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Diffstat (limited to 'comphelper/inc/comphelper/optionalvalue.hxx')
-rw-r--r-- | comphelper/inc/comphelper/optionalvalue.hxx | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/comphelper/inc/comphelper/optionalvalue.hxx b/comphelper/inc/comphelper/optionalvalue.hxx new file mode 100644 index 000000000000..f63e1cde51aa --- /dev/null +++ b/comphelper/inc/comphelper/optionalvalue.hxx @@ -0,0 +1,187 @@ +/************************************************************************* + * + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * Copyright 2000, 2010 Oracle and/or its affiliates. + * + * OpenOffice.org - a multi-platform office productivity suite + * + * This file is part of OpenOffice.org. + * + * OpenOffice.org is free software: you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License version 3 + * only, as published by the Free Software Foundation. + * + * OpenOffice.org 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 version 3 for more details + * (a copy is included in the LICENSE file that accompanied this code). + * + * You should have received a copy of the GNU Lesser General Public License + * version 3 along with OpenOffice.org. If not, see + * <http://www.openoffice.org/license.html> + * for a copy of the LGPLv3 License. + * + ************************************************************************/ + +#ifndef _COMPHELPER_OPTIONALVALUE_HXX +#define _COMPHELPER_OPTIONALVALUE_HXX + +#include <com/sun/star/uno/Any.hxx> + +namespace comphelper +{ + +/** @deprecated + Use boost/optional.hpp instead. +*/ + + + + /* Definition of OptionalValue template */ + + /** This template provides 'optionality' for the given value type. + + Especially for PODs, optionality either needs to be achieved + by special 'magic' values (i.e. an int value is not set when + -1 etc.), or an additional bool denoting value + validity. This template encapsulates the latter into an atomic + data type. + + @tpl Element + The value type that should be made optional + */ + template< typename Element > class OptionalValue + { + public: + typedef Element ValueType; + + /** Default-construct the value. + + A default-constructed value is not valid. You have to + explicitely set a value. + */ + OptionalValue() : + maValue(), + mbValid( false ) + { + } + + /** Construct the value. + + An explicitely constructed value is valid. To create an + invalid value, you have to default-construct it. + */ + OptionalValue( const Element& rValue ) : + maValue( rValue ), + mbValid( true ) + { + } + + // default copy/assignment operators are okay here + //OptionalValue(const OptionalValue&); + //OptionalValue& operator=( const OptionalValue& ); + + /** Query whether the value is valid + + @return true, if this object contains a valid value. + */ + bool isValid() const + { + return mbValid; + } + + /** Set a value. + + After this call, the object contains a valid value. + */ + void setValue( const Element& rValue ) + { + maValue = rValue; + mbValid = true; + } + + /** Get the value. + + The return value of this method is undefined, if the + object does not contain a valid value. + */ + Element getValue() const + { + return maValue; + } + + /** Clear the value. + + After this call, the object no longer contains a valid + value. + */ + void clearValue() + { + mbValid = false; + } + + // NOTE: The following two methods would optimally have been + // implemented as operator>>=/operator<<= + // overloads. Unfortunately, there's already a templatized + // version for those two methods, namely for UNO interface + // types. Adding a second would lead to ambiguities. + + /** Export the value into an Any. + + This method extracts the value into an Any. If the value + is invalid, the Any will be cleared. + + @return true, if the value has been successfully + transferred to the Any. Clearing the Any from an invalid + object is also considered a successful operation. + */ + bool exportValue( ::com::sun::star::uno::Any& o_rAny ) + { + o_rAny.clear(); + + if( isValid() ) + { + if( !(o_rAny <<= getValue()) ) + return false; + } + + return true; + } + + /** Import the value from an Any. + + This method imports the value from an Any. If the Any + is invalid, the object will get an invalid value. + + @return true, if the value has been successfully + transferred from the Any. Setting the value to invalid + from an empty Any is also considered a successful + operation. + */ + bool importValue( const ::com::sun::star::uno::Any& rAny ) + { + clearValue(); + + if( rAny.hasValue() ) + { + Element tmp; + + if( !(rAny >>= tmp) ) + return false; + + setValue( tmp ); + } + + return true; + } + + private: + Element maValue; + bool mbValid; + }; + +} + +#endif /* _COMPHELPER_OPTIONALVALUE_HXX */ |