/*
* Copyright 2020 The Android Open Source Project
*
* 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.
*/
// @exportToFramework:skipFile()
package androidx.appsearch.app;
import android.annotation.SuppressLint;
import androidx.annotation.NonNull;
import com.google.common.util.concurrent.ListenableFuture;
import java.io.Closeable;
import java.util.Set;
/**
* Provides a connection to a single AppSearch database.
*
* <p>An {@link AppSearchSession} instance provides access to database operations such as setting
* a schema, adding documents, and searching.
*
* <p>Instances of this interface are usually obtained from a storage implementation, e.g.
* {@code LocalStorage.createSearchSession()} or {@code PlatformStorage.createSearchSession()}.
*
* <p>All implementations of this interface must be thread safe.
*
* @see GlobalSearchSession
*/
public interface AppSearchSession extends Closeable {
/**
* Sets the schema that represents the organizational structure of data within the AppSearch
* database.
*
* <p>Upon creating an {@link AppSearchSession}, {@link #setSchema} should be called. If the
* schema needs to be updated, or it has not been previously set, then the provided schema
* will be saved and persisted to disk. Otherwise, {@link #setSchema} is handled efficiently
* as a no-op call.
*
* @param request the schema to set or update the AppSearch database to.
* @return a {@link ListenableFuture} which resolves to a {@link SetSchemaResponse} object.
*/
@NonNull
ListenableFuture<SetSchemaResponse> setSchema(
@NonNull SetSchemaRequest request);
/**
* Retrieves the schema most recently successfully provided to {@link #setSchema}.
*
* @return The pending {@link GetSchemaResponse} of performing this operation.
*/
// This call hits disk; async API prevents us from treating these calls as properties.
@SuppressLint("KotlinPropertyAccess")
@NonNull
ListenableFuture<GetSchemaResponse> getSchema();
/**
* Retrieves the set of all namespaces in the current database with at least one document.
*
* @return The pending result of performing this operation.
*/
@NonNull
ListenableFuture<Set<String>> getNamespaces();
/**
* Indexes documents into the {@link AppSearchSession} database.
*
* <p>Each {@link GenericDocument} object must have a {@code schemaType} field set to an
* {@link AppSearchSchema} type that has been previously registered by calling the
* {@link #setSchema} method.
*
* @param request containing documents to be indexed.
* @return a {@link ListenableFuture} which resolves to an {@link AppSearchBatchResult}.
* The keys of the returned {@link AppSearchBatchResult} are the IDs of the input documents.
* The values are either {@code null} if the corresponding document was successfully indexed,
* or a failed {@link AppSearchResult} otherwise.
*/
@NonNull
ListenableFuture<AppSearchBatchResult<String, Void>> put(@NonNull PutDocumentsRequest request);
/**
* Gets {@link GenericDocument} objects by document IDs in a namespace from the
* {@link AppSearchSession} database.
*
* @param request a request containing a namespace and IDs to get documents for.
* @return A {@link ListenableFuture} which resolves to an {@link AppSearchBatchResult}.
* The keys of the {@link AppSearchBatchResult} represent the input document IDs from the
* {@link GetByDocumentIdRequest} object. The values are either the corresponding
* {@link GenericDocument} object for the ID on success, or an {@link AppSearchResult}
* object on failure. For example, if an ID is not found, the value for that ID will be set
* to an {@link AppSearchResult} object with result code:
* {@link AppSearchResult#RESULT_NOT_FOUND}.
*/
@NonNull
ListenableFuture<AppSearchBatchResult<String, GenericDocument>> getByDocumentId(
@NonNull GetByDocumentIdRequest request);
/**
* Retrieves documents from the open {@link AppSearchSession} that match a given query string
* and type of search provided.
*
* <p>Query strings can be empty, contain one term with no operators, or contain multiple
* terms and operators.
*
* <p>For query strings that are empty, all documents that match the {@link SearchSpec} will be
* returned.
*
* <p>For query strings with a single term and no operators, documents that match the
* provided query string and {@link SearchSpec} will be returned.
*
* <p>The following operators are supported:
*
* <ul>
* <li>AND (implicit)
* <p>AND is an operator that matches documents that contain <i>all</i>
* provided terms.
* <p><b>NOTE:</b> A space between terms is treated as an "AND" operator. Explicitly
* including "AND" in a query string will treat "AND" as a term, returning documents that
* also contain "AND".
* <p>Example: "apple AND banana" matches documents that contain the
* terms "apple", "and", "banana".
* <p>Example: "apple banana" matches documents that contain both "apple" and
* "banana".
* <p>Example: "apple banana cherry" matches documents that contain "apple", "banana", and
* "cherry".
*
* <li>OR
* <p>OR is an operator that matches documents that contain <i>any</i> provided term.
* <p>Example: "apple OR banana" matches documents that contain either "apple" or "banana".
* <p>Example: "apple OR banana OR cherry" matches documents that contain any of
* "apple", "banana", or "cherry".
