org.infinispan.commons.api.functional.FunctionalMap Maven / Gradle / Ivy
package org.infinispan.commons.api.functional;
import org.infinispan.commons.api.functional.EntryView.ReadEntryView;
import org.infinispan.commons.api.functional.EntryView.ReadWriteEntryView;
import org.infinispan.commons.api.functional.EntryView.WriteEntryView;
import org.infinispan.commons.api.functional.Listeners.ReadWriteListeners;
import org.infinispan.commons.api.functional.Listeners.WriteListeners;
import org.infinispan.commons.marshall.MarshallableFunctions;
import org.infinispan.commons.util.Experimental;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ConcurrentMap;
import java.util.function.BiConsumer;
import java.util.function.BiFunction;
import java.util.function.Consumer;
import java.util.function.Function;
/**
* Top level functional map interface offering common functionality for the
* read-only, read-write, and write-only operations that can be run against a
* functional map asynchronously.
*
* Lambdas passed in as parameters to functional map methods define the
* type of operation that is executed, but since lambdas are transparent to
* the internal logic, it was decided to separate the API into three types
* of operation: read-only, write-only, and read-write. This separation helps
* the user understand the group of functions and their possibilities.
*
*
This conscious decision to separate read-only, write-only and
* read-write interfaces helps type safety. So, if a user gets a read-only
* map, it can't write to it by mistake since no such APIs are exposed.
* The same happens with write-only maps, the user can only write and cannot
* make the mistake of reading from the entry view because read operations
* are not exposed.
*
*
Lambdas passed in to read-write and write-only operations, when
* running in a cluster, must be marshallable. One option to do so is to
* mark them as being {@link java.io.Serializable} but this is expensive
* in terms of payload size. Alternatively, you can provide an Infinispan
* {@link org.infinispan.commons.marshall.Externalizer} for it which
* drastically reduces the payload size. Marshallable lambdas for some of
* the most popular lambda functions used by {@link ConcurrentMap} and
* javax.cache.Cache are available via the
* {@link MarshallableFunctions} helper class.
*
*
Being an asynchronous API, all methods that return a single result,
* return a {@link CompletableFuture} which wraps the result. To avoid
* blocking, it offers the possibility to receive callbacks when the
* {@link CompletableFuture} has completed, or it can be chained or composes
* with other {@link CompletableFuture} instances.
*
*
For those operations that return multiple results, the API returns
* instances of a {@link Traversable} interface which offers a lazy pullstyle
* API for working with multiple results. Although pushstyle interfaces for
* handling multiple results, such as RxJava, are fully asynchronous, they're
* harder to use from a user’s perspective. {@link Traversable}, being a lazy
* pullstyle API, can still be asynchronous underneath since the user can
* decide to work on the {@link Traversable} at a later stage, and the
* implementation itself can decide when to compute those results.
*
* @since 8.0
*/
@Experimental
public interface FunctionalMap extends AutoCloseable {
/**
* Tweak functional map executions providing {@link Param} instances.
*/
FunctionalMap withParams(Param... ps);
/**
* Functional map's name.
*/
String getName();
/**
* Functional map's status.
*/
Status getStatus();
/**
* Exposes read-only operations that can be executed against the functional map.
* The information that can be read per entry in the functional map is
* exposed by {@link ReadEntryView}.
*
* Read-only operations have the advantage that no locks are acquired
* for the duration of the operation and so it makes sense to have them
* a top-level interface dedicated to them.
*
*
Browsing methods that provide a read-only view of the cached data
* are available via {@link #keys()} and {@link #entries()}.
* Having {@link #keys()} makes sense since that way keys can be traversed
* without having to bring values. Having {@link #entries()} makes sense
* since it allows traversing both keys, values and any meta parameters
* associated with them, but this is no extra cost to exposing just values
* since keys are the main index and hence will always be available.
* Hence, adding a method to only browse values offers nothing extra to
* the API.
*
* @since 8.0
*/
@Experimental
interface ReadOnlyMap extends FunctionalMap {
/**
* Tweak read-only functional map executions providing {@link Param} instances.
*/
ReadOnlyMap withParams(Param... ps);
/**
* Evaluate a read-only function on the value associated with the key
* and return a {@link CompletableFuture} with the return type of the function.
* If the user is not sure if the key is present, {@link ReadEntryView#find()}
* can be used to find out for sure. Typically, function implementations
* would return value or {@link MetaParam} information from the cache
* entry in the functional map.
*
* By returning {@link CompletableFuture} instead of the function's
* return type directly, the method hints at the possibility that to
* execute the function might require to go remote to retrieve data in
* persistent store or another clustered node.
*
*
This method can be used to implement read-only single-key based
* operations in {@link ConcurrentMap} and javax.cache.Cache
* such as:
*
*
* - {@link ConcurrentMap#get(Object)}
* - {@link ConcurrentMap#containsKey(Object)}
* - {@code javax.cache.Cache#get(Object)}
* - {@code javax.cache.Cache#containsKey(Object)}
*
*
* @param key the key associated with the {@link ReadEntryView} to be
* passed to the function.
* @param f function that takes a {@link ReadEntryView} associated with
* the key, and returns a value.
* @param function return type
* @return a {@link CompletableFuture} which will be completed with the
* returned value from the function
*/
CompletableFuture eval(K key, Function, R> f);
/**
* Evaluate a read-only function on a key and potential value associated in
* the functional map, for each of the keys in the set passed in, and
* returns an {@link Traversable} to work on each computed function's result.
*
* The function passed in will be executed for as many keys
* present in keys collection set. Similar to {@link #eval(Object, Function)},
* if the user is not sure whether a particular key is present,
* {@link ReadEntryView#find()} can be used to find out for sure.
*
*
This method can be used to implement operations such as
* {@code javax.cache.Cache#getAll(Set)}.
*
* DESIGN RATIONALE:
*
* - It makes sense to expose global operation like this instead of
* forcing users to iterate over the keys to lookup and call get
* individually since Infinispan can do things more efficiently.
*
*
*
* @param keys the keys associated with each of the {@link ReadEntryView}
* passed in the function callbacks
* @param f function that takes a {@link ReadEntryView} associated with
* the key, and returns a value. It'll be invoked once for each key
* passed in
* @param function return type
* @return a sequential {@link Traversable} that can be navigated to
* retrieve each function return value
*/
Traversable evalMany(Set keys, Function, R> f);
/**
* Provides a {@link Traversable} that allows clients to navigate all cached keys.
*
* This method can be used to implement operations such as:
*
* - {@link ConcurrentMap#size()}
* - {@link ConcurrentMap#keySet()}
* - {@link ConcurrentMap#isEmpty()}
*
*
* @return a sequential {@link Traversable} to navigate each cached key
*/
Traversable keys();
/**
* Provides a {@link Traversable} that allows clients to navigate all cached entries.
*
* This method can be used to implement operations such as:
*
* - {@link ConcurrentMap#containsValue(Object)}
* - {@link ConcurrentMap#values()}
* - {@link ConcurrentMap#entrySet()}
* - {@code javax.cache.Cache#iterator()}
*
*
* @return a sequential {@link Traversable} to navigate each cached entry
*/
Traversable> entries();
}
/**
* Exposes write-only operations that can be executed against the functional map.
* The write operations that can be applied per entry are exposed by
* {@link WriteEntryView}.
*
* Write-only operations require locks to be acquired but crucially
* they do not require reading previous value or metadata parameter
* information associated with the cached entry, which sometimes can be
* expensive since they involve talking to a remote node in the cluster
* or the persistence layer So, exposing write-only operations makes it
* easy to take advantage of this important optimisation.
*
*
Method parameters for write-only operations, including lambdas,
* must be marshallable when running in a cluster.
*
* @since 8.0
*/
@Experimental
interface WriteOnlyMap extends FunctionalMap {
/**
* Tweak write-only functional map executions providing {@link Param} instances.
