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Dominique Villardolim7t
Dominique Villard
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olim7t
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JAVA-808: Add generic filtering policy that can be used to exclude specific DCs.
1 parent 7e70c44 commit 2cdd4af

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Lines changed: 367 additions & 106 deletions

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‎changelog/README.md‎

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- [bug] JAVA-966: Count uninitialized connections in conviction policy.
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- [improvement] JAVA-917: Document SSL configuration.
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- [improvement] JAVA-652: Add DCAwareRoundRobinPolicy builder.
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- [improvement] JAVA-808: Add generic filtering policy that can be used to exclude specific DCs.
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### 2.0.11

‎driver-core/src/main/java/com/datastax/driver/core/policies/HostFilterPolicy.java‎

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/*
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* Copyright (C) 2012-2015 DataStax Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.datastax.driver.core.policies;
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import java.net.InetSocketAddress;
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import java.util.ArrayList;
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import java.util.Collection;
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import java.util.Iterator;
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import java.util.List;
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import com.google.common.base.Predicate;
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import com.google.common.base.Predicates;
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import com.google.common.collect.ImmutableSet;
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import com.datastax.driver.core.Cluster;
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import com.datastax.driver.core.Host;
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import com.datastax.driver.core.HostDistance;
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import com.datastax.driver.core.Statement;
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/**
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* A load balancing policy wrapper that ensures that only hosts matching the predicate
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* will ever be returned.
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* <p>
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* This policy wraps another load balancing policy and will delegate the choice
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* of hosts to the wrapped policy with the exception that only hosts matching
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* the predicate provided when constructing this policy will ever be
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* returned. Any host not matching the predicate will be considered {@code IGNORED}
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* and thus will not be connected to.
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*/
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public class HostFilterPolicy implements ChainableLoadBalancingPolicy, CloseableLoadBalancingPolicy {
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private final LoadBalancingPolicy childPolicy;
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private final Predicate<Host> predicate;
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/**
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* Create a new policy that wraps the provided child policy but only "allows" hosts
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* matching the predicate.
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*
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* @param childPolicy the wrapped policy.
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* @param predicate the host predicate. Only hosts matching this predicate may get connected
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* to (whether they will get connected to or not depends on the child policy).
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*/
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public HostFilterPolicy(LoadBalancingPolicy childPolicy, Predicate<Host> predicate) {
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this.childPolicy = childPolicy;
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this.predicate = predicate;
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}
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@Override
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public LoadBalancingPolicy getChildPolicy() {
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return childPolicy;
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}
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/**
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* {@inheritDoc}
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*
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* @throws IllegalArgumentException if none of the host in {@code hosts}
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* (which will correspond to the contact points) matches the predicate.
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*/
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@Override
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public void init(Cluster cluster, Collection<Host> hosts) {
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List<Host> whiteHosts = new ArrayList<Host>(hosts.size());
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for (Host host : hosts)
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if (predicate.apply(host))
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whiteHosts.add(host);
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if (whiteHosts.isEmpty())
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throw new IllegalArgumentException(String.format("Cannot use HostFilterPolicy where the filter allows none of the contacts points (%s)", hosts));
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childPolicy.init(cluster, whiteHosts);
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}
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/**
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* {@inheritDoc}
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*
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* @return {@link HostDistance#IGNORED} if {@code host} is not matching the predicate, the HostDistance
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* as returned by the wrapped policy otherwise.
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*/
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@Override
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public HostDistance distance(Host host) {
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return predicate.apply(host)
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? childPolicy.distance(host)
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: HostDistance.IGNORED;
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}
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/**
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* {@inheritDoc}
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* <p>
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* It is guaranteed that only hosts matching the predicate will be returned.
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*/
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@Override
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public Iterator<Host> newQueryPlan(String loggedKeyspace, Statement statement) {
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// Just delegate to the child policy, since we filter the hosts not white
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// listed upfront, the child policy will never see a host that is not white
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// listed and thus can't return one.
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return childPolicy.newQueryPlan(loggedKeyspace, statement);
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}
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@Override
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public void onUp(Host host) {
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if (predicate.apply(host))
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childPolicy.onUp(host);
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}
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@SuppressWarnings("deprecation")
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@Override
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public void onSuspected(Host host) {
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if (predicate.apply(host))
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childPolicy.onSuspected(host);
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}
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@Override
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public void onDown(Host host) {
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if (predicate.apply(host))
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childPolicy.onDown(host);
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}
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@Override
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public void onAdd(Host host) {
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if (predicate.apply(host))
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childPolicy.onAdd(host);
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}
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@Override
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public void onRemove(Host host) {
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if (predicate.apply(host))
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childPolicy.onRemove(host);
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}
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@Override
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public void close() {
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if (childPolicy instanceof CloseableLoadBalancingPolicy)
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((CloseableLoadBalancingPolicy)childPolicy).close();
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}
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/**
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* Create a new policy that wraps the provided child policy but only "allows" hosts
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* whose DC belongs to the provided list.
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*
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* @param childPolicy the wrapped policy.
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* @param dcs the DCs.
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*
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* @return the policy.
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*/
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public static HostFilterPolicy fromDCWhiteList(LoadBalancingPolicy childPolicy, Iterable<String> dcs) {
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return new HostFilterPolicy(childPolicy, hostDCPredicate(dcs, true));
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}
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/**
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* Create a new policy that wraps the provided child policy but only "forbids" hosts
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* whose DC belongs to the provided list.
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*
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* @param childPolicy the wrapped policy.
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* @param dcs the DCs.
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*
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* @return the policy.
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*/
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public static HostFilterPolicy fromDCBlackList(LoadBalancingPolicy childPolicy, Iterable<String> dcs) {
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return new HostFilterPolicy(childPolicy, Predicates.not(hostDCPredicate(dcs, false)));
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}
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private static Predicate<Host> hostDCPredicate(Iterable<String> dcs, final boolean includeNullDC) {
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final ImmutableSet<String> _dcs = ImmutableSet.copyOf(dcs);
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return new Predicate<Host>() {
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@Override
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public boolean apply(Host host) {
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String hdc = host.getDatacenter();
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return (hdc == null) ? includeNullDC : _dcs.contains(hdc);
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}
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};
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}
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}

