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+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed
+ * with this work for additional information regarding copyright
+ * ownership. The ASF licenses this file to you under the Apache
+ * License, Version 2.0 (the "License"); you may not use this file
+ * except in compliance with the License. You may obtain a copy of
+ * the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#pragma once
+
+#include <rtl/ustring.hxx>
+#include <com/sun/star/uno/Reference.hxx>
+
+// forward declaractions
+namespace com::sun::star
+{
+ namespace xml
+ {
+ namespace dom { class XNode; }
+ namespace dom { class XNodeset; }
+ namespace xpath { class XXPathAPI; }
+ namespace xpath { class XXPathObject; }
+ }
+ namespace container { class XNameContainer; }
+}
+namespace xforms { class EvaluationContext; }
+
+
+namespace xforms
+{
+
+/** ComputedExpression represents an XPath Expression and caches results.
+ *
+ * As this class has no virtual methods, it should never be used
+ * polymorphically. */
+class ComputedExpression
+{
+ /// the expression string
+ OUString msExpression;
+
+ /// is msExpression empty?
+ bool mbIsEmpty;
+
+protected:
+ /// is msExpression a simple expression?
+ bool mbIsSimple;
+
+ /// the result from the last bind
+ css::uno::Reference<css::xml::xpath::XXPathObject> mxResult;
+
+
+ /// implementation of isSimpleExpression
+ bool _checkExpression( const char* pExpression ) const;
+
+ /// allow manipulation of the expression before it is evaluated
+ // the default implementation is to do nothing...
+ const OUString& _getExpressionForEvaluation() const { return msExpression; }
+
+ /// obtain a (suitable) XPathAPI implementation
+ static css::uno::Reference<css::xml::xpath::XXPathAPI> _getXPathAPI(const xforms::EvaluationContext& aContext);
+
+ /// evaluate the expression relative to the content node.
+ bool _evaluate( const xforms::EvaluationContext& rContext,
+ const OUString& sExpression );
+
+
+public:
+ ComputedExpression();
+ ~ComputedExpression();
+
+
+ /// get the expression string
+ const OUString& getExpression() const { return msExpression;}
+
+ /// set a new expression string
+ void setExpression( const OUString& rExpression );
+
+ /// do we have an actual expression?
+ bool isEmptyExpression() const { return mbIsEmpty;}
+
+ /// heuristically determine whether this expression is 'simple',
+ /// i.e. whether its value will change depending on the values
+ /// of other nodes
+ bool isSimpleExpression() const;
+
+
+ /// evaluate the expression relative to the content node.
+ bool evaluate( const xforms::EvaluationContext& rContext );
+
+
+ /// does this expression have a value?
+ bool hasValue() const;
+
+
+ /// remove value/evaluate results
+ void clear();
+
+
+ // get the result of this expression as string/bool/...
+ // (Results will be based on the last call of evaluate(..). The caller
+ // must call evaluate to ensure current results.)
+ css::uno::Reference<css::xml::xpath::XXPathObject> const & getXPath() const { return mxResult;}
+ bool getBool( bool bDefault = false ) const;
+ OUString getString() const;
+
+};
+
+} // namespace xforms
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */