Java example source code file (DefaultCurrencyUnitDataProvider.java)

This example Java source code file (DefaultCurrencyUnitDataProvider.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

a-z, arraylist, bufferedreader, defaultcurrencyunitdataprovider, exception, filenotfoundexception, inputstreamreader, ioexception, matcher, override, pattern, regex, regex_line, string, utf-8, util

The DefaultCurrencyUnitDataProvider.java Java example source code

/*
 *  Copyright 2009-present, Stephen Colebourne
 *
 *  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.joda.money;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Provider for available currencies using a file.
 * <p>
 * This reads currencies from two files.
 * Firstly it reads the mandatory resource named {@code /org/joda/money/MoneyData.csv}.
 * Then it reads the optional resource named {@code /org/joda/money/MoneyDataExtension.csv}.
 * Both will be read as the first found on the classpath.
 * The second file may replace entries in the first file.
 */
class DefaultCurrencyUnitDataProvider extends CurrencyUnitDataProvider {

    /** Regex format for the csv line. */
    private static final Pattern REGEX_LINE = Pattern.compile("([A-Z]{3}),(-1|[0-9]{1,3}),(-1|[0-9]),([A-Z]*)#?.*");

    /**
     * Registers all the currencies known by this provider.
     * 
     * @throws Exception if an error occurs
     */ 
    @Override
    protected void registerCurrencies() throws Exception {
        loadCurrenciesFromFile("/org/joda/money/MoneyData.csv", true);
        loadCurrenciesFromFile("/org/joda/money/MoneyDataExtension.csv", false);
    }
    
    /**
     * Loads Currencies from a file
     *  
     * @param fileName  the file to load, not null
     * @param isNecessary  whether or not the file is necessary
     * @throws Exception if a necessary file is not found
     */
    private void loadCurrenciesFromFile(String fileName, boolean isNecessary) throws Exception {
        InputStream in = null;
        Exception resultEx = null;
        try {
            in = getClass().getResourceAsStream(fileName);
            if (in == null && isNecessary) {
                throw new FileNotFoundException("Data file " + fileName + " not found");
            } else if (in == null && !isNecessary) {
                return; // no extension file found, no problem. just return
            }
            BufferedReader reader = new BufferedReader(new InputStreamReader(in, "UTF-8"));
            String line;
            while ((line = reader.readLine()) != null) {
                Matcher matcher = REGEX_LINE.matcher(line);
                if (matcher.matches()) {
                    List<String> countryCodes = new ArrayList();
                    String codeStr = matcher.group(4);
                    String currencyCode = matcher.group(1);
                    if (codeStr.length() % 2 == 1) {
                        continue;  // invalid line
                    }
                    for (int i = 0; i < codeStr.length(); i += 2) {
                        countryCodes.add(codeStr.substring(i, i + 2));
                    }
                    int numericCode = Integer.parseInt(matcher.group(2));
                    int digits = Integer.parseInt(matcher.group(3));
                    registerCurrency(currencyCode, numericCode, digits, countryCodes);
                }
            }
        } catch (Exception ex) {
            resultEx = ex;
            throw ex;
        } finally {
            if (in != null) {
                if (resultEx != null) {
                    try {
                        in.close();
                    } catch (IOException ignored) {
                        throw resultEx;
                    }
                } else {
                    in.close();
                }
            }
        }
    }

}