Users of the service are responsible for creating their own configuration objects which are * then registered via this class. The config object registry then performs a few functions: * *
Users of this service will want to use {@link AccessController}s on their configuration
* distributed objects to prevent non-administrators from subscribing to or modifying the objects.
*/
public abstract class ConfigRegistry
{
/**
* Registers the supplied configuration object with the system.
*
* @param key a string that identifies this object. These are generally hierarchical in nature
* (of the form system.subsystem), for example: yohoho.crew.
* @param path The the path in the persistent configuration repository. This may mean
* something to the underlying persistent store, for example in the preferences backed
* implementation it defines the path to the preferences node in the package hierarchy.
* @param object the object to be registered.
*/
public void registerObject (String key, String path, DObject object)
{
ObjectRecord record = createObjectRecord(path, object);
record.init();
_configs.put(key, record);
}
/**
* Returns the config object mapped to the specified key, or null if none exists for that key.
*/
public DObject getObject (String key)
{
ObjectRecord record = _configs.get(key);
return (record == null) ? null : record.object;
}
/**
* Returns an array containing the keys of all registered configuration objects.
*/
public String[] getKeys ()
{
return _configs.keySet().toArray(new String[_configs.size()]);
}
/**
* Creates an object record derivation that will handle the management of the specified object.
*/
protected abstract ObjectRecord createObjectRecord (String path, DObject object);
/**
* Contains all necessary info for a configuration object registration.
*/
protected abstract class ObjectRecord
implements AttributeChangeListener, SetListener, ElementUpdateListener
{
public DObject object;
public ObjectRecord (DObject object)
{
this.object = object;
}
public void init ()
{
// read in the initial configuration settings from the persistent config repository
Class cclass = object.getClass();
try {
Field[] fields = cclass.getFields();
for (int ii = 0; ii < fields.length; ii++) {
int mods = fields[ii].getModifiers();
if ((mods & Modifier.STATIC) != 0 || (mods & Modifier.PUBLIC) == 0 ||
(mods & Modifier.TRANSIENT) != 0) {
continue;
}
initField(fields[ii]);
}
// listen for attribute updates
object.addListener(this);
} catch (SecurityException se) {
Log.warning("Unable to reflect on " + cclass.getName() + ": " + se + ". " +
"Refusing to monitor object.");
}
}
public void entryAdded (EntryAddedEvent event)
{
serializeAttribute(event.getName());
}
public void entryUpdated (EntryUpdatedEvent event)
{
serializeAttribute(event.getName());
}
public void entryRemoved (EntryRemovedEvent event)
{
serializeAttribute(event.getName());
}
public void elementUpdated (ElementUpdatedEvent event)
{
Object value;
try {
value = object.getAttribute(event.getName());
} catch (ObjectAccessException oae) {
Log.warning("Exception getting field [name=" + event.getName() +
", exception=" + oae + "].");
return;
}
updateValue(event.getName(), value);
}
public void attributeChanged (AttributeChangedEvent event)
{
// mirror this configuration update to the persistent config
Object value = event.getValue();
if (value instanceof DSet) {
serializeAttribute(event.getName());
} else {
updateValue(event.getName(), value);
}
}
protected void updateValue (String name, Object value)
{
String key = nameToKey(name);
if (value instanceof Boolean) {
setValue(key, ((Boolean)value).booleanValue());
} else if (value instanceof Short) {
setValue(key, ((Short)value).shortValue());
} else if (value instanceof Integer) {
setValue(key, ((Integer)value).intValue());
} else if (value instanceof Long) {
setValue(key, ((Long)value).longValue());
} else if (value instanceof Float) {
setValue(key, ((Float)value).floatValue());
} else if (value instanceof String) {
setValue(key, (String)value);
} else if (value instanceof float[]) {
setValue(key, (float[])value);
} else if (value instanceof int[]) {
setValue(key, (int[])value);
} else if (value instanceof String[]) {
setValue(key, (String[])value);
} else if (value instanceof long[]) {
setValue(key, (long[]) value);
} else {
Log.info("Unable to flush config obj change [cobj=" + object.getClass().getName() +
", key=" + key + ", type=" + value.getClass().getName() +
", value=" + value + "].");
}
}
/** Initializes a single field of a config distributed object from its corresponding value
* in the associated config repository. */
protected void initField (Field field)
{
String key = nameToKey(field.getName());
Class type = field.getType();
