/**
* Constructs a Database object from a set of properties
*
* @param props the properties by which this Database is configured
* @throws ClassNotFoundException if there is a class in props that cannot be found
*/
protected Database(Properties props) throws ClassNotFoundException {
settings = props;
configure(props);
try {
LOG.info(
"Creating new Database "
+ getURL()
+ "("
+ toString()
+ ") with ClassLoader "
+ getClass().getClassLoader()
+ " and parallelism "
+ parallel);
} catch (Exception e) {
LOG.info("Creating new invalid Database with ClassLoader " + getClass().getClassLoader(), e);
}
ShutdownHook.registerObject(new WeakReference<Database>(this));
}
/**
* Configures a datasource from a Properties object
*
* @param props the properties for configuring the Database
* @throws ClassNotFoundException if the class given in the properties file cannot be found
* @throws IllegalArgumentException if the configuration properties are empty
* @throws NullPointerException if props is null
*/
protected void configure(Properties props) throws ClassNotFoundException {
if (props == null) {
throw new NullPointerException("Props cannot be null");
}
if (props.size() == 0) {
throw new IllegalArgumentException("No configuration details");
}
Properties subProps = new Properties();
for (Map.Entry<Object, Object> entry : props.entrySet()) {
String propertyName = (String) entry.getKey();
String propertyValue = (String) entry.getValue();
Field field = null;
// Get the first part of the string - this is the attribute we are taking about
String attribute = propertyName;
String subAttribute = "";
int index = propertyName.indexOf(".");
if (index != -1) {
attribute = propertyName.substring(0, index);
subAttribute = propertyName.substring(index + 1);
}
try {
field = Database.class.getDeclaredField(attribute);
} catch (Exception e) {
LOG.warn("Ignoring field for Database: " + attribute);
// Ignore this property - no such field
continue;
}
if ("class".equals(subAttribute)) {
// make a new instance of this class for this attribute
Class<?> clazz = Class.forName(propertyValue.toString());
Object obj;
try {
obj = clazz.newInstance();
} catch (Exception e) {
throw new ClassNotFoundException(
"Cannot instantiate class " + clazz.getName() + " " + e.getMessage());
}
// Set the field to this newly instantiated class
try {
field.set(this, obj);
} catch (Exception e) {
continue;
}
} else if ("".equals(subAttribute)) {
// Set this attribute directly
try {
field.set(this, propertyValue);
} catch (Exception e) {
continue;
}
} else {
// Set parameters on the attribute
Method m = null;
// Set this configuration parameter on the DataSource;
try {
// Strings first
Object o = field.get(this);
// Sometimes the class will not have been instantiated yet
if (o == null) {
subProps.put(propertyName, propertyValue);
continue;
}
Class<?> clazz = o.getClass();
m =
clazz.getMethod(
"set" + StringUtil.capitalise(subAttribute), new Class[] {String.class});
if (m != null) {
m.invoke(field.get(this), new Object[] {propertyValue});
}
// now integers
} catch (Exception e) {
// Don't do anything - either the method not found or cannot be invoked
}
try {
if (m == null) {
m =
field
.get(this)
.getClass()
.getMethod(
"set" + StringUtil.capitalise(subAttribute), new Class[] {int.class});
if (m != null) {
m.invoke(field.get(this), new Object[] {Integer.valueOf(propertyValue.toString())});
}
}
} catch (Exception e) {
// Don't do anything - either the method not found or cannot be invoked
}
}
if (subProps.size() > 0) {
configure(subProps);
}
}
}
