com.opencsv.bean.CsvToBeanFilter Maven / Gradle / Ivy

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A simple library for reading and writing CSV in Java
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/*
 * Copyright 2013 Mark Rogers.
 *
 * 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;

/**
 * Filters allow lines of input to be ignored before a bean is created.
 * Using a filter means you are looking at the data from the input after it
 * has been parsed, but before a bean has been created and populated.
 * Filters must be thread-safe.
 * Here's an example showing how to use {@link CsvToBean} with a column
 * name mapping and line filtering.  It assumes that there is a class named
 * Feature defined with setters setName(String) and
 * setState(String).  The FEATURE_NAME and STATE columns in the
 * CSV file will be used.  Any additional columns will be ignored.  The filter
 * will eliminate any lines where the STATE value is "production".
 *
 *  * {@code
 * private class StateFilter implements CsvToBeanFilter {
 *
 * 	private final MappingStrategy strategy;
 *
 * 	public NonProductionFilter(MappingStrategy strategy) {
 * 		this.strategy = strategy;
 * 	}
 *
 * 	public boolean allowLine(String[] line) {
 * 		int index = strategy.getColumnIndex("STATE");
 * 		String value = line[index];
 * 		boolean result = !"production".equals(value);
 * 		return result;
 * 	}
 *
 * }
 *
 * public List parseCsv(InputStreamReader streamReader) {
 * 	HeaderColumnNameTranslateMappingStrategy strategy = new HeaderColumnNameTranslateMappingStrategy();
 * 	Map columnMap = new HashMap();
 * 	columnMap.put("FEATURE_NAME", "name");
 * 	columnMap.put("STATE", "state");
 * 	strategy.setColumnMapping(columnMap);
 * 	strategy.setType(Feature.class);
 * 	CSVReader reader = new CSVReader(streamReader);
 * 	CsvToBeanFilter filter = new StateFilter(strategy);
 * 	return new CsvToBean().parse(strategy, reader, filter);
 * }
 * }
 * 
 */
public interface CsvToBeanFilter {

   /**
    * Determines if a line from the CSV file will be included in the
    * output of {@link CsvToBean}.  If the CSV file has a header row, it
    * may be useful for implementations to call
    * {@link MappingStrategy#getColumnIndex} to identify the correct column
    * indices to examine.
    *
    * @param line A line of data from the CSV file
    * @return True if the line is to be included in the output. Otherwise,
    * false.
    */
   boolean allowLine(String[] line);

}