    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;
    025import java.util.Iterator;
    026import java.util.stream.Stream;
    027
    028import org.apache.bcel.Const;
    029
    030/**
    031 * This class represents a BootstrapMethods attribute.
    032 *
    033 * @see <a href="https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.7.23"> The class File Format :
    034 *      The BootstrapMethods Attribute</a>
    035 * @since 6.0
    036 */
    037public class BootstrapMethods extends Attribute implements Iterable<BootstrapMethod> {
    038
    039    private BootstrapMethod[] bootstrapMethods; // TODO this could be made final (setter is not used)
    040
    041    /**
    042     * Initialize from another object. Note that both objects use the same references (shallow copy). Use clone() for a
    043     * physical copy.
    044     *
    045     * @param c Source to copy.
    046     */
    047    public BootstrapMethods(final BootstrapMethods c) {
    048        this(c.getNameIndex(), c.getLength(), c.getBootstrapMethods(), c.getConstantPool());
    049    }
    050
    051    /**
    052     * @param nameIndex Index in constant pool to CONSTANT_Utf8
    053     * @param length Content length in bytes
    054     * @param bootstrapMethods array of bootstrap methods
    055     * @param constantPool Array of constants
    056     */
    057    public BootstrapMethods(final int nameIndex, final int length, final BootstrapMethod[] bootstrapMethods, final ConstantPool constantPool) {
    058        super(Const.ATTR_BOOTSTRAP_METHODS, nameIndex, length, constantPool);
    059        setBootstrapMethods(bootstrapMethods);
    060    }
    061
    062    /**
    063     * Constructs object from Input stream.
    064     *
    065     * @param nameIndex Index in constant pool to CONSTANT_Utf8
    066     * @param length Content length in bytes
    067     * @param input Input stream
    068     * @param constantPool Array of constants
    069     * @throws IOException if an I/O error occurs.
    070     */
    071    BootstrapMethods(final int nameIndex, final int length, final DataInput input, final ConstantPool constantPool) throws IOException {
    072        this(nameIndex, length, (BootstrapMethod[]) null, constantPool);
    073
    074        final int numBootstrapMethods = input.readUnsignedShort();
    075        bootstrapMethods = new BootstrapMethod[numBootstrapMethods];
    076        for (int i = 0; i < numBootstrapMethods; i++) {
    077            bootstrapMethods[i] = new BootstrapMethod(input);
    078        }
    079    }
    080
    081    /**
    082     * @param v Visitor object
    083     */
    084    @Override
    085    public void accept(final Visitor v) {
    086        v.visitBootstrapMethods(this);
    087    }
    088
    089    /**
    090     * @return deep copy of this attribute
    091     */
    092    @Override
    093    public BootstrapMethods copy(final ConstantPool constantPool) {
    094        final BootstrapMethods c = (BootstrapMethods) clone();
    095        c.bootstrapMethods = new BootstrapMethod[bootstrapMethods.length];
    096
    097        for (int i = 0; i < bootstrapMethods.length; i++) {
    098            c.bootstrapMethods[i] = bootstrapMethods[i].copy();
    099        }
    100        c.setConstantPool(constantPool);
    101        return c;
    102    }
    103
    104    /**
    105     * Dump bootstrap methods attribute to file stream in binary format.
    106     *
    107     * @param file Output file stream
    108     * @throws IOException if an I/O error occurs.
    109     */
    110    @Override
    111    public final void dump(final DataOutputStream file) throws IOException {
    112        super.dump(file);
    113
    114        file.writeShort(bootstrapMethods.length);
    115        for (final BootstrapMethod bootstrapMethod : bootstrapMethods) {
    116            bootstrapMethod.dump(file);
    117        }
    118    }
    119
    120    /**
    121     * @return array of bootstrap method "records"
    122     */
    123    public final BootstrapMethod[] getBootstrapMethods() {
    124        return bootstrapMethods;
    125    }
    126
    127    @Override
    128    public Iterator<BootstrapMethod> iterator() {
    129        return Stream.of(bootstrapMethods).iterator();
    130    }
    131
    132    /**
    133     * @param bootstrapMethods the array of bootstrap methods
    134     */
    135    public final void setBootstrapMethods(final BootstrapMethod[] bootstrapMethods) {
    136        this.bootstrapMethods = bootstrapMethods != null ? bootstrapMethods : BootstrapMethod.EMPTY_ARRAY;
    137    }
    138
    139    /**
    140     * @return String representation.
    141     */
    142    @Override
    143    public final String toString() {
    144        final StringBuilder buf = new StringBuilder();
    145        buf.append("BootstrapMethods(");
    146        buf.append(bootstrapMethods.length);
    147        buf.append("):");
    148        for (int i = 0; i < bootstrapMethods.length; i++) {
    149            buf.append("\n");
    150            final int start = buf.length();
    151            buf.append("  ").append(i).append(": ");
    152            final int indentCount = buf.length() - start;
    153            final String[] lines = bootstrapMethods[i].toString(super.getConstantPool()).split("\\r?\\n");
    154            buf.append(lines[0]);
    155            for (int j = 1; j < lines.length; j++) {
    156                buf.append("\n").append("          ", 0, indentCount).append(lines[j]);
    157            }
    158        }
    159        return buf.toString();
    160    }
    161}