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;
030import org.apache.bcel.util.Args;
031
032/**
033 * This class represents a MethodParameters attribute.
034 *
035 * @see <a href="https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.7.24"> The class File Format :
036 *      The MethodParameters Attribute</a>
037 * @since 6.0
038 */
039public class MethodParameters extends Attribute implements Iterable<MethodParameter> {
040
041    /**
042     * Empty array.
043     */
044    private static final MethodParameter[] EMPTY_ARRAY = {};
045
046    private MethodParameter[] parameters = EMPTY_ARRAY;
047
048    MethodParameters(final int nameIndex, final int length, final DataInput input, final ConstantPool constantPool) throws IOException {
049        super(Const.ATTR_METHOD_PARAMETERS, nameIndex, length, constantPool);
050        final int parameterCount = input.readUnsignedByte();
051        parameters = new MethodParameter[parameterCount];
052        for (int i = 0; i < parameterCount; i++) {
053            parameters[i] = new MethodParameter(input);
054        }
055    }
056
057    @Override
058    public void accept(final Visitor v) {
059        v.visitMethodParameters(this);
060    }
061
062    @Override
063    public Attribute copy(final ConstantPool constantPool) {
064        final MethodParameters c = (MethodParameters) clone();
065        c.parameters = new MethodParameter[parameters.length];
066        Arrays.setAll(c.parameters, i -> parameters[i].copy());
067        c.setConstantPool(constantPool);
068        return c;
069    }
070
071    /**
072     * Dumps method parameters attribute to file stream in binary format.
073     *
074     * @param file Output file stream.
075     * @throws IOException Thrown if an I/O error occurs.
076     */
077    @Override
078    public void dump(final DataOutputStream file) throws IOException {
079        super.dump(file);
080        file.writeByte(Args.requireU1(parameters.length, "parameters.length"));
081        for (final MethodParameter parameter : parameters) {
082            parameter.dump(file);
083        }
084    }
085
086    /**
087     * Gets the method parameters.
088     *
089     * @return The method parameters.
090     */
091    public MethodParameter[] getParameters() {
092        return parameters;
093    }
094
095    @Override
096    public Iterator<MethodParameter> iterator() {
097        return Stream.of(parameters).iterator();
098    }
099
100    /**
101     * Sets the method parameters.
102     *
103     * @param parameters The method parameters to set.
104     */
105    public void setParameters(final MethodParameter[] parameters) {
106        this.parameters = parameters != null ? parameters : EMPTY_ARRAY;
107    }
108}