ASTRewrite

From Arnout Engelen

Javadoc

In fact, current ASTRewrite API allow you to add comment in the code... Here's an example of what can be done with it:

[edit] Example code

Let's say that cu was the ICompilationUnit corresponding to following java file:

package test1;
public class E {
    public void foo() {
        while (i == j) {
            System.beep();
        }
    }
}

Let's say that you want to add a block comment before beep method invocation. Then following code is an example of doing it using ASTRewrite API:

   // Create ASTRewrite object from compilation unit
   CompilationUnit astRoot= createAST(cu);
   ASTRewrite rewrite= ASTRewrite.create(astRoot.getAST());
   
   // Get while statement block
   TypeDeclaration typeDecl = (TypeDeclaration) astRoot.types().get(0);
   MethodDeclaration methodDecl= typeDecl.getMethods()[0];
   Block block= methodDecl.getBody();
   List statements= block.statements();
   WhileStatement whileStatement= (WhileStatement) statements.get(0);
   Statement whileBlock= whileStatement.getBody();
   
   // insert block comment as first statement
   StringBuffer comment = new StringBuffer();
   comment.append("/*\n");
   comment.append(" * Here's the block comment I want to insert :-)\n");
   comment.append(" */");
   ASTNode placeHolder= rewrite.createStringPlaceholder(comment.toString(), ASTNode.RETURN_STATEMENT);
   ListRewrite list = rewrite.getListRewrite(whileBlock, Block.STATEMENTS_PROPERTY);
   list.insertFirst(placeHolder, null);
   
   // Get new code
   String preview= evaluateRewrite(cu, rewrite);
      

Then preview looks now as follow: package test1;

public class E {
    public void foo() { 
        while (i == j) { 
            /*
             * Here's the block comment I want to insert :-)
             */
            System.beep();
        }
    }
}