com.google.gwt.core.ext
Class IncrementalGenerator

java.lang.Object
  com.google.gwt.core.ext.Generator
      com.google.gwt.core.ext.IncrementalGenerator

public abstract class IncrementalGenerator
extends Generator

An extension to the Generator class which supports incremental generation. It adds a generateIncrementally(com.google.gwt.core.ext.TreeLogger, com.google.gwt.core.ext.GeneratorContext, java.lang.String) method.

IncrementalGenerator

public IncrementalGenerator()

generateNonIncrementally

public static RebindResult generateNonIncrementally(TreeLogger logger,
                                                    Generator generator,
                                                    GeneratorContext context,
                                                    java.lang.String typeName)
                                             throws UnableToCompleteException

A static helper method to wrap a non-incremental generator's result. It calls the generator's Generator.generate(com.google.gwt.core.ext.TreeLogger, com.google.gwt.core.ext.GeneratorContext, java.lang.String) method, and synthesizes a RebindResult instance to be returned.

Parameters:

logger - A TreeLogger

generator - A non-incremental generator

context - The generator context

typeName - The type for which a subclass will be generated

Returns:

a RebindResult

Throws:

UnableToCompleteException

generate

public final java.lang.String generate(TreeLogger logger,
                                       GeneratorContext context,
                                       java.lang.String typeName)
                                throws UnableToCompleteException

This method overrides Generator.generate(com.google.gwt.core.ext.TreeLogger, com.google.gwt.core.ext.GeneratorContext, java.lang.String), and is included only for backwards compatibility. It wraps a call to generateIncrementally(com.google.gwt.core.ext.TreeLogger, com.google.gwt.core.ext.GeneratorContext, java.lang.String). This method won't normally be called by the gwt rebind process, and it is declared final and can't be overridden. It is provided in support of existing applications and other generators which call this method directly, outside of the gwt framework.

The passed in context is wrapped with an instance of NonIncrementalGeneratorContext, to ensure that no generator result caching is attempted, since the cached result will be ignored by callers of this method anyway.

Specified by:

generate in class Generator

Parameters:

logger - A TreeLogger

context - The generator context

typeName - The type for which a subclass will be generated

Returns:

the name of a subclass to substitute for the requested class, or return null to cause the requested type itself to be used

Throws:

UnableToCompleteException

See Also:

Generator.generate(com.google.gwt.core.ext.TreeLogger, com.google.gwt.core.ext.GeneratorContext, java.lang.String)

generateIncrementally

public abstract RebindResult generateIncrementally(TreeLogger logger,
                                                   GeneratorContext context,
                                                   java.lang.String typeName)
                                            throws UnableToCompleteException

Incrementally generate a default constructible subclass of the requested type. The generator can use information from the context to make decisions on whether to incrementally reuse cached output from previous invocations.

It returns a RebindResult, which contains a RebindMode field, which indicates whether to use previously cached output, newly generated output, or a partial mixture of both cached and newly generated output.

The result also includes a field for the name of the subclass to substitute for the requested class. It may also contain extra client data added by specific generator implementations.

This method throws an UnableToCompleteException if for any reason it cannot complete successfully.

Parameters:

logger - A TreeLogger

context - The generator context

typeName - The type for which a subclass will be generated

Returns:

a RebindResult

Throws:

UnableToCompleteException

See Also:

RebindResult, RebindMode

getVersionId

public abstract long getVersionId()

Returns a version id for an IncrementalGenerator. It is used by the system to invalidate CachedGeneratorResult's that were generated by a different version of this generator. This is useful when new versions of a generator are developed, which might alter the structure of generated output, or alter semantics for cache reusability checking.

It is the responsibility of the developer to maintain this version id consistently.

Returns:

a version id