    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 * This class represents an entry in the provides table of the Module attribute. Each entry describes a service
    030 * implementation that the parent module provides.
    031 *
    032 * @see Module
    033 * @since 6.4.0
    034 */
    035public final class ModuleProvides implements Cloneable, Node {
    036
    037    private static String getImplementationClassNameAtIndex(final ConstantPool constantPool, final int index, final boolean compactClassName) {
    038        final String className = constantPool.getConstantString(index, Const.CONSTANT_Class);
    039        if (compactClassName) {
    040            return Utility.compactClassName(className, false);
    041        }
    042        return className;
    043    }
    044    private final int providesIndex; // points to CONSTANT_Class_info
    045    private final int providesWithCount;
    046
    047    private final int[] providesWithIndex; // points to CONSTANT_Class_info
    048
    049    /**
    050     * Constructs object from file stream.
    051     *
    052     * @param file Input stream
    053     * @throws IOException if an I/O Exception occurs in readUnsignedShort
    054     */
    055    ModuleProvides(final DataInput file) throws IOException {
    056        providesIndex = file.readUnsignedShort();
    057        providesWithCount = file.readUnsignedShort();
    058        providesWithIndex = new int[providesWithCount];
    059        for (int i = 0; i < providesWithCount; i++) {
    060            providesWithIndex[i] = file.readUnsignedShort();
    061        }
    062    }
    063
    064    /**
    065     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
    066     * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
    067     *
    068     * @param v Visitor object
    069     */
    070    @Override
    071    public void accept(final Visitor v) {
    072        v.visitModuleProvides(this);
    073    }
    074
    075    /**
    076     * @return deep copy of this object
    077     */
    078    public ModuleProvides copy() {
    079        try {
    080            return (ModuleProvides) clone();
    081        } catch (final CloneNotSupportedException e) {
    082            // TODO should this throw?
    083        }
    084        return null;
    085    }
    086
    087    /**
    088     * Dump table entry to file stream in binary format.
    089     *
    090     * @param file Output file stream
    091     * @throws IOException if an I/O Exception occurs in writeShort
    092     */
    093    public void dump(final DataOutputStream file) throws IOException {
    094        file.writeShort(providesIndex);
    095        file.writeShort(providesWithCount);
    096        for (final int entry : providesWithIndex) {
    097            file.writeShort(entry);
    098        }
    099    }
    100
    101    /**
    102     * Gets the array of implementation class names for this ModuleProvides.
    103     * @param constantPool Array of constants usually obtained from the ClassFile object
    104     * @param compactClassName false for original constant pool value, true to replace '/' with '.'
    105     * @return array of implementation class names
    106     * @since 6.10.0
    107     */
    108    public String[] getImplementationClassNames(final ConstantPool constantPool, final boolean compactClassName) {
    109        final String[] implementationClassNames = new String[providesWithCount];
    110        for (int i = 0; i < providesWithCount; i++) {
    111            implementationClassNames[i] = getImplementationClassNameAtIndex(constantPool, providesWithIndex[i], compactClassName);
    112        }
    113        return implementationClassNames;
    114    }
    115
    116    /**
    117     * Gets the interface name for this ModuleProvides.
    118     * @param constantPool Array of constants usually obtained from the ClassFile object
    119     * @return interface name
    120     * @since 6.10.0
    121     */
    122    public String getInterfaceName(final ConstantPool constantPool) {
    123        return constantPool.constantToString(providesIndex, Const.CONSTANT_Class);
    124    }
    125
    126    /**
    127     * @return String representation
    128     */
    129    @Override
    130    public String toString() {
    131        return "provides(" + providesIndex + ", " + providesWithCount + ", ...)";
    132    }
    133
    134    /**
    135     * @return Resolved string representation
    136     */
    137    public String toString(final ConstantPool constantPool) {
    138        final StringBuilder buf = new StringBuilder();
    139        final String interfaceName = getInterfaceName(constantPool);
    140        buf.append(interfaceName);
    141        buf.append(", with(").append(providesWithCount).append("):\n");
    142        for (final int index : providesWithIndex) {
    143            final String className = getImplementationClassNameAtIndex(constantPool, index, true);
    144            buf.append("      ").append(className).append("\n");
    145        }
    146        return buf.substring(0, buf.length() - 1); // remove the last newline
    147    }
    148}