pulsar-broker/src/main/java/org/apache/pulsar/broker/service/EntryFilterSupport.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.pulsar.broker.service;

import java.util.Collections;
import java.util.List;
import org.apache.bookkeeper.mledger.Entry;
import org.apache.commons.collections4.CollectionUtils;
import org.apache.pulsar.broker.service.plugin.EntryFilter;
import org.apache.pulsar.broker.service.plugin.FilterContext;
import org.apache.pulsar.common.api.proto.MessageMetadata;

public class EntryFilterSupport {

    protected final List<EntryFilter> entryFilters;
    protected final boolean hasFilter;
    protected final FilterContext filterContext;
    protected final Subscription subscription;

    public EntryFilterSupport(Subscription subscription) {
        this.subscription = subscription;
        if (subscription != null && subscription.getTopic() != null
                && !subscription.getTopic().isSystemTopic()) {
            final BrokerService brokerService = subscription.getTopic().getBrokerService();
            final boolean allowOverrideEntryFilters = brokerService
                    .pulsar().getConfiguration().isAllowOverrideEntryFilters();
            if (!allowOverrideEntryFilters) {
                this.entryFilters = brokerService.getEntryFilterProvider().getBrokerEntryFilters();
            } else {
                List<EntryFilter> topicEntryFilters =
                        subscription.getTopic().getEntryFilters();
                if (topicEntryFilters != null && !topicEntryFilters.isEmpty()) {
                    this.entryFilters = topicEntryFilters;
                } else {
                    this.entryFilters = brokerService.getEntryFilterProvider().getBrokerEntryFilters();
                }
            }
            this.filterContext = new FilterContext();
        } else {
            this.entryFilters = Collections.emptyList();
            this.filterContext = FilterContext.FILTER_CONTEXT_DISABLED;
        }
        hasFilter = CollectionUtils.isNotEmpty(entryFilters);
    }

    public EntryFilter.FilterResult runFiltersForEntry(Entry entry, MessageMetadata msgMetadata,
                                                       Consumer consumer) {
        if (hasFilter) {
            fillContext(filterContext, msgMetadata, subscription, consumer);
            return getFilterResult(filterContext, entry, entryFilters);
        } else {
            return EntryFilter.FilterResult.ACCEPT;
        }
    }

    private void fillContext(FilterContext context, MessageMetadata msgMetadata,
                             Subscription subscription, Consumer consumer) {
        context.reset();
        context.setMsgMetadata(msgMetadata);
        context.setSubscription(subscription);
        context.setConsumer(consumer);
    }


    private static EntryFilter.FilterResult getFilterResult(FilterContext filterContext, Entry entry,
                                                            List<EntryFilter> entryFilters) {
        for (EntryFilter entryFilter : entryFilters) {
            EntryFilter.FilterResult filterResult =
                    entryFilter.filterEntry(entry, filterContext);
            if (filterResult == null) {
                filterResult = EntryFilter.FilterResult.ACCEPT;
            }
            if (filterResult != EntryFilter.FilterResult.ACCEPT) {
                return filterResult;
            }
        }
        return EntryFilter.FilterResult.ACCEPT;
    }
}