com.google.gwt.dev.jjs.impl.codesplitter

Class FragmentExtractor

java.lang.Object

com.google.gwt.dev.jjs.impl.codesplitter.FragmentExtractor

public class FragmentExtractor
extends Object

Extracts multiple JS statements (called a fragment) out of the complete JS program based on supplied type/method/field/string liveness conditions.

Liveness as defined here is not an intuitive concept. A type or method (note that constructors are methods) is considered live for the current fragment when that type can only be instantiated or method executed when the current fragment has already been loaded. That does not always mean that it was caused by direct execution of the current fragment. It may instead mean that direction execution of some other fragment has been affected by the loading of the current fragment in a way that results in the instantiation of the type or execution of the method. It is this second case that can lead to seemingly contradictory but valid situations like having a type which is not currently live but which has a currently live constructor. For example it might be possible to instantiate type Foo even with fragment Bar being loaded (i.e. Foo is not live for Bar) but the loading of fragment Bar might be required to reach a particular one of Bar's multiple constructor (i.e. that constructor is live for Bar).

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	FragmentExtractor.StatementLogger A logger for statements that the fragment extractor encounters.

Constructor Summary

Constructors

Constructor and Description
FragmentExtractor(JProgram jprogram, JsProgram jsprogram, JavaToJavaScriptMap map)

Method Summary

Modifier and Type	Method and Description
List<JsStatement>	createOnLoadedCall(int fragmentId) Create a call to AsyncFragmentLoader#onLoad.
List<JsStatement>	extractStatements(LivenessPredicate livenessPredicate, LivenessPredicate alreadyLoadedPredicate) Assume that all code described by alreadyLoadedPredicate has been downloaded.
Set<JMethod>	findAllMethodsInJavaScript() Find all Java methods that still exist in the resulting JavaScript, even after JavaScript inlining and pruning.
static JMethod	methodFor(JsStatement stat, JavaToJavaScriptMap map) Return the Java method corresponding to stat, or null if there isn't one.
void	setStatementLogger(FragmentExtractor.StatementLogger logger)

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, toString

Constructor Detail

FragmentExtractor

public FragmentExtractor(JProgram jprogram,
                         JsProgram jsprogram,
                         JavaToJavaScriptMap map)

Method Detail

methodFor

public static JMethod methodFor(JsStatement stat,
                                JavaToJavaScriptMap map)

Return the Java method corresponding to stat, or null if there isn't one. It recognizes JavaScript of the form function foo(...) { ...}, where foo is the name of the JavaScript translation of a Java method.

createOnLoadedCall

public List<JsStatement> createOnLoadedCall(int fragmentId)

Create a call to AsyncFragmentLoader#onLoad.

extractStatements

public List<JsStatement> extractStatements(LivenessPredicate livenessPredicate,
                                           LivenessPredicate alreadyLoadedPredicate)

Assume that all code described by alreadyLoadedPredicate has been downloaded. Extract enough JavaScript statements that the code described by livenessPredicate can also run. The caller should ensure that livenessPredicate includes strictly more live code than alreadyLoadedPredicate.

findAllMethodsInJavaScript

public Set<JMethod> findAllMethodsInJavaScript()

Find all Java methods that still exist in the resulting JavaScript, even after JavaScript inlining and pruning.

setStatementLogger

public void setStatementLogger(FragmentExtractor.StatementLogger logger)