You may look at my Build Script Log right which prints the memory available / memory used by the JRE. It is not the amount of memory that is really the problem, it is that since there are (obviously) large
AST objects that the Garbage Collector is unable to clean that causes it to get slower and slower and slower. Whenever System.gc() is invoked, it will hang as it searches (likely) tens of thousands or hundreds of thousands of Node references that it is unable to remove...
Again, I need to null the pointers or - eliminate the
AST's from The Java Heap so that the Java Garbage Collector (a.k.a. System.gc()) can work its magic. I don't want to call it a Java Parser Memory Leak yet - because I cannot tell whether or not the class StaticJavaParser has a just cause in retaining the AST's after it has parsed '.java' source files...
First you don't have to setup LexicalPreservingPrinter more than once per CompilationUnit. Secondly you can tune memory heap to make the gc footprint smaller and thirdly you can use toString() to print every statement. LexicalPreservingPrinter keep track of the original syntaxe in each node which uses more memory. I hope these tips can help you.
Are you trying to say that the
AST Nodes that are being retained in memory / on the Java Heap - permanently - are in fact being retained by the class LexicalPreservingPrinter AND NOT by the class StaticJavaParser? If so, how might one enforce that those AST's are nulled (set to null) so that they may be Garbage Collected ?
I was sort of hoping that Van Bruggen / Matazoid was out there... He seems to know JP the best on
Gitter. Hey! Danny van Bruggen if you happen to read this, I'm trying to identify whether there is a way to clear the Heap of all AST's or Nodes after I am done using them. My Build Script uses (quite well, actually) Java Parser to parse well over 300 source code '.java' files - and all I can tell is that when the class Visitor / Handler I use "goes out of scope" for one '.java' source code file and moves on to the next one - all of the AST Nodes are retained in memory and cannot be garbage collected (from the last source-code file) I would just like to know if there were a way to 'null' their references in whichever JP class these references are being retrained.
Um... And here is the
VoidVisitorAdapter class I use, here's The JavaDoc for it... Here are the other classes the retrieve the java.lang.String that I need for my HTML Documentation Tool.... Here is Callable, (JavaDoc), and 'Method' (JavaDoc), and 'Constructor' (JavaDoc), and 'Field' (JavaDoc)
UnsolvedSymbolException{context='null', name='List', cause='null'}
Hi everyone. I came across some behaviour but I'm not sure if it's a bug or if I'm missing something (RE how Lexical Preservation is intended to be used). Trying to addExtendedType to a class, I get an unsupported operation if there isn't a space before the opening brace of the class (which I want to add the extends to) with lexical preservation enabled. So
public class Customer{} won't work, but if I change it to public class Customer {}I can add an extends no problem. The problem also goes away if I don't set the configuration of the parser to enable lexical preservation, and if I don't setup the LexicalPreservingPrinter for each Compilation Unit. If I'm not being clear I can post more details in the issues on Github, might be easier.
I have classe bellow, so I would like to have output
OUTPUT:
WebServiceXpto
method_1
call_1
call_2
String x = "end";
method_2
call_2
String x = "end";
Maybe on an map having list of method as key and list os all call stack.
CLASSE:
public class WebServiceXpto {
public void method_1() {
call_1()
}
public void method_2() {
call_2()
}
public void call_1() {
call_2()
}
public void call_2() {
String x = "end";
}
}
Hi @jlerbsc I tried but did't found solution. I din't found I way to have all children of MethodCallExpr or recursive have it
My MethodCallCheck extends VoidVisitorAdapter<Void>
public void visit(MethodCallExpr methodCallExpr, Void arg) {
super.visit(methodCallExpr, arg);
}
This is my MethodCheck extends VoidVisitorAdapter<Void>
@Override
public void visit(MethodDeclaration methodDeclaration, Void arg) {
super.visit(methodDeclaration, arg);
LOG.info("> MethodDeclaration: " + methodDeclaration.getNameAsString());
NodeList<Statement> nodeList = methodDeclaration.getBody().get().getStatements();
if (nodeList != null) {
startCheck = false;
for (Statement statement : nodeList) {
// LOG.info("> Statement: " + statement + " - " + statement.isExpressionStmt());
VoidVisitor<Void> methodCallCheck = new MethodCallCheck(packageNameBase, classNameBase, methodDeclaration.getNameAsString());
statement.accept(methodCallCheck, arg);
}
}
}
Hi @marcosvasousa What you have represented in your example is an internal stack trace of the class but i think you want to extend it to all the classes of a project. I don't have time to implement your algorithm but what I recommend at first glance is to use the plain capacity of the visitor pattern and use the second argument to propagate an execution context which keep track of current class declaration, method declaration, method call expression for each class and use graph to modelize each relationship... Personnally i use this technique to implement a java class/package/module relationship in 3D representation (example http://www.jperf.com/jp/). Unfortunately i can't help you more without spending a lot more time on it, but I think you need to look further into these solutions or even study others if this one does not allow you to achieve your objective.
Good evening, everyone! If someone would be so kind as to help me setup javaparser into NetBeans I would appreciate it. I want Netbeans to playback some feedback sounds whenever the parser detects an error as the user types code. How would I go about to do that? If there is already a video or resource explaining how to do that let me know.
And if there is someone I can contact directly that can help me, please let me know.
@makbro I think you want to look into creating Netbeans plugins for that - Netbeans already parses the code and shows the errors, so there must be a parser and some handling in there that you might be able to plug into. This project, JavaParser, is not in use in Netbeans.
