ball_defaultattributecontainer.h

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/// @file ball_defaultattributecontainer.h
///
/// The content of this file has been pre-processed for Doxygen.
///
 
 
// ball_defaultattributecontainer.h                                   -*-C++-*-
#ifndef INCLUDED_BALL_DEFAULTATTRIBUTECONTAINER
#define INCLUDED_BALL_DEFAULTATTRIBUTECONTAINER
 
#include <bsls_ident.h>
BSLS_IDENT("$Id: $")
 
/// @defgroup ball_defaultattributecontainer ball_defaultattributecontainer
/// @brief  Provide a default container for storing attribute name/value pairs.
/// @addtogroup bal
/// @{
/// @addtogroup ball
/// @{
/// @addtogroup ball_defaultattributecontainer
/// @{
///
/// <h1> Outline </h1>
/// * <a href="#ball_defaultattributecontainer-purpose"> Purpose</a>
/// * <a href="#ball_defaultattributecontainer-classes"> Classes </a>
/// * <a href="#ball_defaultattributecontainer-description"> Description </a>
///   * <a href="#ball_defaultattributecontainer-thread-safety"> Thread Safety </a>
///   * <a href="#ball_defaultattributecontainer-usage"> Usage </a>
///     * <a href="#ball_defaultattributecontainer-example-1-basic-usage-of-ball-defaultattributecontainer"> Example 1: Basic Usage of ball::DefaultAttributeContainer </a>
///
/// # Purpose {#ball_defaultattributecontainer-purpose}
/// Provide a default container for storing attribute name/value pairs.
///
/// # Classes {#ball_defaultattributecontainer-classes}
///
/// -  ball::DefaultAttributeContainer: a collection of unique attributes
///
/// @see  ball_attributecontainer
///
/// # Description {#ball_defaultattributecontainer-description}
/// This component provides a default implementation of the
/// `ball::AttributeContainer` protocol, `ball::DefaultAttributeContainer`
/// providing an `unordered_set`-based container of `ball::Attribute` values.
/// Each attribute within the default attribute container holds a
/// (case-sensitive) name and a value, which may be an `int`, a 64-bit integer,
/// or a `bsl::string`.
///
/// This component participates in the implementation of "Rule-Based Logging".
/// For more information on how to use that feature, please see the package
/// level documentation and usage examples for "Rule-Based Logging".
///
/// ## Thread Safety {#ball_defaultattributecontainer-thread-safety}
///
///
/// `ball::DefaultAttributeContainer` is *const* *thread-safe*, meaning that
/// accessors may be invoked concurrently from different threads, but it is not
/// safe to access or modify a `ball::DefaultAttributeContainer` in one thread
/// while another thread modifies the same object.
///
/// ## Usage {#ball_defaultattributecontainer-usage}
///
///
/// This section illustrates the intended use of this component.
///
/// ### Example 1: Basic Usage of ball::DefaultAttributeContainer {#ball_defaultattributecontainer-example-1-basic-usage-of-ball-defaultattributecontainer}
///
///
/// A `ball::DefaultAttributeContainer` initially has no attributes when created
/// by the default constructor:
/// @code
///   ball::DefaultAttributeContainer attributeContainer;
/// @endcode
/// Let's now create some attributes and add them to the attribute map:
/// @code
///   ball::Attribute a1("uuid", 1111);
///   ball::Attribute a2("sid", "111-1");
///   assert(true == attributeContainer.addAttribute(a1));
///   assert(true == attributeContainer.addAttribute(a2));
/// @endcode
/// New attributes with a name that already exists in the map can be added, as
/// long as they have a different value:
/// @code
///   ball::Attribute a3("uuid", 2222);
///   ball::Attribute a4("sid", "222-2");
///   assert(true == attributeContainer.addAttribute(a3));
///   assert(true == attributeContainer.addAttribute(a4));
/// @endcode
/// But attributes having the same name and value cannot be added:
/// @code
///   ball::Attribute a5("uuid", 1111);                 // same as 'a1'
///   assert(false == attributeContainer.addAttribute(a5));
/// @endcode
/// Note that the attribute name is case-sensitive:
/// @code
///   ball::Attribute a6("UUID", 1111);
///   assert(true == attributeContainer.addAttribute(a6));
/// @endcode
/// Existing attributes can be looked up by the `hasValue` method:
/// @code
///   assert(true == attributeContainer.hasValue(a1));
///   assert(true == attributeContainer.hasValue(a2));
///   assert(true == attributeContainer.hasValue(a3));
///   assert(true == attributeContainer.hasValue(a4));
///   assert(true == attributeContainer.hasValue(a5));
///   assert(true == attributeContainer.hasValue(a6));
/// @endcode
/// Or removed by the `removeAttribute` method:
/// @code
///   defaultattributecontainer.removeAttribute(a1);
///   assert(false == attributeContainer.hasValue(a1));
/// @endcode
/// Also, the `ball::DefaultAttributeContainer` class provides an iterator:
/// @code
///   ball::DefaultAttributeContainer::const_iterator iter =
///                                                 attributeContainer.begin();
///   for ( ; iter != attributeContainer.end(); ++iter ) {
///       bsl::cout << *iter << bsl::endl;
///   }
/// @endcode
/// Finally, we can provide a visitor functor and visit all attributes in the
/// container.  Note that this usage example uses lambdas and requires C++11.
/// Lambdas can be replaced with named functions for C++03.
/// @code
///   bsl::vector<ball::Attribute> result;
///   attributeContainer.visitAttributes(
///       [&result](const ball::Attribute& attribute)
///         {
///             result.push_back(attribute);
///         });
///   assert(4 == result.size());
/// @endcode
/// @}
/** @} */
/** @} */
 
