/*
* FindBugs - Find bugs in Java programs
* Copyright (C) 2003-2005 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 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;
import edu.umd.cs.findbugs.ba.AnalysisContext;
import edu.umd.cs.findbugs.ba.ClassContext;
import edu.umd.cs.findbugs.ba.ch.Subtypes2;
import edu.umd.cs.findbugs.classfile.ClassDescriptor;
import edu.umd.cs.findbugs.classfile.DescriptorFactory;
public class IteratorIdioms extends BytecodeScanningDetector implements StatelessDetector {
private final ClassDescriptor iteratorDescriptor = DescriptorFactory.createClassDescriptor(java.util.Iterator.class);
private final BugReporter bugReporter;
private boolean sawNoSuchElement;
private boolean sawCall;
private boolean shouldVisitCode;
public IteratorIdioms(BugReporter bugReporter) {
this.bugReporter = bugReporter;
}
@Override
public void visitClassContext(ClassContext classContext) {
Subtypes2 subtypes2 = AnalysisContext.currentAnalysisContext().getSubtypes2();
try {
if (subtypes2.isSubtype(classContext.getClassDescriptor(), iteratorDescriptor)) {
super.visitClassContext(classContext);
}
} catch (ClassNotFoundException e) {
bugReporter.reportMissingClass(e);
}
}
@Override
public void visit(Method method) {
if(method.isPublic() && method.getName().equals("next") && method.getArgumentTypes().length == 0){
shouldVisitCode = true;
super.visit(method);
} else {
shouldVisitCode = false;
}
}
@Override
public void visit(Code obj) {
if(!shouldVisitCode){
return;
}
sawNoSuchElement = false;
sawCall = false;
super.visit(obj);
if (!sawNoSuchElement) {
BugInstance bug = new BugInstance(this, "IT_NO_SUCH_ELEMENT", sawCall ? LOW_PRIORITY : NORMAL_PRIORITY);
bug.addClassAndMethod(this);
bugReporter.reportBug(bug);
}
}
@Override
public void sawOpcode(int seen) {
if (seen == NEW && getClassConstantOperand().equals("java/util/NoSuchElementException")) {
sawNoSuchElement = true;
} else if (seen == INVOKESPECIAL || seen == INVOKEVIRTUAL || seen == INVOKEINTERFACE) {
sawCall = true;
String name = getNameConstantOperand().toLowerCase();
if (name.indexOf("next") >= 0
|| name.indexOf("previous") >= 0) {
sawNoSuchElement = true;
}
}
}
}