package com.github.tuserver.api.configuration.serialization;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.HashMap;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;
import com.github.tuserver.api.configuration.Configuration;
import com.google.common.base.Preconditions;
/**
* Utility class for storing and retrieving classes for {@link Configuration}.
*/
public class ConfigurationSerialization {
public static final String SERIALIZED_TYPE_KEY = "==";
private final Class<? extends ConfigurationSerializable> clazz;
private static Map<String, Class<? extends ConfigurationSerializable>> aliases = new HashMap<String, Class<? extends ConfigurationSerializable>>();
protected ConfigurationSerialization(Class<? extends ConfigurationSerializable> clazz) {
this.clazz = clazz;
}
protected Method getMethod(String name, boolean isStatic) {
try {
Method method = clazz.getDeclaredMethod(name, Map.class);
if (!ConfigurationSerializable.class.isAssignableFrom(method.getReturnType())) {
return null;
}
if (Modifier.isStatic(method.getModifiers()) != isStatic) {
return null;
}
return method;
} catch (NoSuchMethodException ex) {
return null;
} catch (SecurityException ex) {
return null;
}
}
protected Constructor<? extends ConfigurationSerializable> getConstructor() {
try {
return clazz.getConstructor(Map.class);
} catch (NoSuchMethodException ex) {
return null;
} catch (SecurityException ex) {
return null;
}
}
protected ConfigurationSerializable deserializeViaMethod(Method method, Map<String, Object> args) {
try {
ConfigurationSerializable result = (ConfigurationSerializable) method.invoke(null, args);
if (result == null) {
Logger.getLogger(ConfigurationSerialization.class.getName()).log(Level.SEVERE, "Could not call method '" + method.toString() + "' of " + clazz + " for deserialization: method returned null");
} else {
return result;
}
} catch (Throwable ex) {
Logger.getLogger(ConfigurationSerialization.class.getName()).log(Level.SEVERE, "Could not call method '" + method.toString() + "' of " + clazz + " for deserialization", ex instanceof InvocationTargetException ? ex.getCause() : ex);
}
return null;
}
protected ConfigurationSerializable deserializeViaCtor(Constructor<? extends ConfigurationSerializable> ctor, Map<String, Object> args) {
try {
return ctor.newInstance(args);
} catch (Throwable ex) {
Logger.getLogger(ConfigurationSerialization.class.getName()).log(Level.SEVERE, "Could not call constructor '" + ctor.toString() + "' of " + clazz + " for deserialization", ex instanceof InvocationTargetException ? ex.getCause() : ex);
}
return null;
}
public ConfigurationSerializable deserialize(Map<String, Object> args) {
Preconditions.checkNotNull(args, "Args must not be null");
ConfigurationSerializable result = null;
Method method = null;
if (result == null) {
method = getMethod("deserialize", true);
if (method != null) {
result = deserializeViaMethod(method, args);
}
}
if (result == null) {
method = getMethod("valueOf", true);
if (method != null) {
result = deserializeViaMethod(method, args);
}
}
if (result == null) {
Constructor<? extends ConfigurationSerializable> constructor = getConstructor();
if (constructor != null) {
result = deserializeViaCtor(constructor, args);
}
}
return result;
}
/**
* Attempts to deserialize the given arguments into a new instance of the
* given class.
* <p />
* The class must implement {@link ConfigurationSerializable}, including the
* extra methods as specified in the javadoc of ConfigurationSerializable.
* <p />
* If a new instance could not be made, an example being the class not fully
* implementing the interface, null will be returned.
*
* @param args
* Arguments for deserialization
* @param clazz
* Class to deserialize into
* @return New instance of the specified class
*/
public static ConfigurationSerializable deserializeObject(Map<String, Object> args, Class<? extends ConfigurationSerializable> clazz) {
return new ConfigurationSerialization(clazz).deserialize(args);
}
/**
* Attempts to deserialize the given arguments into a new instance of the
* given class.
* <p />
* The class must implement {@link ConfigurationSerializable}, including the
* extra methods as specified in the javadoc of ConfigurationSerializable.
* <p />
* If a new instance could not be made, an example being the class not fully
* implementing the interface, null will be returned.
*
* @param args
* Arguments for deserialization
* @return New instance of the specified class
*/
public static ConfigurationSerializable deserializeObject(Map<String, Object> args) {
Class<? extends ConfigurationSerializable> clazz = null;
if (args.containsKey(SERIALIZED_TYPE_KEY)) {
try {
String alias = (String) args.get(SERIALIZED_TYPE_KEY);
if (alias == null) {
throw new IllegalArgumentException("Cannot have null alias");
}
clazz = getClassByAlias(alias);
if (clazz == null) {
throw new IllegalArgumentException("Specified class does not exist ('" + alias + "')");
}
} catch (ClassCastException ex) {
ex.fillInStackTrace();
throw ex;
}
} else {
throw new IllegalArgumentException("Args doesn't contain type key ('" + SERIALIZED_TYPE_KEY + "')");
}
return new ConfigurationSerialization(clazz).deserialize(args);
}
/**
* Registers the given {@link ConfigurationSerializable} class by its alias
*
* @param clazz
* Class to register
*/
public static void registerClass(Class<? extends ConfigurationSerializable> clazz) {
DelegateDeserialization delegate = clazz.getAnnotation(DelegateDeserialization.class);
if (delegate == null) {
registerClass(clazz, getAlias(clazz));
registerClass(clazz, clazz.getName());
}
}
/**
* Registers the given alias to the specified
* {@link ConfigurationSerializable} class
*
* @param clazz
* Class to register
* @param alias
* Alias to register as
* @see SerializableAs
*/
public static void registerClass(Class<? extends ConfigurationSerializable> clazz, String alias) {
aliases.put(alias, clazz);
}
/**
* Unregisters the specified alias to a {@link ConfigurationSerializable}
*
* @param alias
* Alias to unregister
*/
public static void unregisterClass(String alias) {
aliases.remove(alias);
}
/**
* Unregisters any aliases for the specified
* {@link ConfigurationSerializable} class
*
* @param clazz
* Class to unregister
*/
public static void unregisterClass(Class<? extends ConfigurationSerializable> clazz) {
while (aliases.values().remove(clazz)) {
;
}
}
/**
* Attempts to get a registered {@link ConfigurationSerializable} class by
* its alias
*
* @param alias
* Alias of the serializable
* @return Registered class, or null if not found
*/
public static Class<? extends ConfigurationSerializable> getClassByAlias(String alias) {
return aliases.get(alias);
}
/**
* Gets the correct alias for the given {@link ConfigurationSerializable}
* class
*
* @param clazz
* Class to get alias for
* @return Alias to use for the class
*/
public static String getAlias(Class<? extends ConfigurationSerializable> clazz) {
DelegateDeserialization delegate = clazz.getAnnotation(DelegateDeserialization.class);
if (delegate != null) {
if ((delegate.value() == null) || (delegate.value() == clazz)) {
delegate = null;
} else {
return getAlias(delegate.value());
}
}
if (delegate == null) {
SerializableAs alias = clazz.getAnnotation(SerializableAs.class);
if ((alias != null) && (alias.value() != null)) {
return alias.value();
}
}
return clazz.getName();
}
}