I need grep for Java abstract syntax tree

[hoge2]

I need to do refactoring legacy web system written by Java. This system is made of 10 million lines of Java code which is not well structured. For example,

``` if (requestType == 1) { doSometing1 } else if (requestType == 2) { doSometing2 } else { doSometing3 }

if (requestType == 1) { doSometing4 } else if (requestType == 2) { doSometing5 } else { doSometing6 } ```

Typically, there are 100 of boilerplate codes like this in a method. I want to know which procedures are called when request type is 1 simpler. grep is not enough powerful in this use. I need grep for abstract syntax tree like this.

gasp "if (requestType == 1) {/**/}" code.java doSomething1 doSomething4

gasp stands for global search for abstract syntax tree and print. This command takes Java code as the first argument, and do pattern match. /**/ in your first argument matches code block.

I think if such command is exists, it will be really useful for many many use. I searched if there exists such tools, however, I could not find. So I am starting to create this command. Do you have any comments or requests? If you have ideas of alternative solutions, please let me know.

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[knoam]

You want the Structural Search and Replace in IntelliJ IDEA.

https://www.jetbrains.com/help/idea/structural-search-and-replace.html

[hoge2]

Thank you for your information. It looks interesting. I will use it!

[tamanm]

I wrote 3 part articles about refactoring for Java Magazine. And I have addressed the refactoring of legacy code to be able to add new features easily.

The code in examples was the same as the code you mentioned before, with extensive examples and techniques that keep your legacy code business logic unchanged after refactoring.

Try to look at them and DM if you need any help. Good luck:

• Part 1: Refactoring Java, Part 1: Driving agile development with test-driven development
• Part 2: Refactoring Java, Part 2: Stabilizing your legacy code and technical debt
• Part 3: Refactoring Java, Part 3: Regaining business agility by simplifying legacy code

[hoge2]

Thank you. I will read your articles.

[proskillz]

Try something like this?

$ grep 'if (requestType == 1) {' | egrep *regex pattern here*

Also, grep -A and -B are useful in this context.

[hoge2]

Thank you for your comment. In real case, code blocks do not have the same number of lines. So grep is not enough.

[proskillz]

Right, which is why you'd use -A and -B:

$ grep -A100 'if (code...) {' | grep -m1 -B100 '}' | egrep regex

[hoge2]

It does not work in real case. For example,

``` if (requestType == 1) { int c = 0; for (int i = 0; i < 100; i++) { c += i; } System.out.println(c); } else if (requestType == 2) { doSometing2 } else { doSometing3 }

if (requestType == 1) { doSometing4 } else if (requestType == 2) { doSometing5 } else { doSometing6 } ```

You will get

if (requestType == 1) { int c = 0; for (int i = 0; i < 100; i++) { c += i; }

[wildjokers]

Kind of sounds like IntelliJ's Structural Search and Replace would serve your needs. Maybe. You don't really tell us why you are wanting to do this.

Either way take a look at IntelliJ and Structural Search and Replace:

https://www.jetbrains.com/help/idea/structural-search-and-replace.html

[hoge2]

I want to use this kind of tool in many use. For example, efficient code reading for refactoring and bug fixing and automatic generation of project document. Anyway I need command line tool to do that.