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 dataInput Input stream.
053     * @throws IOException if an I/O Exception occurs in readUnsignedShort.
054     */
055    ModuleProvides(final DataInput dataInput) throws IOException {
056        providesIndex = dataInput.readUnsignedShort();
057        providesWithIndex = ClassParser.readU2U2Table(dataInput);
058        providesWithCount = providesWithIndex.length;
059    }
060
061    /**
062     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
063     * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
064     *
065     * @param v Visitor object.
066     */
067    @Override
068    public void accept(final Visitor v) {
069        v.visitModuleProvides(this);
070    }
071
072    /**
073     * @return deep copy of this object.
074     */
075    public ModuleProvides copy() {
076        try {
077            return (ModuleProvides) clone();
078        } catch (final CloneNotSupportedException e) {
079            // TODO should this throw?
080        }
081        return null;
082    }
083
084    /**
085     * Dumps table entry to file stream in binary format.
086     *
087     * @param file Output file stream.
088     * @throws IOException if an I/O Exception occurs in writeShort.
089     */
090    public void dump(final DataOutputStream file) throws IOException {
091        file.writeShort(providesIndex);
092        file.writeShort(providesWithCount);
093        for (final int entry : providesWithIndex) {
094            file.writeShort(entry);
095        }
096    }
097
098    /**
099     * Gets the array of implementation class names for this ModuleProvides.
100     *
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     *
117     * @param constantPool Array of constants usually obtained from the ClassFile object.
118     * @return interface name.
119     * @since 6.10.0
120     */
121    public String getInterfaceName(final ConstantPool constantPool) {
122        return constantPool.constantToString(providesIndex, Const.CONSTANT_Class);
123    }
124
125    /**
126     * @return String representation.
127     */
128    @Override
129    public String toString() {
130        return "provides(" + providesIndex + ", " + providesWithCount + ", ...)";
131    }
132
133    /**
134     * @return Resolved string representation.
135     */
136    public String toString(final ConstantPool constantPool) {
137        final StringBuilder buf = new StringBuilder();
138        final String interfaceName = getInterfaceName(constantPool);
139        buf.append(interfaceName);
140        buf.append(", with(").append(providesWithCount).append("):\n");
141        for (final int index : providesWithIndex) {
142            final String className = getImplementationClassNameAtIndex(constantPool, index, true);
143            buf.append("      ").append(className).append("\n");
144        }
145        return buf.substring(0, buf.length() - 1); // remove the last newline
146    }
147}