org.joda.convert.RenameHandler Maven / Gradle / Ivy
/*
* Copyright 2010-present Stephen Colebourne
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.joda.convert;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
/**
* A general purpose utility for registering renames.
*
* This handles type and enum constant renames.
* For example, use as follows:
*
* RenameHandler.INSTANCE.renamedType("org.joda.OldName", NewName.class);
* RenameHandler.INSTANCE.renamedEnum("CORRECT", Status.VALID);
* RenameHandler.INSTANCE.renamedEnum("INCORRECT", Status.INVALID);
*
* The recommended usage is to edit the static singleton before using other classes.
* Editing a static is acceptable because renames are driven by bytecode which is static.
* For additional security, an application should lock the rename handler instance
* once any types and enums have been registered using {@link #lock()}.
*
* This class is thread-safe with concurrent caches.
*
* @since 1.6
*/
public final class RenameHandler {
/**
* A mutable global instance.
* This is a singleton instance which is mutated.
*/
public static final RenameHandler INSTANCE = new RenameHandler();
/**
* The lock flag.
*/
private volatile boolean locked;
/**
* The type renames.
*/
private final ConcurrentHashMap> typeRenames =
new ConcurrentHashMap>(16, 0.75f, 2);
/**
* The enum renames.
*/
private final ConcurrentHashMap, Map>> enumRenames =
new ConcurrentHashMap, Map>>(16, 0.75f, 2);
//-----------------------------------------------------------------------
/**
* Creates an instance.
*
* This is not normally used as the preferred option is to edit the singleton.
*
* @return a new instance, not null
*/
public static RenameHandler create() {
return new RenameHandler();
}
//-----------------------------------------------------------------------
/**
* Restricted constructor.
*/
private RenameHandler() {
}
//-----------------------------------------------------------------------
/**
* Register the fact that a type was renamed.
*
* This handles the use case where a class is renamed.
*
* @param oldName the old name of the type including the package name, not null
* @param currentValue the current type, not null
*/
public void renamedType(String oldName, Class currentValue) {
if (oldName == null) {
throw new IllegalArgumentException("oldName must not be null");
}
if (currentValue == null) {
throw new IllegalArgumentException("currentValue must not be null");
}
if (oldName.startsWith("java.") || oldName.startsWith("javax.") || oldName.startsWith("org.joda.")) {
throw new IllegalArgumentException("oldName must not be a java.*, javax.* or org.joda.* type");
}
checkNotLocked();
typeRenames.put(oldName, currentValue);
}
/**
* Gets the map of renamed types.
*
* An empty map is returned if there are no renames.
*
* @return a copy of the set of enum types with renames, not null
*/
public Map> getTypeRenames() {
return new HashMap>(typeRenames);
}
/**
* Lookup a type from a name, handling renames.
*
* @param name the name of the type to lookup, not null
* @return the type, not null
* @throws ClassNotFoundException if the name is not a valid type
*/
public Class lookupType(String name) throws ClassNotFoundException {
if (name == null) {
throw new IllegalArgumentException("name must not be null");
}
Class type = typeRenames.get(name);
if (type == null) {
type = loadType(name);
}
return type;
}
/**
* Loads a type avoiding nulls
*
* @param fullName the full class name
* @return the loaded class
* @throws ClassNotFoundException if the class is not found
*/
Class loadType(String fullName) throws ClassNotFoundException {
try {
ClassLoader loader = Thread.currentThread().getContextClassLoader();
return loader != null ? loader.loadClass(fullName) : Class.forName(fullName);
} catch (ClassNotFoundException ex) {
return loadPrimitiveType(fullName, ex);
}
}
// handle primitive types
private Class loadPrimitiveType(String fullName, ClassNotFoundException ex) throws ClassNotFoundException {
if (fullName.equals("int")) {
return int.class;
} else if (fullName.equals("long")) {
return long.class;
} else if (fullName.equals("double")) {
return double.class;
} else if (fullName.equals("boolean")) {
return boolean.class;
} else if (fullName.equals("short")) {
return short.class;
} else if (fullName.equals("byte")) {
return byte.class;
} else if (fullName.equals("char")) {
return char.class;
} else if (fullName.equals("float")) {
return float.class;
} else if (fullName.equals("void")) {
return void.class;
}
throw ex;
}
//-----------------------------------------------------------------------
/**
* Register the fact that an enum constant was renamed.
*
* This handles the use case where an enum constant is renamed, but the enum class remains the same.
*
* @param oldName the old name of the enum constant, not null
* @param currentValue the current enum constant, not null
*/
public void renamedEnum(String oldName, Enum currentValue) {
if (oldName == null) {
throw new IllegalArgumentException("oldName must not be null");
}
if (currentValue == null) {
throw new IllegalArgumentException("currentValue must not be null");
}
checkNotLocked();
Class enumType = currentValue.getDeclaringClass();
Map> perClass = enumRenames.get(enumType);
if (perClass == null) {
enumRenames.putIfAbsent(enumType, new ConcurrentHashMap>(16, 0.75f, 2));
perClass = enumRenames.get(enumType);
}
perClass.put(oldName, currentValue);
}
/**
* Gets the set of enum types that have renames.
*
* An empty set is returned if there are no renames.
*
* @return a copy of the set of enum types with renames, not null
*/
public Set> getEnumTypesWithRenames() {
return new HashSet>(enumRenames.keySet());
}
/**
* Gets the map of renamed for an enum type.
*
* An empty map is returned if there are no renames.
*
* @param type the enum type, not null
* @return a copy of the set of enum renames, not null
*/
public Map> getEnumRenames(Class type) {
if (type == null) {
throw new IllegalArgumentException("type must not be null");
}
Map> map = enumRenames.get(type);
if (map == null) {
return new HashMap>();
}
return new HashMap>(map);
}
/**
* Lookup an enum from a name, handling renames.
*
* @param the type of the desired enum
* @param type the enum type, not null
* @param name the name of the enum to lookup, not null
* @return the enum value, not null
* @throws IllegalArgumentException if the name is not a valid enum constant
*/
public > T lookupEnum(Class type, String name) {
if (type == null) {
throw new IllegalArgumentException("type must not be null");
}
if (name == null) {
throw new IllegalArgumentException("name must not be null");
}
Map> map = getEnumRenames(type);
Enum value = map.get(name);
if (value != null) {
return type.cast(value);
}
return Enum.valueOf(type, name);
}
//-----------------------------------------------------------------------
/**
* Locks this instance of the rename handler.
*
* For additional security, an application should lock the rename handler
* once any types and enums have been registered.
*/
public void lock() {
checkNotLocked();
locked = true;
}
// ensure not locked
private void checkNotLocked() {
if (locked) {
throw new IllegalStateException("RenameHandler has been locked and it cannot now be changed");
}
}
//-----------------------------------------------------------------------
@Override
public String toString() {
return "RenamedTypes" + typeRenames + ",RenamedEnumConstants" + enumRenames;
}
}