PMD Xpath's issues with PrimaryPrefix and nested condtions

[ttback]

I spent about 4 hours trying to make PMD being able to validate my Java code but XPath proved to be very painful to work with when developing fairly original custom rules.

My rule requires me to apply them only to methods without 'get' as part of their name. In another words, my rules need to apply to only non-getter methods in the class. I know to get a hold of all the non-getter methods, I can use

//MethodDeclarator[not(contains(@Image,'get'))]

However, I don't know the syntax about where I insert my logic for the rules. Is it like

//MethodDeclarator[
not(contains(@Image,'get'))

'Some Rule Statements'
]
I saw the use of . in the beginning of statement inside [] in some example code. what are they used for?

For my rule statements, I need PMD XPath to be able to distinguish between the following lines:
int var = this.nocall;
int var = nocall;

From AST, I see that PrimaryPrefix:this But I am unable to select the first statement with any of the following statements:
//PrimaryPrefix

//PrimaryExpression/PrimaryPrefix]

//PrimaryPrefix[@image='this']

I wonder if anyone has a hint on how to retrieve all the expression with 'this.' in assignment part through XPath.

Example code trying to parse:

class testRuleOne {
    private int nocall;
    public void myMethod() {
        int var = this.nocall;
        var = this.getNoCall();
    }
}

Raw XML from AST:

<MethodDeclaration Abstract="false" BeginColumn="16" BeginLine="3" EndColumn="9" EndLine="6" Final="false" Image="" InterfaceMember="false" Label="" MethodName="myMethod" Modifiers="1" Native="false" PackagePrivate="false" Private="false" Protected="false" Public="true" Static="false" Strictfp="false" Synchronized="false" SyntacticallyAbstract="false" SyntacticallyPublic="true" Transient="false" Void="true" Volatile="false">
                    <ResultType BeginColumn="16" BeginLine="3" EndColumn="19" EndLine="3" Image="" Label="" Void="true" returnsArray="false"/>
                    <MethodDeclarator BeginColumn="21" BeginLine="3" EndColumn="30" EndLine="3" Image="myMethod" Label="" ParameterCount="0">
                        <FormalParameters BeginColumn="29" BeginLine="3" EndColumn="30" EndLine="3" Image="" Label="" ParameterCount="0"/>
                    </MethodDeclarator>
                    <Block BeginColumn="32" BeginLine="3" EndColumn="9" EndLine="6" Image="" Label="" containsComment="false">
                        <BlockStatement Allocation="false" BeginColumn="17" BeginLine="4" EndColumn="38" EndLine="4" Image="" Label="">
                            <LocalVariableDeclaration Abstract="false" Array="false" ArrayDepth="0" BeginColumn="17" BeginLine="4" EndColumn="37" EndLine="4" Final="false" Image="" Label="" Modifiers="0" Native="false" PackagePrivate="true" Private="false" Protected="false" Public="false" Static="false" Strictfp="false" Synchronized="false" Transient="false" VariableName="var" Volatile="false">
                                <Type Array="false" ArrayDepth="0" BeginColumn="17" BeginLine="4" EndColumn="19" EndLine="4" Image="" Label="" TypeImage="int">
                                    <PrimitiveType Array="false" ArrayDepth="0" BeginColumn="17" BeginLine="4" Boolean="false" EndColumn="19" EndLine="4" Image="int" Label=""/>
                                </Type>
                                <VariableDeclarator BeginColumn="21" BeginLine="4" EndColumn="37" EndLine="4" Image="" Label="">
                                    <VariableDeclaratorId Array="false" ArrayDepth="0" BeginColumn="21" BeginLine="4" EndColumn="23" EndLine="4" ExceptionBlockParameter="false" Image="var" Label=""/>
                                    <VariableInitializer BeginColumn="27" BeginLine="4" EndColumn="37" EndLine="4" Image="" Label="">
                                        <Expression BeginColumn="27" BeginLine="4" EndColumn="37" EndLine="4" Image="" Label="">
                                            <PrimaryExpression BeginColumn="27" BeginLine="4" EndColumn="37" EndLine="4" Image="" Label="">
                                                <PrimaryPrefix BeginColumn="27" BeginLine="4" EndColumn="30" EndLine="4" Image="" Label="this" SuperModifier="false" ThisModifier="true"/>
                                                <PrimarySuffix ArgumentCount="" Arguments="false" ArrayDereference="false" BeginColumn="31" BeginLine="4" EndColumn="37" EndLine="4" Image="nocall" Label=""/>
                                            </PrimaryExpression>
                                        </Expression>
                                    </VariableInitializer>
                                </VariableDeclarator>
                            </LocalVariableDeclaration>
                        </BlockStatement>
                        <BlockStatement Allocation="false" BeginColumn="17" BeginLine="5" EndColumn="39" EndLine="5" Image="" Label="">