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A simple library for reading and writing CSV in Java
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/*
* Copyright 2018 Andrew Rucker Jones.
*
* Licensed 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 com.opencsv.bean;
import com.opencsv.ICSVParser;
import com.opencsv.exceptions.CsvRequiredFieldEmptyException;
import org.apache.commons.collections4.MultiValuedMap;
import org.apache.commons.collections4.iterators.LazyIteratorChain;
import org.apache.commons.collections4.iterators.TransformIterator;
import java.lang.reflect.Field;
import java.util.*;
import java.util.stream.Collectors;
/**
* This class maintains a mapping from column position out of a CSV file to bean
* fields.
*
* @param Type of the bean being converted
* @author Andrew Rucker Jones
* @since 4.2
*/
public class FieldMapByPosition extends AbstractFieldMap, T> implements Iterable> {
private int maxIndex = Integer.MAX_VALUE;
/** Holds a {@link java.util.Comparator} to sort columns on writing. */
private Comparator writeOrder = null;
/**
* Initializes this {@link FieldMap}.
*
* @param errorLocale The locale to be used for error messages
*/
public FieldMapByPosition(final Locale errorLocale) {
super(errorLocale);
}
/**
* This method generates a header that can be used for writing beans of the
* type provided back to a file.
* The ordering of the headers can be determined with the
* {@link java.util.Comparator} passed in to
* {@link #setColumnOrderOnWrite(Comparator)}. Otherwise, it is ascending
* according to position.
*/
// The rest of the Javadoc is inherited.
@Override
public String[] generateHeader(final T bean) throws CsvRequiredFieldEmptyException {
final List missingRequiredHeaders = new LinkedList<>();
final SortedMap headerMap = new TreeMap<>(writeOrder);
for(Map.Entry> entry : simpleMap.entrySet()) {
headerMap.put(entry.getKey(), entry.getValue().getField().getName());
}
for(ComplexFieldMapEntry r : complexMapList) {
@SuppressWarnings("unchecked")
final MultiValuedMap m = (MultiValuedMap) r.getBeanField().getFieldValue(bean);
boolean oneEntryMatched = false;
if(m != null && !m.isEmpty()) {
for(Map.Entry entry : m.entries()) {
Integer key = entry.getKey();
if(r.contains(key)) {
headerMap.put(entry.getKey(), r.getBeanField().getField().getName());
oneEntryMatched = true;
}
}
}
if(m == null || m.isEmpty() || !oneEntryMatched) {
if(r.getBeanField().isRequired()) {
missingRequiredHeaders.add(r.getBeanField().getField());
}
}
}
// Convert to an array of header "names".
// Since the user can pass in an arbitrary collation, we have to
// re-sort to get the highest value.
SortedSet headerSet = new TreeSet<>(headerMap.keySet());
int arraySize = headerSet.isEmpty() ? 0 : headerSet.last()+1;
final String[] headers = new String[arraySize];
int previousIndex = headerSet.isEmpty() ? 0 : headerSet.first();
for(Integer i : headerSet) { // Fill in gaps
for(int j = previousIndex+1; j < i ; j++) {
headerMap.put(j, null);
}
previousIndex = i;
}
previousIndex = 0;
for(String value : headerMap.values()) {
headers[previousIndex++] = value;
}
// Report headers that should have been present
if(!missingRequiredHeaders.isEmpty()) {
String errorMessage = String.format(
ResourceBundle
.getBundle(ICSVParser.DEFAULT_BUNDLE_NAME, errorLocale)
.getString("header.required.field.absent"),
missingRequiredHeaders.stream()
.map(Field::getName)
.collect(Collectors.joining(" ")),
String.join(" ", headers));
throw new CsvRequiredFieldEmptyException(bean.getClass(), missingRequiredHeaders, errorMessage);
}
return headers;
}
/**
* @param rangeDefinition A string describing the column positions to be
* matched.
* @see CsvBindAndJoinByPosition#position()
*/
// The rest of the Javadoc is inherited
@Override
public void putComplex(final String rangeDefinition, final BeanField field) {
complexMapList.add(new PositionToBeanField<>(rangeDefinition, maxIndex, field, errorLocale));
}
/**
* Sets the maximum index for all ranges specified in the entire field map.
* No ranges or mappings are ever removed so as to preserve information
* about required fields, but upper boundries are shortened as much as
* possible. If ranges or individual column positions were specified that
* lie wholly above {@code maxIndex}, these are preserved, though ranges
* are shortened to a single value (the lower boundry).
*
* @param maxIndex The maximum index in the data being imported
*/
public void setMaxIndex(int maxIndex) {
this.maxIndex = maxIndex;
// Attenuate all ranges that end past the last index down to the last index
complexMapList.forEach(p -> p.attenuateRanges(maxIndex));
}
@Override
public Iterator> iterator() {
return new LazyIteratorChain>() {
@Override
protected Iterator> nextIterator(int count) {
if(count <= complexMapList.size()) {
return complexMapList.get(count-1).iterator();
}
if(count == complexMapList.size()+1) {
return new TransformIterator<>(
simpleMap.entrySet().iterator(),
input -> new FieldMapByPositionEntry(input.getKey(), input.getValue()));
}
return null;
}
};
}
/**
* Sets the {@link java.util.Comparator} to be used to sort columns when
* writing beans to a CSV file.
*
* @param writeOrder The {@link java.util.Comparator} to use. May be
* {@code null}, in which case the natural ordering is used.
* @since 4.3
*/
public void setColumnOrderOnWrite(Comparator writeOrder) {
this.writeOrder = writeOrder;
}
}