de.hypoport.ep2.support.configuration.properties.PropertiesLoader.java Source code

Introduction

Here is the source code for de.hypoport.ep2.support.configuration.properties.PropertiesLoader.java

Source

/**
 * Copyright 2012 HYPOPORT AG
 *
 *  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 de.hypoport.ep2.support.configuration.properties;

import org.apache.log4j.Logger;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Properties;
import java.util.Set;

import static java.lang.String.format;
import static org.apache.commons.lang.StringUtils.isBlank;

/**
 * @author Timmo Freudl-Gierke
 */
public class PropertiesLoader {

    public static final String PROPERTY_LOCATIONS = "propertyLocations";

    private static final Logger LOG = Logger.getLogger(PropertiesLoader.class);

    static boolean initialized = false;
    private static final Set<Object> sslPropertiesKeys;

    static {
        sslPropertiesKeys = new HashSet<>();
        sslPropertiesKeys.add("javax.net.ssl.trustStore");
        sslPropertiesKeys.add("javax.net.ssl.trustStorePassword");
    }

    /** Evaluates system property "propertyLocations" to find property files. */
    public static void loadPropertiesLocationsIntoSystemProperties() {
        if (initialized) {
            return;
        }

        initializeInternal();
    }

    private static synchronized void initializeInternal() {
        if (!initialized) {
            String propertyLocations = System.getProperty(PROPERTY_LOCATIONS);

            Properties loadedProperties = loadPropertiesLocations(propertyLocations);
            Set<Object> loadedPropertyKeys = new HashSet<Object>(loadedProperties.keySet());

            mergePropertiesIntoSystemPropertiesWithoutOverwriting(loadedProperties);

            replacePropertyPlaceHolder(System.getProperties());

            logProperties(loadedPropertyKeys, System.getProperties());
            logProperties(sslPropertiesKeys, System.getProperties());
            initialized = true;
        }
    }

    private static void logProperties(Set<Object> filter, Properties properties) {
        String propertiesAsText = "";
        for (Object key : filter) {
            propertiesAsText = propertiesAsText + "\n" + key + "=" + properties.get(key);
        }
        LOG.info("Loaded properties: " + propertiesAsText);
    }

    static Properties loadPropertiesLocations(String propertyLocations) {
        if (isBlank(propertyLocations)) {
            return new Properties();
        }

        Properties loadedProperties = new Properties();
        for (String location : propertyLocations.split(",")) {
            try {
                Properties locationProperties = loadPropertiesFromLocation(location);
                if (propertyLocationsPresent(locationProperties)) {
                    Properties recursiveLoadedProperties = loadPropertiesLocations(
                            locationProperties.getProperty(PROPERTY_LOCATIONS));
                    locationProperties.putAll(recursiveLoadedProperties);
                }
                loadedProperties.putAll(locationProperties);
            } catch (IOException e) {
                LOG.warn(format("Cannot load properties from location %s. Error: %s", location, e.getMessage()));
            }
        }

        return loadedProperties;
    }

    private static boolean propertyLocationsPresent(Properties locationProperties) {
        return locationProperties.containsKey(PROPERTY_LOCATIONS);
    }

    private static void mergePropertiesIntoSystemPropertiesWithoutOverwriting(Properties properties) {
        if (properties == null || properties.size() == 0) {
            return;
        }
        Properties systemProperties = System.getProperties();
        properties.putAll(systemProperties);
        systemProperties.putAll(properties);
    }

    private static Properties loadPropertiesFromLocation(String location) throws IOException {
        if (LOG.isDebugEnabled()) {
            LOG.debug("loading from location " + location);
        }
        Properties properties = new Properties();
        if (location.startsWith("classpath:")) {
            properties = loadPropertiesFromClasspathLocation(stripSchema("classpath:", location));
        } else if (location.startsWith("file:")) {
            properties = loadPropertiesFromFile(stripSchema("file:", location));
        } else {
            throw new IOException("Use one schema from {\"classpath:\",\"file:\"}");
        }
        return properties;
    }

    static String stripSchema(String schema, String location) {
        return location.substring(schema.length(), location.length());
    }

    private static Properties loadPropertiesFromClasspathLocation(String location) throws IOException {
        if (isBlank(location)) {
            return new Properties();
        }
        InputStream inputStream = PropertiesLoader.class.getResourceAsStream(location);
        return loadPropertiesFromInputStream(inputStream);
    }

    private static Properties loadPropertiesFromFile(String location) throws IOException {
        if (isBlank(location)) {
            return new Properties();
        }
        FileInputStream inputStream = new FileInputStream(location);
        return loadPropertiesFromInputStream(inputStream);
    }

    private static Properties loadPropertiesFromInputStream(InputStream inputStream) throws IOException {
        Properties properties = new Properties();

        if (inputStream != null) {
            properties.load(inputStream);
        }

        return properties;
    }

    static void replacePropertyPlaceHolder(Properties properties) {

        Enumeration<?> keyEnum = properties.propertyNames();
        while (keyEnum.hasMoreElements()) {
            String key = (String) keyEnum.nextElement();
            Object value = properties.get(key);
            if (value != null && value instanceof String) {
                String valueString = (String) value;
                valueString = replacePropertyPlaceHolder(valueString, properties);
                properties.put(key, valueString);
            }
        }
    }

    private static String replacePropertyPlaceHolder(String value, Properties properties) {
        while (value.contains("${")) {
            int start = value.indexOf("${");
            int end = value.indexOf("}");
            if (start < end) {
                String propertyPlaceHolder = value.substring(start, end + 1);
                String propertyName = propertyPlaceHolder.substring(2, propertyPlaceHolder.length() - 1);
                Object propertyValue = properties.get(propertyName);
                if (propertyValue == null) {
                    propertyValue = "";
                }
                value = value.replace(propertyPlaceHolder, (String) propertyValue);
            } else {
                value = value.replace("${", "");
                LOG.warn("Cannot resolve all properties in " + value);
            }
        }
        return value;
    }
}