com.github.robozonky.internal.async.Reloadable Maven / Gradle / Ivy
/*
* Copyright 2020 The RoboZonky Project
*
* 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.github.robozonky.internal.async;
import java.time.Duration;
import java.util.function.Supplier;
import com.github.robozonky.internal.util.functional.Either;
/**
* Allows the user to have a variable which reloads from a remote source on-demand.
*
* @param Type of the variable.
*/
public interface Reloadable {
/**
* Start a builder chain with the supplier as the operation used to reload the variable.
*
* @param supplier Operation that loads the variable.
* @param Type of the variable.
* @return The builder.
*/
static ReloadableBuilder with(final Supplier supplier) {
return new ReloadableBuilder<>(supplier);
}
/**
* Marks the {@link Reloadable} for reload. Next time {@link #get()} is called, the operation will be re-attempted.
*/
void clear();
/**
* Get the previous value of the operation (see {@link #with(Supplier)}, potentially executing it anew. The behavior
* of this method is greatly influenced by {@link ReloadableBuilder}, most importantly its methods
* {@link ReloadableBuilder#async()} and {@link ReloadableBuilder#reloadAfter(Duration)}.
*
* @return Result of the last call of the operation.
*/
Either get();
boolean hasValue();
}