[Custom Language Plugin]How to find the duplicate element

public static @NotNull List<BjscClass> findClasses(Project project, String javaPackageDesc, String className) {
    List<BjscClass> result = new ArrayList<>();
    Collection<VirtualFile> virtualFiles =
        FileTypeIndex.getFiles(BjscFileType.INSTANCE, GlobalSearchScope.allScope(project));

    for (VirtualFile virtualFile : virtualFiles) {
        BjscFile bjscFile = (BjscFile)PsiManager.getInstance(project).findFile(virtualFile);
        if (Objects.isNull(bjscFile)) {
            continue;
        }
        List<BjscJavaPackageDesc> javaPackageDescList =
            new ArrayList<>(PsiTreeUtil.findChildrenOfType(bjscFile, BjscJavaPackageDesc.class));
        if (CollectionUtils.isEmpty(javaPackageDescList)) {
            continue;
        }
        String currentJavaPackageDesc = javaPackageDescList.get(0).getText();
        if (!StringUtil.equals(currentJavaPackageDesc, javaPackageDesc)) {
            continue;
        }
        List<BjscClass> bjscClassList = new ArrayList<>(PsiTreeUtil.findChildrenOfType(bjscFile, BjscClass.class));
        List<BjscClass> subBjscClassList = bjscClassList.stream()
            .filter(item -> StringUtil.equals(item.getClassName(), className)).collect(Collectors.toList());
        result.addAll(subBjscClassList);
    }
    return result;
}

if a class's javaPackageDesc and className is same with another class's, then them are duplicate. My idea is use a static variable to store all the classes in the project to avoid to query all the classes everytime. Is this possible？

if possible, when the project changed, how can i update the static variable promptly？

Hi,

I'm not sure I understand your use case. If you want to highlight an element if there is a "duplicate" element in the project, then you should find it in the annotator in a regular way and cache the result. See https://plugins.jetbrains.com/docs/intellij/psi-performance.html#cache-results-of-heavy-computations.

You can also use indexes to speed up finding duplicates, if possible. See all the sections under https://plugins.jetbrains.com/docs/intellij/indexing-and-psi-stubs.html.

Hi Karol, thank you for your advice. The stubIndex is useful

Thanks, it seems that i use the wrong method. StubIndex.getElements() is useful !