialized. */
private final transient CSVParser parser;
CSVRecord(final CSVParser parser, final String[] values, final String comment, final long recordNumber,
final long characterPosition) {
this.recordNumber = recordNumber;
this.values = values != null ? values : EMPTY_STRING_ARRAY;
this.parser = parser;
this.comment = comment;
this.characterPosition = characterPosition;
}
/**
* Returns a value by {@link Enum}.
*
* @param e
* an enum
* @return the String at the given enum String
*/
public String get(final Enum e) {
return get(Objects.toString(e, null));
}
/**
* Returns a value by index.
*
* @param i
* a column index (0-based)
* @return the String at the given index
*/
public String get(final int i) {
return values[i];
}
/**
* Returns a value by name.
*
*
* Note: This requires a field mapping obtained from the original parser.
* A check using {@link #isMapped(String)} should be used to determine if a
* mapping exists from the provided {@code name} to a field index. In this case an
* exception will only be thrown if the record does not contain a field corresponding
* to the mapping, that is the record length is not consistent with the mapping size.
*
*
* @param name
* the name of the column to be retrieved.
* @return the column value, maybe null depending on {@link CSVFormat#getNullString()}.
* @throws IllegalStateException
* if no header mapping was provided
* @throws IllegalArgumentException
* if {@code name} is not mapped or if the record is inconsistent
* @see #isMapped(String)
* @see #isConsistent()
* @see #getParser()
* @see CSVFormat#withNullString(String)
*/
public String get(final String name) {
final Map headerMap = getHeaderMapRaw();
if (headerMap == null) {
throw new IllegalStateException(
"No header mapping was specified, the record values can't be accessed by name");
}
final Integer index = headerMap.get(name);
if (index == null) {
throw new IllegalArgumentException(String.format("Mapping for %s not found, expected one of %s", name,
headerMap.keySet()));
}
try {
return values[index.intValue()];
} catch (final ArrayIndexOutOfBoundsException e) {
throw new IllegalArgumentException(String.format(
"Index for header '%s' is %d but CSVRecord only has %d values!", name, index,
Integer.valueOf(values.length)));
}
}
/**
* Returns the start position of this record as a character position in the source stream. This may or may not
* correspond to the byte position depending on the character set.
*
* @return the position of this record in the source stream.
*/
public long getCharacterPosition() {
return characterPosition;
}
/**
* Returns the comment for this record, if any.
* Note that comments are attached to the following record.
* If there is no following record (i.e. the comment is at EOF)
* the comment will be ignored.
*
* @return the comment for this record, or null if no comment for this record is available.
*/
public String getComment() {
return comment;
}
private Map getHeaderMapRaw() {
return parser == null ? null : parser.getHeaderMapRaw();
}
/**
* Returns the parser.
*
*
* Note: The parser is not part of the serialized state of the record. A null check
* should be used when the record may have originated from a serialized form.
*
*
* @return the parser.
* @since 1.7
*/
public CSVParser getParser() {
return parser;
}
/**
* Returns the number of this record in the parsed CSV file.
*
*
* ATTENTION: If your CSV input has multi-line values, the returned number does not correspond to
* the current line number of the parser that created this record.
*
*
* @return the number of this record.
* @see CSVParser#getCurrentLineNumber()
*/
public long getRecordNumber() {
return recordNumber;
}
/**
* Checks whether this record has a comment, false otherwise.
* Note that comments are attached to the following record.
* If there is no following record (i.e. the comment is at EOF)
* the comment will be ignored.
*
* @return true if this record has a comment, false otherwise
* @since 1.3
*/
public boolean hasComment() {
return comment != null;
}
/**
* Tells whether the record size matches the header size.
*
*
* Returns true if the sizes for this record match and false if not. Some programs can export files that fail this
* test but still produce parsable files.
*
*
* @return true of this record is valid, false if not
*/
public boolean isConsistent() {
final Map headerMap = getHeaderMapRaw();
return headerMap == null || headerMap.size() == values.length;
}
/**
* Checks whether a given column is mapped, i.e. its name has been defined to the parser.
*
* @param name
* the name of the column to be retrieved.
* @return whether a given column is mapped.
*/
public boolean isMapped(final String name) {
final Map headerMap = getHeaderMapRaw();
return headerMap != null && headerMap.containsKey(name);
}
/**
* Checks whether a given columns is mapped and has a value.
*
* @param name
* the name of the column to be retrieved.
* @return whether a given columns is mapped and has a value
*/
public boolean isSet(final String name) {
return isMapped(name) && getHeaderMapRaw().get(name).intValue() < values.length;
}
/**
* Checks whether a column with given index has a value.
*
* @param index
* a column index (0-based)
* @return whether a column with given index has a value
*/
public boolean isSet(final int index) {
return 0 <= index && index < values.length;
}
/**
* Returns an iterator over the values of this record.
*
* @return an iterator over the values of this record.
*/
@Override
public Iterator iterator() {
return toList().iterator();
}
/**
* Puts all values of this record into the given Map.
*
* @param map
* The Map to populate.
* @return the given map.
*/
> M putIn(final M map) {
if (getHeaderMapRaw() == null) {
return map;
}
for (final Entry entry : getHeaderMapRaw().entrySet()) {
final int col = entry.getValue().intValue();
if (col < values.length) {
map.put(entry.getKey(), values[col]);
}
}
return map;
}
/**
* Returns the number of values in this record.
*
* @return the number of values.
*/
public int size() {
return values.length;
}
/**
* Converts the values to a List.
*
* TODO: Maybe make this public?
*
* @return a new List
*/
private List toList() {
return Arrays.asList(values);
}
/**
* Copies this record into a new Map of header name to record value.
*
* @return A new Map. The map is empty if the record has no headers.
*/
public Map toMap() {
return putIn(new LinkedHashMap(values.length));
}
/**
* Returns a string representation of the contents of this record. The result is constructed by comment, mapping,
* recordNumber and by passing the internal values array to {@link Arrays#toString(Object[])}.
*
* @return a String representation of this record.
*/
@Override
public String toString() {
return "CSVRecord [comment='" + comment + "', recordNumber=" + recordNumber + ", values=" +
Arrays.toString(values) + "]";
}
String[] values() {
return values;
}
}
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