001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *   https://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019
020package org.apache.bcel.classfile;
021
022import java.io.DataInput;
023import java.io.DataOutputStream;
024import java.io.IOException;
025import java.util.Arrays;
026import java.util.Iterator;
027import java.util.stream.Stream;
028
029import org.apache.bcel.Const;
030
031/**
032 * This class represents a MethodParameters attribute.
033 *
034 * @see <a href="https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.7.24"> The class File Format :
035 *      The MethodParameters Attribute</a>
036 * @since 6.0
037 */
038public class MethodParameters extends Attribute implements Iterable<MethodParameter> {
039
040    /**
041     * Empty array.
042     */
043    private static final MethodParameter[] EMPTY_ARRAY = {};
044
045    private MethodParameter[] parameters = EMPTY_ARRAY;
046
047    MethodParameters(final int nameIndex, final int length, final DataInput input, final ConstantPool constantPool) throws IOException {
048        super(Const.ATTR_METHOD_PARAMETERS, nameIndex, length, constantPool);
049        final int parameterCount = input.readUnsignedByte();
050        parameters = new MethodParameter[parameterCount];
051        for (int i = 0; i < parameterCount; i++) {
052            parameters[i] = new MethodParameter(input);
053        }
054    }
055
056    @Override
057    public void accept(final Visitor v) {
058        v.visitMethodParameters(this);
059    }
060
061    @Override
062    public Attribute copy(final ConstantPool constantPool) {
063        final MethodParameters c = (MethodParameters) clone();
064        c.parameters = new MethodParameter[parameters.length];
065        Arrays.setAll(c.parameters, i -> parameters[i].copy());
066        c.setConstantPool(constantPool);
067        return c;
068    }
069
070    /**
071     * Dump method parameters attribute to file stream in binary format.
072     *
073     * @param file Output file stream
074     * @throws IOException if an I/O error occurs.
075     */
076    @Override
077    public void dump(final DataOutputStream file) throws IOException {
078        super.dump(file);
079        file.writeByte(parameters.length);
080        for (final MethodParameter parameter : parameters) {
081            parameter.dump(file);
082        }
083    }
084
085    public MethodParameter[] getParameters() {
086        return parameters;
087    }
088
089    @Override
090    public Iterator<MethodParameter> iterator() {
091        return Stream.of(parameters).iterator();
092    }
093
094    public void setParameters(final MethodParameter[] parameters) {
095        this.parameters = parameters != null ? parameters : EMPTY_ARRAY;
096    }
097}