/*
    * 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.example;
  
  import java.io.FileReader;
  import java.util.List;
  import java.util.Map;
  
  import org.supercsv.cellprocessor.Optional;
  import org.supercsv.cellprocessor.ParseBool;
  import org.supercsv.cellprocessor.ParseDate;
  import org.supercsv.cellprocessor.ParseInt;
  import org.supercsv.cellprocessor.constraint.LMinMax;
  import org.supercsv.cellprocessor.constraint.NotNull;
  import org.supercsv.cellprocessor.constraint.StrRegEx;
  import org.supercsv.cellprocessor.constraint.UniqueHashCode;
  import org.supercsv.cellprocessor.ift.CellProcessor;
  import org.supercsv.io.CsvBeanReader;
  import org.supercsv.io.CsvListReader;
  import org.supercsv.io.CsvMapReader;
  import org.supercsv.io.ICsvBeanReader;
  import org.supercsv.io.ICsvListReader;
  import org.supercsv.io.ICsvMapReader;
  import org.supercsv.mock.CustomerBean;
  import org.supercsv.prefs.CsvPreference;
  
  /**
   * Examples of reading CSV files.
   */
  public class Reading {
  	
  	private static final String CSV_FILENAME = "src/test/resources/customers.csv";
  	
  	private static final String VARIABLE_CSV_FILENAME = "src/test/resources/customerswithvariablecolumns.csv";
  	
  	public static void main(String[] args) throws Exception {
  		readWithCsvBeanReader();
  		readWithCsvListReader();
  		readVariableColumnsWithCsvListReader();
  		readWithCsvMapReader();
  		partialReadWithCsvBeanReader();
  		partialReadWithCsvMapReader();
  	}
  	
  	/**
  	 * Sets up the processors used for the examples. There are 10 CSV columns, so 10 processors are defined. Empty
  	 * columns are read as null (hence the NotNull() for mandatory columns).
  	 * 
  	 * @return the cell processors
  	 */
  	private static CellProcessor[] getProcessors() {
  		
  		final String emailRegex = "[a-z0-9\\._]+@[a-z0-9\\.]+"; // just an example, not very robust!
  		StrRegEx.registerMessage(emailRegex, "must be a valid email address");
  		
  		final CellProcessor[] processors = new CellProcessor[] { new UniqueHashCode(), // customerNo (must be unique)
  			new NotNull(), // firstName
  			new NotNull(), // lastName
  			new ParseDate("dd/MM/yyyy"), // birthDate
  			new NotNull(), // mailingAddress
  			new Optional(new ParseBool()), // married
  			new Optional(new ParseInt()), // numberOfKids
  			new NotNull(), // favouriteQuote
  			new StrRegEx(emailRegex), // email
  			new LMinMax(0L, LMinMax.MAX_LONG) // loyaltyPoints
  		};
  		
  		return processors;
  	}
  	
  	/**
  	 * An example of reading using CsvBeanReader.
  	 */
  	private static void readWithCsvBeanReader() throws Exception {
  		
  		ICsvBeanReader beanReader = null;
  		try {
  			beanReader = new CsvBeanReader(new FileReader(CSV_FILENAME), CsvPreference.STANDARD_PREFERENCE);
  			
  			// the header elements are used to map the values to the bean (names must match)
  			final String[] header = beanReader.getHeader(true);
  			final CellProcessor[] processors = getProcessors();
  			
  			CustomerBean customer;
  			while( (customer = beanReader.read(CustomerBean.class, header, processors)) != null ) {
  				System.out.println(String.format("lineNo=%s, rowNo=%s, customer=%s", beanReader.getLineNumber(),
 					beanReader.getRowNumber(), customer));
 			}
 			
 		}
 		finally {
 			if( beanReader != null ) {
 				beanReader.close();
 			}
 		}
 	}
 	
 	/**
 	 * An example of reading using CsvListReader.
 	 */
 	private static void readWithCsvListReader() throws Exception {
 		
 		ICsvListReader listReader = null;
 		try {
 			listReader = new CsvListReader(new FileReader(CSV_FILENAME), CsvPreference.STANDARD_PREFERENCE);
 			
 			listReader.getHeader(true); // skip the header (can't be used with CsvListReader)
 			final CellProcessor[] processors = getProcessors();
 			
 			List<Object> customerList;
 			while( (customerList = listReader.read(processors)) != null ) {
 				System.out.println(String.format("lineNo=%s, rowNo=%s, customerList=%s", listReader.getLineNumber(),
 					listReader.getRowNumber(), customerList));
 			}
 			
 		}
 		finally {
 			if( listReader != null ) {
 				listReader.close();
 			}
 		}
 	}
 	
