ca.uhn.hl7v2.util.PropertyLoader Maven / Gradle / Ivy
package ca.uhn.hl7v2.util;
import java.io.BufferedReader;
import java.io.FileReader;
import java.util.StringTokenizer;
import java.util.*;
import java.io.FileNotFoundException;
import java.io.IOException;
import ca.uhn.log.HapiLog;
import ca.uhn.log.HapiLogFactory;
/**
* Loads system properties from a file. This is intended as a convenient way
* of setting multiple system properties.
*/
public class PropertyLoader {
private static final HapiLog log = HapiLogFactory.getHapiLog(PropertyLoader.class);
private static HashSet files = new HashSet();
private PropertyLoader() {
}
/**
* Calls loadProperties() if it has not been called before for
* the given file. If the given property file has already been loaded, this
* method does nothing.
*/
public static void loadOnce(String propertyFileName) throws IOException {
if (!files.contains(propertyFileName)) {
loadProperties(propertyFileName);
files.add(propertyFileName);
}
}
/**
* Reads given "property file" and sets system properties accordingly. In the property file,
* there should be one property per line. A line should consist of 1) the fully qualified property name,
* 2) one or more tabs, and 3) the value (everything after the first group of tabs and before any subsequent
* groups will be considered "the value").
* Lines in the file are consdidered comments if they begin with "%".
*/
public static void loadProperties(String propertyFileName) throws IOException {
//open stream from given property file
BufferedReader in = null;
in = new BufferedReader(new FileReader(propertyFileName));
String line, key, value, delim = "\t";
StringTokenizer tok;
while ((line = in.readLine()) != null) {
//ignore comments
if (!line.startsWith("%")) {
key = null; value = null;
//get property key and value
tok = new StringTokenizer(line, delim, false);
if (tok.hasMoreTokens()) key = tok.nextToken();
if (tok.hasMoreTokens()) value = tok.nextToken();
//set property
if (key != null && value != null) {
System.setProperty(key, value);
log.debug("Setting system property " + key + " to " + value);
}
}
}
in.close();
}
/** Test harness */
public static void main(String args[]) {
if (args.length != 1) {
System.out.println("Usage: PropertyLoader file");
System.exit(1);
}
try {
System.setProperty("ca.uhn.hl7v2.util.status.level", "VERBOSE");
System.out.println("Loading properties in file " + args[0]);
loadOnce(args[0]);
System.out.println("Loading properties in file " + args[0] + " again");
loadOnce(args[0]);
} catch (Exception e) {
e.printStackTrace();
}
Properties p = System.getProperties();
Enumeration en = p.propertyNames();
while (en.hasMoreElements()) {
String key = (String) en.nextElement();
System.out.println("Property: " + key + " Value: " + System.getProperty(key));
}
}
}