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A simple library for reading and writing CSV in Java
package com.opencsv;
/*
Copyright 2005 Bytecode Pty Ltd.
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.
*/
import com.opencsv.stream.reader.LineReader;
import java.io.BufferedReader;
import java.io.Closeable;
import java.io.IOException;
import java.io.Reader;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.ResourceBundle;
import org.apache.commons.lang3.ObjectUtils;
/**
* A very simple CSV reader released under a commercial-friendly license.
*
* @author Glen Smith
*/
public class CSVReader implements Closeable, Iterable {
public static final boolean DEFAULT_KEEP_CR = false;
public static final boolean DEFAULT_VERIFY_READER = true;
/** The default line to start reading. */
public static final int DEFAULT_SKIP_LINES = 0;
/**
* The default limit for the number of lines in a multiline record.
* Less than one means no limit.
*/
public static final int DEFAULT_MULTILINE_LIMIT = 0;
public static final int READ_AHEAD_LIMIT = Character.SIZE / Byte.SIZE;
protected ICSVParser parser;
protected int skipLines;
protected BufferedReader br;
protected LineReader lineReader;
protected boolean hasNext = true;
protected boolean linesSkiped;
protected boolean keepCR;
protected boolean verifyReader;
protected int multilineLimit = DEFAULT_MULTILINE_LIMIT;
protected final Locale errorLocale;
protected long linesRead = 0;
protected long recordsRead = 0;
/**
* Constructs CSVReader using defaults for all parameters.
*
* @param reader The reader to an underlying CSV source.
*/
public CSVReader(Reader reader) {
this(reader, ICSVParser.DEFAULT_SEPARATOR,
ICSVParser.DEFAULT_QUOTE_CHARACTER,
ICSVParser.DEFAULT_ESCAPE_CHARACTER);
}
/**
* Constructs CSVReader with supplied separator.
*
* @param reader The reader to an underlying CSV source.
* @param separator The delimiter to use for separating entries.
* @deprecated Please use {@link CSVReaderBuilder} instead.
*/
@Deprecated
public CSVReader(Reader reader, char separator) {
this(reader, separator, ICSVParser.DEFAULT_QUOTE_CHARACTER,
ICSVParser.DEFAULT_ESCAPE_CHARACTER);
}
/**
* Constructs CSVReader with supplied separator and quote char.
*
* @param reader The reader to an underlying CSV source.
* @param separator The delimiter to use for separating entries
* @param quotechar The character to use for quoted elements
* @deprecated Please use {@link CSVReaderBuilder} instead.
*/
@Deprecated
public CSVReader(Reader reader, char separator, char quotechar) {
this(reader, separator, quotechar, ICSVParser.DEFAULT_ESCAPE_CHARACTER,
DEFAULT_SKIP_LINES, ICSVParser.DEFAULT_STRICT_QUOTES);
}
/**
* Constructs CSVReader with supplied separator, quote char, and quote handling
* behavior.
*
* @param reader The reader to an underlying CSV source.
* @param separator The delimiter to use for separating entries
* @param quotechar The character to use for quoted elements
* @param strictQuotes Sets if characters outside the quotes are ignored
* @deprecated Please use {@link CSVReaderBuilder} instead.
*/
@Deprecated
public CSVReader(Reader reader, char separator, char quotechar, boolean strictQuotes) {
this(reader, separator, quotechar, ICSVParser.DEFAULT_ESCAPE_CHARACTER,
DEFAULT_SKIP_LINES, strictQuotes);
}
/**
* Constructs CSVReader.
*
* @param reader The reader to an underlying CSV source.
* @param separator The delimiter to use for separating entries
* @param quotechar The character to use for quoted elements
* @param escape The character to use for escaping a separator or quote
* @deprecated Please use {@link CSVReaderBuilder} instead.
*/
@Deprecated
public CSVReader(Reader reader, char separator,
char quotechar, char escape) {
this(reader, separator, quotechar, escape, DEFAULT_SKIP_LINES,
ICSVParser.DEFAULT_STRICT_QUOTES);
}
/**
* Constructs CSVReader.
*
* @param reader The reader to an underlying CSV source.
* @param separator The delimiter to use for separating entries
* @param quotechar The character to use for quoted elements
* @param line The number of lines to skip before reading
* @deprecated Please use {@link CSVReaderBuilder} instead.
