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DATACASS-739 - Include custom conversions documentation from Commons.

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This commit is contained in:
Mark Paluch
2020-03-17 10:41:21 +01:00
parent d46824ff0d
commit 2a20fb8aa1
4 changed files with 7 additions and 55 deletions
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2
spring-data-cassandra/src/test/java/org/springframework/data/cassandra/example/mapping/Person.java
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@@ -48,7 +48,7 @@ public class Person {
@PrimaryKeyColumn(name = "correlated_type", ordinal = 2, type = PrimaryKeyType.CLUSTERED)
private String correlatedType;
// other getters/setters ommitted
// other getters/setters omitted
}
@PrimaryKey

1
src/main/asciidoc/index.adoc
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@@ -26,7 +26,6 @@ include::{spring-data-commons-docs}/repositories.adoc[leveloffset=+1]
include::reference/introduction.adoc[leveloffset=+1]
include::reference/cassandra.adoc[leveloffset=+1]
include::reference/converters.adoc[leveloffset=+1]
include::reference/reactive-cassandra.adoc[leveloffset=+1]
include::reference/cassandra-repositories.adoc[leveloffset=+1]
include::reference/reactive-cassandra-repositories.adoc[leveloffset=+1]

36
src/main/asciidoc/reference/converters.adoc
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@@ -10,10 +10,7 @@ of the `MappingCassandraConverter` (perhaps for increased performance or other c
need to create an implementation of the Spring `Converter` interface and register it with
the `MappingCassandraConverter`.
NOTE: For more information on Spring's type conversion service, see the reference docs
{spring-framework-docs}core.html#core-convert[here].
[[cassandra.custom-converters.writer]]
[[customconversions.writer]]
=== Saving by Using a Registered Spring Converter
You can combine converting and saving in a single process, basically using the converter to do the saving.
@@ -26,7 +23,7 @@ with Jackson 2:
include::../{example-root}/PersonWriteConverter.java[tags=class]
----
[[cassandra.custom-converters.reader]]
[[customconversions.reader]]
=== Reading by Using a Spring Converter
Similar to how you can combine saving and converting, you can also combine reading and converting.
@@ -39,7 +36,7 @@ with Jackson 2:
include::../{example-root}/PersonReadConverter.java[tags=class]
----
[[cassandra.custom-converters.java]]
[[customconversions.java]]
=== Registering Spring Converters with `CassandraConverter`
Spring Data for Apache Cassandra Java configuration provides a convenient way to register Spring `Converter` instances:
@@ -51,29 +48,4 @@ as well as configure `CustomConversions`:
include::../{example-root}/ConverterConfiguration.java[tags=class]
----
[[cassandra.converter-disambiguation]]
=== Converter Disambiguation
Generally, we inspect the `Converter` implementations for both the source and target types they convert from and to.
Depending on whether one of those is a type Cassandra can handle natively, Spring Data registers the `Converter`
instance as a reading or a writing converter.
Consider the following samples:
[source,java]
----
// Write converter as only the target type is one cassandra can handle natively
class MyConverter implements Converter<Person, String> { … }
// Read converter as only the source type is one cassandra can handle natively
class MyConverter implements Converter<String, Person> { … }
----
If you implement a `Converter` whose source and target types are native Cassandra types,
Spring Data cannot determine whether we should consider it as a reading or a writing `Converter`.
Registering the `Converter` instance as both might lead to unwanted results.
For example, a `Converter<String, Long>` is ambiguous, although it probably does not make sense to try to convert all `String`
instances into `Long` instances when writing. To generally be able to force the infrastructure to register a `Converter`
for one way only, we provide `@ReadingConverter` as well as `@WritingConverter` to indicate the appropriate
`Converter` implementation.
include::../{spring-data-commons-docs}/custom-conversions.adoc[leveloffset=+3]

23
src/main/asciidoc/reference/mapping.adoc
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@@ -406,6 +406,7 @@ include::../{example-root}/mapping/Coordinates.java[tags=class]
----
====
[[mapping.index-creation]]
==== Index Creation
You can annotate particular entity properties with `@Indexed` or `@SASI` if you wish to create secondary indexes
@@ -428,27 +429,7 @@ include::../{example-root}/mapping/PersonWithIndexes.java[tags=class]
CAUTION: Index creation on session initialization may have a severe performance impact on application startup.
[[cassandra.mapping.explicit-converters]]
=== Overriding Mapping with Explicit Converters
When storing and querying objects, it is often convenient to have a `CassandraConverter` instance handle the mapping
of all Java types to rows. However, sometimes you may want the `CassandraConverter` to do most of the work
but still let you selectively handle the conversion for a particular type. Other times, you may want to optimize performance.
To selectively handle the conversion yourself, register one or more `org.springframework.core.convert.converter.Converter`
instances with `CassandraConverter`.
NOTE: Spring 3.0 introduced a `o.s.core.convert` package that provides a general type conversion system.
This system is described in detail in the Spring reference documentation section titled
{spring-framework-docs}core.html#core-convert[`Spring Type Conversion`].
The following example of a Spring `Converter` implementation converts from a row to a `Person` POJO:
[source,java]
----
include::../{example-root}/mapping/PersonReadConverter.java[tags=class]
----
include::./converters.adoc[]
[[cassandra.mapping-usage.events]]
== Lifecycle Events