JsonRpcPromise.java

/*******************************************************************************
 * Copyright (c) 2012-2017 Codenvy, S.A.
 * 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:
 *   Codenvy, S.A. - initial API and implementation
 *******************************************************************************/
package org.eclipse.che.api.core.jsonrpc.commons;

import java.util.function.BiConsumer;
import java.util.function.Consumer;

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;

/**
 * Simple promise like binary consumer holder. First consumer's argument
 * always represents endpoint identifier, while the second can be of
 * arbitrary type and depends on business logic.
 *
 * @param <R>
 *         type of second argument of binary consumer
 */
public class JsonRpcPromise<R> {
    private BiConsumer<String, R>            successConsumer;
    private BiConsumer<String, JsonRpcError> failureConsumer;

    BiConsumer<String, R> getSuccessConsumer() {
        return successConsumer;
    }

    BiConsumer<String, JsonRpcError> getFailureConsumer() {
        return failureConsumer;
    }

    /**
     * Set binary consumer to be called on this promise resolution. The first
     * consumer argument is an endpoint that the responses comes from while
     * the second consumer argument is actually the value of response result.
     *
     * @param biConsumer
     *         binary consumer
     * @return the instance of this very promise
     */
    public JsonRpcPromise<R> onSuccess(BiConsumer<String, R> biConsumer) {
        checkNotNull(biConsumer, "JSON RPC success consumer argument must not be null");
        checkState(this.successConsumer == null, "JSON RPC success field must not be set");
        this.successConsumer = biConsumer;
        return this;
    }

    /**
     * Set consumer to be called on this promise resolution. Ths variant of
     * promise configuration must be used only when you need not the value
     * of endpoint ID. The only consumer argument is the value of response
     * result.
     *
     * @param consumer
     *         consumer
     * @return the instance of this very promise
     */
    public JsonRpcPromise<R> onSuccess(Consumer<R> consumer) {
        checkNotNull(consumer, "JSON RPC success consumer argument must not be null");
        checkState(this.successConsumer == null, "JSON RPC success consumer field must not be set");
        this.successConsumer = (s, r) -> consumer.accept(r);
        return this;
    }

    /**
     * Set runnable to be called on this promise resolution. Ths variant of
     * promise configuration must be used only when you need not both the
     * value of endpoint ID and the value of response result.
     *
     * @param runnable
     *         runnable
     * @return the instance of this very promise
     */
    public JsonRpcPromise<R> onSuccess(Runnable runnable) {
        checkNotNull(runnable, "JSON RPC success runnable argument must not be null");
        checkState(this.successConsumer == null, "JSON RPC success field must not be set");
        this.successConsumer = (s, r) -> runnable.run();
        return this;
    }

    /**
     * Set binary consumer to be called on promise rejection. The first
     * consumer argument is an endpoint that the responses comes from while the
     * second consumer argument is actually the value of response error.
     *
     * @param biConsumer
     *         binary consumer
     * @return the instance of this very promise
     */
    public JsonRpcPromise<R> onFailure(BiConsumer<String, JsonRpcError> biConsumer) {
        checkNotNull(biConsumer, "JSON RPC failure consumer argument must not be null");
        checkState(this.failureConsumer == null, "JSON RPC failure consumer field must not be set");
        this.failureConsumer = biConsumer;
        return this;
    }

    /**
     * Set consumer to be called on this promise rejection. Ths variant of
     * promise configuration must be used only when you need not the value
     * of endpoint ID. The only consumer argument is the value of response
     * result.
     *
     * @param consumer
     *         consumer
     * @return the instance of this very promise
     */
    public JsonRpcPromise<R> onFailure(Consumer<JsonRpcError> consumer) {
        checkNotNull(consumer, "JSON RPC failure consumer argument must not be null");
        checkState(this.failureConsumer == null, "JSON RPC failure consumer field must not be set");
        this.failureConsumer = (s, e) -> consumer.accept(e);
        return this;
    }

    /**
     * Set runnable to be called on this promise rejection. Ths variant of
     * promise configuration must be used only when you need not both the
     * value of endpoint ID and the value of response error.
     *
     * @param runnable
     *         runnable
     * @return the instance of this very promise
     */
    public JsonRpcPromise<R> onFailure(Runnable runnable) {
        checkNotNull(runnable, "JSON RPC success runnable argument must not be null");
        checkState(this.successConsumer == null, "JSON RPC success field must not be set");
        this.successConsumer = (s, e) -> runnable.run();
        return this;
    }
}