/*
    * 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.bcel.classfile;
  
  import java.io.DataInput;
  import java.io.DataOutputStream;
  import java.io.IOException;
  import java.util.Arrays;
  import java.util.Iterator;
  import java.util.stream.Stream;
  
  import org.apache.bcel.Const;
  import org.apache.bcel.util.Args;
  
  /**
   * This class represents a MethodParameters attribute.
   *
   * @see <a href="https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.7.24"> The class File Format :
   *      The MethodParameters Attribute</a>
   * @since 6.0
   */
  public class MethodParameters extends Attribute implements Iterable<MethodParameter> {
  
      /**
       * Empty array.
       */
      private static final MethodParameter[] EMPTY_ARRAY = {};
  
      private MethodParameter[] parameters = EMPTY_ARRAY;
  
      MethodParameters(final int nameIndex, final int length, final DataInput input, final ConstantPool constantPool) throws IOException {
          super(Const.ATTR_METHOD_PARAMETERS, nameIndex, length, constantPool);
          final int parameterCount = input.readUnsignedByte();
          parameters = new MethodParameter[parameterCount];
          for (int i = 0; i < parameterCount; i++) {
              parameters[i] = new MethodParameter(input);
          }
      }
  
      @Override
      public void accept(final Visitor v) {
          v.visitMethodParameters(this);
      }
  
      @Override
      public Attribute copy(final ConstantPool constantPool) {
          final MethodParameters c = (MethodParameters) clone();
          c.parameters = new MethodParameter[parameters.length];
          Arrays.setAll(c.parameters, i -> parameters[i].copy());
          c.setConstantPool(constantPool);
          return c;
      }
  
      /**
       * Dumps method parameters attribute to file stream in binary format.
       *
       * @param file Output file stream.
       * @throws IOException Thrown if an I/O error occurs.
       */
      @Override
      public void dump(final DataOutputStream file) throws IOException {
          super.dump(file);
          file.writeByte(Args.requireU1(parameters.length, "parameters.length"));
          for (final MethodParameter parameter : parameters) {
              parameter.dump(file);
          }
      }
  
      /**
       * Gets the method parameters.
       *
       * @return The method parameters.
       */
      public MethodParameter[] getParameters() {
          return parameters;
      }
  
      @Override
      public Iterator<MethodParameter> iterator() {
          return Stream.of(parameters).iterator();
      }
  
     /**
      * Sets the method parameters.
      *
      * @param parameters The method parameters to set.
      */
     public void setParameters(final MethodParameter[] parameters) {
         this.parameters = parameters != null ? parameters : EMPTY_ARRAY;
     }
 }