http://asm.ow2.io/: Tree API of ASM, a very small and fast Java bytecode manipulation framework (OW2)
  • Eric Bruneton
  • Eugene Kuleshov
  • Remi Forax 
// ASM: a very small and fast Java bytecode manipulation framework
// Copyright (c) 2000-2011 INRIA, France Telecom
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
// 3. Neither the name of the copyright holders nor the names of its
//    contributors may be used to endorse or promote products derived from
//    this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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package org.objectweb.asm.tree;

import java.util.ArrayList;
import java.util.List;
import org.objectweb.asm.AnnotationVisitor;
import org.objectweb.asm.Attribute;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.FieldVisitor;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.ModuleVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.RecordComponentVisitor;
import org.objectweb.asm.TypePath;


A node that represents a class.

Author:Eric Bruneton
/**
 * A node that represents a class.
 *
 * @author Eric Bruneton
 */
public class ClassNode extends ClassVisitor {

  
The class version. The minor version is stored in the 16 most significant bits, and the major
version in the 16 least significant bits.

/**
   * The class version. The minor version is stored in the 16 most significant bits, and the major
   * version in the 16 least significant bits.
   */
  public int version;

  
The class's access flags (see Opcodes). This field also indicates if the class is deprecated Opcodes.ACC_DEPRECATED or a record Opcodes.ACC_RECORD. 
/**
   * The class's access flags (see {@link org.objectweb.asm.Opcodes}). This field also indicates if
   * the class is deprecated {@link Opcodes#ACC_DEPRECATED} or a record {@link Opcodes#ACC_RECORD}.
   */
  public int access;

  
The internal name of this class (see Type.getInternalName). 
/** The internal name of this class (see {@link org.objectweb.asm.Type#getInternalName}). */
  public String name;

  
The signature of this class. May be null. 
/** The signature of this class. May be {@literal null}. */
  public String signature;

  
The internal of name of the super class (see Type.getInternalName). For interfaces, the super class is Object. May be null, but only for the Object class. 
/**
   * The internal of name of the super class (see {@link org.objectweb.asm.Type#getInternalName}).
   * For interfaces, the super class is {@link Object}. May be {@literal null}, but only for the
   * {@link Object} class.
   */
  public String superName;

  
The internal names of the interfaces directly implemented by this class (see Type.getInternalName). 
/**
   * The internal names of the interfaces directly implemented by this class (see {@link
   * org.objectweb.asm.Type#getInternalName}).
   */
  public List<String> interfaces;

  
The name of the source file from which this class was compiled. May be null. 
/** The name of the source file from which this class was compiled. May be {@literal null}. */
  public String sourceFile;

  
The correspondence between source and compiled elements of this class. May be null. 
/**
   * The correspondence between source and compiled elements of this class. May be {@literal null}.
   */
  public String sourceDebug;

  
The module stored in this class. May be null. 
/** The module stored in this class. May be {@literal null}. */
  public ModuleNode module;

  
The internal name of the enclosing class of this class. May be null. 
/** The internal name of the enclosing class of this class. May be {@literal null}. */
  public String outerClass;

  
The name of the method that contains this class, or null if this class is not enclosed in a method. 
/**
   * The name of the method that contains this class, or {@literal null} if this class is not
   * enclosed in a method.
   */
  public String outerMethod;

  
The descriptor of the method that contains this class, or null if this class is not enclosed in a method. 
/**
   * The descriptor of the method that contains this class, or {@literal null} if this class is not
   * enclosed in a method.
   */
  public String outerMethodDesc;

  
The runtime visible annotations of this class. May be null. 
/** The runtime visible annotations of this class. May be {@literal null}. */
  public List<AnnotationNode> visibleAnnotations;

  
The runtime invisible annotations of this class. May be null. 
/** The runtime invisible annotations of this class. May be {@literal null}. */
  public List<AnnotationNode> invisibleAnnotations;

  
The runtime visible type annotations of this class. May be null. 
/** The runtime visible type annotations of this class. May be {@literal null}. */
  public List<TypeAnnotationNode> visibleTypeAnnotations;

  
The runtime invisible type annotations of this class. May be null. 
/** The runtime invisible type annotations of this class. May be {@literal null}. */
  public List<TypeAnnotationNode> invisibleTypeAnnotations;

