/*
 * FindBugs - Find bugs in Java programs
 * Copyright (C) 2004-2006 University of Maryland
 *
 * 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 edu.umd.cs.findbugs.detect;

import java.math.BigDecimal;

import org.apache.bcel.classfile.Code;

import edu.umd.cs.findbugs.BugInstance;
import edu.umd.cs.findbugs.BugReporter;
import edu.umd.cs.findbugs.OpcodeStack;
import edu.umd.cs.findbugs.bcel.OpcodeStackDetector;

public class TestingGround2 extends OpcodeStackDetector {

    BugReporter bugReporter;

    public TestingGround2(BugReporter bugReporter) {
        this.bugReporter = bugReporter;
    }

    @Override
    public void visit(Code code) {
        boolean interesting = true;
        if (interesting) {
            // initialize any variables we want to initialize for the method
            super.visit(code); // make callbacks to sawOpcode for all opcodes
        }
    }

    @Override
    public void sawOpcode(int seen) {
        if (seen == INVOKESPECIAL && getClassConstantOperand().equals("java/math/BigDecimal")
                && getNameConstantOperand().equals("<init>") && getSigConstantOperand().equals("(D)V")) {
            OpcodeStack.Item top = stack.getStackItem(0);
            Object value = top.getConstant();
            if (value instanceof Double) {
                double arg = ((Double) value).doubleValue();
                String dblString = Double.toString(arg);
                String bigDecimalString = new BigDecimal(arg).toString();
                boolean ok = dblString.equals(bigDecimalString) || dblString.equals(bigDecimalString + ".0");

                if (!ok) {
                    boolean scary = dblString.length() <= 8 && dblString.toUpperCase().indexOf("E") == -1;
                    bugReporter.reportBug(new BugInstance(this, "TESTING", scary ? NORMAL_PRIORITY : LOW_PRIORITY)
                            .addClassAndMethod(this).addString(dblString).addSourceLine(this));
                }
            }

        }

    }

}

@@ -2122,25 +2122,159 @@
     
-String bigDecimal
+BigDecimal bigDecimal = new BigDecimal(arg);%0A                String bigDecimalString = bigDecimal.toString();%0A                BigDecimal bigDecimalFrom
 Stri
@@ -2297,22 +2297,24 @@
 mal(
-arg).to
+bigDecimal
 String
-(
 );%0A 
@@ -2420,16 +2420,83 @@
  + %22.0%22)
+%0A                        %7C%7C bigDecimal.equals(bigDecimalFromString)
 ;%0A%0A     
@@ -2799,24 +2799,292 @@
 .add
-String(dblString
+CalledMethod(this).addString(%22Value as double: %22 + dblString)%0A                            .addString(%22Value as BigDecimal: %22 + bigDecimalString)%0A                            .addString(%22Constructing a BigDecimal from a double doesn't give the same result as from the equivalent String%22
 ).ad

Add more information to TESTING bug