Adding and removing fields from a PSIClass programatically through com.jetbrains.openapi

Answered

Created August 20, 2023 14:26

I have the following maven project pom.xml as given below, with an additional source folder in temp/src/main/java, under the basedir.

<build>

<groupId>org.codehaus.mojo</groupId>

<artifactId>build-helper-maven-plugin</artifactId>

<id>add-source</id>

<phase>generate-sources</phase>

<goals>

<goal>add-source</goal>

</goals>

</sources>

</configuration>

</execution>

</executions>

</plugin>

</plugins>

</build>

</project>

In the folder temp/src/main/java/org, the following files exist with the below contents

temp/src/main/java/org/Class1.java

package org;

public class Class1 {

public String b = "b";

}

temp/src/main/java/org/Class3.java

package org;

public class Class3 {

public String x = "x";

}

I have another file by name "changes.txt", which has the following contents

+Class1.a

-Class1.b

+Class2

+Class2.p

Class2.p,q

Class2,Class4

-Class3

+ at the beginning of a line indicates class/member to be created/added, - at the beginning of a line indicates class/member to be deleted & no +/- at the beginning of a line indicates rename refactoring of a class/member.

For the above file, the objective is to have the following done.

Add the line "public String a = "a"; as a member in Class1.java

Remove the line "public String b = "b"; from the file Class1.java

Create a new Class in the folder temp/src/main/java/org/Class2.java

Add the line "public String p = "p"; as a member in Class2.java

Rename Refactor member from p to q in Class2.java

Rename Refactor Class2 to Class4

Remove Class3

The final contents in "temp/src/main/java/org/" should be as below:

temp/src/main/java/org/Class1.java

package org;

public class Class1 {

public String a = "a";

}

temp/src/main/java/org/Class4.java

package org;

public class Class4 {

public String q = "q";

}

Please note that Class2.java & Class3.java should not exist in the folder temp/src/main/java/org/, after the AnActionEvent is trigerred.

I have a MyAction class which extends from (com.intellij.openapi.actionSystem.AnAction), with the member function @Override public void actionPerformed(AnActionEvent event). In the member function I iterate through each line in the changes.txt file. The rename of class/field i am able to do. But addition of class/fields & removal of class/fields I am facing issues. While trying to add a field to the PsiClass, it gives an error, "com.intellij.util.IncorrectOperationException: Must not change PSI outside command or undo-transparent action. "

Could you please send me the relevant code snippet to resolve this.

18 comments

Yann Cebron

Created August 21, 2023 09:33

The full error message points to the API that must be used here:
Must not change PSI outside command or undo-transparent action. See com.intellij.openapi.command.WriteCommandAction or com.intellij.openapi.command.CommandProcessor.

You can simply wrap your PSI modifications using `com.intellij.openapi.command.WriteCommandAction#writeCommandAction()`.

Shenoy Venugopal

Created August 22, 2023 09:56

The following code worked like a charm. Thanks for the valuable information.

However I need the additional things to be done.
While adding a field to the class, I use the following snippet
final PsiElementFactory elementFactory = JavaPsiFacade.getInstance(project).getElementFactory();
PsiField psiField = elementFactory.createField(fieldName, PsiType.INT);
psiClass.add(psiField);

This adds a integer field as the statement "private int <fieldName>;"
However I want the field to be added in the format "public String <fieldName> = "<fieldName>";

Similarly I am not able to add a new Class.
Could you please share the relevant code snippet?

The addition, deletion & rename refactoring of fields is possible.
The deletion & rename refactoring of classes is possible.

--------------------------------------------------------------------------------------------
final String stmt = line;
WriteCommandAction writeCommandAction = new WriteCommandAction(project) {
@Override
protected void run(final Result result) throws Throwable {
String className = null;
String newClassName = null;
String fieldName = null;
String newFieldName = null;
if (!stmt.contains(".")) {
if ( (stmt.startsWith("+")) || (stmt.startsWith("-")) ) {
className = stmt.substring(1);
} else {
className = stmt.split(",")[0];
newClassName = stmt.split(",")[1];
}
} else {
if ( (stmt.startsWith("+")) || (stmt.startsWith("-")) ) {
className = stmt.substring(1).split("\\.")[0];
fieldName = stmt.substring(1).split("\\.")[1];
} else {
className = stmt.split("\\.")[0];
fieldName = stmt.split("\\.")[1].split(",")[0];
newFieldName = stmt.split("\\.")[1].split(",")[1];
}
}
VirtualFile vf = LocalFileSystem.getInstance().findFileByIoFile(new File(basePath + "/temp/src/main/java/com/" + className + ".java"));
PsiFile psiFile = PsiManager.getInstance(project).findFile(vf);
PsiJavaFile psiJavaFile = (PsiJavaFile) psiFile;
PsiClass psiClass = psiJavaFile.getClasses()[0];
if (fieldName == null) {
changeClass(psiClass, newClassName, stmt);
} else {
changeField(psiClass, fieldName, newFieldName, stmt);
}
}

