/*
* Copyright 2007 Kasper B. Graversen
*
* 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 org.supercsv.io;
import java.io.IOException;
import java.io.Reader;
import java.util.ArrayList;
import java.util.List;
import org.supercsv.exception.SuperCsvException;
import org.supercsv.prefs.CsvPreference;
/**
* Defines the standard behaviour of a CSV reader.
*
* @author Kasper B. Graversen
* @author James Bassett
*/
public abstract class AbstractCsvReader implements ICsvReader {
private final ITokenizer tokenizer;
private final CsvPreference preferences;
// the current tokenized columns
private final List<String> columns = new ArrayList<String>();
// the number of CSV records read
private int rowNumber = 0;
/**
* Constructs a new <tt>AbstractCsvReader</tt>, using the default {@link Tokenizer}.
*
* @param reader
* the reader
* @param preferences
* the CSV preferences
* @throws NullPointerException
* if reader or preferences are null
*/
public AbstractCsvReader(final Reader reader, final CsvPreference preferences) {
if( reader == null ) {
throw new NullPointerException("reader should not be null");
} else if( preferences == null ) {
throw new NullPointerException("preferences should not be null");
}
this.preferences = preferences;
this.tokenizer = new Tokenizer(reader, preferences);
}
/**
* Constructs a new <tt>AbstractCsvReader</tt>, using a custom {@link Tokenizer} (which should have already been set
* up with the Reader, CsvPreference, and CsvContext). This constructor should only be used if the default Tokenizer
* doesn't provide the required functionality.
*
* @param tokenizer
* the tokenizer
* @param preferences
* the CSV preferences
* @throws NullPointerException
* if tokenizer or preferences are null
*/
public AbstractCsvReader(final ITokenizer tokenizer, final CsvPreference preferences) {
if( tokenizer == null ) {
throw new NullPointerException("tokenizer should not be null");
} else if( preferences == null ) {
throw new NullPointerException("preferences should not be null");
}
this.preferences = preferences;
this.tokenizer = tokenizer;
}
/**
* Closes the Tokenizer and its associated Reader.
*/
public void close() throws IOException {
tokenizer.close();
}
/**
* {@inheritDoc}
*/
public String get(final int n) {
return columns.get(n - 1); // column numbers start at 1
}
/**
* {@inheritDoc}
*/
public String[] getHeader(final boolean firstLineCheck) throws IOException {
if( firstLineCheck && tokenizer.getLineNumber() != 0 ) {
throw new SuperCsvException(String.format(
"CSV header must be fetched as the first read operation, but %d lines have already been read",
tokenizer.getLineNumber()));
}
if( readRow() ) {
return columns.toArray(new String[columns.size()]);
}
return null;
}
/**
* {@inheritDoc}
*/
public int getLineNumber() {
return tokenizer.getLineNumber();
}
/**
* {@inheritDoc}
*/
public String getUntokenizedRow() {
return tokenizer.getUntokenizedRow();
}
/**
* {@inheritDoc}
*/
public int getRowNumber() {
return rowNumber;
}
/**
* {@inheritDoc}
*/
public int length() {
return columns.size();
}
/**
* Gets the tokenized columns.
*
* @return the tokenized columns
*/
protected List<String> getColumns() {
return columns;
}
/**
* Gets the preferences.
*
* @return the preferences
*/
protected CsvPreference getPreferences() {
return preferences;
}
/**
* Calls the tokenizer to read a CSV row. The columns can then be retrieved using {@link #getColumns()}.
*
* @return true if something was read, and false if EOF
* @throws IOException
* when an IOException occurs
* @throws SuperCsvException
* on errors in parsing the input
*/
protected boolean readRow() throws IOException {
if( tokenizer.readColumns(columns) ) {
rowNumber++;
return true;
}
return false;
}
}
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