com.threewks.thundr.configuration.PropertiesLoader.java Source code

Introduction

Here is the source code for com.threewks.thundr.configuration.PropertiesLoader.java

Source

/*
 * This file is a component of thundr, a software library from 3wks.
 * Read more: http://3wks.github.io/thundr/
 * Copyright (C) 2014 3wks, <thundr@3wks.com.au>
 *
 * 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.threewks.thundr.configuration;

import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Scanner;

import org.apache.commons.lang3.StringUtils;

import com.threewks.thundr.util.Streams;

public class PropertiesLoader {
    /**
     * Loads properties from the given file name as a resource.
     * 
     * @param filename
     * @return
     * @throws ConfigurationException if the file does not exist or there was a problem parsing the file.
     */
    public Map<String, String> load(String filename) {
        try {
            String resourceAsString = Streams.getResourceAsString(filename);
            return readProperties(resourceAsString);
        } catch (Exception e) {
            throw new ConfigurationException(e, "Failed to load properties from %s: %s", filename, e.getMessage());
        }
    }

    /**
     * Loads properties from the given file name as a resource. Returns null if the resource does not exist.
     * 
     * @param filename
     * @return
     * @throws ConfigurationException if there was a problem parsing the file.
     */
    public Map<String, String> loadSafe(String filename) {
        try {
            String resourceAsString = Streams.getResourceAsString(filename);
            return readProperties(resourceAsString);
        } catch (Exception e) {
            return null;
        }
    }

    private Map<String, String> readProperties(String resourceAsString) {
        Map<String, String> properties = new LinkedHashMap<String, String>();
        Scanner scanner = new Scanner(resourceAsString);
        try {
            while (scanner.hasNextLine()) {
                String line = scanner.nextLine();
                line = StringUtils.substringBefore(line, "#");
                line = StringUtils.trimToNull(line);
                String key = StringUtils.substringBefore(line, "=");
                String value = StringUtils.substringAfter(line, "=");
                if (key != null) {
                    properties.put(key, value);
                }
            }
        } finally {
            scanner.close();
        }
        return properties;
    }
}