org.sakaiproject.kernel.util.PropertiesLoader.java Source code

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Here is the source code for org.sakaiproject.kernel.util.PropertiesLoader.java

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/*
 * Licensed to the Sakai Foundation (SF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The SF licenses this file
 * to you 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.sakaiproject.kernel.util;

import com.google.inject.CreationException;
import com.google.inject.spi.Message;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
import java.util.Properties;
import java.util.Map.Entry;

/**
 * Loads properties accepting overrides from named system variables and named
 * environment variables.
 */
public final class PropertiesLoader {
    private static final Log LOG = LogFactory.getLog(PropertiesLoader.class);

    /**
     * @param classLoader
     *          the classloader where the properties are to be loaded from.
     */
    /**
     * @param classLoader
     *          the classloader where the properties are to be loaded from.
     * @param defaultPropertiesLocation
     *          the default location in above name where the property will come
     *          from
     * @param localPropertiesName
     *          the name of the environment varaible that stores the local
     *          properties
     * @param sysPropertiesName
     *          the name of the java system property that contains local
     *          properties.
     * @return a properties set.
     */
    public static Properties load(ClassLoader classLoader, String defaultPropertiesLocation,
            String localPropertiesName, String sysPropertiesName) {
        InputStream is = null;
        Properties properties;
        try {
            is = ResourceLoader.openResource(defaultPropertiesLocation, classLoader);
            properties = new Properties();
            properties.load(is);
            LOG.info("Loaded " + properties.size() + " default properties from: " + defaultPropertiesLocation);
        } catch (IOException e) {
            throw new CreationException(
                    Arrays.asList(new Message("Unable to load properties: " + defaultPropertiesLocation)));
        } finally {
            try {
                if (is != null) {
                    is.close();
                }
            } catch (IOException e) {
                // dont care about this.
            }
        }
        // load local properties if specified as a system property
        String localPropertiesLocation = System.getenv(localPropertiesName);
        String sysLocalPropertiesLocation = System.getProperty(sysPropertiesName);
        if (sysLocalPropertiesLocation != null) {
            localPropertiesLocation = sysLocalPropertiesLocation;
        }
        try {
            if (localPropertiesLocation != null && localPropertiesLocation.trim().length() > 0) {
                is = ResourceLoader.openResource(localPropertiesLocation, classLoader);
                Properties localProperties = new Properties();
                localProperties.load(is);
                for (Entry<Object, Object> o : localProperties.entrySet()) {
                    String k = o.getKey().toString();
                    if (k.startsWith("+")) {
                        String p = properties.getProperty(k.substring(1));
                        if (p != null) {
                            properties.put(k.substring(1), p + o.getValue());
                        } else {
                            properties.put(o.getKey(), o.getValue());
                        }
                    } else {
                        properties.put(o.getKey(), o.getValue());
                    }
                }
                LOG.info("Loaded " + localProperties.size() + " local properties from " + localPropertiesLocation);
            } else {
                LOG.info("No Local Properties Override, set system property " + localPropertiesName
                        + " to a resource location to override kernel properties");
            }

            StringBuilder sb = new StringBuilder();
            sb.append("Merged Property Set includes keys: ");
            for (Entry<?, ?> e : properties.entrySet()) {
                sb.append("\"").append(e.getKey()).append("\"").append("; ");
            }
            LOG.info("Loaded " + properties.size() + " properties into merged property set");
            LOG.debug(sb.toString());

        } catch (IOException e) {
            LOG.info("Failed to startup ", e);
            throw new CreationException(
                    Arrays.asList(new Message("Unable to load properties: " + localPropertiesLocation)));
        } finally {
            try {
                if (is != null) {
                    is.close();
                }
            } catch (IOException e) {
                // dont care about this.
            }
        }
        return properties;
    }

    /**
     * @param classLoader
     * @param defaultProperties
     * @return
     */
    public static Properties load(ClassLoader classLoader, String defaultPropertiesLocation) {
        InputStream is = null;
        Properties properties;
        try {
            is = ResourceLoader.openResource(defaultPropertiesLocation, classLoader);
            properties = new Properties();
            properties.load(is);
            LOG.info("Loaded " + properties.size() + " properties from " + defaultPropertiesLocation);
        } catch (IOException e) {
            throw new CreationException(
                    Arrays.asList(new Message("Unable to load properties: " + defaultPropertiesLocation)));
        } finally {
            try {
                if (is != null) {
                    is.close();
                }
            } catch (IOException e) {
                // dont care about this.
            }
        }
        return properties;
    }
}