fb-contrib-commit

[Dave B. <dbr...@us...>]

Update of /cvsroot/fb-contrib/fb-contrib/src/com/mebigfatguy/fbcontrib/detect
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv11646/src/com/mebigfatguy/fbcontrib/detect

Added Files:
	NeedlessAutoboxing.java 
Log Message:
initial checkin, NAB detector

--- NEW FILE: NeedlessAutoboxing.java ---
package com.mebigfatguy.fbcontrib.detect;

import java.util.HashMap;
import java.util.Map;

import org.apache.bcel.classfile.Method;

import edu.umd.cs.findbugs.BugInstance;
import edu.umd.cs.findbugs.BugReporter;
import edu.umd.cs.findbugs.BytecodeScanningDetector;
import edu.umd.cs.findbugs.StatelessDetector;

public class NeedlessAutoboxing extends BytecodeScanningDetector implements StatelessDetector 
{
	private static final int SEEN_NOTHING = 0;
	private static final int SEEN_VALUE = 1;
	
	private static final Map<String, String[]> boxClasses = new HashMap<String, String[]>();
	static {
		boxClasses.put("java/lang/Boolean", new String[] { "booleanValue()Z", "(Z)V" });
		boxClasses.put("java/lang/Character", new String[] { "charValue()C", "(C)V" });
		boxClasses.put("java/lang/Byte", new String[] { "byteValue()B", "(B)V" });
		boxClasses.put("java.lang/Short", new String[] { "shortValue()S", "(S)V" });
		boxClasses.put("java/lang/Integer", new String[] { "intValue()I", "(I)V" });
		boxClasses.put("java/lang/Long", new String[] { "longValue()J", "(J)V" });
		boxClasses.put("java/lang/Float", new String[] { "floatValue()F", "(F)V" });
		boxClasses.put("java/lang/Double", new String[] { "doubleValue()D", "(D)V" });
	}
	
	private BugReporter bugReporter;
	private int state;
	private String boxClass;
	
	public NeedlessAutoboxing(BugReporter bugReporter) {
		this.bugReporter = bugReporter;
	}
	
	public Object clone() throws CloneNotSupportedException {
		return super.clone();
	}

	public void visitMethod(Method obj) {
		state = SEEN_NOTHING;
	}
	
	public void sawOpcode(int seen) {
		
		switch (state) {
			case SEEN_NOTHING:
				if (seen == INVOKEVIRTUAL) {
					boxClass = getClassConstantOperand();
					String[] boxSigs = boxClasses.get(boxClass);
					if (boxSigs != null) {
						String methodName = getNameConstantOperand();
						String methodSig = getSigConstantOperand();
						if (boxSigs[0].equals(methodName + methodSig)) {
							state = SEEN_VALUE;
						}
					}
				}
			break;
			
			case SEEN_VALUE:
				if (seen == INVOKESPECIAL) {
					if (boxClass.equals(getClassConstantOperand())) {
						String methodName = getNameConstantOperand();
						String boxSig = boxClasses.get(boxClass)[1];
						if ("<init>".equals(methodName)) {
							String methodSig = getSigConstantOperand();
							if (boxSig.equals(methodSig)) {
								bugReporter.reportBug(new BugInstance(this, "NAB_NEEDLESS_AUTOBOXING", NORMAL_PRIORITY)
									.addClass(this)
									.addMethod(this)
									.addSourceLine(this));
							}
						}
					}
				}
				state = SEEN_NOTHING;
			break;
		}
	}
}