org.apache.jackrabbit.oak.spi.whiteboard.DefaultWhiteboard Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of aem-sdk-api Show documentation
The Adobe Experience Manager SDK
There is a newer version: 2024.11.18751.20241128T090041Z-241100
/*
 * 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.jackrabbit.oak.spi.whiteboard;

import static org.apache.jackrabbit.guava.common.base.Preconditions.checkArgument;

import static java.util.Objects.requireNonNull;
import static org.apache.jackrabbit.guava.common.collect.Sets.newIdentityHashSet;
import static java.util.Collections.emptyList;

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.stream.Collectors;

import org.jetbrains.annotations.NotNull;

public class DefaultWhiteboard implements Whiteboard {

    private final Map, Set> registry = new HashMap<>();

    private synchronized  void registered(Class type, Service service) {
        Set services = registry.get(type);
        if (services == null) {
            services = newIdentityHashSet();
            registry.put(type, services);
        }
        services.add(service);
    }

    private synchronized  void unregistered(Class type, Service service) {
        Set services = registry.get(type);
        if (services != null) {
            services.remove(service);
        }
    }

    @SuppressWarnings("unchecked")
    private synchronized  List lookup(Class type) {
        Set services = registry.get(type);
        if (services != null) {
            return (List) services
                    .stream()
                    .map(Service::getService)
                    .collect(Collectors.toList());
        } else {
            return emptyList();
        }
    }

    @SuppressWarnings("unchecked")
    private synchronized  List lookup(Class type, Map filterProperties) {
        Set services = registry.get(type);
        if (services != null) {
            return (List) services
                    .stream()
                    .filter(s -> s.matches(filterProperties))
                    .map(Service::getService)
                    .collect(Collectors.toList());
        } else {
            return emptyList();
        }
    }

    //--------------------------------------------------------< Whiteboard >--

    @Override
    public  Registration register(
            final Class type, final T service, Map properties) {
        requireNonNull(type);
        requireNonNull(service);
        checkArgument(type.isInstance(service));

        Service s = new Service(service, properties);

        registered(type, s);
        return new Registration() {
            @Override
            public void unregister() {
                unregistered(type, s);
            }
        };
    }

    @Override
    public  Tracker track(final Class type) {
        requireNonNull(type);
        return new Tracker() {
            @Override
            public List getServices() {
                return lookup(type);
            }
            @Override
            public void stop() {
            }
        };
    }

    @Override
    public  Tracker track(Class type, Map filterProperties) {

        requireNonNull(type);
        return new Tracker() {
            @Override
            public List getServices() {
                return lookup(type, filterProperties);
            }
            @Override
            public void stop() {
            }
        };
    }

    private static class Service {

        private final Object service;

        private final Map properties;

        private Service(@NotNull Object service, Map properties) {
            requireNonNull(service);
            this.service = service;
            this.properties = properties;
        }

        private Object getService() {
            return service;
        }

        private boolean matches(Map properties) {
            return properties.entrySet().stream()
                    .allMatch(this::propertyMatches);
        }

        private  boolean propertyMatches(Map.Entry filterEntry) {
            String key = filterEntry.getKey();
            String expectedValue = filterEntry.getValue();
            if (properties == null || !properties.containsKey(key)) {
                return expectedValue == null;
            }
            Object value = properties.get(key);
            if (value == null) {
                return expectedValue == null;
            }
            return value.toString().equals(expectedValue);
        }
    }
}