*/
WriteOnlyMap withParams(Param... ps);
/**
* Evaluate a write-only {@link BiConsumer} operation, with a value
* passed in and a {@link WriteEntryView} of the value associated with
* the key, and return a {@link CompletableFuture} which will be
* completed when the operation completes.
*
* Since this is a write-only operation, no entry attributes can be
* queried, hence the only reasonable thing can be returned is Void.
*
*
This method can be used to implement single-key write-only operations
* which do not need to query previous value, such as
* {@code javax.cache.Cache#put(Object, Object)}
*
*
This operation is very similar to {@link #eval(Object, Consumer)}
* and in fact, the functionality provided by this function could indeed
* be implemented with {@link #eval(Object, Consumer)}, but there's a
* crucial difference. If you want to store a value and reference the
* value to be stored from the passed in operation,
* {@link #eval(Object, Consumer)} needs to capture that value.
* Capturing means that each time the operation is called, a new lambda
* needs to be instantiated. By offering a {@link BiConsumer} that
* takes user provided value as first parameter, the operation does not
* capture any external objects when implementing simple operations
* such as {@code javax.cache.Cache#put(Object, Object)}, and hence, the
* {@link BiConsumer} could be cached and reused each time it's invoked.
*
* @param key the key associated with the {@link WriteEntryView} to be
* passed to the operation
* @param value value to write, passed in as first parameter to the
* {@link BiConsumer} operation.
* @param f operation that takes a user defined value, and a
* {@link WriteEntryView} associated with the key, and writes
* to the {@link WriteEntryView} passed in without returning anything
* @return a {@link CompletableFuture} which will be completed when the
* operation completes
*/
CompletableFuture eval(K key, V value, BiConsumer> f);
/**
* Evaluate a write-only {@link Consumer} operation with a
* {@link WriteEntryView} of the value associated with the key,
* and return a {@link CompletableFuture} which will be
* completed with the object returned by the operation.
*
* Since this is a write-only operation, no entry attributes can be
* queried, hence the only reasonable thing can be returned is Void.
*
*
This operation can be used to either remove a cached entry,
* or to write a constant value along with optional metadata parameters.
*
* @param key the key associated with the {@link WriteEntryView} to be
* passed to the operation
* @param f operation that takes a {@link WriteEntryView} associated with
* the key and writes to the it without returning anything
* @return a {@link CompletableFuture} which will be completed when the
* operation completes
*/
CompletableFuture eval(K key, Consumer> f);
/**
* Evaluate a write-only {@link BiConsumer} operation, with a value
* passed in and a {@link WriteEntryView} of the value associated with
* the key, for each of the keys in the set passed in, and returns a
* {@link CompletableFuture} that will be completed when the write-only
* operation has been executed against all the entries.
*
* This method can be used to implement operations such as:
*
*
* - {@link ConcurrentMap#putAll(Map)}
* - {@code javax.cache.Cache#putAll(Map)}
*
*
* These kind of operations are preferred to traditional end user
* iterations because the internal logic can often iterate more
* efficiently since it knows more about the system.
*
*
Since this is a write-only operation, no entry attributes can be
* queried, hence the only reasonable thing can be returned is Void.
*
* @param entries the key/value pairs associated with each of the
* {@link WriteEntryView} passed in the function callbacks
* @param f operation that consumes a value associated with a key in the
* entries collection and the {@link WriteEntryView} associated
* with that key in the cache
* @return a {@link CompletableFuture} which will be completed when
* the {@link BiConsumer} operation has been executed against
* all entries
*/
CompletableFuture evalMany(Map entries, BiConsumer> f);
/**
* Evaluate a write-only {@link Consumer} operation with the
* {@link WriteEntryView} of the value associated with the key, for each
* of the keys in the set passed in, and returns a
* {@link CompletableFuture} that will be completed when the write-only
* operation has been executed against all the entries.
*
* This method can be used to implement operations such as
* {@code javax.cache.Cache#removeAll(Set)}.
*
*
These kind of operations are preferred to traditional end user
* iterations because the internal logic can often iterate more
* efficiently since it knows more about the system.
