Copyright 2018 Netflix, Inc.
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.
/**
 * Copyright 2018 Netflix, Inc.
 *
 * 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.netflix.concurrency.limits.servlet;

import com.netflix.concurrency.limits.Limiter;
import com.netflix.concurrency.limits.limiter.AbstractPartitionedLimiter;

import javax.servlet.http.HttpServletRequest;
import java.security.Principal;
import java.util.Optional;
import java.util.function.Function;

Builder to simplify creating a Limiter specific to a Servlet filter. By default, the same concurrency limit is shared by all requests. The limiter can be partitioned based on one of many request attributes. Only one type of partition may be specified. /**
 * Builder to simplify creating a {@link Limiter} specific to a Servlet filter. By default,
 * the same concurrency limit is shared by all requests.  The limiter can be partitioned
 * based on one of many request attributes.  Only one type of partition may be specified.
 */
public final class ServletLimiterBuilder extends AbstractPartitionedLimiter.Builder<ServletLimiterBuilder, HttpServletRequest> {
    
Partition the limit by header
Returns:
Chainable builder/**
     * Partition the limit by header
     * @return Chainable builder
     */
    public ServletLimiterBuilder partitionByHeader(String name) {
        return partitionResolver(request -> Optional.ofNullable(request.getHeader(name)).orElse(null));
    }
    
    
Partition the limit by Principal. Percentages of the limit are partitioned to named groups. Group membership is derived from the provided mapping function. 
Params:
principalToGroup – Mapping function from Principal to a named group.
Returns:
Chainable builder/**
     * Partition the limit by {@link Principal}. Percentages of the limit are partitioned to named
     * groups.  Group membership is derived from the provided mapping function.
     * @param principalToGroup Mapping function from {@link Principal} to a named group.
     * @return Chainable builder
     */
    public ServletLimiterBuilder partitionByUserPrincipal(Function<Principal, String> principalToGroup) {
        return partitionResolver(request -> Optional.ofNullable(request.getUserPrincipal()).map(principalToGroup).orElse(null));
    }
    
    
Partition the limit by request attribute
Returns:
Chainable builder/**
     * Partition the limit by request attribute
     * @return Chainable builder
     */
    public ServletLimiterBuilder partitionByAttribute(String name) {
        return partitionResolver(request -> Optional.ofNullable(request.getAttribute(name)).map(Object::toString).orElse(null));
    }
    
    
Partition the limit by request parameter
Returns:
Chainable builder/**
     * Partition the limit by request parameter
     * @return Chainable builder
     */
    public ServletLimiterBuilder partitionByParameter(String name) {
        return partitionResolver(request -> Optional.ofNullable(request.getParameter(name)).orElse(null));
    }
    
    
Partition the limit by the full path. Percentages of the limit are partitioned to named
groups.  Group membership is derived from the provided mapping function.
Params:
pathToGroup – Mapping function from full path to a named group.
Returns:
Chainable builder/**
     * Partition the limit by the full path. Percentages of the limit are partitioned to named
     * groups.  Group membership is derived from the provided mapping function.
     * @param pathToGroup Mapping function from full path to a named group.
     * @return Chainable builder
     */
    public ServletLimiterBuilder partitionByPathInfo(Function<String, String> pathToGroup) {
        return partitionResolver(request -> Optional.ofNullable(request.getPathInfo()).map(pathToGroup).orElse(null));
    }
    
    @Override
    protected ServletLimiterBuilder self() {
        return this;
    }
}