/*
    * Copyright  2000-2004 The Apache Software Foundation
    *
    *  Licensed under the Apache License, Version 2.0 (the "License"); 
    *  you may not use this file except in compliance with the License.
    *  You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
    *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License. 
   *
   */
  package org.apache.bcel.generic;
  
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  import org.apache.bcel.Constants;
  import org.apache.bcel.classfile.AccessFlags;
  import org.apache.bcel.classfile.Attribute;
  import org.apache.bcel.classfile.ConstantPool;
  import org.apache.bcel.classfile.Field;
  import org.apache.bcel.classfile.JavaClass;
  import org.apache.bcel.classfile.Method;
  import org.apache.bcel.classfile.SourceFile;
  import org.apache.bcel.util.BCELComparator;
  
  /*** 
   * Template class for building up a java class. May be initialized with an
   * existing java class (file).
   *
   * @see JavaClass
   * @version $Id: ClassGen.java 386056 2006-03-15 11:31:56Z tcurdt $
   * @author  <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
   */
  public class ClassGen extends AccessFlags implements Cloneable {
  
      /* Corresponds to the fields found in a JavaClass object.
       */
      private String class_name, super_class_name, file_name;
      private int class_name_index = -1, superclass_name_index = -1;
      private int major = Constants.MAJOR_1_1, minor = Constants.MINOR_1_1;
      private ConstantPoolGen cp; // Template for building up constant pool
      // ArrayLists instead of arrays to gather fields, methods, etc.
      private List field_vec = new ArrayList();
      private List method_vec = new ArrayList();
      private List attribute_vec = new ArrayList();
      private List interface_vec = new ArrayList();
      private static BCELComparator _cmp = new BCELComparator() {
  
          public boolean equals( Object o1, Object o2 ) {
              ClassGen THIS = (ClassGen) o1;
              ClassGen THAT = (ClassGen) o2;
              return THIS.getClassName().equals(THAT.getClassName());
          }
  
  
          public int hashCode( Object o ) {
              ClassGen THIS = (ClassGen) o;
              return THIS.getClassName().hashCode();
          }
      };
  
  
      /*** Convenience constructor to set up some important values initially.
       *
       * @param class_name fully qualified class name
       * @param super_class_name fully qualified superclass name
       * @param file_name source file name
       * @param access_flags access qualifiers
       * @param interfaces implemented interfaces
       * @param cp constant pool to use
       */
      public ClassGen(String class_name, String super_class_name, String file_name, int access_flags,
              String[] interfaces, ConstantPoolGen cp) {
          this.class_name = class_name;
          this.super_class_name = super_class_name;
          this.file_name = file_name;
          this.access_flags = access_flags;
          this.cp = cp;
          // Put everything needed by default into the constant pool and the vectors
          if (file_name != null) {
              addAttribute(new SourceFile(cp.addUtf8("SourceFile"), 2, cp.addUtf8(file_name), cp
                      .getConstantPool()));
          }
          class_name_index = cp.addClass(class_name);
          superclass_name_index = cp.addClass(super_class_name);
          if (interfaces != null) {
              for (int i = 0; i < interfaces.length; i++) {
                  addInterface(interfaces[i]);
              }
          }
      }
  
  
     /*** Convenience constructor to set up some important values initially.
      *
      * @param class_name fully qualified class name
      * @param super_class_name fully qualified superclass name
      * @param file_name source file name
      * @param access_flags access qualifiers
      * @param interfaces implemented interfaces
      */
     public ClassGen(String class_name, String super_class_name, String file_name, int access_flags,
             String[] interfaces) {
         this(class_name, super_class_name, file_name, access_flags, interfaces,
                 new ConstantPoolGen());
     }
 
 
     /***
      * Initialize with existing class.
      * @param clazz JavaClass object (e.g. read from file)
      */
     public ClassGen(JavaClass clazz) {
         class_name_index = clazz.getClassNameIndex();
         superclass_name_index = clazz.getSuperclassNameIndex();
         class_name = clazz.getClassName();
         super_class_name = clazz.getSuperclassName();
         file_name = clazz.getSourceFileName();
         access_flags = clazz.getAccessFlags();
         cp = new ConstantPoolGen(clazz.getConstantPool());
         major = clazz.getMajor();
         minor = clazz.getMinor();
         Attribute[] attributes = clazz.getAttributes();
         Method[] methods = clazz.getMethods();
         Field[] fields = clazz.getFields();
         String[] interfaces = clazz.getInterfaceNames();
         for (int i = 0; i < interfaces.length; i++) {
             addInterface(interfaces[i]);
         }
         for (int i = 0; i < attributes.length; i++) {
             addAttribute(attributes[i]);
         }
         for (int i = 0; i < methods.length; i++) {
             addMethod(methods[i]);
         }
         for (int i = 0; i < fields.length; i++) {
             addField(fields[i]);
         }
     }
 
