As.java
/*
* *********************************************************************************************************************
*
* TheseFoolishThings: Miscellaneous utilities
* http://tidalwave.it/projects/thesefoolishthings
*
* Copyright (C) 2009 - 2021 by Tidalwave s.a.s. (http://tidalwave.it)
*
* *********************************************************************************************************************
*
* 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.
*
* *********************************************************************************************************************
*
* git clone https://bitbucket.org/tidalwave/thesefoolishthings-src
* git clone https://github.com/tidalwave-it/thesefoolishthings-src
*
* *********************************************************************************************************************
*/
package it.tidalwave.util;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import java.util.Collection;
import java.util.Optional;
import lombok.EqualsAndHashCode;
import lombok.RequiredArgsConstructor;
import lombok.ToString;
/***********************************************************************************************************************
*
* Objects implementing this interface can provide am adapter of the required type. The adapter can be found with a
* variety of approaches that depend on the implementation. This capability can be used to implement a design based
* on the Data, Context and Interaction pattern (DCI).
*
* @author Fabrizio Giudici
* @it.tidalwave.javadoc.stable
*
**********************************************************************************************************************/
public interface As
{
/*******************************************************************************************************************
*
* @it.tidalwave.javadoc.stable
*
******************************************************************************************************************/
public static interface NotFoundBehaviour<T>
{
@Nonnull
public T run (@Nullable final Throwable t);
}
/*******************************************************************************************************************
*
*
******************************************************************************************************************/
public static final class Defaults
{
private Defaults()
{
}
public static <X> NotFoundBehaviour<X> throwAsException (@Nonnull final Class<X> clazz)
{
return new NotFoundBehaviour<X>()
{
// @Override
@Nonnull
public X run (@Nonnull final Throwable t)
{
throw new AsException(clazz, t);
}
};
}
}
/*******************************************************************************************************************
*
* @since 3.2-ALPHA-12
*
******************************************************************************************************************/
@RequiredArgsConstructor @EqualsAndHashCode @ToString
public static final class Ref<T>
{
@Nonnull
private final Class<?> type;
@Nonnull
public Class<T> getType()
{
return (Class<T>)type;
}
}
/*******************************************************************************************************************
*
* Returns an adapter to this object of the specified type. If the implementation can find multiple compliant
* adapters, only one will be returned.
*
* @param <T> the static type
* @param type the dynamic type
* @return the adapter
* @throws AsException if no adapter is found
*
******************************************************************************************************************/
@Nonnull
public <T> T as (@Nonnull Class<T> type);
/*******************************************************************************************************************
*
* Returns an adapter to this object of the specified type. If the implementation can find multiple compliant
* adapters, only one will be returned. If no adapter is found, the result provided by the given default
* behaviour will be returned.
*
* @param <T> the static type
* @param type the dynamic type
* @param notFoundBehaviour the behaviour to apply when an adapter is not found
* @return the adapter
*
******************************************************************************************************************/
@Nonnull
public <T> T as (@Nonnull Class<T> type, @Nonnull NotFoundBehaviour<T> notFoundBehaviour);
/*******************************************************************************************************************
*
* Returns the requested role or an empty {@link Optional}.
*
* @param <T> the static type
* @param type the dynamic type
* @return the optional role
* @since 3.2-ALPHA-3
*
******************************************************************************************************************/
@Nonnull
default <T> Optional<T> maybeAs (@Nonnull final Class<T> type)
{
return Optional.ofNullable(as(type, throwable -> null));
}
/*******************************************************************************************************************
*
* @param <T> the static type
* @param type the dynamic type
* @return the optional role
* @deprecated Use {@link #maybeAs(Class)}.
*
******************************************************************************************************************/
@Nonnull @Deprecated
default <T> Optional<T> asOptional (@Nonnull final Class<T> type)
{
return maybeAs(type);
}
/*******************************************************************************************************************
*
* Searches for multiple adapters of the given type and returns them.
*
* @param <T> the static type
* @param type the dynamic type
* @return a collection of adapters, possibly empty
*
******************************************************************************************************************/
@Nonnull
public <T> Collection<T> asMany (@Nonnull Class<T> type);
/*******************************************************************************************************************
*
* Creates a role type reference.
*
* @param <T> the static type
* @param type the dynamic type
* @return the type reference
* @since 3.2-ALPHA-12
*
******************************************************************************************************************/
@Nonnull
static <T> Ref<T> ref (@Nonnull final Class<?> type) // FIXME: there's no static check of the argument
{
return new Ref<>(type);
}
/*******************************************************************************************************************
*
* Returns a role for this object of the specified type. If the implementation can find multiple compliant
* roles, only one will be returned.
*
* @param <T> the static type
* @param ref the type reference
* @return the role
* @since 3.2-ALPHA-12
*
******************************************************************************************************************/
@Nonnull
default <T> T as (@Nonnull final Ref<T> ref)
{
return as(ref.getType());
}
/*******************************************************************************************************************
*
* Returns the requested role or an empty {@link Optional}.
*
* @param <T> the static type
* @param ref the type reference
* @return the optional role
* @since 3.2-ALPHA-12
*
******************************************************************************************************************/
@Nonnull
default <T> Optional<T> maybeAs (@Nonnull final Ref<T> ref)
{
return maybeAs(ref.getType());
}
/*******************************************************************************************************************
*
* Returns the requested role or an empty {@link Optional}.
*
* @param <T> the static type
* @param ref the type reference
* @return the roles
* @since 3.2-ALPHA-12
*
******************************************************************************************************************/
@Nonnull
default <T> Collection<T> asMany (@Nonnull final Ref<T> ref)
{
return asMany(ref.getType());
}
}