CcsCsvReader.java

/*
 * Copyright 2012 Shared Learning Collaborative, LLC
 *
 * 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.slc.sli.sample.transform;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.RandomAccessFile;
import java.util.HashMap;
import java.util.Map;
import java.util.regex.Pattern;

import org.apache.commons.csv.CSVParser;
import org.apache.commons.csv.CSVStrategy;

public class CcsCsvReader {

    private static Pattern commaAndSpaces = Pattern.compile("^[\\s,]*$");

    private CSVParser csvParser;
    private Map<String, String> currentRecord;
    private String[] firstLine;
    private String copyright;
    private boolean containsCopyright;
    private String fileLocation;

    void setFileLocation(String fileLocation) throws IOException {
        this.fileLocation = fileLocation;
    }

    void setContainsCopyright(boolean containsCopyright) {
        this.containsCopyright = containsCopyright;
    }

    void load() throws IOException {
        File file = new File(fileLocation);
        file = removeEmptyLinesFromCsv(file);
        if (containsCopyright) {
            copyright = removeTrailingCharacters(tail(file), ',');
            file = removeLastLine(file);
        }
        InputStreamReader isReader = new InputStreamReader(new FileInputStream(file), "UTF-8");
        csvParser = new CSVParser(isReader, CSVStrategy.EXCEL_STRATEGY);

        firstLine = csvParser.getLine();
        getNextRecord();
    }

    void getNextRecord() throws IOException {
        String[] line = csvParser.getLine();
        if (line == null) {
            currentRecord = null;
            return;
        }
        Map<String, String> record = new HashMap<String, String>();
        for (int i = 0; i < firstLine.length; i++) {
            record.put(firstLine[i], line[i]);
        }
        currentRecord = record;
    }

    Map<String, String> getCurrentRecord() {
        return currentRecord;
    }

    String getCopyright() {
        return copyright;
    }

    private String tail(File file) {
        try {
            RandomAccessFile fileHandler = new RandomAccessFile(file, "r");
            long fileLength = file.length() - 1;
            long filePointer;

            for (filePointer = fileLength; filePointer != -1; filePointer--) {
                fileHandler.seek(filePointer);
                int readByte = fileHandler.readByte();

                if (readByte == 0xA) {
                    if (filePointer == fileLength) {
                        continue;
                    } else {
                        break;
                    }
                } else if (readByte == 0xD) {
                    if (filePointer == fileLength - 1) {
                        continue;
                    } else {
                        break;
                    }
                }

            }

            String lastLine=fileHandler.readLine();
            fileHandler.close();

            return lastLine.substring(1);
        } catch (java.io.FileNotFoundException e) {
            e.printStackTrace();
            return null;
        } catch (java.io.IOException e) {
            e.printStackTrace();
            return null;
        }
    }

    private String removeTrailingCharacters(String s, char c) {
        int lastNonCommaIndex = -1;
        for (int i = s.length() - 1; i >= 0; i--) {
            if (s.charAt(i) != c) {
                lastNonCommaIndex = i;
                break;
            }
        }
        if (lastNonCommaIndex != -1) {
            return s.substring(0, lastNonCommaIndex + 1);
        }
        return "";
    }

    private File removeLastLine(File fileIn) throws IOException {
        File tempFile = File.createTempFile("temp", "txt");
        tempFile.deleteOnExit();
        BufferedWriter writer = new BufferedWriter(new FileWriter(tempFile));
        BufferedReader reader = new BufferedReader(new FileReader(fileIn));

        String previousLine = reader.readLine();
        if (previousLine != null) {
            for (;;) {
                String line = reader.readLine();
                if (line == null) {
                    break;
                } else {
                    writer.write(previousLine);
                    writer.write('\n');
                    previousLine = line;
                }
            }
        }
        reader.close();
        writer.close();
        return tempFile;
    }

    private File removeEmptyLinesFromCsv(File csvFileIn) throws IOException {
        File tempFile = File.createTempFile("temp", "txt");
        tempFile.deleteOnExit();
        BufferedWriter writer = new BufferedWriter(new FileWriter(tempFile));
        BufferedReader reader = new BufferedReader(new FileReader(csvFileIn));
        for (;;) {
            String line = reader.readLine();
            if (line == null) {
                break;
            } else if ("".equals(line.trim())) {
                continue;
            } else if (!commaAndSpaces.matcher(line).matches()) {
                writer.write(line);
                writer.write('\n');
            }
        }
        reader.close();
        writer.close();
        return tempFile;
    }
}