 
     /***
      * @return the (finally) built up Java class object.
      */
     public JavaClass getJavaClass() {
         int[] interfaces = getInterfaces();
         Field[] fields = getFields();
         Method[] methods = getMethods();
         Attribute[] attributes = getAttributes();
         // Must be last since the above calls may still add something to it
         ConstantPool _cp = this.cp.getFinalConstantPool();
         return new JavaClass(class_name_index, superclass_name_index, file_name, major, minor,
                 access_flags, _cp, interfaces, fields, methods, attributes);
     }
 
 
     /***
      * Add an interface to this class, i.e., this class has to implement it.
      * @param name interface to implement (fully qualified class name)
      */
     public void addInterface( String name ) {
         interface_vec.add(name);
     }
 
 
     /***
      * Remove an interface from this class.
      * @param name interface to remove (fully qualified name)
      */
     public void removeInterface( String name ) {
         interface_vec.remove(name);
     }
 
 
     /***
      * @return major version number of class file
      */
     public int getMajor() {
         return major;
     }
 
 
     /*** Set major version number of class file, default value is 45 (JDK 1.1)
      * @param major major version number
      */
     public void setMajor( int major ) {
         this.major = major;
     }
 
 
     /*** Set minor version number of class file, default value is 3 (JDK 1.1)
      * @param minor minor version number
      */
     public void setMinor( int minor ) {
         this.minor = minor;
     }
 
 
     /***
      * @return minor version number of class file
      */
     public int getMinor() {
         return minor;
     }
 
 
     /***
      * Add an attribute to this class.
      * @param a attribute to add
      */
     public void addAttribute( Attribute a ) {
         attribute_vec.add(a);
     }
 
 
     /***
      * Add a method to this class.
      * @param m method to add
      */
     public void addMethod( Method m ) {
         method_vec.add(m);
     }
 
 
     /***
      * Convenience method.
      *
      * Add an empty constructor to this class that does nothing but calling super().
      * @param access_flags rights for constructor
      */
     public void addEmptyConstructor( int access_flags ) {
         InstructionList il = new InstructionList();
         il.append(InstructionConstants.THIS); // Push `this'
         il.append(new INVOKESPECIAL(cp.addMethodref(super_class_name, "<init>", "()V")));
         il.append(InstructionConstants.RETURN);
         MethodGen mg = new MethodGen(access_flags, Type.VOID, Type.NO_ARGS, null, "<init>",
                 class_name, il, cp);
         mg.setMaxStack(1);
         addMethod(mg.getMethod());
     }
 
 
     /***
      * Add a field to this class.
      * @param f field to add
      */
     public void addField( Field f ) {
         field_vec.add(f);
     }
 
 
     public boolean containsField( Field f ) {
         return field_vec.contains(f);
     }
 
 
     /*** @return field object with given name, or null
      */
     public Field containsField( String name ) {
         for (Iterator e = field_vec.iterator(); e.hasNext();) {
             Field f = (Field) e.next();
             if (f.getName().equals(name)) {
                 return f;
             }
         }
         return null;
     }
 
 
     /*** @return method object with given name and signature, or null
      */
     public Method containsMethod( String name, String signature ) {
         for (Iterator e = method_vec.iterator(); e.hasNext();) {
             Method m = (Method) e.next();
             if (m.getName().equals(name) && m.getSignature().equals(signature)) {
                 return m;
             }
         }
         return null;
     }
 
 
     /***
      * Remove an attribute from this class.
      * @param a attribute to remove
      */
     public void removeAttribute( Attribute a ) {
         attribute_vec.remove(a);
     }
 
 
     /***
      * Remove a method from this class.
      * @param m method to remove
      */
     public void removeMethod( Method m ) {
         method_vec.remove(m);
     }
 
 
     /*** Replace given method with new one. If the old one does not exist
      * add the new_ method to the class anyway.
      */
     public void replaceMethod( Method old, Method new_ ) {
         if (new_ == null) {
             throw new ClassGenException("Replacement method must not be null");
         }
         int i = method_vec.indexOf(old);
         if (i < 0) {
             method_vec.add(new_);
         } else {
             method_vec.set(i, new_);
         }
     }
 
 
     /*** Replace given field with new one. If the old one does not exist
      * add the new_ field to the class anyway.
      */
     public void replaceField( Field old, Field new_ ) {
         if (new_ == null) {
             throw new ClassGenException("Replacement method must not be null");
         }
         int i = field_vec.indexOf(old);
         if (i < 0) {
             field_vec.add(new_);
         } else {
             field_vec.set(i, new_);
         }
     }
 
