Module org.jooq
Package org.jooq.impl

Class CustomQueryPart

java.lang.Object
org.jooq.impl.CustomQueryPart
All Implemented Interfaces:
Serializable, QueryPart, QueryPartInternal
public abstract non-sealed class CustomQueryPart extends Object
A base class for custom QueryPart implementations in client code.

Client code may provide proper Condition implementations extending this useful base class. All necessary parts of the Condition interface are already implemented. Only this method needs further implementation: accept(Context).

Refer to that methods' Javadoc for further details about their expected behaviour.

Such custom QueryPart implementations can be useful in any of these scenarios:

Author:
Lukas Eder
See Also:

  • Constructor Details

    • CustomQueryPart

      protected CustomQueryPart()

  • Method Details

    • of

      public static final CustomQueryPart of(Consumer<? super Context<?>> consumer)
      Create a CustomQueryPart from a lambda expression.

    • accept

      public abstract void accept(Context<?> ctx)
      Subclasses must implement this method.
      This QueryPart can accept a Context object in order to render a SQL string or to bind its variables.
      Specified by:
      accept in interface QueryPartInternal

    • clauses

      public final Clause[] clauses(Context<?> ctx)
      Description copied from interface: QueryPartInternal
      The Clauses that are represented by this query part.

      QueryParts can specify several Clauses for which an event will be emitted before (in forward order) and after (in reverse order) visiting the the query part through Context.visit(QueryPart)

      This method is for JOOQ INTERNAL USE only. Do not reference directly

      Specified by:
      clauses in interface QueryPartInternal
      Returns:
      The Clauses represented by this query part or null or an empty array if this query part does not represent a clause.

    • declaresFields

      public final boolean declaresFields()
      Subclasses may override this
      Specified by:
      declaresFields in interface QueryPartInternal

    • declaresTables

      public final boolean declaresTables()
      Subclasses may override this
      Specified by:
      declaresTables in interface QueryPartInternal

    • $traverse

      default <R> R $traverse(Traverser<?,R> traverser)
      Description copied from interface: QueryPart
      Traverser this QueryPart expression tree using a composable Traverser, producing a result.

      This offers a generic way to traverse expression trees to translate the tree to arbitrary other data structures. The simplest traversal would just count all the tree elements: 

      
 int count = CUSTOMER.NAME.eq(1).$traverse(0, (i, p) -> i + 1);

      The same can be achieved by translating the JDK Collector API to the Traverser API using Traversers.collecting(Collector). 

      
 CUSTOMER.NAME.eq(1).$traverse(Traversers.collecting(Collectors.counting()));

      Unlike a Collector, a Traverser is optimised for tree traversal, not stream traversal:

      • Is not designed for parallelism
      • It can Traverser.abort() traversal early when the result can be produced early (e.g. when running Traversers.containing(QueryPart), and a result has been found).
      • It can decide whether to Traverser.recurse() into a QueryPart subtree, or whether that is not necessary or even undesirable, e.g. to prevent entering new subquery scopes.
      • Unlike a Collector, which can use its Collector.accumulator() to accumulate each element only once, in tree traversal, it's desirable to be able to distinguish between accumulating an item Traverser.before() or Traverser.after() recursing into it. This is useful e.g. to wrap each tree node in XML opening and closing tags.

      This is a commercial jOOQ edition only feature.

      Specified by:
      $traverse in interface QueryPart

    • $replace

      default QueryPart $replace(Replacer replacer)
      Description copied from interface: QueryPart
      Traverse a QueryPart hierarchy and recursively replace its elements by alternatives.

      This is a commercial jOOQ edition only feature.

      Specified by:
      $replace in interface QueryPart

    • rendersContent

      public boolean rendersContent(Context<?> ctx)
      Subclasses may override this
      Specified by:
      rendersContent in interface QueryPartInternal

    • declaresWindows

      public boolean declaresWindows()
      Subclasses may override this
      Specified by:
      declaresWindows in interface QueryPartInternal

    • declaresCTE

      public boolean declaresCTE()
      Subclasses may override this
      Specified by:
      declaresCTE in interface QueryPartInternal

    • declaresParameters

      @Pro public boolean declaresParameters()
      Subclasses may override this
      Specified by:
      declaresParameters in interface QueryPartInternal

    • generatesCast

      public boolean generatesCast()
      Subclasses may override this
      Specified by:
      generatesCast in interface QueryPartInternal

    • equals

      public boolean equals(Object that)
      Description copied from interface: QueryPart
      Check whether this QueryPart can be considered equal to another QueryPart.

      In general, QueryPart equality is defined in terms of QueryPart.toString() equality. In other words, two query parts are considered equal if their rendered SQL (with inlined bind variables) is equal. This means that the two query parts do not necessarily have to be of the same type.

      Some QueryPart implementations may choose to override this behaviour for improved performance, as QueryPart.toString() is an expensive operation, if called many times.

      Specified by:
      equals in interface QueryPart
      Overrides:
      equals in class Object
      Parameters:
      that - The other QueryPart
      Returns:
      Whether the two query parts are equal

    • hashCode

      public int hashCode()
      Description copied from interface: QueryPart
      Generate a hash code from this QueryPart.

      In general, QueryPart hash codes are the same as the hash codes generated from QueryPart.toString(). This guarantees consistent behaviour with QueryPart.equals(Object)

      Some QueryPart implementations may choose to override this behaviour for improved performance, as QueryPart.toString() is an expensive operation, if called many times.

      Specified by:
      hashCode in interface QueryPart
      Overrides:
      hashCode in class Object
      Returns:
      The QueryPart hash code

    • toString

      public String toString()
      Description copied from interface: QueryPart
      Render a SQL string representation of this QueryPart.

      For improved debugging, this renders a SQL string of this QueryPart with inlined bind variables. If this QueryPart is Attachable, then the attached Configuration may be used for rendering the SQL string, including SQLDialect and Settings. Do note that most QueryPart instances are not attached to a Configuration, and thus there is no guarantee that the SQL string will make sense in the context of a specific database.

      Specified by:
      toString in interface QueryPart
      Overrides:
      toString in class Object
      Returns:
      A SQL string representation of this QueryPart

    • create

      @Deprecated protected final DSLContext create()
      Deprecated.
      - 3.11.0 - [#6722] - Use Attachable.configuration() and Configuration.dsl() instead.
      Internal convenience method

    • create

      @Deprecated protected final DSLContext create(Configuration configuration)
      Deprecated.
      - 3.11.0 - [#6722] - Use Attachable.configuration() and Configuration.dsl() instead.
      Internal convenience method

    • create

      @Deprecated protected final DSLContext create(Context<?> ctx)
      Deprecated.
      - 3.11.0 - [#6722] - Use Attachable.configuration() and Configuration.dsl() instead.
      Internal convenience method

    • translate

      protected final DataAccessException translate(String sql, SQLException e)
      Internal convenience method