org.eclipse.xtext.util.concurrent.IWriteAccess Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2010 itemis AG (http://www.itemis.eu) and others.
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License 2.0 which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* SPDX-License-Identifier: EPL-2.0
*******************************************************************************/
package org.eclipse.xtext.util.concurrent;
import java.util.function.Function;
import java.util.function.Supplier;
/**
* @author Sven Efftinge - Initial contribution and API
* @author Jan Koehnlein - Separated read and write access
*/
public interface IWriteAccess {
/**
* Modifies the State by executing {@code work} on it.
*
* WARNING: the State passed to {@code work} can be null.
*
* @param work Work that modifies the State
*
* @return The result of executing {@code work}
* @since 2.7
*/
public Result modify(IUnitOfWork work);
/**
* Tries to modify the State by executing {@code work} on it.
*
* @param work Work that modifies the State
* @param defaultResult Supplies a result in case the State is null
*
* @return The result of executing {@code work}, or
* the result of querying {@code defaultResult} if the State is null
* @since 2.14
*/
default Result tryModify(
IUnitOfWork work,
Supplier defaultResult
) {
// Some implementations rely on the type of {@code work}
if (work instanceof CancelableUnitOfWork) {
return modify(new WrappingCancelableUnitOfWork<>(defaultResult, work));
}
return modify((state) -> {
if (state == null) {
return defaultResult.get();
}
return work.exec(state);
});
}
/**
* Tries to modify the State by executing {@code work} on it.
*
* @param work Work that modifies the State
*
* @return The result of executing {@code work}, or
* null if the State is null
* @since 2.15
*/
default Result tryModify(IUnitOfWork work) {
return tryModify(work, () -> null);
}
/**
* Tries to modify the State by executing {@code work} on it.
*
* @param work Work that modifies the State
* @param defaultResult Supplies a result in case the State is null
* @param exceptionHandler Supplies a result in case an exception is raised during execution
*
* @return The result of executing {@code work},
* the result of querying {@code defaultResult} if the State is null, or
* the result of executing {@code exceptionHandler} in case an exception is raised
* @since 2.14
*/
default Result tryModify(
IUnitOfWork work,
Supplier defaultResult,
Function exceptionHandler
) {
try {
return tryModify(work, defaultResult);
} catch (Exception e) {
return exceptionHandler.apply(e);
}
}
}