org.openxdata.server.OpenXDataPropertyPlaceholderConfigurer.java Source code

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Here is the source code for org.openxdata.server.OpenXDataPropertyPlaceholderConfigurer.java

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/*
 *  Licensed to the OpenXdata Foundation (OXDF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The OXDF 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.
 *
 *  Copyright 2010 http://www.openxdata.org.
 */
package org.openxdata.server;

import java.io.File;
import java.io.IOException;
import java.util.Properties;

import javax.servlet.ServletContext;

import org.apache.log4j.Logger;
import org.springframework.beans.factory.config.PropertyPlaceholderConfigurer;
import org.springframework.core.io.FileSystemResource;
import org.springframework.web.context.ServletContextAware;
import org.springframework.web.context.support.ServletContextResource;

/**
 * Extends the Spring PropertyPlaceholderConfigurer
 * which allows access to variables in the OPENXDATA_SETTINGS.property file.
 *
 * @author simon@cell-life.org
 */
public class OpenXDataPropertyPlaceholderConfigurer extends PropertyPlaceholderConfigurer
        implements ServletContextAware {

    private Logger log = Logger.getLogger(this.getClass());

    static final String SETTINGS_SUFFIX = "_SETTINGS";
    private static final String DEFAULT_CONTEXT_PATH = "/OPENXDATA";
    static final String PROPERTIES_FILENAME = "OPENXDATA_SETTINGS.properties";

    public Properties resolvedProps;

    private ServletContext servletContext;

    @Override
    protected void loadProperties(Properties props) throws IOException {
        setIgnoreResourceNotFound(true);
        super.loadProperties(props);

        loadContextBasedProperties(props);
        resolvedProps = props;
    }

    void loadContextBasedProperties(Properties props) throws IOException {
        // only attempt to load new properties if properties could not be loaded
        // from default location
        if (servletContext != null && props.isEmpty()) {
            loadFromWebappFolder(props, PROPERTIES_FILENAME);
            loadFromEnvironmentVariable(props);
        }
    }

    void loadFromEnvironmentVariable(Properties props) throws IOException {
        String contextPath = servletContext.getContextPath();
        contextPath = contextPath.length() == 0 ? DEFAULT_CONTEXT_PATH : contextPath;
        File settingsFile = getSettingsFile(contextPath);
        if (settingsFile != null) {
            log.info("Attempting to load properties from: " + settingsFile.getAbsolutePath());
            setLocation(settingsFile);
            super.loadProperties(props);
        }
    }

    void loadFromWebappFolder(Properties props, String location) throws IOException {
        log.info("Attempting to load properties from servlet context path: " + location);
        setLocation(location);
        super.loadProperties(props);
    }

    File getSettingsFile(String contextPath) {
        String expectedVariableName = getEnvironmentVariableFromContextPath(contextPath);

        String systemVariable = System.getenv(expectedVariableName);
        if (systemVariable == null) {
            systemVariable = System.getProperty(expectedVariableName);
        }

        File settingsFile = null;
        if (systemVariable != null) {
            settingsFile = new File(systemVariable);
        } else {
            log.warn("Unable to find environment or system variable: " + expectedVariableName);
        }
        return settingsFile;
    }

    String getEnvironmentVariableFromContextPath(String contextPath) {
        if (contextPath.startsWith("/")) {
            contextPath = contextPath.substring(1);
        }
        contextPath = contextPath.toUpperCase().replaceAll("\\W", "_");
        String expectedVariableName = contextPath + SETTINGS_SUFFIX;
        return expectedVariableName;
    }

    private void setLocation(File fileLocation) {
        if (fileLocation != null) {
            FileSystemResource resource = new FileSystemResource(fileLocation);
            setLocation(resource);
        }
    }

    private void setLocation(String location) {
        if (location != null && servletContext != null) {
            ServletContextResource resource = new ServletContextResource(servletContext, location);
            setLocation(resource);
        }
    }

    public Properties getResolvedProps() {
        return resolvedProps;
    }

    @Override
    public void setServletContext(ServletContext servletContext) {
        this.servletContext = servletContext;
    }
}