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/*
* Copyright 2013 Romain Gilles
*
* 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 org.javabits.yar;
import com.google.common.reflect.TypeToken;
import javax.annotation.Nullable;
import javax.annotation.concurrent.ThreadSafe;
import java.lang.reflect.Type;
import java.util.Collection;
import java.util.List;
import java.util.Set;
import java.util.concurrent.TimeUnit;
/**
* It represent a storage to share capabilities with other component.
* The capabilities are represented by Guava {@code Supplier}.
*
* @author Romain Gilles
* @since 1.0
*/
@ThreadSafe
public interface Registry {
TimeUnit DEFAULT_TIME_UNIT = TimeUnit.MILLISECONDS;
//5 minutes
long DEFAULT_TIMEOUT = 1000 * 60 * 5L;
/**
* Returns all the {@link Id}s contained by this registry
* at a certain point of time.
* The returned {@code Set} is not link to the registry. Any modification
* to the content of the registry are not reported to this {@code Set}. You can
* see it as a snapshot.
* This intent of this method is to provide information on the content
* of the {@code Registry}. It can be used for monitoring and supervision.
* Warning: Due to the dynamic nature of the {@code Registry} the returned
* {@code Set} must be immutable. And you must get, it use and discard it. Keeping
* a long reference to it can introduce issues as memory leak. As it is a snapshot
* of the {@code Registry} content it as only informational value.
*
* @return all the ids contained by this registry.
*/
Set> ids();
/**
* Returns all the {@link Type}s contained by this registry
* at a certain point of time. The registry can contains more
* than one {@link Id} for a given type. Therefore the size of the
* {@code Set} returned by {@link #ids()} is {@code >=} to the size
* of the {@code Set} returned by this method.
* The returned {@code Set} can be link to the registry state. Any modification
* to the content of the registry may have to be reported to this {@code Set}. You can
* see it as a in sync with the registry. But it must be unmodifiable.
* This intent of this method is to provide information on the content
* of the {@code Registry}. It can be used for monitoring and supervision.
* Warning: Due to the dynamic nature of the {@code Registry} the returned
* {@code Set} must be immutable. And you must get, it use and discard it. Keeping
* a long reference to it can introduce issues as memory leak. As it is a snapshot
* of the {@code Registry} content it as only informational value.
*
* @return all the types contained by this registry.
*/
Set types();
/**
* Returns the first {@link Supplier} to which the specified type is mapped
* or {@code null} if the map contains no mapping for this type.
*
* More formally, if this registry contains at least a mapping for a type
* then it returns the first available mapping where for a given type {@code t} for all
* ids in the registry returns the first {@link Supplier} where {@code id.type()} == {@code t}
*
* @param type not {@code null} type whose associated {@link Supplier} is to be returned
* @param the matching type between the class parameter and the returned {@link Supplier}
* @return the value to which the specified type is mapped, or
* {@code null} if this map contains no mapping for the key
* @throws NullPointerException if the given type parameter is {@code null}
*/
@Nullable
Supplier get(Class type);
/**
* Returns all {@link Supplier}s to which the specified type is mapped
* or an empty list if the map contains no mapping for this type.
*
* More formally, if this registry contains a mapping for a type
* then it returns all available mapping where for a given type {@code t}
* ids {@code id} in the registry returns {@link Supplier}s
* where {@code id.type()} == {@code t}
*
* @param type not {@code null} type whose associated {@link Supplier}s are to be returned
* @param the matching type between the class parameter and the returned {@link Supplier}s
* @return the list of {@link Supplier}s value to which the specified type is mapped, or
* an empty list if this map contains no mapping for the given type.
* @throws NullPointerException if the given type parameter is {@code null}.
*/
List> getAll(Class type);
/**
* Returns the first {@link Supplier} to which the specified id is mapped
* or {@code null} if the map contains no mapping for this id.
*
* More formally, if this registry contains at least a mapping for an id
* then it returns the first available mapping where for a given identifier {@code id} for all
* ids {@code other} in the registry returns the first {@link Supplier} where {@code id.equals(other)}
* This method is a strict comparison regarding the {@link #get(Class)}
* and {@link #get(com.google.common.reflect.TypeToken)} which are more weak.
*
* @param id not {@code null} {@link Id} whose associated {@link Supplier} is to be returned.
* @param the matching type between the {@link Id} parameter and the returned {@link Supplier}
* @return the value to which the specified {@link Id} is mapped, or
* {@code null} if this map contains no mapping for the given {@link Id}.
* @throws NullPointerException if the given {@link Id} parameter is {@code null}.
*/
@Nullable
Supplier get(Id id);
/**
* Returns all {@link Supplier}s to which the specified {@link Id} is mapped
* or an empty list if the map contains no mapping for this type.