  
The non standard attributes of this class. May be null. 
/** The non standard attributes of this class. May be {@literal null}. */
  public List<Attribute> attrs;

  
The inner classes of this class. 
/** The inner classes of this class. */
  public List<InnerClassNode> innerClasses;

  
The internal name of the nest host class of this class. May be null. 
/** The internal name of the nest host class of this class. May be {@literal null}. */
  public String nestHostClass;

  
The internal names of the nest members of this class. May be null. 
/** The internal names of the nest members of this class. May be {@literal null}. */
  public List<String> nestMembers;

  
The internal names of the permitted subclasses of this class. May be null. 
/** The internal names of the permitted subclasses of this class. May be {@literal null}. */
  public List<String> permittedSubclasses;

  
The record components of this class. May be null. 
/** The record components of this class. May be {@literal null}. */
  public List<RecordComponentNode> recordComponents;

  
The fields of this class. 
/** The fields of this class. */
  public List<FieldNode> fields;

  
The methods of this class. 
/** The methods of this class. */
  public List<MethodNode> methods;

  
Constructs a new ClassNode. Subclasses must not use this constructor. Instead, they must use the ClassNode(int) version. 
Throws:
/**
   * Constructs a new {@link ClassNode}. <i>Subclasses must not use this constructor</i>. Instead,
   * they must use the {@link #ClassNode(int)} version.
   *
   * @throws IllegalStateException If a subclass calls this constructor.
   */
  public ClassNode() {
    this(Opcodes.ASM9);
    if (getClass() != ClassNode.class) {
      throw new IllegalStateException();
    }
  }

  
Constructs a new ClassNode. 
Params:
/**
   * Constructs a new {@link ClassNode}.
   *
   * @param api the ASM API version implemented by this visitor. Must be one of {@link
   *     Opcodes#ASM4}, {@link Opcodes#ASM5}, {@link Opcodes#ASM6}, {@link Opcodes#ASM7}, {@link
   *     Opcodes#ASM8}, or {@link Opcodes#ASM9}.
   */
  public ClassNode(final int api) {
    super(api);
    this.interfaces = new ArrayList<>();
    this.innerClasses = new ArrayList<>();
    this.fields = new ArrayList<>();
    this.methods = new ArrayList<>();
  }

  // -----------------------------------------------------------------------------------------------
  // Implementation of the ClassVisitor abstract class
  // -----------------------------------------------------------------------------------------------

  @Override
  public void visit(
      final int version,
      final int access,
      final String name,
      final String signature,
      final String superName,
      final String[] interfaces) {
    this.version = version;
    this.access = access;
    this.name = name;
    this.signature = signature;
    this.superName = superName;
    this.interfaces = Util.asArrayList(interfaces);
  }

  @Override
  public void visitSource(final String file, final String debug) {
    sourceFile = file;
    sourceDebug = debug;
  }

  @Override
  public ModuleVisitor visitModule(final String name, final int access, final String version) {
    module = new ModuleNode(name, access, version);
    return module;
  }

  @Override
  public void visitNestHost(final String nestHost) {
    this.nestHostClass = nestHost;
  }

  @Override
  public void visitOuterClass(final String owner, final String name, final String descriptor) {
    outerClass = owner;
    outerMethod = name;
    outerMethodDesc = descriptor;
  }

  @Override
  public AnnotationVisitor visitAnnotation(final String descriptor, final boolean visible) {
    AnnotationNode annotation = new AnnotationNode(descriptor);
    if (visible) {
      visibleAnnotations = Util.add(visibleAnnotations, annotation);
    } else {
      invisibleAnnotations = Util.add(invisibleAnnotations, annotation);
    }
    return annotation;
  }

  @Override
  public AnnotationVisitor visitTypeAnnotation(
      final int typeRef, final TypePath typePath, final String descriptor, final boolean visible) {
    TypeAnnotationNode typeAnnotation = new TypeAnnotationNode(typeRef, typePath, descriptor);
    if (visible) {
      visibleTypeAnnotations = Util.add(visibleTypeAnnotations, typeAnnotation);
    } else {
      invisibleTypeAnnotations = Util.add(invisibleTypeAnnotations, typeAnnotation);
    }
    return typeAnnotation;
  }

