SQLUtils.java

package arida.ufc.br.moap.core.database.imp;

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

public class SQLUtils {

    /**
     * Reads properties that inherit from three locations. Properties are first
     * defined in the system resource location (i.e. in the CLASSPATH). These
     * default properties must exist. Properties defined in the users home
     * directory (optional) override default settings. Properties defined in the
     * current directory (optional) override all these settings.
     *
     * @param resourceName the location of the resource that should be loaded.
     * e.g.: "weka/core/Utils.props". (The use of hardcoded forward slashes here
     * is OK - see jdk1.1/docs/guide/misc/resources.html) This routine will also
     * look for the file (in this case) "Utils.props" in the users home
     * directory and the current directory.
     * @return the Properties
     * @exception Exception if no default properties are defined, or if an error
     * occurs reading the properties files.
     */
    public static Properties readProperties(String resourceName)
            throws Exception {

        Properties defaultProps = new Properties();
        try {
            // Apparently hardcoded slashes are OK here
            // jdk1.1/docs/guide/misc/resources.html
            //      defaultProps.load(ClassLoader.getSystemResourceAsStream(resourceName));
            defaultProps.load((new SQLUtils()).getClass().getClassLoader().getResourceAsStream(resourceName));
        } catch (Exception ex) {
            /*      throw new Exception("Problem reading default properties: "
             + ex.getMessage()); */
            System.err.println("Warning, unable to load properties file from "
                    + "system resource (Utils.java)");
        }

        // Hardcoded slash is OK here
        // eg: see jdk1.1/docs/guide/misc/resources.html
        int slInd = resourceName.lastIndexOf('/');
        if (slInd != -1) {
            resourceName = resourceName.substring(slInd + 1);
        }

        // Allow a properties file in the home directory to override
        Properties userProps = new Properties(defaultProps);
        File propFile = new File(System.getProperties().getProperty("user.home")
                + File.separatorChar
                + resourceName);
        if (propFile.exists()) {
            try {
                userProps.load(new FileInputStream(propFile));
            } catch (Exception ex) {
                throw new Exception("Problem reading user properties: " + propFile);
            }
        }

        // Allow a properties file in the current directory to override
        Properties localProps = new Properties(userProps);
        propFile = new File(resourceName);
        if (propFile.exists()) {
            try {
                localProps.load(new FileInputStream(propFile));
            } catch (Exception ex) {
                throw new Exception("Problem reading local properties: " + propFile);
            }
        }

        return localProps;
    }
}