*/
@Deprecated
public CSVReader(Reader reader, char separator, char quotechar, int line) {
this(reader, separator, quotechar, ICSVParser.DEFAULT_ESCAPE_CHARACTER,
line, ICSVParser.DEFAULT_STRICT_QUOTES);
}
/**
* Constructs CSVReader.
*
* @param reader The reader to an underlying CSV source.
* @param separator The delimiter to use for separating entries
* @param quotechar The character to use for quoted elements
* @param escape The character to use for escaping a separator or quote
* @param line The number of lines to skip before reading
* @deprecated Please use {@link CSVReaderBuilder} instead.
*/
@Deprecated
public CSVReader(Reader reader, char separator, char quotechar, char escape, int line) {
this(reader, separator, quotechar, escape, line,
ICSVParser.DEFAULT_STRICT_QUOTES);
}
/**
* Constructs CSVReader.
*
* @param reader The reader to an underlying CSV source.
* @param separator The delimiter to use for separating entries
* @param quotechar The character to use for quoted elements
* @param escape The character to use for escaping a separator or quote
* @param line The number of lines to skip before reading
* @param strictQuotes Sets if characters outside the quotes are ignored
* @deprecated Please use {@link CSVReaderBuilder} instead.
*/
@Deprecated
public CSVReader(Reader reader, char separator, char quotechar, char escape, int line, boolean strictQuotes) {
this(reader, separator, quotechar, escape, line, strictQuotes,
ICSVParser.DEFAULT_IGNORE_LEADING_WHITESPACE);
}
/**
* Constructs CSVReader with all data entered.
*
* @param reader The reader to an underlying CSV source.
* @param separator The delimiter to use for separating entries
* @param quotechar The character to use for quoted elements
* @param escape The character to use for escaping a separator or quote
* @param line The number of lines to skip before reading
* @param strictQuotes Sets if characters outside the quotes are ignored
* @param ignoreLeadingWhiteSpace If true, parser should ignore white space before a quote in a field
* @deprecated Please use {@link CSVReaderBuilder} instead.
*/
@Deprecated
public CSVReader(Reader reader, char separator, char quotechar, char escape, int line, boolean strictQuotes, boolean ignoreLeadingWhiteSpace) {
this(reader, line,
new CSVParser(separator, quotechar, escape, strictQuotes,
ignoreLeadingWhiteSpace,
ICSVParser.DEFAULT_IGNORE_QUOTATIONS,
ICSVParser.DEFAULT_NULL_FIELD_INDICATOR,
Locale.getDefault()));
}
/**
* Constructs CSVReader with all data entered.
*
* @param reader The reader to an underlying CSV source.
* @param separator The delimiter to use for separating entries
* @param quotechar The character to use for quoted elements
* @param escape The character to use for escaping a separator or quote
* @param line The number of lines to skip before reading
* @param strictQuotes Sets if characters outside the quotes are ignored
* @param ignoreLeadingWhiteSpace If true, parser should ignore white space before a quote in a field
* @param keepCR If true the reader will keep carriage returns, otherwise it will discard them.
* @deprecated Please use {@link CSVReaderBuilder} instead.
*/
@Deprecated
public CSVReader(Reader reader, char separator, char quotechar, char escape, int line, boolean strictQuotes,
boolean ignoreLeadingWhiteSpace, boolean keepCR) {
this(reader, line,
new CSVParser(separator, quotechar, escape, strictQuotes,
ignoreLeadingWhiteSpace,
ICSVParser.DEFAULT_IGNORE_QUOTATIONS,
ICSVParser.DEFAULT_NULL_FIELD_INDICATOR,
Locale.getDefault()),
keepCR, DEFAULT_VERIFY_READER, DEFAULT_MULTILINE_LIMIT,
Locale.getDefault());
}
/**
* Constructs CSVReader with supplied CSVParser.
*
* @param reader The reader to an underlying CSV source.
* @param line The number of lines to skip before reading
* @param icsvParser The parser to use to parse input
* @deprecated Please use {@link CSVReaderBuilder} instead.
*/
@Deprecated
public CSVReader(Reader reader, int line, ICSVParser icsvParser) {
this(reader, line, icsvParser, DEFAULT_KEEP_CR, DEFAULT_VERIFY_READER,
DEFAULT_MULTILINE_LIMIT, Locale.getDefault());
}
/**
* Constructs CSVReader with supplied CSVParser.
