/*
    * 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
    *
   *   https://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 || getClass() != obj.getClass() || hashCode() != obj.hashCode()) {
              return false;
          }
          final CPRef other = (CPRef) obj;
          return Objects.equals(className, other.className)
                  && Objects.equals(nameAndType, other.nameAndType);
      }
  
      @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) {
              final String type;
              if (getTag() == CP_Fieldref) {
                  type = "FieldRef"; //$NON-NLS-1$
              } else if (getTag() == CP_Methodref) {
                  type = "MethoddRef"; //$NON-NLS-1$
              } else if (getTag() == 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);
     }
 
 }