org.zalando.riptide.Selector.java Source code

Introduction

Here is the source code for org.zalando.riptide.Selector.java

Source

package org.zalando.riptide;

/*
 * ?
 * Riptide
 * ??
 * Copyright (C) 2015 Zalando SE
 * ??
 * 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.
 * ?
 */

import org.springframework.http.client.ClientHttpResponse;

import java.io.IOException;
import java.util.Map;
import java.util.Optional;

/**
 * A {@link Selector} can be used change the dispatching strategy. Its purpose is to select an attribute
 * of the response and find a binding for it.
 *
 * @param <A> generic response attribute type
 */
@FunctionalInterface
public interface Selector<A> {

    /**
     * Retrieves an attribute from the given response
     *
     * @param response the incoming response
     * @return an attribute based on the response which is then used to select the correct binding
     * @throws IOException if accessing the response failed
     */
    Optional<A> attributeOf(ClientHttpResponse response) throws IOException;

    /**
     * Attempts to find a matching binding for the given attribute. Defaults to a direct map lookup.
     *
     * @param attribute the previously selected attribute
     * @param bindings  all bindings
     * @return an optional binding match, if found
     */
    default Optional<Binding<A>> select(final Optional<A> attribute, final Map<Optional<A>, Binding<A>> bindings) {
        return Optional.ofNullable(bindings.get(attribute));
    }

}