* This constructor sets all necessary parameters for CSVReader, and
* intentionally has package access so only the builder can use it.
*
* @param reader The reader to an underlying CSV source.
* @param line The number of lines to skip before reading
* @param icsvParser The parser to use to parse input
* @param keepCR True to keep carriage returns in data read, false otherwise
* @param verifyReader True to verify reader before each read, false otherwise
*/
CSVReader(Reader reader, int line, ICSVParser icsvParser, boolean keepCR, boolean verifyReader, int multilineLimit, Locale errorLocale) {
this.br =
(reader instanceof BufferedReader ?
(BufferedReader) reader :
new BufferedReader(reader));
this.lineReader = new LineReader(br, keepCR);
this.skipLines = line;
this.parser = icsvParser;
this.keepCR = keepCR;
this.verifyReader = verifyReader;
this.multilineLimit = multilineLimit;
this.errorLocale = ObjectUtils.defaultIfNull(errorLocale, Locale.getDefault());
}
/**
* @return The CSVParser used by the reader.
*/
public ICSVParser getParser() {
return parser;
}
/**
* Returns the number of lines in the CSV file to skip before processing.
* This is useful when there are miscellaneous data at the beginning of a file.
*
* @return The number of lines in the CSV file to skip before processing.
*/
public int getSkipLines() {
return skipLines;
}
/**
* Returns if the reader will keep carriage returns found in data or remove them.
*
* @return True if reader will keep carriage returns, false otherwise.
*/
public boolean keepCarriageReturns() {
return keepCR;
}
/**
* Reads the entire file into a List with each element being a String[] of
* tokens.
*
* @return A List of String[], with each String[] representing a line of the
* file.
* @throws IOException If bad things happen during the read
*/
public List readAll() throws IOException {
List allElements = new ArrayList<>();
while (hasNext) {
String[] nextLineAsTokens = readNext();
if (nextLineAsTokens != null) {
allElements.add(nextLineAsTokens);
}
}
return allElements;
}
/**
* Reads the next line from the buffer and converts to a string array.
*
* @return A string array with each comma-separated element as a separate
* entry, or null if there is no more input.
* @throws IOException If bad things happen during the read
*/
public String[] readNext() throws IOException {
String[] result = null;
int linesInThisRecord = 0;
do {
String nextLine = getNextLine();
linesInThisRecord++;
if (!hasNext) {
return validateResult(result);
}
if(multilineLimit > 0 && linesInThisRecord > multilineLimit) {
throw new IOException(String.format(errorLocale, ResourceBundle.getBundle("opencsv", errorLocale).getString("multiline.limit.broken"), multilineLimit));
}
String[] r = parser.parseLineMulti(nextLine);
if (r.length > 0) {
if (result == null) {
result = r;
} else {
result = combineResultsFromMultipleReads(result, r);
}
}
} while (parser.isPending());
return validateResult(result);
}
/**
* Increments the number of records read if the result passed in is not null.
*
* @param result The result of the read operation
* @return Result that was passed in.
*/
protected String[] validateResult(String[] result) {
if (result != null) {
recordsRead++;
}
return result;
}
/**
* For multi-line records this method combines the current result with the result from previous read(s).
* @param buffer Previous data read for this record
* @param lastRead Latest data read for this record.
* @return String array with union of the buffer and lastRead arrays.
*/
protected String[] combineResultsFromMultipleReads(String[] buffer, String[] lastRead) {
String[] t = new String[buffer.length + lastRead.length];
System.arraycopy(buffer, 0, t, 0, buffer.length);
System.arraycopy(lastRead, 0, t, buffer.length, lastRead.length);
return t;
}
/**
* Reads the next line from the file.
*
* @return The next line from the file without trailing newline, or null if
* there is no more input.
* @throws IOException If bad things happen during the read
*/
protected String getNextLine() throws IOException {
if (isClosed()) {
hasNext = false;
return null;
}
if (!this.linesSkiped) {
for (int i = 0; i < skipLines; i++) {
lineReader.readLine();
linesRead++;
}
this.linesSkiped = true;
}
String nextLine = lineReader.readLine();
if (nextLine == null) {
hasNext = false;
} else {
linesRead++;
}
return hasNext ? nextLine : null;
}
/**
* Only useful for tests.
