/*******************************************************************************
* 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 java.io.Serializable;
import java.util.Objects;
import net.jcip.annotations.Immutable;
import org.eclipse.jdt.annotation.Nullable;
/**
* An immutable option key value pair.
* <p>
* @param <T> is the type of the value (see {@link IOptionKey} for details).
* @since 0.07
* @author Christopher Barber
*/
@Immutable
public class Option<T extends Serializable> implements IOption<T>
{
/*-------
* State
*/
private final IOptionKey<T> _key;
private final @Nullable T _value;
/*--------------
* Construction
*/
/**
* Constructs {@code key} paired with its default value.
* <p>
* The {@link #value} attribute will be set to the {@linkplain IOptionKey#defaultValue() defaultValue}
* attribute of {@code key}.
* <p>
* @param key a non-null option key.
* @since 0.07
*/
public Option(IOptionKey<T> key)
{
this(key, key.defaultValue());
}
/**
* Constructs key/value pair from corresponding arguments.
* @param key a non-null option key.
* @param value a value of the correct type for the key or null if missing.
* @since 0.07
*/
public Option(IOptionKey<T> key, @Nullable T value)
{
_key = key;
_value = value != null ? key.validate(value, null) : null;
}
/**
* Constructs key/value pair from corresponding arguments.
* <p>
* @param key is a non-null option key.
* @param value is either null or a value that can be converted using {@code key}'s
* {@linkplain IOptionKey#convertToValue convertValue} method.
* @throws RuntimeException if {@code value} does not have compatible type for key.
* @since 0.07
*/
@SuppressWarnings("unchecked")
public static <T extends Serializable> Option<T> create(IOptionKey<T> key, @Nullable Object value)
{
return new Option<T>(key, value == null ? null : key.convertToValue(value));
}
/**
* Constructs an option key/value pair by looking it up.
* <p>
* @since 0.07
*/
public static <T extends Serializable> Option<T> lookup(IOptionHolder holder, IOptionKey<T> key)
{
return new Option<T>(key, holder.getOption(key));
}
/**
* Constructs an option key/value pair by looking it up locally in the holder.
* <p>
* @since 0.08
*/
public static <T extends Serializable> Option<T> lookupLocal(IOptionHolder holder, IOptionKey<T> key)
{
return new Option<T>(key, holder.getLocalOption(key));
}
/*----------------
* Static methods
*/
private static <T extends Serializable> void doSet(IOptionHolder holder, IOption<T> option)
{
final IOptionKey<T> key = option.key();
final T value = option.value();
if (value == null)
{
holder.unsetOption(key);
}
else
{
holder.setOption(key, value);
}
}
/**
* Sets multiple options.
* <p>
* Applies each option to {@code holder} in the specified order. The action
* depends on whether the option's {@linkplain #value()} is set: if non-null
* {@linkplain IOptionHolder#setOption setOption} will be invoked on the holder with the
* specified key and value, otherwise {@linkplain IOptionHolder#unsetOption unsetOption}
* will be called.
* <p>
* @param holder is a non-null option holder.
* @param options are zero or more option objects.
* @since 0.07
*/
public static void setOptions(IOptionHolder holder, IOption<?> ... options)
{
for (IOption<?> option : options)
{
doSet(holder, option);
}
}
/*-----------------
* Object methods
*/
@Override
public boolean equals(@Nullable Object other)
{
if (this == other)
{
return true;
}
if (other instanceof Option)
{
Option<?> that = (Option<?>)other;
return _key == that._key && Objects.equals(_value, that._value);
}
return false;
}
@Override
public int hashCode()
{
return _key.hashCode() * 11 + Objects.hashCode(_value);
}
@Override
public String toString()
{
return String.format("%s=%s", OptionKey.qualifiedName(_key), Objects.toString(_value));
}
/*-----------------
* IOption methods
*/
@Override
public final IOptionKey<T> key()
{
return _key;
}
@Override
public final @Nullable T value()
{
return _value;
}
@Override
public @Nullable Object externalValue()
{
T value = _value;
return value == null ? null : _key.convertToExternal(value);
}
@Override
public void setOn(IOptionHolder holder)
{
doSet(holder, this);
}
}