try {
if (type.equals(Boolean.TYPE)) {
boolean defval = field.getBoolean(object);
field.setBoolean(object, getValue(key, defval));
} else if (type.equals(Short.TYPE)) {
short defval = field.getShort(object);
field.setShort(object, getValue(key, defval));
} else if (type.equals(Integer.TYPE)) {
int defval = field.getInt(object);
field.setInt(object, getValue(key, defval));
} else if (type.equals(Long.TYPE)) {
long defval = field.getLong(object);
field.setLong(object, getValue(key, defval));
} else if (type.equals(Float.TYPE)) {
float defval = field.getFloat(object);
field.setFloat(object, getValue(key, defval));
} else if (type.equals(String.class)) {
String defval = (String)field.get(object);
field.set(object, getValue(key, defval));
} else if (type.equals(int[].class)) {
int[] defval = (int[])field.get(object);
field.set(object, getValue(key, defval));
} else if (type.equals(float[].class)) {
float[] defval = (float[])field.get(object);
field.set(object, getValue(key, defval));
} else if (type.equals(String[].class)) {
String[] defval = (String[])field.get(object);
field.set(object, getValue(key, defval));
} else if (type.equals(long[].class)) {
long[] defval = (long[])field.get(object);
field.set(object, getValue(key, defval));
} else if (Streamable.class.isAssignableFrom(type)) {
// don't freak out if the conf is blank.
String value = getValue(key, "");
if (StringUtil.isBlank(value)) {
return;
}
try {
ByteArrayInputStream bin =
new ByteArrayInputStream(StringUtil.unhexlate(value));
ObjectInputStream oin = new ObjectInputStream(bin);
field.set(object, oin.readObject());
} catch (Exception e) {
Log.warning("Failure decoding config value [type=" + type +
", field=" + field + ", exception=" + e + "].");
}
} else {
Log.warning("Can't init field of unknown type " +
"[cobj=" + object.getClass().getName() + ", key=" + key +
", type=" + type.getName() + "].");
}
} catch (IllegalAccessException iae) {
Log.warning("Can't set field [cobj=" + object.getClass().getName() +
", key=" + key + ", error=" + iae + "].");
}
}
/**
* Converts a config object field name (someConfigMember) to a configuration key
* (some_config_member).
*/
protected String nameToKey (String attributeName)
{
return StringUtil.unStudlyName(attributeName).toLowerCase();
}
/**
* Get the specified attribute from the configuration object, and serialize it.
*/
protected void serializeAttribute (String attributeName)
{
String key = nameToKey(attributeName);
Object value;
try {
value = object.getAttribute(attributeName);
} catch (ObjectAccessException oae) {
Log.warning("Exception getting field [name=" + attributeName +
", error=" + oae + "].");
return;
}
if (value instanceof Streamable) {
serialize(key, value);
} else {
Log.info("Unable to flush config obj change [cobj=" + object.getClass().getName() +
", key=" + key + ", type=" + value.getClass().getName() +
", value=" + value + "].");
}
}
/**
* Save the specified object as serialized data associated with the specified key.
*/
protected void serialize (String key, Object value)
{
ByteArrayOutInputStream out = new ByteArrayOutInputStream();
ObjectOutputStream oout = new ObjectOutputStream(out);
try {
oout.writeObject(value);
oout.flush();
setValue(key, StringUtil.hexlate(out.toByteArray()));
} catch (IOException ioe) {
Log.info("Error serializing value " + value);
}
}
protected abstract boolean getValue (String field, boolean defval);
protected abstract short getValue (String field, short defval);
protected abstract int getValue (String field, int defval);
protected abstract long getValue (String field, long defval);
protected abstract float getValue (String field, float defval);
protected abstract String getValue (String field, String defval);
protected abstract int[] getValue (String field, int[] defval);
protected abstract float[] getValue (String field, float[] defval);
protected abstract long[] getValue (String field, long[] defval);
protected abstract String[] getValue (String field, String[] defval);
protected abstract void setValue (String field, boolean value);
protected abstract void setValue (String field, short value);
protected abstract void setValue (String field, int value);
protected abstract void setValue (String field, long value);
protected abstract void setValue (String field, float value);
protected abstract void setValue (String field, String value);
protected abstract void setValue (String field, int[] value);
protected abstract void setValue (String field, float[] value);
protected abstract void setValue (String field, long[] value);
protected abstract void setValue (String field, String[] value);
}
/** A mapping from identifying key to config object. */
protected HashMap