/* 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.*;
import EDU.purdue.cs.bloat.util.*;
/**
* Method represents a method in a Java classfile. A method's name and value
* (the types of its parameters and its return type) are modeled as indices into
* it class's constant pool. A method has modifiers that determine whether it is
* public, private, static, final, etc. Methods have a number of attributes such
* as their Code and any Exceptions they may throw.
*
* @see Code
* @see Exceptions
*
* @author Nate Nystrom (<a
* href="mailto:nystrom@cs.purdue.edu">nystrom@cs.purdue.edu</a>)
*/
public class Method implements MethodInfo {
private ClassInfo classInfo;
private int modifiers;
private int name;
private int type;
private Attribute[] attrs;
private Code code;
private Exceptions exceptions;
public static boolean DEBUG = Boolean.getBoolean("Method.DEBUG");
/**
* Constructor for creating a <code>Method</code> from scratch
*
* @param attrs
* Must include <code>code</code> and <code>exceptions</code>
* which are themselves attributes of this method
*/
Method(final ClassInfo classInfo, final int modifiers, final int name,
final int type, final Attribute[] attrs, final Code code,
final Exceptions exceptions) {
this.classInfo = classInfo;
this.modifiers = modifiers;
this.name = name;
this.type = type;
Assert.isNotNull(attrs, "Every method must have at least a Code "
+ "attribute");
this.attrs = attrs;
this.code = code;
this.exceptions = exceptions;
}
/**
* Constructor. Read a method from a class file.
*
* @param in
* The data stream of the class file.
* @param classInfo
* The class file containing the method.
* @exception IOException
* If an error occurs while reading.
*/
public Method(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 ("Code".equals(name.value())) {
code = new Code(classInfo, in, nameIndex, length);
attrs[i] = code;
} else if ("Exceptions".equals(name.value())) {
exceptions = new Exceptions(classInfo, in, nameIndex,
length);
attrs[i] = exceptions;
}
}
if (attrs[i] == null) {
attrs[i] = new GenericAttribute(in, nameIndex, length);
}
}
}
/**
* Get the class which declared the method.
*
* @return The ClassInfo of the class which declared the method.
*/
public ClassInfo declaringClass() {
return classInfo;
}
/**
* Set the index into the constant pool of the name of the method.
*
* @param name
* The index into the constant pool of the name of the method.
*/
public void setNameIndex(final int name) {
this.name = name;
}
/**
* Set the index into the constant pool of the type of the method.
*
* @param type
* The index into the constant pool of the type of the method.
*/
public void setTypeIndex(final int type) {
this.type = type;
}
/**
* Get the index into the constant pool of the name of the method.
*
* @return The index into the constant pool of the name of the method.
*/
public int nameIndex() {
return name;
}
/**
* Get the index into the constant pool of the type of the method.
*
* @return The index into the constant pool of the type of the method.
*/
public int typeIndex() {
return type;
}
/**
* Set the modifiers of the method. The values correspond to the constants
* in the Modifiers class.
*
* @param modifiers
* A bit vector of modifier flags for the method.
* @see Modifiers
*/
public void setModifiers(final int modifiers) {
this.modifiers = modifiers;
}
/**
* Get the modifiers of the method. The values correspond to the constants
* in the Modifiers class.
*
* @return A bit vector of modifier flags for the method.
* @see Modifiers
*/
public int modifiers() {
return modifiers;
}
/**
* Get the maximum height of the operand stack.
*
* @return The maximum height of the operand stack.
*/
public int maxStack() {
if (code != null) {
return code.maxStack();
}
return 0;
}
/**
* Set the maximum height of the operand stack.
*
* @param maxStack
* The maximum height of the operand stack.
*/
public void setMaxStack(final int maxStack) {
if (code != null) {
code.setMaxStack(maxStack);
}
}
/**
* Get the maximum number of locals used in the method.
*
* @return The maximum number of locals used in the method.
*/
public int maxLocals() {
if (code != null) {
return code.maxLocals();
}
return 0;
}
/**
* Set the maximum number of locals used in the method.
*
* @param maxLocals
* The maximum number of locals used in the method.
*/
public void setMaxLocals(final int maxLocals) {
if (code != null) {
code.setMaxLocals(maxLocals);
}
}
/**
* Get the byte code array of the method.