@matozoid !!! How do I garbage collect an
AST after I am done with it? I have nary a clue where to start looking for that. I load AST's by asking the class StaticJavaParser for a CompilationUnit cu, and then have a straightforward VoidVisitor retrieve several String's from the AST... Is there any simple way to clear the AST out of the Java Heap ("memory") after my build code moves on from one source file to the next source-file ? Would you like to help ?? (Specifically, I mean System.gc() doesn't get the AST's out of memory !!
I know about the
Memory Analyzer (you brought it up, before)... Umm... Do you know how in C/C++ you have to say free(ptr) or dealloc(ptr) (I haven't done C/C++ in 20 years)... But in Java as long as you say objReference = null you are guaranteed that the Object objReference (whatever it was) will be cleared from the Heap by an invokation of System.gc()(because there are no references to it) ... How in the world can I make sure the AST pointers that are being retained by ether LexicalPreservingPrinter or StaticJavaParser are set to null, so that System.gc() will clean the heap out after my code is through with an AST? I've got to clean that out in my build process - when the build moves from one source-file AST and one to the next source-file AST
Hey @ralphcnb_twitter, I'm not active on this project anymore. It looks like the problem (if any, GC is something that is best left to do its thing most of the time) is in your code, and I don't have time to look at that. The few times the GC was failing to do its job was always because a reference to the object to collect was accidentally still in a map or list somewhere.
If you are not running out of memory, there should be no reason to worry. If you depend on finalize() or so, then stop doing so.
You quit Java Parser ... for real? Haven't you been doing this for years and years? I mean, I almost bought your book, but I'm trying not to get into the internals of the JP Code - I used it, and it (Java Parser) worked great. It gets used on hundreds of source-files every time I do a build... I just don't want to memorize the whole JP GitHub Build - I want to concentrate on my build instead... Does that make sense? (Use the API, rather than becoming a JP Developer) I know I mentioned that the JP Jar I use is javaparser-core-3.14.159265359.jar and I literally got it from http://jar-downloader.com
Yeah, you said the right thing, and I have tried to explain that I extract (a bunch / a lot) of java.lang.String using a VoidVisitor -- but after the Visitor completes there is a bunch of stuff in memory, and I'm not keeping any references to the JavaParser classes at all - only java.lang.String ... But OK... If you have quit this project, that's fine... It's been real.... Take care...
Hey all, sorry if this is a silly question, but I've recently been investigating if javaparser would be a good substitute for a dependency in a project I'm working on. I would like to traverse an AST and save context to certain nodes (i.e. saving names of variables in the same scope to a statement node) for later visitor operations. Currently, the only way I see this would be possible is creating subclasses for some nodes, and replacing the nodes with the subclass during a visit. However, this seems a bit messy to me as you would then have to cast the node later to see its context. Is there a better way of doing this? Am I missing something obvious? I've looked a bit around the javadocs and read the book but it doesn't seem obvious to me. Thanks
I would like to translate the book "JavaParser: Visited" into Brazilian Portuguese, has anyone translated this book? do you know if it is allowed? who would i have to talk to? thank you.
so @matozoid aren't you on the project anymore? woah that's big news
I hope there's still someone then :D
Little trivia: what is the difference between the twos? (without looking at the source code
StringLiteralExpr a = new StringLiteralExpr("String with \"");
StringLiteralExpr b = new StringLiteralExpr().setString("String with \"");
I have a method call chain like the following,
a.b().c() and I want to insert an extra method call in the chain to make it like a.b().d().c(). How do I do that ? I tried using new MethodCallExpr making d's scope be b and c's scope be d but when printing I get Exception in thread "main" java.util.NoSuchElementException: No value present
at java.base/java.util.Optional.get(Optional.java:148)
at com.github.javaparser.printer.lexicalpreservation.PhantomNodeLogic.isPhantomNode(PhantomNodeLogic.java:58)
at com.github.javaparser.printer.lexicalpreservation.LexicalPreservingPrinter.findNodeForToken(LexicalPreservingPrinter.java:364)
at com.github.javaparser.printer.lexicalpreservation.LexicalPreservingPrinter.findNodeForToken(LexicalPreservingPrinter.java:375)
at com.github.javaparser.printer.lexicalpreservation.LexicalPreservingPrinter.findNodeForToken(LexicalPreservingPrinter.java:375)
My actualy code is :
MethodCallExpr nameMethod = cu.findAll(MethodCallExpr.class)
.stream()
.filter(mc->
mc.getNameAsString().equals("name") &&
mc.getArguments().size() == 1 &&
mc.getArgument(0).isLiteralStringValueExpr() &&
mc.getArgument(0).asLiteralStringValueExpr().getValue().equals(propertyName)
).findFirst().get();
MethodCallExpr wireClassMethod = nameMethod.findAncestor(MethodCallExpr.class, a->a.getNameAsString().equals("wireClass")).get();
MethodCallExpr wireTypeRef = new MethodCallExpr(wireClassMethod.getScope().get(), "wireTypeReference", NodeList.nodeList(new StringLiteralExpr("test")));
wireClassMethod.setScope(wireTypeRef);
It works when using
PrettyPrinter but that really messes up my code so I need to preserve the lexical structure
@gontijolucas - no response from @SmiddyPence, so I say go ahead! I'm not aware of translations. @ftomassetti is author #3 but I doubt he will protest.
@lucamolteni - I'm in the background, supporting the new team :-) --> @maartenc @jlerbsc @MysterAitch <--
@lucamolteni I bet the answer to your riddle is something about how helpful JavaParser is trying to be with literals, and how it is failing to be consistent :-)
@maartenc @jlerbsc @mysteraitch, @lucamolteni works on RedHat's Drools (https://www.drools.org/) which was prototyped with JavaParser, and if I'm not mistaken it is still based on it. Pretty cool if you ask me.
