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Utility classes developed at Adrian Smith Software (A.S.S.)
package com.databasesandlife.util;
import java.util.*;
/**
* Utility class for manipulating Properties objects, as if they were
* hierarchical objects. Lists can be created with .0. .1., etc, and key/value
* pairs can also be constructed.
*
* @author This source is copyright Adrian Smith and licensed under the LGPL 3.
* @see Project on GitHub
*/
public class PropertiesUtil {
protected static Hashtable propertiesForResouceName = new Hashtable<>();
/**
* Takes a prefix like "rules" and then finds "rules.0.x" etc, puts them
* into lots of Properties objects with keys like "x" and position 0 in
* the array. If prefix is "" then finds "0.x" etc.
*/
public static List splitToList(Properties p, String prefix) {
if ( ! prefix.equals("")) prefix += ".";
var propertiesForIndex = new ArrayList();
for (var e = p.keys(); e.hasMoreElements(); ) {
var key = (String) e.nextElement();
if (! key.startsWith(prefix)) continue; // wrong prefix
var indexAndSubKey = key.substring(prefix.length());
var dotAfterIndex = indexAndSubKey.indexOf('.');
if (dotAfterIndex == -1) continue; // seems to have no "."
var indexStr = indexAndSubKey.substring(0, dotAfterIndex);
var index = Integer.parseInt(indexStr);
while (index >= propertiesForIndex.size()) propertiesForIndex.add(new Properties());
var propsThisIndex = propertiesForIndex.get(index);
var subKey = indexAndSubKey.substring(dotAfterIndex+1);
var value = p.getProperty(key);
propsThisIndex.setProperty(subKey, value);
}
return propertiesForIndex;
}
/**
* Takes a prefix like "rules" and then finds "rules.0.x" etc, puts them
* into lots of Properties objects with keys like "x" and position 0 in
* the array. If prefix is "" then finds "0.x" etc.
*/
public static Properties[] splitToArray(Properties p, String prefix) {
return splitToList(p, prefix).toArray(new Properties[0]);
}
/** Takes a prefix like "rules" and then finds "rules.name.key", puts
* them in a Hashtable of Property objects, where they keys are the
* strings like "name", and the values are Properties objects, from
* "key" to value. If prefix is "" then finds "name.key" etc.
* @return a Hashtable from String objects to Properties objects
* @deprecated use {@link #splitToMap(Properties,String)}
*/
@Deprecated public static Hashtable splitToHashtable(Properties p, String prefix) {
if ( ! prefix.equals("")) prefix += ".";
Hashtable propertiesForName = new Hashtable<>();
for (var e = p.keys(); e.hasMoreElements(); ) {
var key = (String) e.nextElement();
if (! key.startsWith(prefix)) continue; // wrong prefix
var nameAndSubKey = key.substring(prefix.length());
var dotAfterName = nameAndSubKey.indexOf('.');
if (dotAfterName == -1) continue; // seems to have no "."
var name = nameAndSubKey.substring(0, dotAfterName);
var propsThisName = propertiesForName.get(name);
if (propsThisName == null)
propertiesForName.put(name, propsThisName = new Properties());
var subKey = nameAndSubKey.substring(dotAfterName+1);
var value = p.getProperty(key);
propsThisName.setProperty(subKey, value);
}
return propertiesForName;
}
/** Takes a prefix like "rules" and then finds "rules.name.key", puts
* them in a Map. The keys are
* strings like "name", and the values are Properties objects, from
* "key" to value. If prefix is "" then finds "name.key" etc.
*/
public static Map splitToMap(Properties p, String prefix) {
return splitToHashtable(p, prefix);
}
/** Takes a Properties with keys such as "rules.x" and "y", and a prefix
* string such as "rules" and returns a new Properties with keys such
* as "x". */
public static Properties getSubProperties(Properties p, String prefix) {
prefix += ".";
var result = new Properties();
for (var e = p.keys(); e.hasMoreElements(); ) {
var key = (String) e.nextElement();
if (! key.startsWith(prefix)) continue; // wrong prefix
var subKey = key.substring(prefix.length());
result.setProperty(subKey, p.getProperty(key));
}
return result;
}
/** Determines if getSubProperties would return an empty Properties
* or not. (But it's faster than calling getSubProperties)
* @see #getSubProperties */
public static boolean existsSubProperties(Properties p, String prefix) {
prefix += ".";
for (var e = p.keys(); e.hasMoreElements(); ) {
var key = (String) e.nextElement();
if (key.startsWith(prefix)) return true;
}
return false;
}
/** Takes a properties and prefixes all entries with prefix and a dot */
public static Properties prefixAllProperties(Properties p, String prefix) {
prefix += ".";
var result = new Properties();
for (var e = p.keys(); e.hasMoreElements(); ) {
var key = (String) e.nextElement();
result.setProperty(prefix + key, p.getProperty(key));
}
return result;
}
/** Creates a new Properties which is the combination of all the keys in
* p1 and p2. If the same key exists in both preoperties, the behaviour
* is undefined. */
public static Properties union(Properties p1, Properties p2) {
var result = new Properties();
for (var e1 = p1.keys(); e1.hasMoreElements(); ) {
var key = (String) e1.nextElement();
result.setProperty(key, p1.getProperty(key));
}
for (var e2 = p2.keys(); e2.hasMoreElements(); ) {
var key = (String) e2.nextElement();
result.setProperty(key, p2.getProperty(key));
}
return result;
}
/** Takes a ResourceBundle (describing keys/values) and converts the object
* into a Properties object. */
public static Properties newPropertiesForResourceBundle(ResourceBundle b) {
var properties = new Properties();
for (var e = b.getKeys(); e.hasMoreElements(); ) {
var key = (String) e.nextElement(); // ResourceBundle key : String
var value = b.getString(key);
properties.setProperty(key, value);
}
return properties;
}
/**
* @param resourceBundleName name for example "com.ucpag.components.x" where there
* is a properties file called "x.properties"
* in the appropriate directory, and returns a Properties object for that file.
* @throws MissingResourceException if file cannot be found
*/
public static Properties newPropertiesForResourceName(String resourceBundleName)
throws MissingResourceException {
var configRes = ResourceBundle.getBundle(resourceBundleName);
return PropertiesUtil.newPropertiesForResourceBundle(configRes);
}
public static Properties newPropertiesForClass(Class c) {
return newPropertiesForResourceName(c.getName());
}
/**
* @param name name for example "com.ucpag.components.x" where there
* is a properties file called "x.properties"
* in the appropriate directory, and returns a Properties object for that file.
* @throws MissingResourceException if file cannot be found
*/
public synchronized static Properties getCachedPropertiesForResourceName(String name)
throws MissingResourceException {
var result = propertiesForResouceName.get(name);
if (result == null) propertiesForResouceName.put(name, result = newPropertiesForResourceName(name));
return result;
}
public static String getPropertyOrThrow(Properties p, String key) {
var result = p.getProperty(key);
if (result == null) throw new RuntimeException("Mandatory key '" + key + "' not found");
return result;
}
/** @param resourceBundleName name for example "com.databasesandlife.x" where there is a properties file called "x.properties"
* in the appropriate directory, and returns a Properties object for that file. */
public static String getPropertyOrThrow(String resourceBundleName, String key) {
var p = getCachedPropertiesForResourceName(resourceBundleName);
try { return getPropertyOrThrow(p, key); }
catch (RuntimeException e) { throw new RuntimeException("Exception occurred while reading '" +
resourceBundleName + "' properties file"); }
}
}
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