/** @addtogroup bal
 * @{
 */
/** @addtogroup ball
 * @{
 */
/** @addtogroup ball_defaultattributecontainer
 * @{
 */
 
#include <balscm_version.h>
 
#include <ball_attribute.h>
#include <ball_attributecontainer.h>
 
#include <bslma_allocator.h>
#include <bslma_bslallocator.h>
#include <bslma_usesbslmaallocator.h>
 
#include <bslmf_nestedtraitdeclaration.h>
 
#include <bsls_keyword.h>
 
#include <bsl_functional.h>
#include <bsl_unordered_set.h>
 
 
namespace ball {
 
                    // ===============================
                    // class DefaultAttributeContainer
                    // ===============================
 
/// A `DefaultAttributeContainer` object contains a collection of (unique)
/// attributes values.
///
/// See @ref ball_defaultattributecontainer 
class DefaultAttributeContainer : public AttributeContainer {
 
    // PRIVATE TYPES
 
    /// A hash functor for `Attribute`.
    struct AttributeHash {
 
      private:
        // CLASS DATA
        static int s_hashtableSize;  // default hashtable size for which the
                                     // hash value is calculated
      public:
        // ACCESSORS
 
        /// Return the hash value of the specified `attribute`.
        int operator()(const Attribute& attribute) const
        {
            return Attribute::hash(attribute, s_hashtableSize);
        }
    };
 
    // CLASS DATA
    static int                   s_initialSize;   // initial size of the
                                                  // attribute map
 
    // DATA
    bsl::unordered_set<Attribute, AttributeHash>
                                 d_attributeSet;  // hash table that stores
                                                  // all the attributes
                                                  // managed by this object
 
  public:
    // TRAITS
    BSLMF_NESTED_TRAIT_DECLARATION(DefaultAttributeContainer,
                                   bslma::UsesBslmaAllocator);
 
    // TYPES
 
    /// This `typedef` is an alias for the allocator used by this object.
    typedef bsl::allocator<char> allocator_type;
 
    typedef bsl::unordered_set<Attribute, AttributeHash>::const_iterator
                                 const_iterator;  // type of iterator for
                                                  // iterating through the
                                                  // non-modifiable attributes
                                                  // managed by this object
 
    // CREATORS
 
    DefaultAttributeContainer();
    /// Create an empty `DefaultAttributeContainer` object.  Optionally
    /// specify an `allocator` (e.g., the address of a `bslma::Allocator`
    /// object) to supply memory; otherwise, the default allocator is used.
    explicit DefaultAttributeContainer(const allocator_type& allocator);
 
    /// Create a `DefaultAttributeContainer` object having the same value as
    /// the specified `original` object.  Optionally specify an `allocator`
    /// (e.g., the address of a `bslma::Allocator` object) to supply memory;
    /// otherwise, the default allocator is used.
    DefaultAttributeContainer(
               const DefaultAttributeContainer&  original,
               const allocator_type&             allocator = allocator_type());
 
    /// Destroy this object.
    ~DefaultAttributeContainer() BSLS_KEYWORD_OVERRIDE;
 
    // MANIPULATORS
 
    /// Assign to this object the value of the specified `rhs` object, and
    /// return a non-`const` reference to this object.
    DefaultAttributeContainer& operator=(const DefaultAttributeContainer& rhs);
 
    /// Add an attribute having the specified `value` to this object.
    /// Return `true` on success and `false` if an attribute having the
    /// same `value` already exists in this object.
    bool addAttribute(const Attribute& value);
 
    /// Remove the attribute having the specified `value` from this object.
    /// Return the `true` on success and `false` if the attribute having the
    /// `value` does not exist in this object.
    bool removeAttribute(const Attribute& value);
 
    /// Remove every attribute in this attribute set.
    void removeAllAttributes();
 
    // ACCESSORS
 
    /// Return the number of attributes managed by this object.
    int numAttributes() const;
 
    /// Return `true` if the attribute having specified `value` exists in
    /// this object, and `false` otherwise.
    bool hasValue(const Attribute& value) const BSLS_KEYWORD_OVERRIDE;
 
    /// Return an iterator pointing at the beginning of the (unordered)
    /// sequence of attributes managed by this map, or `end()` if
    /// `numAttributes()` is 0.
    const_iterator begin() const;
 
