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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package org.apache.bcel.classfile;
import java.io.DataInput;
import java.io.DataOutputStream;
import java.io.IOException;
import org.apache.bcel.Const;
/**
* This class is derived from <em>Attribute</em> and represents a constant
* value, i.e., a default value for initializing a class field.
* This class is instantiated by the <em>Attribute.readAttribute()</em> method.
*
* @version $Id$
* @see Attribute
*/
public final class ConstantValue extends Attribute {
private int constantvalue_index;
/**
* Initialize from another object. Note that both objects use the same
* references (shallow copy). Use clone() for a physical copy.
*/
public ConstantValue(final ConstantValue c) {
this(c.getNameIndex(), c.getLength(), c.getConstantValueIndex(), c.getConstantPool());
}
/**
* Construct object from input stream.
* @param name_index Name index in constant pool
* @param length Content length in bytes
* @param input Input stream
* @param constant_pool Array of constants
* @throws IOException
*/
ConstantValue(final int name_index, final int length, final DataInput input, final ConstantPool constant_pool)
throws IOException {
this(name_index, length, input.readUnsignedShort(), constant_pool);
}
/**
* @param name_index Name index in constant pool
* @param length Content length in bytes
* @param constantvalue_index Index in constant pool
* @param constant_pool Array of constants
*/
public ConstantValue(final int name_index, final int length, final int constantvalue_index,
final ConstantPool constant_pool) {
super(Const.ATTR_CONSTANT_VALUE, name_index, length, constant_pool);
this.constantvalue_index = constantvalue_index;
}
/**
* Called by objects that are traversing the nodes of the tree implicitely
* defined by the contents of a Java class. I.e., the hierarchy of methods,
* fields, attributes, etc. spawns a tree of objects.
*
* @param v Visitor object
*/
@Override
public void accept( final Visitor v ) {
v.visitConstantValue(this);
}
/**
* Dump constant value attribute to file stream on binary format.
*
* @param file Output file stream
* @throws IOException
*/
@Override
public final void dump( final DataOutputStream file ) throws IOException {
super.dump(file);
file.writeShort(constantvalue_index);
}
/**
* @return Index in constant pool of constant value.
*/
public final int getConstantValueIndex() {
return constantvalue_index;
}
/**
* @param constantvalue_index the index info the constant pool of this constant value
*/
public final void setConstantValueIndex( final int constantvalue_index ) {
this.constantvalue_index = constantvalue_index;
}
/**
* @return String representation of constant value.
*/
@Override
public final String toString() {
Constant c = super.getConstantPool().getConstant(constantvalue_index);
String buf;
int i;
// Print constant to string depending on its type
switch (c.getTag()) {
case Const.CONSTANT_Long:
buf = String.valueOf(((ConstantLong) c).getBytes());
break;
case Const.CONSTANT_Float:
buf = String.valueOf(((ConstantFloat) c).getBytes());
break;
case Const.CONSTANT_Double:
buf = String.valueOf(((ConstantDouble) c).getBytes());
break;
case Const.CONSTANT_Integer:
buf = String.valueOf(((ConstantInteger) c).getBytes());
break;
case Const.CONSTANT_String:
i = ((ConstantString) c).getStringIndex();
c = super.getConstantPool().getConstant(i, Const.CONSTANT_Utf8);
buf = "\"" + Utility.convertString(((ConstantUtf8) c).getBytes()) + "\"";
break;
default:
throw new IllegalStateException("Type of ConstValue invalid: " + c);
}
return buf;
}
/**
* @return deep copy of this attribute
*/
@Override
public Attribute copy( final ConstantPool _constant_pool ) {
final ConstantValue c = (ConstantValue) clone();
c.setConstantPool(_constant_pool);
return c;
}
}
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