private void changeClass(PsiClass psiClass, String newClassName, String stmt) {
if (stmt.startsWith("-")) {
psiClass.delete();
} else {
JavaRefactoringFactory javaRefactoringFactory = JavaRefactoringFactory.getInstance(project);
JavaRenameRefactoring javaRenameRefactoring = javaRefactoringFactory.createRename(psiClass, newClassName);
javaRenameRefactoring.setSearchInComments(false);
UsageInfo[] usages = javaRenameRefactoring.findUsages();
javaRenameRefactoring.doRefactoring(usages);
}
}

private void changeField(PsiClass psiClass, String fieldName, String newFieldName, String stmg) {
if (stmt.startsWith("+")) {
boolean found = false;
for (PsiField psiField : psiClass.getFields()) {
if (psiField.getName().equals(fieldName)) {
found = true;
break;
}
}
if (!found) {
final PsiElementFactory elementFactory = JavaPsiFacade.getInstance(project).getElementFactory();
PsiField psiField = elementFactory.createField(fieldName, PsiType.INT);
psiClass.add(psiField);
}
} else if (stmt.startsWith("-")) {
for (PsiField psiField : psiClass.getFields()) {
if (psiField.getName().equals(fieldName)) {
psiField.delete();
break;
}
}
} else {
for (PsiField psiField : psiClass.getFields()) {
if (psiField.getName().equals(fieldName)) {
JavaRefactoringFactory javaRefactoringFactory = JavaRefactoringFactory.getInstance(project);
JavaRenameRefactoring javaRenameRefactoring = javaRefactoringFactory.createRename(psiField, newFieldName);
javaRenameRefactoring.setSearchInComments(false);
UsageInfo[] usages = javaRenameRefactoring.findUsages();
javaRenameRefactoring.doRefactoring(usages);
break;
}
}
}
}
};
writeCommandAction.execute();

Shenoy Venugopal

Created August 22, 2023 11:03

final PsiElementFactory elementFactory = JavaPsiFacade.getInstance(project).getElementFactory();
PsiField psiField = elementFactory.createField(fieldName, PsiType.INT);

//Newly added line---------------------
PsiUtil.setModifierProperty(psiField, PsiModifier.PUBLIC, true);
//This additional line ensured the field added is "public"

psiClass.add(psiField);




Now how to make the field type "String" instead of "int"

Yann Cebron

Created August 22, 2023 12:26

com.intellij.psi.PsiJavaParserFacade#createTypeFromText using com.intellij.psi.CommonClassNames#JAVA_LANG_STRING

Shenoy Venugopal

Created August 22, 2023 13:07

Is the above lines to resolve the issue of creating a field of type String.

Not able to resolve this.

Appreciate if you can give code snippets only for this.

Yann Cebron

Created August 22, 2023 13:24

Pass in return value from createTypeFromText() instead of PsiType.INT for createField().

Shenoy Venugopal

Created August 22, 2023 14:25

Thanks a ton...Made the appropriate changes as below and it works.

final PsiElementFactory elementFactory = JavaPsiFacade.getInstance(project).getElementFactory();
PsiField psiField = elementFactory.createField(fieldName, elementFactory.createTypeFromText(CommonClassNames.JAVA_LANG_STRING,null));
PsiExpression psiInitializer = elementFactory.createExpressionFromText("\"" + fieldName + "\"", psiField);
psiField.setInitializer(psiInitializer);
PsiUtil.setModifierProperty(psiField, PsiModifier.PUBLIC, true);
psiClass.add(psiField);

Shenoy Venugopal

Created August 22, 2023 14:32

Now the only thing remaining is creation of a new class (say Class1), which extends from another class, with a constructor body and the physical file (Class1.java) being available in the folder \temp\src\main\java\, which is specified in the pom.xml as a source folder.

Let me know, what functions to be used.

Yann Cebron

Created August 22, 2023 14:35

Might be easier to just generate the full .java file as text and use com.intellij.psi.PsiFileFactory#createFileFromText()

Shenoy Venugopal

Created August 22, 2023 16:26

I find different signatures for createFileFromText in the PsiFileFactory

What are the parameters to be passed

& how is that the file will be stored in /temp/src/main/java/com

Shenoy Venugopal

Created August 23, 2023 01:56

Which one of the below signature is to be applied?

