/*******************************************************************************
* Copyright 2014 Analog Devices, Inc.
*
* 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 com.analog.lyric.options;
import net.jcip.annotations.Immutable;
import org.eclipse.jdt.annotation.Nullable;
/**
* Key for options with literal Java class values.
* <p>
* @param <SuperClass> is the super class value. Values of this option must be a
* subclass of this class. The superclass instance may be obtained using the {@link #superClass()} method.
* <p>
* @since 0.07
* @author Christopher Barber
*/
@Immutable
public class ClassOptionKey<SuperClass> extends OptionKey<Class<? extends SuperClass>>
{
private static final long serialVersionUID = 1L;
private final Class<SuperClass> _superClass;
private final Class<? extends SuperClass> _defaultValue;
/**
* Construct a class option key.
* @param declaringClass is the class containing the static field declaration for this key.
* @param name is the name of static field declaration for this key.
* @param superClass is the superclass of all valid values. Should be same as the declared
* <SuperClass> parameter.
* @param defaultValue is the default value of the option. Used when option is not set.
* @since 0.07
*/
public ClassOptionKey(Class<?> declaringClass, String name, Class<SuperClass> superClass,
Class<? extends SuperClass> defaultValue)
{
super(declaringClass, name);
_superClass = superClass;
_defaultValue = defaultValue;
}
@SuppressWarnings("unchecked")
@Override
public Class<Class<? extends SuperClass>> type()
{
return (Class<Class<? extends SuperClass>>) _superClass.getClass();
}
@Override
public Class<? extends SuperClass> defaultValue()
{
return _defaultValue;
}
/**
* {@inheritDoc}
* <p>
* Returns fully qualified name of the class {@code value}.
*/
@Override
public Object convertToExternal(Class<? extends SuperClass> value)
{
return value.getName();
}
/**
* {@inheritDoc}
* <p>
* If {@code value} is a string. This will attempt to load the class from the string using
* {@linkplain Class#forName(String, boolean, ClassLoader) Class.forName} with context class loader.
* Subclasses may want to extend this to allow construction from simple
* class names.
*/
@SuppressWarnings("unchecked")
@Override
public Class<? extends SuperClass> convertToValue(@Nullable Object value)
{
if (value instanceof String)
{
try
{
value = Class.forName((String)value, false, getClass().getClassLoader());
}
catch (ClassNotFoundException ex)
{
throw new OptionValidationException(ex, "Could not construct class from string '%s': %s", value, ex);
}
}
return super.convertToValue(value);
}
@Override
public Class<? extends SuperClass> validate(Class<? extends SuperClass> value, @Nullable IOptionHolder optionHolder)
{
if (!_superClass.isAssignableFrom(value))
{
throw new OptionValidationException("'%s' is not a subclass of '%s'", value, _superClass);
}
return value;
}
/**
* The value of the <SuperClass> parameter.
* @since 0.07
*/
public Class<SuperClass> superClass()
{
return _superClass;
}
}