*
* @return The byte code array of the method.
*/
public byte[] code() {
if (code != null) {
return code.code();
}
return new byte[0];
}
/**
* Returns the length of the Code array.
*/
public int codeLength() {
if (code != null) {
return (code.codeLength());
} else {
return (0);
}
}
/**
* Set the byte code array of the method.
*
* @param bytes
* The byte code array of the method.
*/
public void setCode(final byte[] bytes) {
if (code != null) {
code.setCode(bytes);
if (Method.DEBUG) {
System.out.println("Set code with " + bytes.length + " bytes");
// Thread.dumpStack();
}
}
}
/**
* Get the indices into the constant pool of the types of the exceptions
* thrown by the method.
*
* @return The indices into the constant pool of the types of the exceptions
* thrown by the method.
*/
public int[] exceptionTypes() {
if (exceptions != null) {
return exceptions.exceptionTypes();
}
return new int[0];
}
/**
* Set the line numbers of the instructions in the method.
*
* @param lineNumbers
* The line numbers of the instructions in the method.
*/
public void setLineNumbers(final LineNumberDebugInfo[] lineNumbers) {
if (code != null) {
code.setLineNumbers(lineNumbers);
}
}
/**
* Set the local variable debug info for the method.
*
* @param locals
* The local variable debug info for the method.
*/
public void setLocals(final LocalDebugInfo[] locals) {
if (code != null) {
code.setLocals(locals);
}
}
/**
* Get the line numbers of the instructions in the method.
*
* @return The line numbers of the instructions in the method.
*/
public LineNumberDebugInfo[] lineNumbers() {
if (code != null) {
return code.lineNumbers();
}
return new LineNumberDebugInfo[0];
}
/**
* Get the local variable debug info for the method.
*
* @return The local variable debug info for the method.
*/
public LocalDebugInfo[] locals() {
if (code != null) {
return code.locals();
}
return new LocalDebugInfo[0];
}
/**
* Get the exception handlers in the method.
*
* @return The exception handlers in the method.
*/
public Catch[] exceptionHandlers() {
if (code != null) {
return code.exceptionHandlers();
}
return new Catch[0];
}
/**
* Set the exception handlers in the method.
*
* @param handlers
* The exception handlers in the method.
*/
public void setExceptionHandlers(final Catch[] handlers) {
if (code != null) {
code.setExceptionHandlers(handlers);
}
}
/**
* Write the method 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 {
if (Method.DEBUG) {
System.out.println("Writing method " + this);
System.out.println(" Masked Modifiers: " + (modifiers & 0xf000));
}
out.writeShort(modifiers);
out.writeShort(name);
out.writeShort(type);
out.writeShort(attrs.length);
for (int i = 0; i < attrs.length; i++) {
if (Method.DEBUG) {
System.out.println(" " + attrs[i]);
}
out.writeShort(attrs[i].nameIndex());
out.writeInt(attrs[i].length());
attrs[i].writeData(out);
}
}
/**
* Returns a string representation of the method.
*/
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 += ")";
return "(method " + name + " " + type + x
+ (code != null ? "\n " + code : "")
+ (exceptions != null ? "\n " + exceptions : "") + ")";
}
/**
* Constructor used for cloning a <code>Method</code>
*/
private Method(final ClassInfo classInfo, final int modifiers,
final int name, final int type, final Attribute[] attrs) {
this.classInfo = classInfo;
this.modifiers = modifiers;
this.name = name;
this.type = type;
if (attrs != null) {
this.attrs = new Attribute[attrs.length];
for (int i = 0; i < attrs.length; i++) {
final Attribute attr = (Attribute) attrs[i].clone();
if (attr instanceof Code) {
this.code = (Code) attr;
} else if (attr instanceof Exceptions) {
this.exceptions = (Exceptions) attr;
}
this.attrs[i] = attr;
}
}
Assert.isTrue(code != null, "No Code in attributes");
Assert.isTrue(exceptions != null, "No Exceptions in attributes");
}
/**
* Creates a clone of this <tt>MethodInfo</tt> except that its declaring
* class does not know about it.
*/
public Object clone() {
return (new Method(this.classInfo, this.modifiers, this.name,
this.type, this.attrs));
}
}