‎driver-core/src/main/java/com/datastax/driver/core/policies/WhiteListPolicy.java‎

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package com.datastax.driver.core.policies;
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import java.net.InetSocketAddress;
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import java.util.ArrayList;
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import java.util.Collection;
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import java.util.Iterator;
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import java.util.List;
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import java.util.Set;
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import com.google.common.base.Predicate;
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import com.google.common.collect.ImmutableSet;
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import com.datastax.driver.core.Cluster;
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import com.datastax.driver.core.Host;
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import com.datastax.driver.core.HostDistance;
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import com.datastax.driver.core.Statement;
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/**
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* A load balancing policy wrapper that ensure that only hosts from a provided
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* If all you want to do is limiting connections to hosts of the local
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* data-center then you should use DCAwareRoundRobinPolicy and *not* this policy
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* in particular.
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*
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* @see HostFilterPolicy
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*/
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public class WhiteListPolicy implements ChainableLoadBalancingPolicy, CloseableLoadBalancingPolicy {
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private final LoadBalancingPolicy childPolicy;
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private final Set<InetSocketAddress> whiteList;
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public class WhiteListPolicy extends HostFilterPolicy {
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/**
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* Create a new policy that wraps the provided child policy but only "allow" hosts
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* Creates a new policy that wraps the provided child policy but only "allows" hosts
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* from the provided while list.
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*
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* @param childPolicy the wrapped policy.
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* @param whiteList the white listed hosts. Only hosts from this list may get connected
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* to (whether they will get connected to or not depends on the child policy).
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*/
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public WhiteListPolicy(LoadBalancingPolicy childPolicy, Collection<InetSocketAddress> whiteList) {
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this.childPolicy = childPolicy;
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this.whiteList = ImmutableSet.copyOf(whiteList);
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}
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@Override
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public LoadBalancingPolicy getChildPolicy() {
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return childPolicy;
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}
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/**
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* Initialize this load balancing policy.
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*
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* @param cluster the {@code Cluster} instance for which the policy is created.
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* @param hosts the initial hosts to use.
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*
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* @throws IllegalArgumentException if none of the host in {@code hosts}
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* (which will correspond to the contact points) are part of the white list.
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*/
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@Override
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public void init(Cluster cluster, Collection<Host> hosts) {
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List<Host> whiteHosts = new ArrayList<Host>(hosts.size());
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for (Host host : hosts)
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if (whiteList.contains(host.getSocketAddress()))
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whiteHosts.add(host);
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if (whiteHosts.isEmpty())
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throw new IllegalArgumentException(String.format("Cannot use WhiteListPolicy where the white list (%s) contains none of the contacts points (%s)", whiteList, hosts));
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childPolicy.init(cluster, whiteHosts);
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}
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/**
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* Return the HostDistance for the provided host.
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*
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* @param host the host of which to return the distance of.
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* @return {@link HostDistance#IGNORED} if {@code host} is not part of the white list, the HostDistance
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* as returned by the wrapped policy otherwise.
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*/
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@Override
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public HostDistance distance(Host host) {
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return whiteList.contains(host.getSocketAddress())
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? childPolicy.distance(host)
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: HostDistance.IGNORED;
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}
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/**
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* Returns the hosts to use for a new query.
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* <p>
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* It is guaranteed that only hosts from the white list will be returned.
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*
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* @param loggedKeyspace the currently logged keyspace (the one set through either
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* {@link Cluster#connect(String)} or by manually doing a {@code USE} query) for
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* the session on which this plan need to be built. This can be {@code null} if
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* the corresponding session has no keyspace logged in.
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* @param statement the query for which to build a plan.
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*/
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@Override
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public Iterator<Host> newQueryPlan(String loggedKeyspace, Statement statement) {
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// Just delegate to the child policy, since we filter the hosts not white
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// listed upfront, the child policy will never see a host that is not white
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// listed and thus can't return one.
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return childPolicy.newQueryPlan(loggedKeyspace, statement);
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}
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@Override
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public void onUp(Host host) {
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if (whiteList.contains(host.getSocketAddress()))
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childPolicy.onUp(host);
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super(childPolicy, buildPredicate(whiteList));
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}
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@Override
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public void onSuspected(Host host) {
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if (whiteList.contains(host.getSocketAddress()))
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childPolicy.onSuspected(host);
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private static Predicate<Host> buildPredicate(Collection<InetSocketAddress> whiteList) {
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final ImmutableSet<InetSocketAddress> hosts = ImmutableSet.copyOf(whiteList);
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return new Predicate<Host>() {
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@Override
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public boolean apply(Host host) {
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return hosts.contains(host.getSocketAddress());
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}
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};
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}
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@Override
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public void onDown(Host host) {
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if (whiteList.contains(host.getSocketAddress()))
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childPolicy.onDown(host);
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}
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@Override
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public void onAdd(Host host) {
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if (whiteList.contains(host.getSocketAddress()))
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childPolicy.onAdd(host);
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}
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@Override
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public void onRemove(Host host) {
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if (whiteList.contains(host.getSocketAddress()))
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childPolicy.onRemove(host);
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}
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@Override
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public void close() {
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if (childPolicy instanceof CloseableLoadBalancingPolicy)
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((CloseableLoadBalancingPolicy)childPolicy).close();
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}
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}

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