Java Repository.getSuperClasses方法代码示例

import com.sun.org.apache.bcel.internal.Repository; //导入方法依赖的package包/类
/**
 * This commutative operation returns the first common superclass (narrowest ReferenceType
 * referencing a class, not an interface).
 * If one of the types is a superclass of the other, the former is returned.
 * If "this" is Type.NULL, then t is returned.
 * If t is Type.NULL, then "this" is returned.
 * If "this" equals t ['this.equals(t)'] "this" is returned.
 * If "this" or t is an ArrayType, then Type.OBJECT is returned.
 * If "this" or t is a ReferenceType referencing an interface, then Type.OBJECT is returned.
 * If not all of the two classes' superclasses cannot be found, "null" is returned.
 * See the JVM specification edition 2, "4.9.2 The Bytecode Verifier".
 *
 * @deprecated use getFirstCommonSuperclass(ReferenceType t) which has
 *             slightly changed semantics.
 */
public ReferenceType firstCommonSuperclass(ReferenceType t) {
  if (this.equals(Type.NULL)) return t;
  if (t.equals(Type.NULL)) return this;
  if (this.equals(t)) return this;
  /*
   * TODO: Above sounds a little arbitrary. On the other hand, there is
   * no object referenced by Type.NULL so we can also say all the objects
   * referenced by Type.NULL were derived from java.lang.Object.
   * However, the Java Language's "instanceof" operator proves us wrong:
   * "null" is not referring to an instance of java.lang.Object :)
   */

  if ((this instanceof ArrayType) || (t instanceof ArrayType))
    return Type.OBJECT;
  // TODO: Is there a proof of OBJECT being the direct ancestor of every ArrayType?

  if (((this instanceof ObjectType) && ((ObjectType) this).referencesInterface()) ||
      ((t instanceof ObjectType) && ((ObjectType) t).referencesInterface()))
    return Type.OBJECT;
  // TODO: The above line is correct comparing to the vmspec2. But one could
  // make class file verification a bit stronger here by using the notion of
  // superinterfaces or even castability or assignment compatibility.


  // this and t are ObjectTypes, see above.
  ObjectType thiz = (ObjectType) this;
  ObjectType other = (ObjectType) t;
  JavaClass[] thiz_sups = Repository.getSuperClasses(thiz.getClassName());
  JavaClass[] other_sups = Repository.getSuperClasses(other.getClassName());

  if ((thiz_sups == null) || (other_sups == null)) {
    return null;
  }

  // Waaahh...
  JavaClass[] this_sups = new JavaClass[thiz_sups.length + 1];
  JavaClass[] t_sups = new JavaClass[other_sups.length + 1];
  System.arraycopy(thiz_sups, 0, this_sups, 1, thiz_sups.length);
  System.arraycopy(other_sups, 0, t_sups, 1, other_sups.length);
  this_sups[0] = Repository.lookupClass(thiz.getClassName());
  t_sups[0] = Repository.lookupClass(other.getClassName());

  for (int i = 0; i < t_sups.length; i++) {
    for (int j = 0; j < this_sups.length; j++) {
      if (this_sups[j].equals(t_sups[i])) return new ObjectType(this_sups[j].getClassName());
    }
  }

  // Huh? Did you ask for Type.OBJECT's superclass??
  return null;
}
 

import com.sun.org.apache.bcel.internal.Repository; //导入方法依赖的package包/类
/**
 * This commutative operation returns the first common superclass (narrowest ReferenceType
 * referencing a class, not an interface).
 * If one of the types is a superclass of the other, the former is returned.
 * If "this" is Type.NULL, then t is returned.
 * If t is Type.NULL, then "this" is returned.
 * If "this" equals t ['this.equals(t)'] "this" is returned.
 * If "this" or t is an ArrayType, then Type.OBJECT is returned.
 * If "this" or t is a ReferenceType referencing an interface, then Type.OBJECT is returned.
 * If not all of the two classes' superclasses cannot be found, "null" is returned.
 * See the JVM specification edition 2, "4.9.2 The Bytecode Verifier".
 *
 * @deprecated use getFirstCommonSuperclass(ReferenceType t) which has
 *             slightly changed semantics.
 * @throws ClassNotFoundException on failure to find superclasses of this
 *  type, or the type passed as a parameter
 */
@Deprecated
public ReferenceType firstCommonSuperclass( final ReferenceType t ) throws ClassNotFoundException {
    if (this.equals(Type.NULL)) {
        return t;
    }
    if (t.equals(Type.NULL)) {
        return this;
    }
    if (this.equals(t)) {
        return this;
        /*
         * TODO: Above sounds a little arbitrary. On the other hand, there is
         * no object referenced by Type.NULL so we can also say all the objects
         * referenced by Type.NULL were derived from java.lang.Object.
         * However, the Java Language's "instanceof" operator proves us wrong:
         * "null" is not referring to an instance of java.lang.Object :)
         */
    }
    if ((this instanceof ArrayType) || (t instanceof ArrayType)) {
        return Type.OBJECT;
        // TODO: Is there a proof of OBJECT being the direct ancestor of every ArrayType?
    }
    if (((this instanceof ObjectType) && ((ObjectType) this).referencesInterface())
            || ((t instanceof ObjectType) && ((ObjectType) t).referencesInterface())) {
        return Type.OBJECT;
        // TODO: The above line is correct comparing to the vmspec2. But one could
        // make class file verification a bit stronger here by using the notion of
        // superinterfaces or even castability or assignment compatibility.
    }
    // this and t are ObjectTypes, see above.
    final ObjectType thiz = (ObjectType) this;
    final ObjectType other = (ObjectType) t;
    final JavaClass[] thiz_sups = Repository.getSuperClasses(thiz.getClassName());
    final JavaClass[] other_sups = Repository.getSuperClasses(other.getClassName());
    if ((thiz_sups == null) || (other_sups == null)) {
        return null;
    }
    // Waaahh...
    final JavaClass[] this_sups = new JavaClass[thiz_sups.length + 1];
    final JavaClass[] t_sups = new JavaClass[other_sups.length + 1];
    System.arraycopy(thiz_sups, 0, this_sups, 1, thiz_sups.length);
    System.arraycopy(other_sups, 0, t_sups, 1, other_sups.length);
    this_sups[0] = Repository.lookupClass(thiz.getClassName());
    t_sups[0] = Repository.lookupClass(other.getClassName());
    for (final JavaClass t_sup : t_sups) {
        for (final JavaClass this_sup : this_sups) {
            if (this_sup.equals(t_sup)) {
                return ObjectType.getInstance(this_sup.getClassName());
            }
        }
    }
    // Huh? Did you ask for Type.OBJECT's superclass??
    return null;
}