1 /*
   2  * reserved comment block
   3  * DO NOT REMOVE OR ALTER!
   4  */
   5 /*
   6  * Licensed to the Apache Software Foundation (ASF) under one or more
   7  * contributor license agreements.  See the NOTICE file distributed with
   8  * this work for additional information regarding copyright ownership.
   9  * The ASF licenses this file to You under the Apache License, Version 2.0
  10  * (the "License"); you may not use this file except in compliance with
  11  * the License.  You may obtain a copy of the License at
  12  *
  13  *      http://www.apache.org/licenses/LICENSE-2.0
  14  *
  15  *  Unless required by applicable law or agreed to in writing, software
  16  *  distributed under the License is distributed on an "AS IS" BASIS,
  17  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  18  *  See the License for the specific language governing permissions and
  19  *  limitations under the License.
  20  *
  21  */
  22 package com.sun.org.apache.bcel.internal.classfile;
  23 
  24 import java.io.DataInput;
  25 import java.io.DataOutputStream;
  26 import java.io.IOException;
  27 
  28 import com.sun.org.apache.bcel.internal.Const;
  29 
  30 /**
  31  * This class is derived from the abstract {@link Constant}
  32  * and represents a reference to a package.
  33  *
  34  * <p>Note: Early access Java 9 support- currently subject to change</p>
  35  *
  36  * @see     Constant
  37  * @since 6.1
  38  */
  39 public final class ConstantPackage extends Constant implements ConstantObject {
  40 
  41     private int name_index;
  42 
  43 
  44     /**
  45      * Initialize from another object.
  46      */
  47     public ConstantPackage(final ConstantPackage c) {
  48         this(c.getNameIndex());
  49     }
  50 
  51 
  52     /**
  53      * Initialize instance from file data.
  54      *
  55      * @param file Input stream
  56      * @throws IOException
  57      */
  58     ConstantPackage(final DataInput file) throws IOException {
  59         this(file.readUnsignedShort());
  60     }
  61 
  62 
  63     /**
  64      * @param name_index Name index in constant pool.  Should refer to a
  65      * ConstantUtf8.
  66      */
  67     public ConstantPackage(final int name_index) {
  68         super(Const.CONSTANT_Package);
  69         this.name_index = name_index;
  70     }
  71 
  72 
  73     /**
  74      * Called by objects that are traversing the nodes of the tree implicitly
  75      * defined by the contents of a Java class. I.e., the hierarchy of methods,
  76      * fields, attributes, etc. spawns a tree of objects.
  77      *
  78      * @param v Visitor object
  79      */
  80     @Override
  81     public void accept( final Visitor v ) {
  82         v.visitConstantPackage(this);
  83     }
  84 
  85 
  86     /**
  87      * Dump constant package to file stream in binary format.
  88      *
  89      * @param file Output file stream
  90      * @throws IOException
  91      */
  92     @Override
  93     public void dump( final DataOutputStream file ) throws IOException {
  94         file.writeByte(super.getTag());
  95         file.writeShort(name_index);
  96     }
  97 
  98 
  99     /**
 100      * @return Name index in constant pool of package name.
 101      */
 102     public int getNameIndex() {
 103         return name_index;
 104     }
 105 
 106 
 107     /**
 108      * @param name_index the name index in the constant pool of this Constant Package
 109      */
 110     public void setNameIndex( final int name_index ) {
 111         this.name_index = name_index;
 112     }
 113 
 114 
 115     /** @return String object
 116      */
 117     @Override
 118     public Object getConstantValue( final ConstantPool cp ) {
 119         final Constant c = cp.getConstant(name_index, Const.CONSTANT_Utf8);
 120         return ((ConstantUtf8) c).getBytes();
 121     }
 122 
 123 
 124     /** @return dereferenced string
 125      */
 126     public String getBytes( final ConstantPool cp ) {
 127         return (String) getConstantValue(cp);
 128     }
 129 
 130 
 131     /**
 132      * @return String representation.
 133      */
 134     @Override
 135     public String toString() {
 136         return super.toString() + "(name_index = " + name_index + ")";
 137     }
 138 }