*
* <li>Exclusion (-)
* <p>Exclusion (-) is an operator that matches documents that <i>do not</i> contain the
* provided term.
* <p>Example: "-apple" matches documents that do not contain "apple".
*
* <li>Grouped Terms
* <p>For queries that require multiple operators and terms, terms can be grouped into
* subqueries. Subqueries are contained within an open "(" and close ")" parenthesis.
* <p>Example: "(donut OR bagel) (coffee OR tea)" matches documents that contain
* either "donut" or "bagel" and either "coffee" or "tea".
*
* <li>Property Restricts
* <p>For queries that require a term to match a specific {@link AppSearchSchema}
* property of a document, a ":" must be included between the property name and the term.
* <p>Example: "subject:important" matches documents that contain the term "important" in
* the "subject" property.
* </ul>
*
* <p>Additional search specifications, such as filtering by {@link AppSearchSchema} type or
* adding projection, can be set by calling the corresponding {@link SearchSpec.Builder} setter.
*
* <p>This method is lightweight. The heavy work will be done in
* {@link SearchResults#getNextPage}.
*
* @param queryExpression query string to search.
* @param searchSpec spec for setting document filters, adding projection, setting term
* match type, etc.
* @return a {@link SearchResults} object for retrieved matched documents.
*/
@NonNull
SearchResults search(@NonNull String queryExpression, @NonNull SearchSpec searchSpec);
/**
* Reports usage of a particular document by namespace and ID.
*
* <p>A usage report represents an event in which a user interacted with or viewed a document.
*
* <p>For each call to {@link #reportUsage}, AppSearch updates usage count and usage recency
* metrics for that particular document. These metrics are used for ordering {@link #search}
* results by the {@link SearchSpec#RANKING_STRATEGY_USAGE_COUNT} and
* {@link SearchSpec#RANKING_STRATEGY_USAGE_LAST_USED_TIMESTAMP} ranking strategies.
*
* <p>Reporting usage of a document is optional.
*
* @param request The usage reporting request.
* @return The pending result of performing this operation which resolves to {@code null} on
* success.
*/
@NonNull
ListenableFuture<Void> reportUsage(@NonNull ReportUsageRequest request);
/**
* Removes {@link GenericDocument} objects by document IDs in a namespace from the
* {@link AppSearchSession} database.
*
* <p>Removed documents will no longer be surfaced by {@link #search} or
* {@link #getByDocumentId}
* calls.
*
* <p>Once the database crosses the document count or byte usage threshold, removed documents
* will be deleted from disk.
*
* @param request {@link RemoveByDocumentIdRequest} with IDs in a namespace to remove from the
* index.
* @return a {@link ListenableFuture} which resolves to an {@link AppSearchBatchResult}.
* The keys of the {@link AppSearchBatchResult} represent the input IDs from the
* {@link RemoveByDocumentIdRequest} object. The values are either {@code null} on success,
* or a failed {@link AppSearchResult} otherwise. IDs that are not found will return a failed
* {@link AppSearchResult} with a result code of {@link AppSearchResult#RESULT_NOT_FOUND}.
*/
@NonNull
ListenableFuture<AppSearchBatchResult<String, Void>> remove(
@NonNull RemoveByDocumentIdRequest request);
/**
* Removes {@link GenericDocument}s from the index by Query. Documents will be removed if they
* match the {@code queryExpression} in given namespaces and schemaTypes which is set via
* {@link SearchSpec.Builder#addFilterNamespaces} and
* {@link SearchSpec.Builder#addFilterSchemas}.
*
* <p> An empty {@code queryExpression} matches all documents.
*
* <p> An empty set of namespaces or schemaTypes matches all namespaces or schemaTypes in
* the current database.
*
* @param queryExpression Query String to search.
* @param searchSpec Spec containing schemaTypes, namespaces and query expression
* indicates how document will be removed. All specific about how to
* scoring, ordering, snippeting and resulting will be ignored.
* @return The pending result of performing this operation.
*/
@NonNull
ListenableFuture<Void> remove(@NonNull String queryExpression, @NonNull SearchSpec searchSpec);
/**
* Gets the storage info for this {@link AppSearchSession} database.
*
* <p>This may take time proportional to the number of documents and may be inefficient to
* call repeatedly.
*
* @return a {@link ListenableFuture} which resolves to a {@link StorageInfo} object.
*/
@NonNull
ListenableFuture<StorageInfo> getStorageInfo();
/**
* Flush all schema and document updates, additions, and deletes to disk if possible.
*
* <p>The request is not guaranteed to be handled and may be ignored by some implementations of
* AppSearchSession.
*
* @return The pending result of performing this operation.
* {@link androidx.appsearch.exceptions.AppSearchException} with
* {@link AppSearchResult#RESULT_INTERNAL_ERROR} will be set to the future if we hit error when
* save to disk.
*/
@NonNull
ListenableFuture<Void> requestFlush();
/**
* Closes the {@link AppSearchSession} to persist all schema and document updates, additions,
* and deletes to disk.
*/
@Override
void close();
}