[Fb-contrib-commit] SF.net SVN: fb-contrib:[1215] trunk/fb-contrib/src/com/mebigfatguy/ fbcontrib/detect/TristateBooleanPattern.java

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

Revision: 1215
          http://fb-contrib.svn.sourceforge.net/fb-contrib/?rev=1215&view=rev
Author:   dbrosius
Date:     2009-07-03 05:42:30 +0000 (Fri, 03 Jul 2009)

Log Message:
-----------
initial checkin

Added Paths:
-----------
    trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/TristateBooleanPattern.java

Added: trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/TristateBooleanPattern.java
===================================================================
--- trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/TristateBooleanPattern.java	                        (rev 0)
+++ trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/TristateBooleanPattern.java	2009-07-03 05:42:30 UTC (rev 1215)
@@ -0,0 +1,109 @@
+/*
+ * fb-contrib - Auxiliary detectors for Java programs
+ * Copyright (C) 2005-2009 Dave Brosius
+ * 
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ * 
+ * This library 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
+ * Lesser General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+package com.mebigfatguy.fbcontrib.detect;
+
+import org.apache.bcel.classfile.Code;
+import org.apache.bcel.classfile.Method;
+
+import com.sun.org.apache.bcel.internal.generic.Type;
+
+import edu.umd.cs.findbugs.BugInstance;
+import edu.umd.cs.findbugs.BugReporter;
+import edu.umd.cs.findbugs.BytecodeScanningDetector;
+import edu.umd.cs.findbugs.OpcodeStack;
+import edu.umd.cs.findbugs.ba.ClassContext;
+
+/**
+ * looks for methods that are defined to return Boolean, but return null. This thus
+ * allows three return values, Boolean.FALSE, Boolean.TRUE and null. If three values
+ * intended, it would be more clear to just create an enumeration with three values
+ * and return that type.
+ */
+public class TristateBooleanPattern extends BytecodeScanningDetector 
+{
+	private BugReporter bugReporter;
+	private OpcodeStack stack;
+	private boolean methodReported;
+	
+	/**
+     * constructs a TBP detector given the reporter to report bugs on
+     * @param bugReporter the sync of bug reports
+	 */
+	public TristateBooleanPattern(BugReporter bugReporter) {
+		this.bugReporter = bugReporter;
+	}
+	
+	/**
+	 * implements the visitor to allocate the opcode stack
+	 * 
+	 * @param classContext the context object of the currently parsed class
+	 */
+	@Override
+	public void visitClassContext(ClassContext classContext) {
+		try {
+			stack = new OpcodeStack();
+			super.visitClassContext(classContext);
+		} finally {
+			stack = null;
+		}
+	}
+	
+	/**
+	 * implements the visitor to filter out methods that don't return Boolean,
+	 * and to reset the methodReported flag
+	 *
+	 * @param obj the context object for the currently parsed code block
+	 */
+	@Override
+	public void visitCode(Code obj) {
+		Method m = getMethod();
+		if (Type.BOOLEAN.equals(m.getReturnType())) {
+			stack.resetForMethodEntry(this);
+			methodReported = false;
+			super.visitCode(obj);
+		}
+	}
+	
+	/**
+	 * implements the visitor to look for null returns
+	 */
+	@Override
+	public void sawOpcode(int seen) {
+		try {
+			if (methodReported)
+				return;
+			
+			if (seen == ARETURN) {
+				if (stack.getStackDepth() > 0) {
+					OpcodeStack.Item item = stack.getStackItem(0);
+					if (item.isNull()) {
+						bugReporter.reportBug(new BugInstance(this, "TBP_TRISTATE_BOOLEAN_PATTERN", NORMAL_PRIORITY)
+						           .addClass(this)
+						           .addMethod(this)
+						           .addSourceLine(this));
+						methodReported = true;
+					}
+				}
+			}
+		} finally {
+			stack.sawOpcode(this, seen);
+		}
+	}
+
+}


Property changes on: trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/TristateBooleanPattern.java
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Added: svn:mime-type
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Added: svn:eol-style
   + native


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