[jira] Closed: (CAY-457) Cayenne Naming and Sequence Generator Configuration

["Andrus Adamchik (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CAY-457?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Andrus Adamchik closed CAY-457.
-------------------------------


closing in bulk all issues marked as "Resolved"

> Cayenne Naming and Sequence Generator Configuration
> ---------------------------------------------------
>
>                 Key: CAY-457
>                 URL: https://issues.apache.org/jira/browse/CAY-457
>             Project: Cayenne
>          Issue Type: New Feature
>          Components: Cayenne Core Library
>    Affects Versions: 1.2 branch
>            Reporter: Heiko Erhardt
>            Assignee: Andrey Razumovsky
>             Fix For: 3.0
>
>         Attachments: cay-457-fullpatch-src.txt, Patch.zip
>
>
> Here is an excerpt from the feature descritpion of the Cayenne xdocs file.
> I felt this becomes important when reengineering databases or creating new objects in the Modeler, so I placed it in the Modeler guide though the implementation resides in the Cayenne core.
> I couldn't place it in the Wiki because the common-tasks-section has not been entered there yet.
> Heiko Erhardt
> ----
> When reverse engineering a database or synchronizing object
> entities with database entities, Cayenne applies various
> rules for converting database names to object, member and
> relationship names. Also, a sequence generator definition may be
> created automatically for each reverse-engineered database entitiy.
> The file cayenne-naming.properties in the .cayenne directory
> in the classpath allows for customizing the behavior of
> the Cayenne modeler and the database loader to some extent.
> The .cayenne/cayenne-naming.properties will be searched
> in the classpath. Just like the cayenne-log.properties file,
> You may copy the file from within the cayenne.jar archive and
> place it into an archive or folder that will be prepended
> to the classpath. Cayenne will read the contents of this
> file only once, so note that you must restart the Cayenne
> modeler if you change the file's contents.
> Strategies.
> The naming algorithm is implemented
> using the strategy pattern, which allows you to plug in your
> own naming implementations. The naming strategy must implement
> the org.objectstyle.cayenne.util.NamingStrategy
> interface and can extend from the default naming strategy
> org.objectstyle.cayenne.util.DefaultNamingStrategy class.
> You may specify the strategy class name in the cayenne-naming.properties
> file.
> Likewise, a key generator strategy may be specified.
> It must implement org.objectstyle.cayenne.access.DbLoaderKeyGeneratorStrategy
> and may extend from DbLoaderPropertyBasedKeyGeneratorStrategy.
> Name Conversion.
> In general, names of
> object entities or object members are generated by converting
> the underscore-based database names to proper Java names.
> This behaviour is hard-coded at the moment.
> However, before this conversion is performed, some modifications
> may be applied.
> Entity Naming.
> Sometimes, database tables are named
> in a plural form whereas Java class names reflect the singular form
> if a term. If your set the <code>Naming.SingularizeObjEntities</code>
> property to true, the database entity name will be converted to its
> singular form by stripping the traling "s". For exceptions to this rule
> where this simple operation won't do (e. g. "ADDRESSES"), you may specify
> the singular form of the entity using the <code>Naming.Singular.</code>
> property prefix (e. g. <code>Naming.Singular.ADDRESSES=ADDRESS</code>).
> object entities or object members are generated by converting
> the underscore-based database names to proper Java names.
> This behaviour is hard-coded at the moment.
> However, before this conversion is performed, some modifications
> may be applied.
> Attribute Naming.
> It may be desirable to remove an auto-generated
> prefix from database column names before converting the to Java member names
> in order to generate object property names. The <code>Naming.DbAttributeNamePrefixToRemove</code>
> property supports this. If specified, any text up to (and including) the
> specified prefix will be removed. For example, some database design tools
> automatically add a table-specific prefix to all column names of the table
> like "PERS_FIRST_NAME". The property entry 
> <code>Naming.DbAttributeNamePrefixToRemove=_</code>
> will remove everything up to the first underscore, leaving "FIRST_NAME"
> for generating the object attribute name.
> Relationship Naming.
> The relationship naming controls
> the names of the generated relationship getter, setter, addition and removal
> methods of a data object class.
> The default naming strategy of the cayenne-naming.properties file supports specifying 
> prefixes and postfixes for to-one and to-many relations. By default, to-one
> relations will be prefixed by "TO_", resuling in the method prefix "to" (e. g. a
> relation to the "PAINTING" entity will result in a "setToPainting" setter method.
> To-many relations will have the postfix "_ARRAY", resuling in "addToPaintingArray"
> adder methods.
> Setting for example
> <code>Naming.ToOneRelationPrefix=</code>
> and
> <code>Naming.ToManyRelationSuffix=_LIST</code>
> will remove the "to" prefix from to-one relations and change the to-many postfix to "List".
> The <code>org.objectstyle.cayenne.util.RelationsshipFkNamingStrategy</code> naming strategy
> extends the default naming strategy. It will add the name of the foreign key of a relationship
> before the target entity name to the relationsship name. This has two advantages:
> 1. Relations between the same entities (e. g. two relations between entity A and entity B)
> will have a speaking difference instead of merely a running number appended in order to
> make the unique (e. g. "goodPainting" and "badPainting" instead of "painting" and "painting1").
> 2. It might be more descriptive than just using the target entity name.
> Similar to <code>Naming.DbAttributeNamePrefixToRemove</code>, the
> Similar to <code>Naming.Relationship.AttrNamePrefixToRemove</code> allows to remove
> a prefix from the foreign key before applying it to the name conversion.
> For example, for foreign keys like "PAINTING_ID_GOOD", the property entry
> <code>Naming.Relationship.AttrNamePrefixToRemove=_ID_</code> will leave the "GOOD"
> text for relationship name generation, resulting in a method name like
> "setGoodPainting".
> Key Generator Settings.
> As with Cayenne object naming, a key generator
> definition can be bound to each reverse-engineered database entity using a pluggable
> strategy class, which must implement the
> org.objectstyle.cayenne.access.DbLoaderKeyGeneratorStrategy interface.
> The default implementation is the 
> org.objectstyle.cayenne.access.DbLoaderPropertyBasedKeyGeneratorStrategy class.
> The properties of the cayenne-naming.properties file allow to specify
> the generator type, key cache size and the name of the generator (i. e. the name
> of the sequence). It may be generated from the table name or the entire name or a prefix of
> the key attribute.

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