* @return The maximum number of lines allowed in a multiline record.
*/
public int getMultilineLimit() {
return multilineLimit;
}
/**
* Sets the maximum number of lines allowed in a multiline record.
* More than this number in one record results in an IOException.
*
* @param multilineLimit No more than this number of lines is allowed in a
* single input record. The default is {@link #DEFAULT_MULTILINE_LIMIT}.
* @deprecated Please use {@link CSVReaderBuilder#withMultilineLimit(int)} instead.
*/
@Deprecated
public void setMultilineLimit(int multilineLimit) {
this.multilineLimit = multilineLimit;
}
/**
* Checks to see if the file is closed.
* @return True if the reader can no longer be read from.
*/
protected boolean isClosed() {
if (!verifyReader) {
return false;
}
try {
br.mark(READ_AHEAD_LIMIT);
int nextByte = br.read();
br.reset(); // resets stream position, possible because its buffered
return nextByte == -1; // read() returns -1 at end of stream
} catch (IOException e) {
return true;
}
}
/**
* Closes the underlying reader.
*
* @throws IOException If the close fails
*/
@Override
public void close() throws IOException {
br.close();
}
/**
* Creates an Iterator for processing the CSV data.
* @return A String[] iterator.
*/
@Override
public Iterator iterator() {
try {
CSVIterator it = new CSVIterator(this);
it.setErrorLocale(errorLocale);
return it;
} catch (IOException e) {
throw new RuntimeException(e);
}
}
/**
* Returns if the CSVReader will verify the reader before each read.
*
* By default the value is true, which is the functionality for version 3.0.
* If set to false the reader is always assumed ready to read - this is the functionality
* for version 2.4 and before.
*
*
* The reason this method was needed was that certain types of readers would return
* false for their ready() methods until a read was done (namely readers created using Channels).
* This caused opencsv not to read from those readers.
*
*
* @return True if CSVReader will verify the reader before reads. False otherwise.
* @see Bug 108
* @since 3.3
*/
public boolean verifyReader() {
return this.verifyReader;
}
/**
* Used for debugging purposes, this method returns the number of lines that
* has been read from the reader passed into the CSVReader.
*
* Given the following data:
*
* First line in the file
* some other descriptive line
* a,b,c
*
* a,"b\nb",c
*
*
* With a CSVReader constructed like so:
*
* CSVReader c = builder.withCSVParser(new CSVParser())
* .withSkipLines(2)
* .build();
*
* The initial call to getLinesRead() will be 0. After the first call to
* readNext() then getLinesRead() will return 3 (because header was read).
* After the second call to read the blank line then getLinesRead() will
* return 4 (still a read). After third call to readNext() getLinesRead()
* will return 6 because it took two line reads to retrieve this record.
* Subsequent calls to readNext() (since we are out of data) will not
* increment the number of lines read.
*
* An example of this is in the linesAndRecordsRead() test in CSVReaderTest.
*
*
* @return The number of lines read by the reader (including skip lines).
* @see Feature Request 73
* @since 3.6
*/
public long getLinesRead() {
return linesRead;
}
/**
* Used for debugging purposes, this method returns the number of records
* that has been read from the CSVReader.
*
* Given the following data:
*
* First line in the file
* some other descriptive line
* a,b,c
* a,"b\nb",c
*
* With a CSVReader constructed like so:
*
* CSVReader c = builder.withCSVParser(new CSVParser())
* .withSkipLines(2)
* .build();
*
* The initial call to getRecordsRead() will be 0. After the first call to
* readNext() then getRecordsRead() will return 1. After the second call to
* read the blank line then getRecordsRead() will return 2 (a blank line is
* considered a record with one empty field). After third call to readNext()
* getRecordsRead() will return 3 because even though it reads to retrieve
* this record, it is still a single record read. Subsequent calls to
* readNext() (since we are out of data) will not increment the number of
* records read.
*
*
* An example of this is in the linesAndRecordsRead() test in CSVReaderTest.
*
*
* @return The number of records (array of Strings[]) read by the reader.
* @see Feature Request 73
* @since 3.6
*/
public long getRecordsRead() {
return recordsRead;
}
}