*
* More formally, if this registry contains a mapping for a {@link Id}
* then it returns all available mapping where for a given {@link Id} id
* ids {@code otherId} in the registry {@code id.equals(otherId)}
* This method is a strict comparison regarding the {@link #getAll(Class)}
* and {@link #getAll(com.google.common.reflect.TypeToken)} which are more weak.
*
* @param id not {@code null} {@link Id} whose associated {@link Supplier}s are to be returned
* @param the matching type between the class parameter and the returned {@link Supplier}s
* @return the list of {@link Supplier}s value to which the specified {@link Id} is mapped, or
* an empty list if this map contains no mapping for the given {@link Id}.
* @throws NullPointerException if the given {@link Id} parameter is {@code null}.
*/
List> getAll(Id id);
/**
* Returns the first {@link Supplier} to which the specified type is mapped
* or {@code null} if the map contains no mapping for this type.
*
* More formally, if this registry contains at least a mapping for a type
* then it returns the first available mapping where for a given {@code TypeToken} {@code t} for all
* ids in the registry if {@code id.type()} == {@code t.getType()}
* This implementation is lest strict that the {@link #get(Id)} because it just validate
* the type and forget the annotation.
*
* @param type not {@code null} type whose associated {@link Supplier} is to be returned
* @param the matching type between the class parameter and the returned {@link Supplier}
* @return the value to which the specified type is mapped, or
* {@code null} if this map contains no mapping for the key
* @throws NullPointerException if the given type parameter is {@code null}
*/
@Nullable
Supplier get(TypeToken type);
/**
* Returns all {@link Supplier}s to which the specified {@code TypeToken} is mapped
* or an empty list if the map contains no mapping for this type.
*
* More formally, if this registry contains a mapping for a {@code TypeToken}
* then it returns all available mapping where for a given {@code TypeToken} {@code t},
* ids ({@code otherId}) in the registry match: {@code t.getType() == otherId.type()}
* This method is not strict comparison regarding the {@link #getAll(Id)}
* as it just validate the type and not the annotation.
* This version of the getAll(...) method provide more type safety than the {@link #get(Class)}.
*
* @param type not {@code null} {@code TypeToken} whose associated {@link Supplier}s are to be returned.
* @param the matching type between the type parameter and the returned {@link Supplier}s
* @return the list of {@link Supplier}s value to which the specified {@link Id} is mapped, or
* an empty list if this map contains no mapping for the given {@link Id}.
* @throws NullPointerException if the given {@code TypeToken} parameter is {@code null}.
*/
List> getAll(TypeToken type);
/**
* Associates the specified supplier with the specified id in this registry.
* If the map previously contained a mapping for the id, the new supplier is
* added after the old one or an runtime exception is throw for duplicated entry,
* This behaviour depends on the implementation.
*
* (A registry {@code r} is said to contain a mapping for a id {@code i} if
* and only if {@link #contains(Id) r.contains(i)} would return {@code true}.)
*
* @param id id with which the specified supplier is to be associated.
* @param supplier supplier to be associated with the specified id
* @return the registration handle for use by the caller to remove this
* registration action. It not intents to be shared by the caller.
* @throws NullPointerException if the specified key or value is null
* and this map does not permit null keys or values
* @see Registration
* @see #remove(Registration)
*/
Registration put(Id id, com.google.common.base.Supplier supplier);
/**
* Removes the supplier referenced by the specified
* {@code Registration} object.
*
* @param registration A reference to the supplier to be released.
*/
void remove(Registration registration);
/**
* Bulk remove the suppliers referenced by the specified list of
* {@code Registration} objects.
*
* @param registrations A list of references to the suppliers to be released.
*/
void removeAll(Collection> registrations);
/**
* Registers a listener / watcher for suppliers life-cycle events (add / remove).
* The registry will notify the listener when a supplier is added of removed
* and its Id is matched by the given {@link Id} matcher.
* Warning: To avoid memory leak watcher are stored in the registry
* with weak reference. Therefore the caller must keep a strong reference to
* the registration to avoid premature garbage collection of the watcher.
*
* @param idMatcher the matcher that matches supplier ids the listener
* should be notified of.
* @param watcher the watcher for suppliers whose associated ids are
* matched by idMatcher
* @param the supplied type
* @return the registration that represent this action. This registration is
* the only way to remove this watcher from the registry. It is not intended
* to be shared by the caller
*/
Registration addWatcher(IdMatcher idMatcher, Watcher watcher);
/**
* Removes the {@link Watcher} instance referenced by the specified
* {@code Registration} object.
*
* @param watcherRegistration A reference to the watcher to be released.
*/
void removeWatcher(Registration watcherRegistration);
/**
* Bulk remove the {@link Watcher Watchers} referenced by the specified list of
* {@code Registration Registration}.
*
* @param watcherRegistrations A list of references to the watchers to be released.
*/
void removeAllWatchers(Collection> watcherRegistrations);
}