io.undertow.server.handlers.proxy.ConnectionPoolErrorHandler Maven / Gradle / Ivy
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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
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/*
* 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.proxy;
/**
* The connection pool error handler is intended to be used per node and will therefore be shared across I/O threads.
*
* @author Emanuel Muckenhuber
*/
public interface ConnectionPoolErrorHandler {
/**
* Check whether pool is available
*
* @return whether the pool is available
*/
boolean isAvailable();
/**
* Handle a connection error.
*
* @return {@code true} if the pool is still available, {@code false} otherwise
*/
boolean handleError();
/**
* Clear the connection errors.
*
* @return {@code true} if the pool is available again, {@code false} otherwise
*/
boolean clearError();
class SimpleConnectionPoolErrorHandler implements ConnectionPoolErrorHandler {
private volatile boolean problem;
@Override
public boolean isAvailable() {
return !problem;
}
@Override
public boolean handleError() {
problem = true;
return false;
}
@Override
public boolean clearError() {
problem = false;
return true;
}
}
/**
* Counting error handler, this only propagates the state to the delegate handler after reaching a given limit.
*/
class CountingErrorHandler implements ConnectionPoolErrorHandler {
private int count;
private long timeout;
private final long interval;
private final int errorCount;
private final int successCount;
private final ConnectionPoolErrorHandler delegate;
public CountingErrorHandler(int errorCount, int successCount, long interval) {
this(errorCount, successCount, interval, new SimpleConnectionPoolErrorHandler());
}
public CountingErrorHandler(int errorCount, int successCount, long interval, ConnectionPoolErrorHandler delegate) {
this.errorCount = Math.max(errorCount, 1);
this.successCount = Math.max(successCount, 1);
this.interval = Math.max(interval, 0);
this.delegate = delegate;
}
@Override
public boolean isAvailable() {
return delegate.isAvailable();
}
@Override
public synchronized boolean handleError() {
if (delegate.isAvailable()) {
final long time = System.currentTimeMillis();
// If the timeout is reached reset the error count
if (time >= timeout) {
count = 1;
timeout = time + interval;
} else {
if (count++ == 1) {
timeout = time + interval;
}
}
if (count >= errorCount) {
return delegate.handleError();
}
return true;
} else {
count = 0; // if in error reset the successful count
return false;
}
}
@Override
public synchronized boolean clearError() {
if (delegate.isAvailable()) {
count = 0; // Just reset the error count
return true;
} else {
// Count the successful attempts
if (count++ == successCount) {
return delegate.clearError();
}
return false;
}
}
}
}