    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.
    028 * Each entry describes a service 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 final int providesIndex;  // points to CONSTANT_Class_info
    036    private final int providesWithCount;
    037    private final int[] providesWithIndex;  // points to CONSTANT_Class_info
    038
    039
    040    /**
    041     * Construct object from file stream.
    042     *
    043     * @param file Input stream
    044     * @throws IOException if an I/O Exception occurs in readUnsignedShort
    045     */
    046    ModuleProvides(final DataInput file) throws IOException {
    047        providesIndex = file.readUnsignedShort();
    048        providesWithCount = file.readUnsignedShort();
    049        providesWithIndex = new int[providesWithCount];
    050        for (int i = 0; i < providesWithCount; i++) {
    051            providesWithIndex[i] = file.readUnsignedShort();
    052        }
    053    }
    054
    055
    056    /**
    057     * Called by objects that are traversing the nodes of the tree implicitely
    058     * defined by the contents of a Java class. I.e., the hierarchy of methods,
    059     * fields, attributes, etc. spawns a tree of objects.
    060     *
    061     * @param v Visitor object
    062     */
    063    @Override
    064    public void accept( final Visitor v ) {
    065        v.visitModuleProvides(this);
    066    }
    067
    068    // TODO add more getters and setters?
    069
    070    /**
    071     * Dump table entry to file stream in binary format.
    072     *
    073     * @param file Output file stream
    074     * @throws IOException if an I/O Exception occurs in writeShort
    075     */
    076    public void dump( final DataOutputStream file ) throws IOException {
    077        file.writeShort(providesIndex);
    078        file.writeShort(providesWithCount);
    079        for (final int entry : providesWithIndex) {
    080            file.writeShort(entry);
    081        }
    082    }
    083
    084
    085    /**
    086     * @return String representation
    087     */
    088    @Override
    089    public String toString() {
    090        return "provides(" + providesIndex + ", " + providesWithCount + ", ...)";
    091    }
    092
    093
    094    /**
    095     * @return Resolved string representation
    096     */
    097    public String toString( final ConstantPool constant_pool ) {
    098        final StringBuilder buf = new StringBuilder();
    099        final String interface_name = constant_pool.constantToString(providesIndex, Const.CONSTANT_Class);
    100        buf.append(Utility.compactClassName(interface_name, false));
    101        buf.append(", with(").append(providesWithCount).append("):\n");
    102        for (final int index : providesWithIndex) {
    103            final String class_name = constant_pool.getConstantString(index, Const.CONSTANT_Class);
    104            buf.append("      ").append(Utility.compactClassName(class_name, false)).append("\n");
    105        }
    106        return buf.substring(0, buf.length()-1); // remove the last newline
    107    }
    108
    109
    110    /**
    111     * @return deep copy of this object
    112     */
    113    public ModuleProvides copy() {
    114        try {
    115            return (ModuleProvides) clone();
    116        } catch (final CloneNotSupportedException e) {
    117            // TODO should this throw?
    118        }
    119        return null;
    120    }
    121}