/*
* JBoss, Home of Professional Open Source.
* Copyright 2014 Red Hat, Inc., and individual contributors
* as indicated by the @author tags.
*
* 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 io.undertow.server.handlers;
import java.util.
Collections;
import java.util.
Map;
import java.util.
Set;
import io.undertow.server.
HandlerWrapper;
import io.undertow.server.
HttpHandler;
import io.undertow.server.
HttpServerExchange;
import io.undertow.server.handlers.builder.
HandlerBuilder;
/**
* A handler which limits the maximum number of concurrent requests. Requests beyond the limit will
* block until the previous request is complete.
*
* @author <a href="mailto:david.lloyd@redhat.com">David M. Lloyd</a>
*/
public final class
RequestLimitingHandler implements
HttpHandler {
private final
HttpHandler nextHandler;
private final
RequestLimit requestLimit;
/**
* Construct a new instance. The maximum number of concurrent requests must be at least one. The next handler
* must not be {@code null}.
*
* @param maximumConcurrentRequests the maximum concurrent requests
* @param nextHandler the next handler
*/
public
RequestLimitingHandler(int
maximumConcurrentRequests,
HttpHandler nextHandler) {
this(
maximumConcurrentRequests, -1,
nextHandler);
}
/**
* Construct a new instance. The maximum number of concurrent requests must be at least one. The next handler
* must not be {@code null}.
*
* @param maximumConcurrentRequests the maximum concurrent requests
* @param queueSize the maximum number of requests to queue
* @param nextHandler the next handler
*/
public
RequestLimitingHandler(int
maximumConcurrentRequests, int
queueSize,
HttpHandler nextHandler) {
if (
nextHandler == null) {
throw new
IllegalArgumentException("nextHandler is null");
}
if (
maximumConcurrentRequests < 1) {
throw new
IllegalArgumentException("Maximum concurrent requests must be at least 1");
}
this.
requestLimit = new
RequestLimit(
maximumConcurrentRequests,
queueSize);
this.
nextHandler =
nextHandler;
}
/**
* Construct a new instance. This version takes a {@link RequestLimit} directly which may be shared with other
* handlers.
*
* @param requestLimit the request limit information.
* @param nextHandler the next handler
*/
public
RequestLimitingHandler(
RequestLimit requestLimit,
HttpHandler nextHandler) {
if (
nextHandler == null) {
throw new
IllegalArgumentException("nextHandler is null");
}
this.
requestLimit =
requestLimit;
this.
nextHandler =
nextHandler;
}
public void
handleRequest(final
HttpServerExchange exchange) throws
Exception {
requestLimit.
handleRequest(
exchange,
nextHandler);
}
public
RequestLimit getRequestLimit() {
return
requestLimit;
}
public static class
Builder implements
HandlerBuilder {
@
Override
public
String name() {
return "request-limit";
}
@
Override
public
Map<
String,
Class<?>>
parameters() {
return
Collections.<
String,
Class<?>>
singletonMap("requests", int.class);
}
@
Override
public
Set<
String>
requiredParameters() {
return
Collections.
singleton("requests");
}
@
Override
public
String defaultParameter() {
return "requests";
}
@
Override
public
HandlerWrapper build(
Map<
String,
Object>
config) {
return new
Wrapper((
Integer)
config.
get("requests"));
}
}
private static class
Wrapper implements
HandlerWrapper {
private final int
requests;
private
Wrapper(int
requests) {
this.
requests =
requests;
}
@
Override
public
HttpHandler wrap(
HttpHandler handler) {
return new
RequestLimitingHandler(
requests,
handler);
}
}
}