    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;
    025
    026import org.apache.bcel.Const;
    027
    028/**
    029 * Entry of the parameters table.
    030 * <p>
    031 * Implements {@link Node} as of 6.7.0.
    032 * </p>
    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 MethodParameter implements Cloneable, Node {
    039
    040    /** Index of the CONSTANT_Utf8_info structure in the constant_pool table representing the name of the parameter */
    041    private int nameIndex;
    042
    043    /** The access flags */
    044    private int accessFlags;
    045
    046    /**
    047     * Constructs a MethodParameter.
    048     */
    049    public MethodParameter() {
    050    }
    051
    052    /**
    053     * Constructs an instance from a DataInput.
    054     *
    055     * @param input Input stream.
    056     * @throws IOException if an I/O error occurs.
    057     * @throws ClassFormatException if a class is malformed or cannot be interpreted as a class file
    058     */
    059    MethodParameter(final DataInput input) throws IOException {
    060        nameIndex = input.readUnsignedShort();
    061        accessFlags = input.readUnsignedShort();
    062    }
    063
    064    @Override
    065    public void accept(final Visitor v) {
    066        v.visitMethodParameter(this);
    067    }
    068
    069    /**
    070     * Creates a deep copy of this object.
    071     *
    072     * @return deep copy of this object.
    073     */
    074    public MethodParameter copy() {
    075        try {
    076            return (MethodParameter) clone();
    077        } catch (final CloneNotSupportedException e) {
    078            // TODO should this throw?
    079        }
    080        return null;
    081    }
    082
    083    /**
    084     * Dumps object to file stream on binary format.
    085     *
    086     * @param file Output file stream.
    087     * @throws IOException if an I/O error occurs.
    088     */
    089    public final void dump(final DataOutputStream file) throws IOException {
    090        file.writeShort(nameIndex);
    091        file.writeShort(accessFlags);
    092    }
    093
    094    /**
    095     * Gets the access flags.
    096     *
    097     * @return the access flags.
    098     */
    099    public int getAccessFlags() {
    100        return accessFlags;
    101    }
    102
    103    /**
    104     * Gets the name index.
    105     *
    106     * @return the name index.
    107     */
    108    public int getNameIndex() {
    109        return nameIndex;
    110    }
    111
    112    /**
    113     * Gets the name of the parameter.
    114     *
    115     * @param constantPool The pool to query.
    116     * @return Constant from the given pool.
    117     */
    118    public String getParameterName(final ConstantPool constantPool) {
    119        if (nameIndex == 0) {
    120            return null;
    121        }
    122        return constantPool.getConstantUtf8(nameIndex).getBytes();
    123    }
    124
    125    /**
    126     * Checks if this parameter is final.
    127     *
    128     * @return true if this parameter is final.
    129     */
    130    public boolean isFinal() {
    131        return (accessFlags & Const.ACC_FINAL) != 0;
    132    }
    133
    134    /**
    135     * Checks if this parameter is mandated.
    136     *
    137     * @return true if this parameter is mandated.
    138     */
    139    public boolean isMandated() {
    140        return (accessFlags & Const.ACC_MANDATED) != 0;
    141    }
    142
    143    /**
    144     * Checks if this parameter is synthetic.
    145     *
    146     * @return true if this parameter is synthetic.
    147     */
    148    public boolean isSynthetic() {
    149        return (accessFlags & Const.ACC_SYNTHETIC) != 0;
    150    }
    151
    152    /**
    153     * Sets the access flags.
    154     *
    155     * @param accessFlags the access flags.
    156     */
    157    public void setAccessFlags(final int accessFlags) {
    158        this.accessFlags = accessFlags;
    159    }
    160
    161    /**
    162     * Sets the name index.
    163     *
    164     * @param nameIndex the name index.
    165     */
    166    public void setNameIndex(final int nameIndex) {
    167        this.nameIndex = nameIndex;
    168    }
    169}