/*
    *  Licensed to the Apache Software Foundation (ASF) under one or more
    *  contributor license agreements.  See the NOTICE file distributed with
    *  this work for additional information regarding copyright ownership.
    *  The ASF licenses this file to You 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.commons.compress.harmony.unpack200.bytecode;
  
  import java.io.DataOutputStream;
  import java.io.IOException;
  import java.util.Objects;
  
  /**
   * Abstract superclass for reference constant pool entries, such as a method or field reference.
   */
  public abstract class CPRef extends ConstantPoolEntry {
  
      CPClass className;
      transient int classNameIndex;
  
      protected CPNameAndType nameAndType;
      transient int nameAndTypeIndex;
  
      protected String cachedToString;
  
      /**
       * Constructs a new CPRef.
       *
       * @param type        TODO
       * @param className   TODO
       * @param descriptor  TODO
       * @param globalIndex index in CpBands
       * @throws NullPointerException if descriptor or className is null
       */
      public CPRef(final byte type, final CPClass className, final CPNameAndType descriptor, final int globalIndex) {
          super(type, globalIndex);
          this.className = Objects.requireNonNull(className, "className");
          this.nameAndType = Objects.requireNonNull(descriptor, "descriptor");
      }
  
      @Override
      public boolean equals(final Object obj) {
          if (this == obj) {
              return true;
          }
          if (obj == null) {
              return false;
          }
          if (getClass() != obj.getClass()) {
              return false;
          }
          if (this.hashCode() != obj.hashCode()) {
              return false;
          }
          final CPRef other = (CPRef) obj;
          if (!className.equals(other.className)) {
              return false;
          }
          if (!nameAndType.equals(other.nameAndType)) {
              return false;
          }
          return true;
      }
  
      @Override
      protected ClassFileEntry[] getNestedClassFileEntries() {
          final ClassFileEntry[] entries = new ClassFileEntry[2];
          entries[0] = className;
          entries[1] = nameAndType;
          return entries;
      }
  
      @Override
      protected void resolve(final ClassConstantPool pool) {
          super.resolve(pool);
          nameAndTypeIndex = pool.indexOf(nameAndType);
          classNameIndex = pool.indexOf(className);
      }
  
      @Override
      public String toString() {
          if (cachedToString == null) {
              String type;
              if (getTag() == ConstantPoolEntry.CP_Fieldref) {
                  type = "FieldRef"; //$NON-NLS-1$
              } else if (getTag() == ConstantPoolEntry.CP_Methodref) {
                  type = "MethoddRef"; //$NON-NLS-1$
              } else if (getTag() == ConstantPoolEntry.CP_InterfaceMethodref) {
                  type = "InterfaceMethodRef"; //$NON-NLS-1$
             } else {
                 type = "unknown"; //$NON-NLS-1$
             }
             cachedToString = type + ": " + className + "#" + nameAndType; //$NON-NLS-1$ //$NON-NLS-2$
         }
         return cachedToString;
     }
 
     @Override
     protected void writeBody(final DataOutputStream dos) throws IOException {
         dos.writeShort(classNameIndex);
         dos.writeShort(nameAndTypeIndex);
     }
 
 }