org.apache.metamodel.csv.CsvWriter Maven / Gradle / Ivy
/**
* 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.metamodel.csv;
import org.apache.metamodel.util.Resource;
/**
* This class is an adaptation of the CSVWriter class of OpenCSV. We've made the
* writer work without having the output stream as state (suiting for
* {@link Resource} usage).
*/
public final class CsvWriter {
public static final int INITIAL_STRING_SIZE = 128;
private final CsvConfiguration _configuration;
public CsvWriter(CsvConfiguration configuration) {
_configuration = configuration;
}
/**
* Builds a line for the CSV file output
*
* @param nextLine
* a string array with each comma-separated element as a separate
* entry.
*/
public String buildLine(String[] nextLine) {
final StringBuilder sb = new StringBuilder(INITIAL_STRING_SIZE);
for (int i = 0; i < nextLine.length; i++) {
if (i != 0) {
sb.append(_configuration.getSeparatorChar());
}
final String nextElement = nextLine[i];
if (nextElement == null) {
continue;
}
final char quoteChar = _configuration.getQuoteChar();
if (quoteChar != CsvConfiguration.NOT_A_CHAR) {
sb.append(quoteChar);
}
sb.append(valueNeedsEscaping(nextElement) ? processValue(nextElement) : nextElement);
if (quoteChar != CsvConfiguration.NOT_A_CHAR) {
sb.append(quoteChar);
}
}
sb.append('\n');
return sb.toString();
}
private boolean valueNeedsEscaping(String line) {
boolean result = line.indexOf(_configuration.getQuoteChar()) != -1
|| line.indexOf(_configuration.getEscapeChar()) != -1;
if (!result) {
result = _configuration.getQuoteChar() == CsvConfiguration.NOT_A_CHAR
&& line.indexOf(_configuration.getSeparatorChar()) != -1;
}
return result;
}
private String processValue(String value) {
final char escapeChar = _configuration.getEscapeChar();
if (escapeChar == CsvConfiguration.NOT_A_CHAR) {
return value;
}
final char quoteChar = _configuration.getQuoteChar();
final char separatorChar = _configuration.getSeparatorChar();
final StringBuilder sb = new StringBuilder(value.length() + 10);
for (int j = 0; j < value.length(); j++) {
final char nextChar = value.charAt(j);
if (nextChar == quoteChar) {
sb.append(escapeChar).append(nextChar);
} else if (nextChar == escapeChar) {
sb.append(escapeChar).append(nextChar);
} else if (quoteChar == CsvConfiguration.NOT_A_CHAR && nextChar == separatorChar) {
sb.append(escapeChar).append(nextChar);
} else {
sb.append(nextChar);
}
}
return sb.toString();
}
}