  @Override
  public void visitAttribute(final Attribute attribute) {
    attrs = Util.add(attrs, attribute);
  }

  @Override
  public void visitNestMember(final String nestMember) {
    nestMembers = Util.add(nestMembers, nestMember);
  }

  @Override
  public void visitPermittedSubclass(final String permittedSubclass) {
    permittedSubclasses = Util.add(permittedSubclasses, permittedSubclass);
  }

  @Override
  public void visitInnerClass(
      final String name, final String outerName, final String innerName, final int access) {
    InnerClassNode innerClass = new InnerClassNode(name, outerName, innerName, access);
    innerClasses.add(innerClass);
  }

  @Override
  public RecordComponentVisitor visitRecordComponent(
      final String name, final String descriptor, final String signature) {
    RecordComponentNode recordComponent = new RecordComponentNode(name, descriptor, signature);
    recordComponents = Util.add(recordComponents, recordComponent);
    return recordComponent;
  }

  @Override
  public FieldVisitor visitField(
      final int access,
      final String name,
      final String descriptor,
      final String signature,
      final Object value) {
    FieldNode field = new FieldNode(access, name, descriptor, signature, value);
    fields.add(field);
    return field;
  }

  @Override
  public MethodVisitor visitMethod(
      final int access,
      final String name,
      final String descriptor,
      final String signature,
      final String[] exceptions) {
    MethodNode method = new MethodNode(access, name, descriptor, signature, exceptions);
    methods.add(method);
    return method;
  }

  @Override
  public void visitEnd() {
    // Nothing to do.
  }

  // -----------------------------------------------------------------------------------------------
  // Accept method
  // -----------------------------------------------------------------------------------------------

  
Checks that this class node is compatible with the given ASM API version. This method checks
that this node, and all its children recursively, do not contain elements that were introduced
in more recent versions of the ASM API than the given version.

Params:
/**
   * Checks that this class node is compatible with the given ASM API version. This method checks
   * that this node, and all its children recursively, do not contain elements that were introduced
   * in more recent versions of the ASM API than the given version.
   *
   * @param api an ASM API version. Must be one of {@link Opcodes#ASM4}, {@link Opcodes#ASM5},
   *     {@link Opcodes#ASM6}, {@link Opcodes#ASM7}, {@link Opcodes#ASM8} or {@link Opcodes#ASM9}.
   */
  public void check(final int api) {
    if (api < Opcodes.ASM9 && permittedSubclasses != null) {
      throw new UnsupportedClassVersionException();
    }
    if (api < Opcodes.ASM8 && ((access & Opcodes.ACC_RECORD) != 0 || recordComponents != null)) {
      throw new UnsupportedClassVersionException();
    }
    if (api < Opcodes.ASM7 && (nestHostClass != null || nestMembers != null)) {
      throw new UnsupportedClassVersionException();
    }
    if (api < Opcodes.ASM6 && module != null) {
      throw new UnsupportedClassVersionException();
    }
    if (api < Opcodes.ASM5) {
      if (visibleTypeAnnotations != null && !visibleTypeAnnotations.isEmpty()) {
        throw new UnsupportedClassVersionException();
      }
      if (invisibleTypeAnnotations != null && !invisibleTypeAnnotations.isEmpty()) {
        throw new UnsupportedClassVersionException();
      }
    }
    // Check the annotations.
    if (visibleAnnotations != null) {
      for (int i = visibleAnnotations.size() - 1; i >= 0; --i) {
        visibleAnnotations.get(i).check(api);
      }
    }
    if (invisibleAnnotations != null) {
      for (int i = invisibleAnnotations.size() - 1; i >= 0; --i) {
        invisibleAnnotations.get(i).check(api);
      }
    }
    if (visibleTypeAnnotations != null) {
      for (int i = visibleTypeAnnotations.size() - 1; i >= 0; --i) {
        visibleTypeAnnotations.get(i).check(api);
      }
    }
    if (invisibleTypeAnnotations != null) {
      for (int i = invisibleTypeAnnotations.size() - 1; i >= 0; --i) {
        invisibleTypeAnnotations.get(i).check(api);
      }
    }
    if (recordComponents != null) {
      for (int i = recordComponents.size() - 1; i >= 0; --i) {
        recordComponents.get(i).check(api);
      }
    }
    for (int i = fields.size() - 1; i >= 0; --i) {
      fields.get(i).check(api);
    }
    for (int i = methods.size() - 1; i >= 0; --i) {
      methods.get(i).check(api);
    }
  }

  
Makes the given class visitor visit this class.

