/*
    *  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.nio.charset.StandardCharsets;
  import java.util.Objects;
  
  /**
   * UTF8 constant pool entry, used for storing long Strings.
   */
  public class CPUTF8 extends ConstantPoolEntry {
  
      private final String utf8;
  
      private boolean hashCodeComputed;
  
      private int cachedHashCode;
  
      public CPUTF8(final String string) {
          this(string, -1);
      }
  
      /**
       * Creates a new CPUTF8 instance
       *
       * @param utf8        TODO
       * @param globalIndex - index in CpBands
       * @throws NullPointerException if utf8 is null
       */
      public CPUTF8(final String utf8, final int globalIndex) {
          super(ConstantPoolEntry.CP_UTF8, globalIndex);
          this.utf8 = Objects.requireNonNull(utf8, "utf8");
      }
  
      @Override
      public boolean equals(final Object obj) {
          if (this == obj) {
              return true;
          }
          if (obj == null) {
              return false;
          }
          if (this.getClass() != obj.getClass()) {
              return false;
          }
          final CPUTF8 other = (CPUTF8) obj;
          return utf8.equals(other.utf8);
      }
  
      private void generateHashCode() {
          hashCodeComputed = true;
          final int PRIME = 31;
          cachedHashCode = PRIME + utf8.hashCode();
      }
  
      @Override
      public int hashCode() {
          if (!hashCodeComputed) {
              generateHashCode();
          }
          return cachedHashCode;
      }
  
      public void setGlobalIndex(final int index) {
          globalIndex = index;
      }
  
      @Override
      public String toString() {
          return StandardCharsets.UTF_8.name() + ":" + utf8;
      }
  
      public String underlyingString() {
          return utf8;
      }
  
      @Override
      protected void writeBody(final DataOutputStream dos) throws IOException {
          dos.writeUTF(utf8);
      }
  }