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; 023import java.util.Arrays; 024 025import org.apache.bcel.Const; 026 027/** 028 * This class represents a bootstrap method attribute, i.e., the bootstrap 029 * method ref, the number of bootstrap arguments and an array of the 030 * bootstrap arguments. 031 * 032 * @see <a href="http://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.7.23"> 033 * The class File Format : The BootstrapMethods Attribute</a> 034 * @since 6.0 035 */ 036public class BootstrapMethod implements Cloneable { 037 038 /** Index of the CONSTANT_MethodHandle_info structure in the constant_pool table */ 039 private int bootstrap_method_ref; 040 041 /** Array of references to the constant_pool table */ 042 private int[] bootstrap_arguments; 043 044 045 /** 046 * Initialize from another object. 047 */ 048 public BootstrapMethod(final BootstrapMethod c) { 049 this(c.getBootstrapMethodRef(), c.getBootstrapArguments()); 050 } 051 052 /** 053 * Construct object from input stream. 054 * 055 * @param input Input stream 056 * @throws IOException 057 */ 058 BootstrapMethod(final DataInput input) throws IOException { 059 this(input.readUnsignedShort(), input.readUnsignedShort()); 060 061 for (int i = 0; i < bootstrap_arguments.length; i++) { 062 bootstrap_arguments[i] = input.readUnsignedShort(); 063 } 064 } 065 066 // helper method 067 private BootstrapMethod(final int bootstrap_method_ref, final int num_bootstrap_arguments) { 068 this(bootstrap_method_ref, new int[num_bootstrap_arguments]); 069 } 070 071 /** 072 * @param bootstrap_method_ref int index into constant_pool of CONSTANT_MethodHandle 073 * @param bootstrap_arguments int[] indices into constant_pool of CONSTANT_[type]_info 074 */ 075 public BootstrapMethod(final int bootstrap_method_ref, final int[] bootstrap_arguments) { 076 this.bootstrap_method_ref = bootstrap_method_ref; 077 this.bootstrap_arguments = bootstrap_arguments; 078 } 079 080 /** 081 * @return index into constant_pool of bootstrap_method 082 */ 083 public int getBootstrapMethodRef() { 084 return bootstrap_method_ref; 085 } 086 087 /** 088 * @param bootstrap_method_ref int index into constant_pool of CONSTANT_MethodHandle 089 */ 090 public void setBootstrapMethodRef(final int bootstrap_method_ref) { 091 this.bootstrap_method_ref = bootstrap_method_ref; 092 } 093 094 /** 095 * @return int[] of bootstrap_method indices into constant_pool of CONSTANT_[type]_info 096 */ 097 public int[] getBootstrapArguments() { 098 return bootstrap_arguments; 099 } 100 101 /** 102 * @return count of number of boostrap arguments 103 */ 104 public int getNumBootstrapArguments() { 105 return bootstrap_arguments.length; 106 } 107 108 /** 109 * @param bootstrap_arguments int[] indices into constant_pool of CONSTANT_[type]_info 110 */ 111 public void setBootstrapArguments(final int[] bootstrap_arguments) { 112 this.bootstrap_arguments = bootstrap_arguments; 113 } 114 115 /** 116 * @return String representation. 117 */ 118 @Override 119 public final String toString() { 120 return "BootstrapMethod(" + bootstrap_method_ref + ", " + bootstrap_arguments.length + ", " 121 + Arrays.toString(bootstrap_arguments) + ")"; 122 } 123 124 /** 125 * @return Resolved string representation 126 */ 127 public final String toString( final ConstantPool constant_pool ) { 128 final StringBuilder buf = new StringBuilder(); 129 String bootstrap_method_name; 130 bootstrap_method_name = constant_pool.constantToString(bootstrap_method_ref, 131 Const.CONSTANT_MethodHandle); 132 buf.append(Utility.compactClassName(bootstrap_method_name, false)); 133 final int num_bootstrap_arguments = bootstrap_arguments.length; 134 if (num_bootstrap_arguments > 0) { 135 buf.append("\nMethod Arguments:"); 136 for (int i = 0; i < num_bootstrap_arguments; i++) { 137 buf.append("\n ").append(i).append(": "); 138 buf.append(constant_pool.constantToString(constant_pool.getConstant(bootstrap_arguments[i]))); 139 } 140 } 141 return buf.toString(); 142 } 143 144 /** 145 * Dump object to file stream in binary format. 146 * 147 * @param file Output file stream 148 * @throws IOException 149 */ 150 public final void dump(final DataOutputStream file) throws IOException { 151 file.writeShort(bootstrap_method_ref); 152 file.writeShort(bootstrap_arguments.length); 153 for (final int bootstrap_argument : bootstrap_arguments) { 154 file.writeShort(bootstrap_argument); 155 } 156 } 157 158 /** 159 * @return deep copy of this object 160 */ 161 public BootstrapMethod copy() { 162 try { 163 return (BootstrapMethod) clone(); 164 } catch (final CloneNotSupportedException e) { 165 // TODO should this throw? 166 } 167 return null; 168 } 169}