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#8 - Replace exchange() method with map(…) and then() methods.
DatabaseClient now no longer exposes the exchange() method but rather provides map(…) and then(…) methods. Calling map(…) extracts values from tabular results by propagating the mapping function to Result.map(…). then() allows statement execution without returning the result propagating only completion and error signals. Original pull request: #33.
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‎README.adoc

Lines changed: 10 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@ The state of R2DBC is incubating to evaluate how an reactive integration could l
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== This is NOT an ORM
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11-
Spring Data R2DBC does not try to be an ORM.
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Spring Data R2DBC does not try to be an ORM.
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Instead it is more of a construction kit for your personal reactive relational data access component that you can define the way you like or need it.
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== Maven Coordinates
@@ -64,12 +64,13 @@ Mono<Integer> count = databaseClient.execute()
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Flux<Map<String, Object>> rows = databaseClient.execute()
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.sql("SELECT id, name, manual FROM legoset")
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.fetch().all();
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.fetch()
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.all();
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Flux<Long> result = db.execute()
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.sql("SELECT txid_current();")
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.exchange()
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.flatMapMany(it -> it.extract((r, md) -> r.get(0, Long.class)).all());
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.map((r, md) -> r.get(0, Long.class))
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.all();
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----
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=== Examples selecting data
@@ -100,14 +101,13 @@ Flux<Integer> ids = databaseClient.insert()
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.value("id", 42055)
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.value("name", "Description")
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.nullValue("manual", Integer.class)
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.exchange() //
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.flatMapMany(it -> it.extract((r, m) -> r.get("id", Integer.class)).all())
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.map((r, m) -> r.get("id", Integer.class)
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.all();
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Flux<Integer> ids = databaseClient.insert()
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Mono<Void> completion = databaseClient.insert()
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.into(LegoSet.class)
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.using(legoSet)
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.exchange()
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.flatMapMany(it -> it.extract((r, m) -> r.get("id", Integer.class)).all())
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.then();
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----
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=== Examples using reactive repositories
@@ -162,7 +162,7 @@ Flux<Integer> rowsUpdated = databaseClient.inTransaction(db -> {
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[source,java]
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----
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Flux<Long> txId = databaseClient.execute().sql("SELECT txid_current();").exchange()
165-
.flatMapMany(it -> it.extract((r, md) -> r.get(0, Long.class)).all());
165+
.flatMapMany(it -> it.map((r, md) -> r.get(0, Long.class)).all());
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Mono<Void> then = databaseClient.enableTransactionSynchronization(databaseClient.beginTransaction() //
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.thenMany(txId)) //

‎src/main/java/org/springframework/data/r2dbc/function/DatabaseClient.java

Lines changed: 63 additions & 35 deletions
Original file line numberDiff line numberDiff line change
@@ -156,17 +156,26 @@ interface GenericExecuteSpec extends BindSpec<GenericExecuteSpec> {
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*/
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<R> TypedExecuteSpec<R> as(Class<R> resultType);
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/**
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* Configure a result mapping {@link java.util.function.BiFunction function}.
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*
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* @param mappingFunction must not be {@literal null}.
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* @param <R> result type.
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* @return
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*/
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<R> FetchSpec<R> map(BiFunction<Row, RowMetadata, R> mappingFunction);
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/**
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* Perform the SQL call and retrieve the result.
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*/
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FetchSpec<Map<String, Object>> fetch();
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/**
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* Perform the SQL request and return a {@link SqlResult}.
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* Perform the SQL call and return a {@link Mono} that completes without result on statement completion.
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*
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* @return a {@code Mono} for the result
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* @return a {@link Mono} ignoring its payload (actively dropping).
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*/
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Mono<SqlResult<Map<String, Object>>> exchange();
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Mono<Void> then();
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}
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/**
@@ -183,17 +192,26 @@ interface TypedExecuteSpec<T> extends BindSpec<TypedExecuteSpec<T>> {
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*/
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<R> TypedExecuteSpec<R> as(Class<R> resultType);
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/**
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* Configure a result mapping {@link java.util.function.BiFunction function}.
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*
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* @param mappingFunction must not be {@literal null}.
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* @param <R> result type.
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* @return
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*/
202+
<R> FetchSpec<R> map(BiFunction<Row, RowMetadata, R> mappingFunction);
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/**
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* Perform the SQL call and retrieve the result.
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*/
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FetchSpec<T> fetch();
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/**
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* Perform the SQL request and return a {@link SqlResult}.
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* Perform the SQL call and return a {@link Mono} that completes without result on statement completion.
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*
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* @return a {@code Mono} for the result
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* @return a {@link Mono} ignoring its payload (actively dropping).
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*/
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Mono<SqlResult<T>> exchange();
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Mono<Void> then();
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}
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/**
@@ -229,7 +247,7 @@ interface InsertIntoSpec {
229247
* @param table must not be {@literal null} or empty.
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* @return
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*/
232-
GenericInsertSpec into(String table);
250+
GenericInsertSpec<Map<String, Object>> into(String table);
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234252
/**
235253
* Specify the target table to insert to using the {@link Class entity class}.
@@ -255,16 +273,18 @@ interface GenericSelectSpec extends SelectSpec<GenericSelectSpec> {
255273
<R> TypedSelectSpec<R> as(Class<R> resultType);
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257275
/**
258-
* Perform the SQL call and retrieve the result.
276+
* Configure a result mapping {@link java.util.function.BiFunction function}.
277+
*
278+
* @param mappingFunction must not be {@literal null}.
279+
* @param <R> result type.
280+
* @return
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*/
260-
FetchSpec<Map<String, Object>> fetch();
282+
<R> FetchSpec<R> map(BiFunction<Row, RowMetadata, R> mappingFunction);
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262284
/**
263-
* Perform the SQL request and return a {@link SqlResult}.
264-
*
265-
* @return a {@code Mono} for the result
285+
* Perform the SQL call and retrieve the result.
266286
*/
267-
Mono<SqlResult<Map<String, Object>>> exchange();
287+
FetchSpec<Map<String, Object>> fetch();
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}
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270290
/**
@@ -279,28 +299,21 @@ interface TypedSelectSpec<T> extends SelectSpec<TypedSelectSpec<T>> {
279299
* @param resultType must not be {@literal null}.
280300
* @param <R> result type.
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*/
282-
<R> TypedSelectSpec<R> as(Class<R> resultType);
302+
<R> FetchSpec<R> as(Class<R> resultType);
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284304
/**
285-
* Configure a result mapping {@link java.util.function.Function}.
305+
* Configure a result mapping {@link java.util.function.BiFunction function}.
286306
*
287307
* @param mappingFunction must not be {@literal null}.
288308
* @param <R> result type.
289309
* @return
290310
*/
291-
<R> TypedSelectSpec<R> extract(BiFunction<Row, RowMetadata, R> mappingFunction);
311+
<R> FetchSpec<R> map(BiFunction<Row, RowMetadata, R> mappingFunction);
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293313
/**
294314
* Perform the SQL call and retrieve the result.
295315
*/
296316
FetchSpec<T> fetch();
297-
298-
/**
299-
* Perform the SQL request and return a {@link SqlResult}.
300-
*
301-
* @return a {@code Mono} for the result
302-
*/
303-
Mono<SqlResult<T>> exchange();
304317
}
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306319
/**
@@ -332,24 +345,26 @@ interface SelectSpec<S extends SelectSpec<S>> {
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333346
/**
334347
* Contract for specifying {@code INSERT} options leading to the exchange.
348+
*
349+
* @param <T> Result type of tabular insert results.
335350
*/
336-
interface GenericInsertSpec extends InsertSpec {
351+
interface GenericInsertSpec<T> extends InsertSpec<T> {
337352