Params:
  • classVisitor – a class visitor.
/**
   * Makes the given class visitor visit this class.
   *
   * @param classVisitor a class visitor.
   */
  public void accept(final ClassVisitor classVisitor) {
    // Visit the header.
    String[] interfacesArray = new String[this.interfaces.size()];
    this.interfaces.toArray(interfacesArray);
    classVisitor.visit(version, access, name, signature, superName, interfacesArray);
    // Visit the source.
    if (sourceFile != null || sourceDebug != null) {
      classVisitor.visitSource(sourceFile, sourceDebug);
    }
    // Visit the module.
    if (module != null) {
      module.accept(classVisitor);
    }
    // Visit the nest host class.
    if (nestHostClass != null) {
      classVisitor.visitNestHost(nestHostClass);
    }
    // Visit the outer class.
    if (outerClass != null) {
      classVisitor.visitOuterClass(outerClass, outerMethod, outerMethodDesc);
    }
    // Visit the annotations.
    if (visibleAnnotations != null) {
      for (int i = 0, n = visibleAnnotations.size(); i < n; ++i) {
        AnnotationNode annotation = visibleAnnotations.get(i);
        annotation.accept(classVisitor.visitAnnotation(annotation.desc, true));
      }
    }
    if (invisibleAnnotations != null) {
      for (int i = 0, n = invisibleAnnotations.size(); i < n; ++i) {
        AnnotationNode annotation = invisibleAnnotations.get(i);
        annotation.accept(classVisitor.visitAnnotation(annotation.desc, false));
      }
    }
    if (visibleTypeAnnotations != null) {
      for (int i = 0, n = visibleTypeAnnotations.size(); i < n; ++i) {
        TypeAnnotationNode typeAnnotation = visibleTypeAnnotations.get(i);
        typeAnnotation.accept(
            classVisitor.visitTypeAnnotation(
                typeAnnotation.typeRef, typeAnnotation.typePath, typeAnnotation.desc, true));
      }
    }
    if (invisibleTypeAnnotations != null) {
      for (int i = 0, n = invisibleTypeAnnotations.size(); i < n; ++i) {
        TypeAnnotationNode typeAnnotation = invisibleTypeAnnotations.get(i);
        typeAnnotation.accept(
            classVisitor.visitTypeAnnotation(
                typeAnnotation.typeRef, typeAnnotation.typePath, typeAnnotation.desc, false));
      }
    }
    // Visit the non standard attributes.
    if (attrs != null) {
      for (int i = 0, n = attrs.size(); i < n; ++i) {
        classVisitor.visitAttribute(attrs.get(i));
      }
    }
    // Visit the nest members.
    if (nestMembers != null) {
      for (int i = 0, n = nestMembers.size(); i < n; ++i) {
        classVisitor.visitNestMember(nestMembers.get(i));
      }
    }
    // Visit the permitted subclasses.
    if (permittedSubclasses != null) {
      for (int i = 0, n = permittedSubclasses.size(); i < n; ++i) {
        classVisitor.visitPermittedSubclass(permittedSubclasses.get(i));
      }
    }
    // Visit the inner classes.
    for (int i = 0, n = innerClasses.size(); i < n; ++i) {
      innerClasses.get(i).accept(classVisitor);
    }
    // Visit the record components.
    if (recordComponents != null) {
      for (int i = 0, n = recordComponents.size(); i < n; ++i) {
        recordComponents.get(i).accept(classVisitor);
      }
    }
    // Visit the fields.
    for (int i = 0, n = fields.size(); i < n; ++i) {
      fields.get(i).accept(classVisitor);
    }
    // Visit the methods.
    for (int i = 0, n = methods.size(); i < n; ++i) {
      methods.get(i).accept(classVisitor);
    }
    classVisitor.visitEnd();
  }
}