/*
 * 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);
                BigDecimal bigDecimal = new BigDecimal(arg);
                String bigDecimalString = bigDecimal.toString();
                BigDecimal bigDecimalFromString = new BigDecimal(bigDecimalString);
                boolean ok = dblString.equals(bigDecimalString) || dblString.equals(bigDecimalString + ".0")
                        || bigDecimal.equals(bigDecimalFromString);

                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).addCalledMethod(this).addString("Value as double: " + dblString)
                            .addString("Value as BigDecimal: " + bigDecimalString)
                            .addString("Constructing a BigDecimal from a double doesn't give the same result as from the equivalent String").addSourceLine(this));
                }
            }

        }

    }

}

/*
 * 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 org.apache.bcel.classfile.Code;

import edu.umd.cs.findbugs.BugReporter;
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) {
     
    }

}

Clean out TestingGround 2. Warning for new BigDecimal(double) has graduated.