org.multijava.mjc
Class TypeLoader

java.lang.Object
  org.multijava.util.Utils
      org.multijava.mjc.TypeLoader

All Implemented Interfaces:

CClass.Observer, Cloneable

Direct Known Subclasses:

JmlTypeLoader

public class TypeLoader

extends Utils

implements CClass.Observer

This class acts as a symbol table and a cache for types, type signatures, and external generic functions. It includes methods to load unknown type signatures. It maintains a mapping from fully qualified names to the CClass instances representing their signatures. Specifically the mapping is from a fully qualified type name to a set of instances that can be sorted. In MultiJava that set is a singleton set; however, for tools like JML where a single fully qualified name can refer to a specification and one or more refinements to that specification, the set may contain multiple items.

Field Summary
private  HashMap	compilationSessionRepCache           Maintains a mapping of qualified names to type representations; that is, it maps a fully qualified name to the CClassType instance that represents the type.
protected  MjcHashRelation	compilationSessionTypeCache           This relation stores a mapping from fully qualified type names to their CClass instances.
protected  FileFinder	fileFinder
private  String	oldClassPath
private static TypeLoader	singletonInstance
private  HashMap	vmSessionRepCache           Maintains a mapping of qualified names to type representations; that is, it maps a fully qualified name to the CClassType instance that represents the type.
protected  MjcHashRelation	vmSessionTypeCache           This relation stores a mapping from fully qualified type names to their CClass instances.

 

Fields inherited from class org.multijava.util.Utils

DBG_LEVEL_HIGH, DBG_LEVEL_LOW, DBG_LEVEL_NO

 

Constructor Summary
private	TypeLoader()
protected	TypeLoader(FileFinder fileFinder)           This constructor is only for use by subclasses.

 

Method Summary
boolean	addToTypeCache(CClass typ)           Adds the given source class to the table of loaded classes.
void	addTypeRep(String qName, CClassType typeRep)           Adds the given type representation, which must represent a fully qualified type name, to the cache.
protected  boolean	checkUniqueness(CClass typ, CClass last)           Returns true if typ is a legal unique type declaration.
boolean	classExists(String qName)           Checks whether a class with the given name is available in the class path.
protected  ClassInfo	createClassInfo(String qName)           Creates and returns a class info object by reading the symbol file for the class with the given fully qualified name qName.
FileFinder	fileFinder()           Returns the FileFinder instance that is used by the current loader when searching for classes and generic functions.
ClassPath.ClassDescription	find(String name)           This method finds a file for the given class name; it looks for both a java file on the source path and a class file on the class path, returning the newer one if both are found (and null if neither is found).
ClassPath.ClassDescription	findSourceFile(String name)
protected  void	forgetEverythingAbout(File f, JCompilationUnitType cunit)           Called by Main when the given file, from which the given compilation unit AST was derived, did not contain an expected result; this method removes all cached info. for the file.
static TypeLoader	getSingleton()
CClassType	getTypeRep(String name, CUniverse univ, CClassType[][] arguments, boolean isFullyQualified)           Returns the lightweight type representation of the class with the given name, generating a new one if necessary.
void	initSession()           Empties the compilation session caches to prepare for a new compilation session.
boolean	isDeclaredInDifferentSourceFiles(boolean isUnique, CClass clazz)           This method is needed so it can be overridden by JML in order to handle classes that have been refined, e.g., when its specifications have intentionally been declared in a separate file.
protected  boolean	isTrusted(String qName)           Returns true if the information for the type or package of the given qualified name should be retained for subsequent compilation sessions.
boolean	isTypeLoaded(String qName)           Checks whether a class with the given name has already been successfully loaded.
CClass	loadType(String qName)
CClass	lookupType(String qName)           Returns the first CClass instance in the set mapped to by the given fully qualified name, or null if no such instance exists.
CClassType	lookupTypeRep(String qName)
private static boolean	mayShare(CClassType type, CUniverse univ, CClassType[][] arguments)           Returns whether the given type can be shared by another type having the given univ and type arguments.
CClass	reloadType(CClass clazz)           Reloads the specified class if this class has been defined during a previous compilation session.
protected  void	removeFromTypeCache(CClass typ)           Removes the qualified name of the given source class from the table of loaded classes (so it can be reloaded without causing conflicts).
void	signatureCompleted(CClass typ)           Implements CClass.Observer by moving typ from compilationSessionTypeCache to vmSessionTypeCache if typ is trusted.