 
     /***
      * Remove a field to this class.
      * @param f field to remove
      */
     public void removeField( Field f ) {
         field_vec.remove(f);
     }
 
 
     public String getClassName() {
         return class_name;
     }
 
 
     public String getSuperclassName() {
         return super_class_name;
     }
 
 
     public String getFileName() {
         return file_name;
     }
 
 
     public void setClassName( String name ) {
         class_name = name.replace('/', '.');
         class_name_index = cp.addClass(name);
     }
 
 
     public void setSuperclassName( String name ) {
         super_class_name = name.replace('/', '.');
         superclass_name_index = cp.addClass(name);
     }
 
 
     public Method[] getMethods() {
         return (Method[]) method_vec.toArray(new Method[method_vec.size()]);
     }
 
 
     public void setMethods( Method[] methods ) {
         method_vec.clear();
         for (int m = 0; m < methods.length; m++) {
             addMethod(methods[m]);
         }
     }
 
 
     public void setMethodAt( Method method, int pos ) {
         method_vec.set(pos, method);
     }
 
 
     public Method getMethodAt( int pos ) {
         return (Method) method_vec.get(pos);
     }
 
 
     public String[] getInterfaceNames() {
         int size = interface_vec.size();
         String[] interfaces = new String[size];
         interface_vec.toArray(interfaces);
         return interfaces;
     }
 
 
     public int[] getInterfaces() {
         int size = interface_vec.size();
         int[] interfaces = new int[size];
         for (int i = 0; i < size; i++) {
             interfaces[i] = cp.addClass((String) interface_vec.get(i));
         }
         return interfaces;
     }
 
 
     public Field[] getFields() {
         return (Field[]) field_vec.toArray(new Field[field_vec.size()]);
     }
 
 
     public Attribute[] getAttributes() {
         return (Attribute[]) attribute_vec.toArray(new Attribute[attribute_vec.size()]);
     }
 
 
     public ConstantPoolGen getConstantPool() {
         return cp;
     }
 
 
     public void setConstantPool( ConstantPoolGen constant_pool ) {
         cp = constant_pool;
     }
 
 
     public void setClassNameIndex( int class_name_index ) {
         this.class_name_index = class_name_index;
         class_name = cp.getConstantPool().getConstantString(class_name_index,
                 Constants.CONSTANT_Class).replace('/', '.');
     }
 
 
     public void setSuperclassNameIndex( int superclass_name_index ) {
         this.superclass_name_index = superclass_name_index;
         super_class_name = cp.getConstantPool().getConstantString(superclass_name_index,
                 Constants.CONSTANT_Class).replace('/', '.');
     }
 
 
     public int getSuperclassNameIndex() {
         return superclass_name_index;
     }
 
 
     public int getClassNameIndex() {
         return class_name_index;
     }
 
     private ArrayList observers;
 
 
     /*** Add observer for this object.
      */
     public void addObserver( ClassObserver o ) {
         if (observers == null) {
             observers = new ArrayList();
         }
         observers.add(o);
     }
 
 
     /*** Remove observer for this object.
      */
     public void removeObserver( ClassObserver o ) {
         if (observers != null) {
             observers.remove(o);
         }
     }
 
 
     /*** Call notify() method on all observers. This method is not called
      * automatically whenever the state has changed, but has to be
      * called by the user after he has finished editing the object.
      */
     public void update() {
         if (observers != null) {
             for (Iterator e = observers.iterator(); e.hasNext();) {
                 ((ClassObserver) e.next()).notify(this);
             }
         }
     }
 
 
     public Object clone() {
         try {
             return super.clone();
         } catch (CloneNotSupportedException e) {
             System.err.println(e);
             return null;
         }
     }
 
 
     /***
      * @return Comparison strategy object
      */
     public static BCELComparator getComparator() {
         return _cmp;
     }
 
 
     /***
      * @param comparator Comparison strategy object
      */
     public static void setComparator( BCELComparator comparator ) {
         _cmp = comparator;
     }
 
 
     /***
      * Return value as defined by given BCELComparator strategy.
      * By default two ClassGen objects are said to be equal when
      * their class names are equal.
      * 
      * @see java.lang.Object#equals(java.lang.Object)
      */
     public boolean equals( Object obj ) {
         return _cmp.equals(this, obj);
     }
 
 
     /***
      * Return value as defined by given BCELComparator strategy.
      * By default return the hashcode of the class name.
      * 
      * @see java.lang.Object#hashCode()
      */
     public int hashCode() {
         return _cmp.hashCode(this);
     }
 }