atunitremover.java

《Java编程思想》第四版

//: net/mindview/atunit/AtUnitRemover.java
// Displays @Unit annotations in compiled class files. If
// first argument is "-r", @Unit annotations are removed.
// {Args: ..}
// {Requires: javassist.bytecode.ClassFile;
// You must install the Javassist library from
// http://sourceforge.net/projects/jboss/ }
package net.mindview.atunit;
import javassist.*;
import javassist.expr.*;
import javassist.bytecode.*;
import javassist.bytecode.annotation.*;
import java.io.*;
import java.util.*;
import net.mindview.util.*;
import static net.mindview.util.Print.*;

public class AtUnitRemover
implements ProcessFiles.Strategy {
  private static boolean remove = false;
  public static void main(String[] args) throws Exception {
    if(args.length > 0 && args[0].equals("-r")) {
      remove = true;
      String[] nargs = new String[args.length - 1];
      System.arraycopy(args, 1, nargs, 0, nargs.length);
      args = nargs;
    }
    new ProcessFiles(
      new AtUnitRemover(), "class").start(args);
  }
  public void process(File cFile) {
    boolean modified = false;
    try {
      String cName = ClassNameFinder.thisClass(
        BinaryFile.read(cFile));
      if(!cName.contains("."))
        return; // Ignore unpackaged classes
      ClassPool cPool = ClassPool.getDefault();
      CtClass ctClass = cPool.get(cName);
      for(CtMethod method : ctClass.getDeclaredMethods()) {
        MethodInfo mi = method.getMethodInfo();
        AnnotationsAttribute attr = (AnnotationsAttribute)
          mi.getAttribute(AnnotationsAttribute.visibleTag);
        if(attr == null) continue;
        for(Annotation ann : attr.getAnnotations()) {
          if(ann.getTypeName()
             .startsWith("net.mindview.atunit")) {
            print(ctClass.getName() + " Method: "
              + mi.getName() + " " + ann);
            if(remove) {
              ctClass.removeMethod(method);
              modified = true;
            }
          }
        }
      }
      // Fields are not removed in this version (see text).
      if(modified)
        ctClass.toBytecode(new DataOutputStream(
          new FileOutputStream(cFile)));
      ctClass.detach();
    } catch(Exception e) {
      throw new RuntimeException(e);
    }
  }
} ///:~