    /// Return an iterator pointing at one past the end of the map.
    const_iterator end() const;
 
    /// Format this object to the specified output `stream` at the (absolute
    /// value of) the optionally specified indentation `level` and return a
    /// reference to `stream`.  If `level` is specified, optionally specify
    /// `spacesPerLevel`, the number of spaces per indentation level for
    /// this and all of its nested objects.  If `level` is negative,
    /// suppress indentation of the first line.  If `spacesPerLevel` is
    /// negative, format the entire output on one line, suppressing all but
    /// the initial indentation (as governed by `level`).  If `stream` is
    /// not valid on entry, this operation has no effect.
    bsl::ostream& print(bsl::ostream& stream,
                        int           level = 0,
                        int           spacesPerLevel = 4) const
                                                         BSLS_KEYWORD_OVERRIDE;
 
    /// Invoke the specified `visitor` function for all attributes in this
    /// container.
    void visitAttributes(
             const bsl::function<void(const ball::Attribute&)> &visitor) const
                                                         BSLS_KEYWORD_OVERRIDE;
 
                                  // Aspects
 
    /// Return the allocator used by this object to supply memory.  Note
    /// that if no allocator was supplied at construction the default
    /// allocator in effect at construction is used.
    allocator_type get_allocator() const;
 
};
 
// FREE OPERATORS
 
/// Return `true` if the specified `lhs` and `rhs` objects have the same
/// value, and `false` otherwise.  Two `DefaultAttributeContainer` objects
/// have the same value if they contain the same number of (unique)
/// attributes, and every attribute that appears in one object also appears
/// in the other.
bool operator==(const DefaultAttributeContainer& lhs,
                const DefaultAttributeContainer& rhs);
 
/// Return `true` if the specified `lhs` and `rhs` objects do not have the
/// same value, and `false` otherwise.  Two `DefaultAttributeContainer`
/// objects do not have the same value if they contain differing numbers of
/// attributes or if there is at least one attribute that appears in one
/// object, but not in the other.
bool operator!=(const DefaultAttributeContainer& lhs,
                const DefaultAttributeContainer& rhs);
 
/// Write the value of the specified `attributeContainer` to the specified
/// `output` stream in some single-line, human readable format.  Return the
/// `output` stream.
bsl::ostream& operator<<(bsl::ostream&                    output,
                         const DefaultAttributeContainer& attributeContainer);
 
// ============================================================================
//                              INLINE DEFINITIONS
// ============================================================================
 
                    // -------------------------------
                    // class DefaultAttributeContainer
                    // -------------------------------
 
// CREATORS
inline
DefaultAttributeContainer::DefaultAttributeContainer()
: d_attributeSet(s_initialSize,                    // initial size
                 AttributeHash(),                  // hash functor
                 bsl::equal_to<Attribute>(),       // equal functor
                 allocator_type())
{
}
 
inline
DefaultAttributeContainer::DefaultAttributeContainer(
                                               const allocator_type& allocator)
: d_attributeSet(s_initialSize,                    // initial size
                 AttributeHash(),                  // hash functor
                 bsl::equal_to<Attribute>(),       // equal functor
                 allocator)
{
}
 
inline
DefaultAttributeContainer::DefaultAttributeContainer(
                                   const DefaultAttributeContainer&  original,
                                   const allocator_type&             allocator)
: d_attributeSet(original.d_attributeSet, allocator)
{
}
 
inline
DefaultAttributeContainer::~DefaultAttributeContainer()
{
}
 
// MANIPULATORS
inline
bool DefaultAttributeContainer::addAttribute(const Attribute& value)
{
    return d_attributeSet.insert(value).second;
}
 
inline
bool DefaultAttributeContainer::removeAttribute(const Attribute& value)
{
    return d_attributeSet.erase(value) != 0;
}
 
inline
void DefaultAttributeContainer::removeAllAttributes()
{
    d_attributeSet.clear();
}
 
// ACCESSORS
inline
int DefaultAttributeContainer::numAttributes() const
{
    return static_cast<int>(d_attributeSet.size());
}
 
inline
DefaultAttributeContainer::const_iterator
DefaultAttributeContainer::begin() const
{
    return d_attributeSet.begin();
}
 
inline
DefaultAttributeContainer::const_iterator
DefaultAttributeContainer::end() const
{
    return d_attributeSet.end();
}
 
                                  // Aspects
 
inline
DefaultAttributeContainer::allocator_type
DefaultAttributeContainer::get_allocator() const
{
    return d_attributeSet.get_allocator();
}
 
}  // close package namespace
 
// FREE OPERATORS
inline
bsl::ostream& ball::operator<<(
                           bsl::ostream&                    output,
                           const DefaultAttributeContainer& attributeContainer)
{
    return attributeContainer.print(output, 0, -1);
}
 
 
 
#endif
 
// ----------------------------------------------------------------------------
// Copyright 2015 Bloomberg Finance L.P.
//
// Licensed 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
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ----------------------------- END-OF-FILE ----------------------------------
 
/** @} */
/** @} */
/** @} */