com.github.triceo.robozonky.api.marketplaces.Marketplace Maven / Gradle / Ivy

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/*
 * Copyright 2017 Lukáš Petrovický
 *
 * 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.triceo.robozonky.api.marketplaces;

import java.util.Collection;
import java.util.function.Consumer;

import com.github.triceo.robozonky.api.remote.entities.Loan;

/**
 * Represents code that checks some remote marketplace for new loans. Use {@link #registerListener(Consumer)} as an
 * entry point. It is expected that implementations will be executed off the main thread. Implementations may only
 * become active when the {@link #run()} method has been called, and will cease all operations when {@link #close()}
 * is called.
 */
public interface Marketplace extends AutoCloseable, Runnable {

    /**
     * Tell the marketplace to send all new loans to a particular endpoint. The runtime promises to execute this
     * method before any calls to {@link #run()} are made and never after that.
     *
     * @param listener The endpoint to send loans to.
     * @return True if the listener has been set up to receive new loans, false if already registered before.
     */
    boolean registerListener(Consumer> listener);

    /**
     * Allows the implementation to specify how it should be treated by the runtime.
     *
     * @return Treatment expected by the marketplace provider.
     */
    ExpectedTreatment specifyExpectedTreatment();

    /**
     * If {@link #specifyExpectedTreatment()} is {@link ExpectedTreatment#POLLING}, this method is supposed to check
     * the marketplace once and terminate.
     *
     * If {@link ExpectedTreatment#LISTENING}, this method is expected to open a connection and listen for incoming
     * loans - it may be interrupted at any time, after which {@link #close()} will be called to clean up any lasting
     * resources.
     *
     * If any endless loops are created, implementors must check for {@link Thread#currentThread()}'s
     * {@link Thread#isInterrupted()} method in order to know when to terminate them.
     */
    @Override
    void run();

    @Override
    default void close() throws Exception {
        // don't force implementations to override
    }

}