/* This file is part of the db4o object database http://www.db4o.com
Copyright (C) 2004 - 2011 Versant Corporation http://www.versant.com
db4o is free software; you can redistribute it and/or modify it under
the terms of version 3 of the GNU General Public License as published
by the Free Software Foundation.
db4o is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License along
with this program. If not, see http://www.gnu.org/licenses/. */
package EDU.purdue.cs.bloat.file;
import java.io.*;
import EDU.purdue.cs.bloat.reflect.*;
/**
* Field models a field (member variable) in a class. The Field class grants
* access to information such as the field's modifiers, its name and type
* descriptor (represented as indices into the constant pool), and any
* attributes of the field. Static fields have a ConstantValue attribute.
*
* @see ConstantValue
*
* @author Nate Nystrom (<a
* href="mailto:nystrom@cs.purdue.edu">nystrom@cs.purdue.edu</a>)
*/
public class Field implements FieldInfo {
private ClassInfo classInfo;
private int modifiers;
private int name;
private int type;
private Attribute[] attrs;
private ConstantValue constantValue;
/**
* Constructor for creating a new field from scratch
*/
Field(final ClassInfo classInfo, final int modifiers, final int typeIndex,
final int nameIndex) {
this.classInfo = classInfo;
this.modifiers = modifiers;
this.name = nameIndex;
this.type = typeIndex;
this.attrs = new Attribute[0];
this.constantValue = null;
}
/**
* Constructor for creating a new field that has a constant value from
* scratch
*/
Field(final ClassInfo classInfo, final int modifiers, final int typeIndex,
final int nameIndex, final int cvNameIndex,
final int constantValueIndex) {
this.classInfo = classInfo;
this.modifiers = modifiers;
this.name = nameIndex;
this.type = typeIndex;
this.constantValue = new ConstantValue(cvNameIndex, 2,
constantValueIndex);
// The constant value is an attribute
this.attrs = new Attribute[1];
this.attrs[0] = constantValue;
}
/**
* Constructor. Read a field from a class file.
*
* @param in
* The data stream of the class file.
* @param classInfo
* The class file containing the field.
* @exception IOException
* If an error occurs while reading.
*/
public Field(final DataInputStream in, final ClassInfo classInfo)
throws IOException {
this.classInfo = classInfo;
modifiers = in.readUnsignedShort();
name = in.readUnsignedShort();
type = in.readUnsignedShort();
final int numAttributes = in.readUnsignedShort();
attrs = new Attribute[numAttributes];
for (int i = 0; i < numAttributes; i++) {
final int nameIndex = in.readUnsignedShort();
final int length = in.readInt();
final Constant name = classInfo.constants()[nameIndex];
if (name != null) {
if ("ConstantValue".equals(name.value())) {
constantValue = new ConstantValue(in, nameIndex, length);
attrs[i] = constantValue;
}
}
if (attrs[i] == null) {
attrs[i] = new GenericAttribute(in, nameIndex, length);
}
}
}
/**
* Get the class which declared the field.
*
* @return The ClassInfo of the class which declared the field.
*/
public ClassInfo declaringClass() {
return classInfo;
}
/**
* Set the index into the constant pool of the name of the field.
*
* @param name
* The name of the field.
*/
public void setNameIndex(final int name) {
this.name = name;
}
/**
* Set the index into the constant pool of the type of the field.
*
* @param type
* The type of the field.
*/
public void setTypeIndex(final int type) {
this.type = type;
}
/**
* Get the index into the constant pool of the name of the field.
*
* @return The index into the constant pool of the name of the field.
*/
public int nameIndex() {
return name;
}
/**
* Get the index into the constant pool of the type of the field.
*
* @return The index into the constant pool of the type of the field.
*/
public int typeIndex() {
return type;
}
/**
* Set the modifiers of the field. The values correspond to the constants in
* the Modifiers class.
*
* @param modifiers
* A bit vector of modifier flags for the field.
* @see Modifiers
*/
public void setModifiers(final int modifiers) {
this.modifiers = modifiers;
}
/**
* Get the modifiers of the field. The values correspond to the constants in
* the Modifiers class.
*
* @return A bit vector of modifier flags for the field.
* @see Modifiers
*/
public int modifiers() {
return modifiers;
}
/**
* Get the index into the constant pool of the field's constant value, if
* any. Returns 0 if the field does not have a constant value.
*
* @see ClassInfo#constants
*/
public int constantValue() {
if (constantValue != null) {
return constantValue.constantValueIndex();
}
return 0;
}
/**
* Set the index into the constant pool of the field's constant value.
*
* @see ClassInfo#constants
*/
public void setConstantValue(final int index) {
if (constantValue != null) {
constantValue.setConstantValueIndex(index);
}
}
/**
* Write the field to a class file.
*
* @param out
* The data stream of the class file.
* @exception IOException
* If an error occurs while writing.
*/
public void write(final DataOutputStream out) throws IOException {
out.writeShort(modifiers);
out.writeShort(name);
out.writeShort(type);
out.writeShort(attrs.length);
for (int i = 0; i < attrs.length; i++) {
out.writeShort(attrs[i].nameIndex());
out.writeInt(attrs[i].length());
attrs[i].writeData(out);
}
}
/**
* Convert the field to a string.
*
* @return A string representation of the field.
*/
public String toString() {
String x = "";
x += " (modifiers";
if ((modifiers & Modifiers.PUBLIC) != 0) {
x += " PUBLIC";
}
if ((modifiers & Modifiers.PRIVATE) != 0) {
x += " PRIVATE";
}
if ((modifiers & Modifiers.PROTECTED) != 0) {
x += " PROTECTED";
}
if ((modifiers & Modifiers.STATIC) != 0) {
x += " STATIC";
}
if ((modifiers & Modifiers.FINAL) != 0) {
x += " FINAL";
}
if ((modifiers & Modifiers.SYNCHRONIZED) != 0) {
x += " SYNCHRONIZED";
}
if ((modifiers & Modifiers.VOLATILE) != 0) {
x += " VOLATILE";
}
if ((modifiers & Modifiers.TRANSIENT) != 0) {
x += " TRANSIENT";
}
if ((modifiers & Modifiers.NATIVE) != 0) {
x += " NATIVE";
}
if ((modifiers & Modifiers.INTERFACE) != 0) {
x += " INTERFACE";
}
if ((modifiers & Modifiers.ABSTRACT) != 0) {
x += " ABSTRACT";
}
x += ")";
if (constantValue != null) {
x += " " + constantValue;
}
return "(field " + name + " " + type + x + ")";
}
}