    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 *  Unless required by applicable law or agreed to in writing, software
    012 *  distributed under the License is distributed on an "AS IS" BASIS,
    013 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 *  See the License for the specific language governing permissions and
    015 *  limitations under the License.
    016 */
    017
    018package org.apache.bcel.classfile;
    019
    020import java.io.DataInput;
    021import java.io.DataOutputStream;
    022import java.io.IOException;
    023
    024import org.apache.bcel.Const;
    025
    026/**
    027 * Entry of the parameters table.
    028 * <p>
    029 * Implements {@link Node} as of 6.7.0.
    030 * </p>
    031 *
    032 * @see <a href="https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.7.24"> The class File Format :
    033 *      The MethodParameters Attribute</a>
    034 * @since 6.0
    035 */
    036public class MethodParameter implements Cloneable, Node {
    037
    038    /** Index of the CONSTANT_Utf8_info structure in the constant_pool table representing the name of the parameter */
    039    private int nameIndex;
    040
    041    /** The access flags */
    042    private int accessFlags;
    043
    044    public MethodParameter() {
    045    }
    046
    047    /**
    048     * Constructs an instance from a DataInput.
    049     *
    050     * @param input Input stream
    051     * @throws IOException if an I/O error occurs.
    052     * @throws ClassFormatException if a class is malformed or cannot be interpreted as a class file
    053     */
    054    MethodParameter(final DataInput input) throws IOException {
    055        nameIndex = input.readUnsignedShort();
    056        accessFlags = input.readUnsignedShort();
    057    }
    058
    059    @Override
    060    public void accept(final Visitor v) {
    061        v.visitMethodParameter(this);
    062    }
    063
    064    /**
    065     * @return deep copy of this object
    066     */
    067    public MethodParameter copy() {
    068        try {
    069            return (MethodParameter) clone();
    070        } catch (final CloneNotSupportedException e) {
    071            // TODO should this throw?
    072        }
    073        return null;
    074    }
    075
    076    /**
    077     * Dumps object to file stream on binary format.
    078     *
    079     * @param file Output file stream
    080     * @throws IOException if an I/O error occurs.
    081     */
    082    public final void dump(final DataOutputStream file) throws IOException {
    083        file.writeShort(nameIndex);
    084        file.writeShort(accessFlags);
    085    }
    086
    087    public int getAccessFlags() {
    088        return accessFlags;
    089    }
    090
    091    public int getNameIndex() {
    092        return nameIndex;
    093    }
    094
    095    /**
    096     * Gets the name of the parameter.
    097     *
    098     * @param constantPool The pool to query.
    099     * @return Constant from the given pool.
    100     */
    101    public String getParameterName(final ConstantPool constantPool) {
    102        if (nameIndex == 0) {
    103            return null;
    104        }
    105        return constantPool.getConstantUtf8(nameIndex).getBytes();
    106    }
    107
    108    public boolean isFinal() {
    109        return (accessFlags & Const.ACC_FINAL) != 0;
    110    }
    111
    112    public boolean isMandated() {
    113        return (accessFlags & Const.ACC_MANDATED) != 0;
    114    }
    115
    116    public boolean isSynthetic() {
    117        return (accessFlags & Const.ACC_SYNTHETIC) != 0;
    118    }
    119
    120    public void setAccessFlags(final int accessFlags) {
    121        this.accessFlags = accessFlags;
    122    }
    123
    124    public void setNameIndex(final int nameIndex) {
    125        this.nameIndex = nameIndex;
    126    }
    127}