 

Methods inherited from class org.multijava.util.Utils

assertTrue, assertTrue, combineArrays, escapeString, escapeString, fail, fail, getFilePath, hasFlag, hasOtherFlags, parsePathParts, relativePathTo, splitQualifiedName, splitQualifiedName, stripJavaModifiers, stripNonJavaModifiers, stripPrivateModifier, unescapeString, vectorToArray, vectorToIntArray

 

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

 

Field Detail

compilationSessionTypeCache

protected MjcHashRelation compilationSessionTypeCache

This relation stores a mapping from fully qualified type names to their CClass instances. The mappings are for the types processed during this compilation session that are likely to change for the next compilation session.

See Also:

vmSessionTypeCache, isTrusted(String)

vmSessionTypeCache

protected MjcHashRelation vmSessionTypeCache

This relation stores a mapping from fully qualified type names to their CClass instances. The mappings are for the types processed during this compilation session that are not likely to change for subsequent compilation sessions and that have been processed to the point that they can be used for field and method lookup.

See Also:

compilationSessionTypeCache, isTrusted(String)

compilationSessionRepCache

private HashMap compilationSessionRepCache

Maintains a mapping of qualified names to type representations; that is, it maps a fully qualified name to the CClassType instance that represents the type. The mappings are for the types processed during this compilation session that are likely to change for the next compilation session.

See Also:

vmSessionRepCache, isTrusted(String)

vmSessionRepCache

private HashMap vmSessionRepCache

Maintains a mapping of qualified names to type representations; that is, it maps a fully qualified name to the CClassType instance that represents the type. The mappings are for the types processed during this compilation session that are not likely to change for the next compilation session.

See Also:

compilationSessionRepCache, isTrusted(String)

fileFinder

protected FileFinder fileFinder

oldClassPath

private String oldClassPath

singletonInstance

private static TypeLoader singletonInstance

TypeLoader

private TypeLoader()

TypeLoader

protected TypeLoader(FileFinder fileFinder)

This constructor is only for use by subclasses. Clients should use the factory method getSingleton().

See Also:

getSingleton()

getSingleton

public static TypeLoader getSingleton()

getTypeRep

public CClassType getTypeRep(String name,
                             CUniverse univ,
                             CClassType[][] arguments,
                             boolean isFullyQualified)

Returns the lightweight type representation of the class with the given name, generating a new one if necessary.

Parameters:

name - the name of the class

isFullyQualified - the name is known to be fully qualified

Returns:

an object representing the type of the named class (singleton within this compilation session if isFullyQualified)

 requires name != null;
 modifies compilationSessionRepCache;
 ensures isFullyQualified ==> 
   compilationSessionRepCache.containsKey(name) ||
   vmSessionRepCache.containsKey(name);
 

mayShare

private static boolean mayShare(CClassType type,
                                CUniverse univ,
                                CClassType[][] arguments)

Returns whether the given type can be shared by another type having the given univ and type arguments. This is the case iff the Universe modifier and the type arguments of the type are equivalent to the ones provided here.

Parameters:

type - The target type.

univ - The Universe modifier.

arguments - The generic type arguments.

Returns:

Whether the given type may be shared.

lookupTypeRep

public CClassType lookupTypeRep(String qName)

addTypeRep

public void addTypeRep(String qName,
                       CClassType typeRep)

Adds the given type representation, which must represent a fully qualified type name, to the cache.

 requires qName != null && typeRep != null &&
          (* all separators in qName are '/' not '.' *);
 modifies compilationSessionRepCache, vmSessionRepCache;
 ensures compilationSessionRepCache.containsKey(qName) ||
         vmSessionRepCache.containsKey(qName);
 

findSourceFile

public ClassPath.ClassDescription findSourceFile(String name)

find

public ClassPath.ClassDescription find(String name)

This method finds a file for the given class name; it looks for both a java file on the source path and a class file on the class path, returning the newer one if both are found (and null if neither is found).

addToTypeCache

public boolean addToTypeCache(CClass typ)

Adds the given source class to the table of loaded classes. Returns true if the class was not declared in more than one source file and false otherwise.

requires typ != null;
modifies compilationSessionTypeCache, vmSessionTypeCache;
 

checkUniqueness

protected boolean checkUniqueness(CClass typ,
                                  CClass last)

Returns true if typ is a legal unique type declaration.

