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/*****************************************************************************
* Copyright (c) 2016 Christian W. Damus and others.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Christian W. Damus - Initial API and implementation
*
*****************************************************************************/
package org.eclipse.papyrus.infra.emf.gmf.command;
import java.util.Map;
import java.util.Optional;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.function.Function;
import org.eclipse.emf.common.command.Command;
import org.eclipse.gmf.runtime.common.core.command.ICommand;
/**
* A protocol for wrappers that adapt commands of one framework to another.
*
* @param <T>
* the wrapped command type
*/
public interface ICommandWrapper<T> {
Registry REGISTRY = new Registry();
/**
* Unwraps the wrapper to get the wrapped command of the other framework.
*
* @return the wrapped command (never {@code null})
*/
T getWrappedCommand();
/**
* Wraps a {@code command} as another {@code type}. This also handles wrappers
* that are not {@link ICommandWrapper}s, such as those provided by GMF or
* other projects externally to Papyrus.
*
* @param command
* a command to wrap
* @param type
* the command type to obtain
*
* @return the wrapped command
*
* @throws IllegalArgumentException
* if no wrapper is available of the required {@code type}
*/
static <F, T> T wrap(F command, Class<T> type) {
return REGISTRY.getWrapper(command, type).apply(command);
}
/**
* Queries whether a {@code command} is a wrapper of some other type of command.
* This also handles wrappers that are not {@link ICommandWrapper}s, such as
* those provided by GMF or other projects externally to Papyrus.
*
* @param command
* a command to wrapper
* @param type
* the command type that perhaps it wraps
*
* @return the wrapped command
*
* @throws IllegalArgumentException
* if no wrapper is available of the required {@code type}
*/
static <F, T> boolean isWrapper(T command, Class<F> ofType) {
return REGISTRY.hasUnwrapper(command, ofType);
}
/**
* Unwraps a {@code command} as another {@code type}. This also handles wrappers
* that are not {@link ICommandWrapper}s, such as those provided by GMF or
* other projects externally to Papyrus.
*
* @param command
* a command to unwrap
* @param type
* the command type to obtain
*
* @return the wrapped command
*
* @throws IllegalArgumentException
* if no wrapper is available of the required {@code type}
*/
static <F, T> F unwrap(T command, Class<F> type) {
return REGISTRY.getUnwrapper(command, type).apply(command);
}
//
// Nested types
//
class Registry {
private final ConcurrentMap<Class<?>, ConcurrentMap<Class<?>, Function<?, ?>>> wrappers = new ConcurrentHashMap<>();
private final ConcurrentMap<Class<?>, ConcurrentMap<Class<?>, Function<?, ?>>> unwrappers = new ConcurrentHashMap<>();
private Registry() {
super();
registerWrapper(Command.class, ICommand.class, EMFtoGMFCommandWrapper::wrap);
registerUnwrapper(EMFtoGMFCommandWrapper.class, Command.class, EMFtoGMFCommandWrapper::getWrappedCommand);
registerWrapper(ICommand.class, Command.class, GMFtoEMFCommandWrapper::wrap);
registerUnwrapper(GMFtoEMFCommandWrapper.class, ICommand.class, GMFtoEMFCommandWrapper::getWrappedCommand);
}
/**
* Registers a functions to wrap commands of a source type as a target type.
*
* @param fromType
* the source command type
* @param toType
* the target command type
* @param wrapper
* the wrapper function
*
* @throws IllegalStateException
* if this pair of {@code fromType} and {@code toType} already has a wrapper registered
*/
public <F, T> void registerWrapper(Class<F> fromType, Class<T> toType, Function<? super F, ? extends T> wrapper) {
ConcurrentMap<Class<?>, Function<?, ?>> wrappers = this.wrappers.computeIfAbsent(fromType, key -> new ConcurrentHashMap<>());
if (wrappers.putIfAbsent(toType, wrapper) != null) {
throw new IllegalStateException(String.format("Wrapper already registered for %s -> %s", fromType.getSimpleName(), toType.getSimpleName()));
}
}
/**
* Registers a function to unwrap commands of a source type to obtain the original command type.
*
* @param fromType
* the source command type
* @param toType
* the target command type
* @param unwrapper
* the unwrapper function
*
* @throws IllegalStateException
* if this pair of {@code fromType} and {@code toType} already has an unwrapper registered
*/
public <F, T> void registerUnwrapper(Class<F> fromType, Class<T> toType, Function<? super F, ? extends T> unwrapper) {
ConcurrentMap<Class<?>, Function<?, ?>> unwrappers = this.unwrappers.computeIfAbsent(fromType, key -> new ConcurrentHashMap<>());
if (unwrappers.putIfAbsent(toType, unwrapper) != null) {
throw new IllegalStateException(String.format("Unwrapper already registered for %s <- %s", toType.getSimpleName(), fromType.getSimpleName()));
}
}
@SuppressWarnings("unchecked")
<F, T> Function<F, T> getWrapper(F command, Class<T> type) {
return (Function<F, T>) wrappers.entrySet().stream()
.filter(e -> e.getKey().isInstance(command))
.flatMap(e -> e.getValue().entrySet().stream())
.filter(e -> type.isAssignableFrom(e.getKey()))
.map(Map.Entry::getValue)
.findFirst()
.orElseThrow(IllegalArgumentException::new);
}
<F, T> Function<T, F> getUnwrapper(T command, Class<F> type) {
return maybeGetUnwrapper(command, type).orElseThrow(IllegalArgumentException::new);
}
boolean hasUnwrapper(Object command, Class<?> type) {
return maybeGetUnwrapper(command, type).isPresent();
}
@SuppressWarnings({ "unchecked", "rawtypes" })
<F, T> Optional<Function<T, F>> maybeGetUnwrapper(T command, Class<F> type) {
return (Optional) unwrappers.entrySet().stream()
.filter(e -> e.getKey().isInstance(command))
.flatMap(e -> e.getValue().entrySet().stream())
.filter(e -> type.isAssignableFrom(e.getKey()))
.map(Map.Entry::getValue)
.findFirst();
}
}
}
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