## org.biojava.bio.seq.projection
Class ProjectionEngine

    java.lang.Object
      org.biojava.bio.seq.projection.ProjectionEngine

    public class ProjectionEngine

extends Object

Factory for proxy objects which project BioJava features into alternate coordinate systems. This class binds together a feature and a `ProjectionContext` object, and returns the resulting projected feature. New feature-projection wrapper classes are generated automatically as they are required. Don't use this class directly. This class contains deep voodoo code. Run away while you still can. You may find that for some bizaare reason you need to manually project a feature through a ProjectionContext. You should be using @link ProjectionContext.projectFeature(). If this is not practical for some reason, use this class. However, this probably indicates that you are doing something mad. Projected feature classes will be named as org.biojava.bio.seq.projection.{$ctxt}.{$feat} where $ctxt and $feat are the full class names of the context and feature respectively with each "." character replaced with "_". Delegate into this from your ProjectionContext to do the dirty work of actually projecting features from the underlying data. This factory generate a new class that is unique to the combination of your projection context and the Feature interface that the projected feature implements. Then, it will instantiate that class with your context and the underlying feature. The returned feature will currently be an implementation of the package-private class org.biojava.bio.seq.projection.ProjectedFeature, but this is implementation detail and should not be relied upon.

Since:
  1.2
Author:
  Thomas Down

Nested Class Summary
`static interface` `ProjectionEngine.Instantiator` Internal helper class.
`static interface` `ProjectionEngine.TemplateProjector` This is an interface for things that project feature templates.

Field Summary
`static ProjectionEngine` `DEFAULT` The standard projection engine object.

Method Summary
`Feature` `projectFeature(Feature f, ProjectionContext ctx)` Return a projection of Feature `f` into the system defined by a given ProjectionContext.
`Feature.Template` `revertTemplate(Feature.Template templ, ProjectionContext ctxt)` Revert a template so that it can be used on the original feature-space.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

### DEFAULT

    public static final ProjectionEngine DEFAULT

  The standard projection engine object.

Method Detail

### projectFeature

    public Feature projectFeature(Feature f,
                                  ProjectionContext ctx)

  Return a projection of Feature `f` into the system defined by a given ProjectionContext. The returned object will implement the same Feature interface (sub-interface of `Feature` as the underlying feature, and will also implement the `Projection` interface.

### revertTemplate

    public Feature.Template revertTemplate(Feature.Template templ,
                                           ProjectionContext ctxt)

  Revert a template so that it can be used on the original feature-space.

  This will use the revertFoo methods defined in the context to revert all of the transformed properties.

  Parameters:
    `templ` - the template to revert
    `ctxt` - the context defining the reversion
  Returns:
    a new template of the same type as templ, with reverted fields