Parameters:

typ - a type to be added to the cache

last - the previous cache entry mapped to by typ.qualifiedName()

forgetEverythingAbout

protected void forgetEverythingAbout(File f,
                                     JCompilationUnitType cunit)

Called by Main when the given file, from which the given compilation unit AST was derived, did not contain an expected result; this method removes all cached info. for the file.

removeFromTypeCache

protected void removeFromTypeCache(CClass typ)

Removes the qualified name of the given source class from the table of loaded classes (so it can be reloaded without causing conflicts). This is only done if the conflict occurs because the names were added during two different compilation sessions.

    requires typ != null;
    modifies compilationSessionTypeCache, vmSessionTypeCache;
 

lookupType

public CClass lookupType(String qName)

Returns the first CClass instance in the set mapped to by the given fully qualified name, or null if no such instance exists.

  requires qName != null && 
	    (* any separators in qName are slashes ('/'), not dots ('.') *);
 

loadType

public CClass loadType(String qName)

createClassInfo

protected ClassInfo createClassInfo(String qName)

Creates and returns a class info object by reading the symbol file for the class with the given fully qualified name qName. If no symbol file is found, null is returned. This method also create a binary class object and adds it to the system cache. This is a factory method that may be overridden by subclasses.

reloadType

public CClass reloadType(CClass clazz)

Reloads the specified class if this class has been defined during a previous compilation session. Note that this method can return either null or CLS_UNDEFINED or a valid CClass value.

isTypeLoaded

public boolean isTypeLoaded(String qName)

Checks whether a class with the given name has already been successfully loaded.

Parameters:

qName - the fully qualified name of the type with slash separators not dots

Returns:

true iff the class has already been loaded.

classExists

public boolean classExists(String qName)

Checks whether a class with the given name is available in the class path. Note that this is true if the class has already been successfully loaded or if there is a file that can be expected to hold its definition. The file may actually not hold a valid definition, so classExists is not a guarantee that the class with the given name actually does exist.

Parameters:

qName - the fully qualified name of the type with slash separators not dots

Returns:

true iff the class is in the class path

isDeclaredInDifferentSourceFiles

public boolean isDeclaredInDifferentSourceFiles(boolean isUnique,
                                                CClass clazz)

This method is needed so it can be overridden by JML in order to handle classes that have been refined, e.g., when its specifications have intentionally been declared in a separate file. In MultiJava, this method always returns isUnique since addToTypeCache has already determined whether the Type has already been declared in another file.

signatureCompleted

public void signatureCompleted(CClass typ)

Implements CClass.Observer by moving typ from compilationSessionTypeCache to vmSessionTypeCache if typ is trusted.

 also
 old String qName = typ.qualifiedName();
 requires typ != null && isTrusted(qName);
 ensures \old(compilationSessionTypeCache.getImage(qName).contains(typ))
         ==> !compilationSessionTypeCache.getImage(qName).contains(typ) &&
             vmSessionTypeCache.getImage(qName).contains(typ);
 

Specified by:

signatureCompleted in interface CClass.Observer

isTrusted

protected boolean isTrusted(String qName)

Returns true if the information for the type or package of the given qualified name should be retained for subsequent compilation sessions.

  requires qName != null && (* package separators in qName are '/' not '.' *);
 

initSession

public void initSession()

Empties the compilation session caches to prepare for a new compilation session.

 requires (* ClassPath.init() has been called with to set the 
             class path for this upcoming session *);
 

fileFinder

public FileFinder fileFinder()

Returns the FileFinder instance that is used by the current loader when searching for classes and generic functions.