Given that I have a certain "text" to be put in a file "Class1.java" at the location "/temp/src/main/java/com"

1. PsiFileFactory.createFileFromText(String,String)

2. PsiFileFactory.createFileFromText(String,FileType,CharSequence)

3. PsiFileFactory.createFileFromText(String,FileType,CharSequence,long,boolean)

4. PsiFileFactory.createFileFromText(String,FileType,CharSequence,long,boolean,boolean)

5. PsiFileFactory.createFileFromText(String,Language,CharSequence)

6. PsiFileFactory.createFileFromText(Language,CharSequence)

7. PsiFileFactory.createFileFromText(String,Language,CharSequence,boolean,boolean)

8. PsiFileFactory.createFileFromText(String,Language,CharSequence,boolean,boolean,boolean)

9. PsiFileFactory.createFileFromText(String,Language,CharSequence,boolean,boolean,boolean,VirtualFile)

10.PsiFileFactory.createFileFromText(FileType,String,CharSequence,int,int)

PsiFileFactory.createFileFromText(CharSequence,PsiFile)

Yann Cebron

Created August 23, 2023 09:39

Please see https://plugins.jetbrains.com/docs/intellij/psi-files.html#how-do-i-create-a-psi-file There are thousands of sample usages in IntelliJ Community sources.

Shenoy Venugopal

Created August 23, 2023 10:14

I tried the below code. It gives an error

non-static method add(PsiElement) cannot be referenced from a static context
PsiDirectory.add(psiFile);
^

final PsiFileFactory factory = PsiFileFactory.getInstance(project);
String text = "package com;\n";
text += "public class " + className + " {\n";
text += "}\n";
File file = new File(basePath + "/temp/src/main/java/com/" + className + ".java");
final PsiFile psiFile = factory.createFileFromText(file.getAbsolutePath(), text);
PsiDirectory.add(psiFile);

Shenoy Venugopal

Created August 23, 2023 10:35

is is the only issue that needs resolution now....all other features of adding, rename & removing fields is successfully done.

Rename of classes & deletion of classes is successfuly happening. Only for addition I am stuck with this issue.

Shenoy Venugopal

Created August 23, 2023 12:08

Anything else to be added in my code

Yann Cebron

Created August 24, 2023 11:36

You need to locate and provide that PsiDirectory instance, e.g. coming from VirtualFile https://plugins.jetbrains.com/docs/intellij/virtual-file.html and then locating it as described in https://plugins.jetbrains.com/docs/intellij/psi-files.html

Shenoy Venugopal

Created August 24, 2023 15:39

The below code worked for me. Succesfully the class gets created in the folder "/temp/src/main/java/com/". The only thing required now is to add " extends net.DataRecord" and adding a constructor body

public <className> (String str) {

super(str);

}

What function needs to be called at the psiClass to implement this?

File file = new File(basePath + "/temp/src/main/java/com/" + className + ".java");
if (!file.exists()) {
    File folder = new File(basePath + "/temp/src/main/java/com/");
    VirtualFile vFolder = LocalFileSystem.getInstance().findFileByIoFile(folder);
    final PsiDirectory psiDirectory = PsiManager.getInstance(project).findDirectory(vFolder);
    psiClass = PsiElementFactory.getInstance(project).createClass(className);

    psiClass = (PsiClass) psiDirectory.add(psiClass);
    psiClass.navigate(true);
}

Shenoy Venugopal

Created August 25, 2023 18:25

Everything worked finally successfully with the below code.

if (stmt.startsWith("+")) {
    File file = new File(basePath + "/temp/src/main/java/com/" + className + ".java");
    if (!file.exists()) {
        File folder = new File(basePath + "/temp/src/main/java/com/");
        VirtualFile vFolder = LocalFileSystem.getInstance().findFileByIoFile(folder);
        final PsiDirectory psiDirectory = PsiManager.getInstance(project).findDirectory(vFolder);
        //psiClass = PsiElementFactory.getInstance(project).createClass(className);
        String text = "package com;\n";
        text += "import net.DataRecord;\n";
        text += "public class " + className + " extends DataRecord {\n";
        text += "\tpublic " + className + "(String " + className + ") {\n";
        text += "\t\tsuper(" + className + ");\n\t}\n}";
        PsiFile psiFile = PsiFileFactory.getInstance(project).createFileFromText(className + ".java",text);
        PsiJavaFile psiJavaFile = (PsiJavaFile) psiFile;
        psiClass = psiJavaFile.getClasses()[0];
        psiClass = (PsiClass) psiDirectory.add(psiClass);
        psiClass.navigate(true);
    }
}

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