UseVarArgsResolution.java

package quickfix;

import java.util.List;

import edu.umd.cs.findbugs.BugInstance;
import edu.umd.cs.findbugs.plugin.eclipse.quickfix.BugResolution;
import edu.umd.cs.findbugs.plugin.eclipse.quickfix.exception.BugResolutionException;

import org.eclipse.jdt.core.dom.ArrayType;
import org.eclipse.jdt.core.dom.CompilationUnit;
import org.eclipse.jdt.core.dom.Dimension;
import org.eclipse.jdt.core.dom.MethodDeclaration;
import org.eclipse.jdt.core.dom.SingleVariableDeclaration;
import org.eclipse.jdt.core.dom.Type;
import org.eclipse.jdt.core.dom.rewrite.ASTRewrite;
import org.eclipse.jdt.core.dom.rewrite.ListRewrite;

import util.TraversalUtil;

public class UseVarArgsResolution extends BugResolution {

    public static final String DESCRIPTION = "Changing the last parameter to use varargs instead of an array is backwards compatible and makes it easier for clients to call the method";

    @Override
    protected boolean resolveBindings() {
        return false;
    }

    @Override
    public String getDescription() {
        return DESCRIPTION;
    }

    @Override
    protected void repairBug(ASTRewrite rewrite, CompilationUnit workingUnit, BugInstance bug) throws BugResolutionException {
        MethodDeclaration thisMethod = TraversalUtil.findEnclosingMethod(workingUnit, bug.getPrimarySourceLineAnnotation());

        @SuppressWarnings("unchecked")
        List<SingleVariableDeclaration> params = thisMethod.parameters();
        SingleVariableDeclaration lastParam = params.get(params.size() - 1);

        removeArrayDimensions(rewrite, lastParam);
        rewrite.set(lastParam, SingleVariableDeclaration.VARARGS_PROPERTY, Boolean.TRUE, null);

        Type lastType = lastParam.getType();
        if (lastType.isArrayType()) { // can be false for the int a[] declaration
            Type bareType = ((ArrayType) lastType).getElementType();
            rewrite.replace(lastType, rewrite.createCopyTarget(bareType), null);
        }
    }

    @SuppressWarnings({ "unchecked" })
    private void removeArrayDimensions(ASTRewrite rewrite, SingleVariableDeclaration lastParam) {
        // removes any additional dimensions (for variables declared like int a[])
        ListRewrite extraDimensionsRewrite = rewrite.getListRewrite(lastParam,
                SingleVariableDeclaration.EXTRA_DIMENSIONS2_PROPERTY);
        List<Dimension> extraDimensions = lastParam.extraDimensions();
        for (Dimension d : extraDimensions) {
            extraDimensionsRewrite.remove(d, null);
        }
    }

}