 	/**
 	 * An example of reading a file with a variable number of columns using CsvListReader. It demonstrates that you can
 	 * still use cell processors, but you must execute them by calling the executeProcessors() method on the reader,
 	 * instead of supplying processors to the read() method. In this scenario, the last column (birthDate) is sometimes
 	 * missing.
 	 */
 	private static void readVariableColumnsWithCsvListReader() throws Exception {
 		
 		final CellProcessor[] allProcessors = new CellProcessor[] { new UniqueHashCode(), // customerNo (must be unique)
 			new NotNull(), // firstName
 			new NotNull(), // lastName
 			new ParseDate("dd/MM/yyyy") }; // birthDate
 		
 		final CellProcessor[] noBirthDateProcessors = new CellProcessor[] { allProcessors[0], // customerNo
 			allProcessors[1], // firstName
 			allProcessors[2] }; // lastName
 		
 		ICsvListReader listReader = null;
 		try {
 			listReader = new CsvListReader(new FileReader(VARIABLE_CSV_FILENAME), CsvPreference.STANDARD_PREFERENCE);
 			
 			listReader.getHeader(true); // skip the header (can't be used with CsvListReader)
 			
 			while( (listReader.read()) != null ) {
 				
 				// use different processors depending on the number of columns
 				final CellProcessor[] processors;
 				if( listReader.length() == noBirthDateProcessors.length ) {
 					processors = noBirthDateProcessors;
 				} else {
 					processors = allProcessors;
 				}
 				
 				final List<Object> customerList = listReader.executeProcessors(processors);
 				System.out.println(String.format("lineNo=%s, rowNo=%s, columns=%s, customerList=%s",
 					listReader.getLineNumber(), listReader.getRowNumber(), customerList.size(), customerList));
 			}
 			
 		}
 		finally {
 			if( listReader != null ) {
 				listReader.close();
 			}
 		}
 	}
 	
 	/**
 	 * An example of reading using CsvMapReader.
 	 */
 	private static void readWithCsvMapReader() throws Exception {
 		
 		ICsvMapReader mapReader = null;
 		try {
 			mapReader = new CsvMapReader(new FileReader(CSV_FILENAME), CsvPreference.STANDARD_PREFERENCE);
 			
 			// the header columns are used as the keys to the Map
 			final String[] header = mapReader.getHeader(true);
 			final CellProcessor[] processors = getProcessors();
 			
 			Map<String, Object> customerMap;
 			while( (customerMap = mapReader.read(header, processors)) != null ) {
 				System.out.println(String.format("lineNo=%s, rowNo=%s, customerMap=%s", mapReader.getLineNumber(),
 					mapReader.getRowNumber(), customerMap));
 			}
 			
 		}
 		finally {
 			if( mapReader != null ) {
 				mapReader.close();
 			}
 		}
 	}
 	
 	/**
 	 * An example of partial reading using CsvBeanReader.
 	 */
 	private static void partialReadWithCsvBeanReader() throws Exception {
 		
 		ICsvBeanReader beanReader = null;
 		try {
 			beanReader = new CsvBeanReader(new FileReader(CSV_FILENAME), CsvPreference.STANDARD_PREFERENCE);
 			
 			beanReader.getHeader(true); // skip past the header (we're defining our own)
 			
 			// only map the first 3 columns - setting header elements to null means those columns are ignored
 			final String[] header = new String[] { "customerNo", "firstName", "lastName", null, null, null, null, null,
 				null, null };
 			
 			// no processing required for ignored columns
 			final CellProcessor[] processors = new CellProcessor[] { new UniqueHashCode(), new NotNull(),
 				new NotNull(), null, null, null, null, null, null, null };
 			
 			CustomerBean customer;
 			while( (customer = beanReader.read(CustomerBean.class, header, processors)) != null ) {
 				System.out.println(String.format("lineNo=%s, rowNo=%s, customer=%s", beanReader.getLineNumber(),
 					beanReader.getRowNumber(), customer));
 			}
 			
 		}
 		finally {
 			if( beanReader != null ) {
 				beanReader.close();
 			}
 		}
 	}
 	
 	/**
 	 * An example of partial reading using CsvMapReader.
 	 */
 	private static void partialReadWithCsvMapReader() throws Exception {
 		
 		ICsvMapReader mapReader = null;
 		try {
 			mapReader = new CsvMapReader(new FileReader(CSV_FILENAME), CsvPreference.STANDARD_PREFERENCE);
 			
 			mapReader.getHeader(true); // skip past the header (we're defining our own)
 			
 			// only map the first 3 columns - setting header elements to null means those columns are ignored
 			final String[] header = new String[] { "customerNo", "firstName", "lastName", null, null, null, null, null,
 				null, null };
 			
 			// apply some constraints to ignored columns (just because we can)
 			final CellProcessor[] processors = new CellProcessor[] { new UniqueHashCode(), new NotNull(),
 				new NotNull(), new NotNull(), new NotNull(), new Optional(), new Optional(), new NotNull(),
 				new NotNull(), new LMinMax(0L, LMinMax.MAX_LONG) };
 			
 			Map<String, Object> customerMap;
 			while( (customerMap = mapReader.read(header, processors)) != null ) {
 				System.out.println(String.format("lineNo=%s, rowNo=%s, customerMap=%s", mapReader.getLineNumber(),
 					mapReader.getRowNumber(), customerMap));
 			}
 			
 		}
 		finally {
 			if( mapReader != null ) {
 				mapReader.close();
 			}
 		}
 	}
 	
 }