*
*
Since this is a write-only operation, no entry attributes can be
* queried, hence the only reasonable thing can be returned is Void.
*
* @param keys the keys associated with each of the {@link WriteEntryView}
* passed in the function callbacks
* @param f operation that the {@link WriteEntryView} associated with
* one of the keys passed in
* @return a {@link CompletableFuture} which will be completed when
* the {@link Consumer} operation has been executed against all
* entries
*/
CompletableFuture evalMany(Set keys, Consumer> f);
/**
* Evaluate a write-only {@link Consumer} operation with the
* {@link WriteEntryView} of the value associated with the key, for all
* existing keys in functional map, and returns a {@link CompletableFuture}
* that will be completed when the write-only operation has been executed
* against all the entries.
*
* This method can be used to implement operations such as
* {@code javax.cache.Cache#removeAll()}.
*
* @param f operation that the {@link WriteEntryView} associated with
* one of the keys passed in
* @return a {@link CompletableFuture} which will be completed when
* the {@link Consumer} operation has been executed against all
* entries
*/
CompletableFuture evalAll(Consumer> f);
/**
* Truncate the contents of the cache, returning a {@link CompletableFuture}
* that will be completed when the truncate process completes.
*
* This method can be used to implement:
*
*
* - {@link ConcurrentMap#clear()}
* - {@code javax.cache.Cache#clear()}
*
*
* @return a {@link CompletableFuture} that completes when the truncat
* has finished
*/
CompletableFuture truncate();
/**
* Allows to write-only listeners to be registered.
*/
WriteListeners listeners();
}
/**
* Exposes read-write operations that can be executed against the functional map.
* The read-write operations that can be applied per entry are exposed by
* {@link ReadWriteEntryView}.
*
* Read-write operations offer the possibility of writing values or
* metadata parameters, and returning previously stored information.
* Read-write operations are also crucial for implementing conditional,
* compare-and-swap (CAS) like operations.
*
*
Locks are acquired before executing the read-write lambda.
*
*
Method parameters for read-write operations, including lambdas,
* must be marshallable when running in a cluster.
*
* @since 8.0
*/
@Experimental
interface ReadWriteMap extends FunctionalMap {
/**
* Tweak read-write functional map executions providing {@link Param} instances.
*/
ReadWriteMap withParams(Param... ps);
/**
* Evaluate a read-write function on the value and metadata associated
* with the key and return a {@link CompletableFuture} with the return
* type of the function. If the user is not sure if the key is present,
* {@link ReadWriteEntryView#find()} can be used to find out for sure.
*
* This method can be used to implement single-key read-write operations
* in {@link ConcurrentMap} and {@code javax.cache.Cache} that do not
* depend on value information given by the user such as:
*
*
* - {@link ConcurrentMap#remove(Object)}
* - {@code javax.cache.Cache#remove(Object)}
* - {@code javax.cache.Cache#getAndRemove(Object)}
* - {@code javax.cache.Cache#invoke(Object, EntryProcessor, Object...)}
*
*
* @param key the key associated with the {@link ReadWriteEntryView} to be
* passed to the function.
* @param f function that takes a {@link ReadWriteEntryView} associated with
* the key, and returns a value.
* @param function return type
* @return a {@link CompletableFuture} which will be completed with the
* returned value from the function
*/
CompletableFuture eval(K key, Function, R> f);
/**
* Evaluate a read-write function, with a value passed in and a
* {@link WriteEntryView} of the value associated with the key, and
* return a {@link CompletableFuture} which will be completed with the
* returned value by the function.
*
* This method provides the the capability to both update the value and
* metadata associated with that key, and return previous value or metadata.