338353
/**
339354
* Specify a field and non-{@literal null} value to insert.
340355
*
341356
* @param field must not be {@literal null} or empty.
342357
* @param value must not be {@literal null}
343358
*/
344-
GenericInsertSpec value(String field, Object value);
359+
GenericInsertSpec<T> value(String field, Object value);
345360

346361
/**
347362
* Specify a {@literal null} value to insert.
348363
*
349364
* @param field must not be {@literal null} or empty.
350365
* @param type must not be {@literal null}.
351366
*/
352-
GenericInsertSpec nullValue(String field, Class<?> type);
367+
GenericInsertSpec<T> nullValue(String field, Class<?> type);
353368
}
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355370
/**
@@ -363,7 +378,7 @@ interface TypedInsertSpec<T> {
363378
* @param objectToInsert
364379
* @return
365380
*/
366-
InsertSpec using(T objectToInsert);
381+
InsertSpec<Map<String, Object>> using(T objectToInsert);
367382

368383
/**
369384
* Use the given {@code tableName} as insert target.
@@ -374,30 +389,43 @@ interface TypedInsertSpec<T> {
374389
TypedInsertSpec<T> table(String tableName);
375390

376391
/**
377-
* Insert the given {@link Publisher} to insert one or more objects.
392+
* Insert the given {@link Publisher} to insert one or more objects. Inserts only a single object when calling
393+
* {@link FetchSpec#one()} or {@link FetchSpec#first()}.
378394
*
379395
* @param objectToInsert
380396
* @return
397+
* @see InsertSpec#fetch()
381398
*/
382-
InsertSpec using(Publisher<T> objectToInsert);
399+
InsertSpec<Map<String, Object>> using(Publisher<T> objectToInsert);
383400
}
384401

385402
/**
386403
* Contract for specifying {@code INSERT} options leading to the exchange.
404+
*
405+
* @param <T> Result type of tabular insert results.
387406
*/
388-
interface InsertSpec {
407+
interface InsertSpec<T> {
408+
409+
/**
410+
* Configure a result mapping {@link java.util.function.BiFunction function}.
411+
*
412+
* @param mappingFunction must not be {@literal null}.
413+
* @param <R> result type.
414+
* @return
415+
*/
416+
<R> FetchSpec<R> map(BiFunction<Row, RowMetadata, R> mappingFunction);
389417

390418
/**
391-
* Perform the SQL call.
419+
* Perform the SQL call and retrieve the result.
392420
*/
393-
Mono<Void> then();
421+
FetchSpec<T> fetch();
394422

395423
/**
396-
* Perform the SQL request and return a {@link SqlResult}.
424+
* Perform the SQL call and return a {@link Mono} that completes without result on statement completion.
397425
*
398-
* @return a {@code Mono} for the result
426+
* @return a {@link Mono} ignoring its payload (actively dropping).
399427
*/
400-
Mono<SqlResult<Map<String, Object>>> exchange();
428+
Mono<Void> then();
401429
}
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403431
/**

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