    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 * This class represents an entry in the provides table of the Module attribute. Each entry describes a service
    028 * implementation that the parent module provides.
    029 *
    030 * @see Module
    031 * @since 6.4.0
    032 */
    033public final class ModuleProvides implements Cloneable, Node {
    034
    035    private static String getImplementationClassNameAtIndex(final ConstantPool constantPool, final int index, final boolean compactClassName) {
    036        final String className = constantPool.getConstantString(index, Const.CONSTANT_Class);
    037        if (compactClassName) {
    038            return Utility.compactClassName(className, false);
    039        }
    040        return className;
    041    }
    042    private final int providesIndex; // points to CONSTANT_Class_info
    043    private final int providesWithCount;
    044
    045    private final int[] providesWithIndex; // points to CONSTANT_Class_info
    046
    047    /**
    048     * Constructs object from file stream.
    049     *
    050     * @param file Input stream
    051     * @throws IOException if an I/O Exception occurs in readUnsignedShort
    052     */
    053    ModuleProvides(final DataInput file) throws IOException {
    054        providesIndex = file.readUnsignedShort();
    055        providesWithCount = file.readUnsignedShort();
    056        providesWithIndex = new int[providesWithCount];
    057        for (int i = 0; i < providesWithCount; i++) {
    058            providesWithIndex[i] = file.readUnsignedShort();
    059        }
    060    }
    061
    062    /**
    063     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
    064     * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
    065     *
    066     * @param v Visitor object
    067     */
    068    @Override
    069    public void accept(final Visitor v) {
    070        v.visitModuleProvides(this);
    071    }
    072
    073    /**
    074     * @return deep copy of this object
    075     */
    076    public ModuleProvides copy() {
    077        try {
    078            return (ModuleProvides) clone();
    079        } catch (final CloneNotSupportedException e) {
    080            // TODO should this throw?
    081        }
    082        return null;
    083    }
    084
    085    /**
    086     * Dump table entry to file stream in binary format.
    087     *
    088     * @param file Output file stream
    089     * @throws IOException if an I/O Exception occurs in writeShort
    090     */
    091    public void dump(final DataOutputStream file) throws IOException {
    092        file.writeShort(providesIndex);
    093        file.writeShort(providesWithCount);
    094        for (final int entry : providesWithIndex) {
    095            file.writeShort(entry);
    096        }
    097    }
    098
    099    /**
    100     * Gets the array of implementation class names for this ModuleProvides.
    101     * @param constantPool Array of constants usually obtained from the ClassFile object
    102     * @param compactClassName false for original constant pool value, true to replace '/' with '.'
    103     * @return array of implementation class names
    104     * @since 6.10.0
    105     */
    106    public String[] getImplementationClassNames(final ConstantPool constantPool, final boolean compactClassName) {
    107        final String[] implementationClassNames = new String[providesWithCount];
    108        for (int i = 0; i < providesWithCount; i++) {
    109            implementationClassNames[i] = getImplementationClassNameAtIndex(constantPool, providesWithIndex[i], compactClassName);
    110        }
    111        return implementationClassNames;
    112    }
    113
    114    /**
    115     * Gets the interface name for this ModuleProvides.
    116     * @param constantPool Array of constants usually obtained from the ClassFile object
    117     * @return interface name
    118     * @since 6.10.0
    119     */
    120    public String getInterfaceName(final ConstantPool constantPool) {
    121        return constantPool.constantToString(providesIndex, Const.CONSTANT_Class);
    122    }
    123
    124    /**
    125     * @return String representation
    126     */
    127    @Override
    128    public String toString() {
    129        return "provides(" + providesIndex + ", " + providesWithCount + ", ...)";
    130    }
    131
    132    /**
    133     * @return Resolved string representation
    134     */
    135    public String toString(final ConstantPool constantPool) {
    136        final StringBuilder buf = new StringBuilder();
    137        final String interfaceName = getInterfaceName(constantPool);
    138        buf.append(interfaceName);
    139        buf.append(", with(").append(providesWithCount).append("):\n");
    140        for (final int index : providesWithIndex) {
    141            final String className = getImplementationClassNameAtIndex(constantPool, index, true);
    142            buf.append("      ").append(className).append("\n");
    143        }
    144        return buf.substring(0, buf.length() - 1); // remove the last newline
    145    }
    146}