*
*
This method can be used to implement the vast majority of single-key
* read-write operations in {@link ConcurrentMap} and {@code javax.cache.Cache}
* such as:
*
*
* - {@link ConcurrentMap#put(Object, Object)}
* - {@link ConcurrentMap#putIfAbsent(Object, Object)}
* - {@link ConcurrentMap#replace(Object, Object)}
* - {@link ConcurrentMap#replace(Object, Object, Object)}
* - {@link ConcurrentMap#remove(Object, Object)}
* - {@code javax.cache.Cache#getAndPut(Object, Object)}
* - {@code javax.cache.Cache#putIfAbsent(Object, Object)}
* - {@code javax.cache.Cache#remove(Object, Object)}
* - {@code javax.cache.Cache#replace(Object, Object, Object)}
* - {@code javax.cache.Cache#replace(Object, Object)}
* - {@code javax.cache.Cache#getAndReplace(Object, Object)}
*
*
* The functionality provided by this function could indeed be
* implemented with {@link #eval(Object, Function)}, but there's a
* crucial difference. If you want to store a value and reference the
* value to be stored from the passed in operation,
* {@link #eval(Object, Function)} needs to capture that value.
* Capturing means that each time the operation is called, a new lambda
* needs to be instantiated. By offering a {@link BiFunction} that
* takes user provided value as first parameter, the operation does
* not capture any external objects when implementing
* simple operations such as {@code javax.cache.Cache#getAndPut(Object, Object)},
* and hence, the {@link BiFunction} could be cached and reused each
* time it's invoked.
*
* @param key the key associated with the {@link ReadWriteEntryView} to be
* passed to the operation
* @param value value to write, passed in as first parameter to the {@link BiFunction}.
* @param f operation that takes a user defined value, and a
* {@link ReadWriteEntryView} associated with the key, and writes
* to the {@link ReadWriteEntryView} passed in, possibly
* returning previously stored value or metadata information
* @param type of the function's return
* @return a {@link CompletableFuture} which will be completed with the
* returned value from the function
*/
CompletableFuture eval(K key, V value, BiFunction, R> f);
/**
* Evaluate a read-write {@link BiFunction}, with a value passed in and
* a {@link ReadWriteEntryView} of the value associated with
* the key, for each of the keys in the set passed in, and
* returns an {@link Traversable} to navigate each of the
* {@link BiFunction} invocation returns.
*
* This method can be used to implement operations that store a set of
* keys and return previous values or metadata parameters.
*
*
These kind of operations are preferred to traditional end user
* iterations because the internal logic can often iterate more
* efficiently since it knows more about the system.
*
* @param entries the key/value pairs associated with each of the
* {@link ReadWriteEntryView} passed in the function callbacks
* @param f function that takes in a value associated with a key in the
* entries collection and the {@link ReadWriteEntryView} associated
* with that key in the cache
* @return a {@link Traversable} to navigate each {@link BiFunction} return
*/
Traversable evalMany(Map entries, BiFunction, R> f);
/**
* Evaluate a read-write {@link Function} operation with the
* {@link ReadWriteEntryView} of the value associated with the key, for each
* of the keys in the set passed in, and returns a {@link Traversable}
* to navigate each of the {@link Function} invocation returns.
*
* This method can be used to implement operations such as
* {@code javax.cache.Cache#invokeAll(Set, EntryProcessor, Object...)},
* or a remove a set of keys returning previous values or metadata
* parameters.
*
* @param keys the keys associated with each of the {@link ReadWriteEntryView}
* passed in the function callbacks
* @param f function that the {@link ReadWriteEntryView} associated with
* one of the keys passed in, and returns a value
* @return a {@link Traversable} to navigate each {@link Function} return
*/
Traversable evalMany(Set keys, Function, R> f);
/**
* Evaluate a read-write {@link Function} operation with the
* {@link ReadWriteEntryView} of the value associated with the key, for all
* existing keys, and returns a {@link Traversable} to navigate each of
* the {@link Function} invocation returns.
*
* This method can be used to an operation that removes all cached
* entries individually, and returns previous value and/or metadata
* parameters.
*
* @return a {@link Traversable} to navigate each {@link Function} return
*/
Traversable evalAll(Function, R> f);
/**
* Allows to read-write listeners to be registered.
*/
ReadWriteListeners listeners();
}
}