Package org.aspectj.org.eclipse.jdt.internal.compiler.util

Class CtSym

java.lang.Object

org.aspectj.org.eclipse.jdt.internal.compiler.util.CtSym

public class CtSym
extends Object

Abstraction to the ct.sym file access (see https://openjdk.java.net/jeps/247). The ct.sym file is required to implement JEP 247 feature (compile with "--release" option against class stubs for older releases) and is currently (Java 15) a jar file with undocumented internal structure, currently existing in at least two different format versions (pre Java 12 and Java 12 and later).

The only documentation known seem to be the current implementation of com.sun.tools.javac.platform.JDKPlatformProvider and probably some JDK build tools that construct ct.sym file. Root directories inside the file are somehow related to the Java release number, encoded as single digit or letter (single digits for releases 7 to 9, capital letters for 10 and higher).

If a release directory contains "system-modules" file, it is a flag that this release files are not inside ct.sym file because it is the current release, and jrt file system should be used instead.

All other release directories contain encoded signature (*.sig) files with class stubs for classes in the release.

Some directories contain files that are shared between different releases, exact logic how they are distributed is not known.

Known format versions of ct.sym:

Pre JDK 12:

 ct.sym -> 9 -> java/ -> lang/
 ct.sym -> 9-modules -> java.base -> module-info.sig
 

From JDK 12 onward:

 ct.sym -> 9 -> java.base -> java/ -> lang/
 ct.sym -> 9 -> java.base -> module-info.sig
 

Notably,

1. in JDK 12 modules classes and ordinary classes are located in the same location
2. in JDK 12, ordinary classes are found inside their respective modules

Searching a file for a given release in ct.sym means finding and traversing all possible release related directories and searching for matching path.

Field Summary

Fields

Modifier and Type	Field	Description
static final boolean	DISABLE_CACHE

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object obj)
byte[]	getFileBytes(Path path)
FileSystem	getFs()
Path	getFullPath(String releaseCode, String qualifiedSignatureFileName, String moduleName)	Retrieves the full path in ct.sym file fro given signature file in given release
String	getModuleInJre12plus(String releaseCode, String qualifiedSignatureFileName)
static String	getReleaseCode(String release)	Tries to translate numeric Java version to the corresponding release "code".
Path	getRoot()
int	hashCode()
boolean	isJRE12Plus()
List<Path>	releaseRoots(String releaseCode)
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Details

DISABLE_CACHE

public static final boolean DISABLE_CACHE

Method Details

getFs

public FileSystem getFs()

Returns:

never null

isJRE12Plus

public boolean isJRE12Plus()

Returns:

true if this file is from Java 12+ JRE

getRoot

public Path getRoot()

Returns:

never null

releaseRoots

public List<Path> releaseRoots(String releaseCode)

Parameters:

releaseCode - major JDK version segment as version code (8, 9, A, etc)

Returns:

set with all root paths related to given release in ct.sym file

getFullPath

public Path getFullPath(String releaseCode,
 String qualifiedSignatureFileName,
 String moduleName)

Retrieves the full path in ct.sym file fro given signature file in given release

12+: something like

java/io/Reader.sig -> /879/java.base/java/io/Reader.sig

before 12:

java/io/Reader.sig -> /8769/java/io/Reader.sig

Parameters:

releaseCode - release number encoded (7,8,9,A,B...)

qualifiedSignatureFileName - signature file name (without module)

Returns:

corresponding path in ct.sym file system or null if not found

getModuleInJre12plus

public String getModuleInJre12plus(String releaseCode,
 String qualifiedSignatureFileName)

getFileBytes

public byte[] getFileBytes(Path path)
                    throws IOException

Throws:

IOException

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object

getReleaseCode

public static String getReleaseCode(String release)

Tries to translate numeric Java version to the corresponding release "code".

• 7, 8 and 9 are just returned "as is"
• versions up from 10 are returned as upper letters starting with "A", so 10 is "A", 11 is "B" and so on.

Parameters:

release - release version as number (8, 9, 10, ...)

Returns:

the "code" used by ct.sym for given Java version