bdld_datummapbuilder.h

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/// @file bdld_datummapbuilder.h
///
/// The content of this file has been pre-processed for Doxygen.
///
 
 
// bdld_datummapbuilder.h                                             -*-C++-*-
#ifndef INCLUDED_BDLD_DATUMMAPBUILDER
#define INCLUDED_BDLD_DATUMMAPBUILDER
 
#include <bsls_ident.h>
BSLS_IDENT("$Id$ $CSID$")
 
/// @defgroup bdld_datummapbuilder bdld_datummapbuilder
/// @brief  Provide a utility to build a `Datum` object holding a map.
/// @addtogroup bdl
/// @{
/// @addtogroup bdld
/// @{
/// @addtogroup bdld_datummapbuilder
/// @{
///
/// <h1> Outline </h1>
/// * <a href="#bdld_datummapbuilder-purpose"> Purpose</a>
/// * <a href="#bdld_datummapbuilder-classes"> Classes </a>
/// * <a href="#bdld_datummapbuilder-description"> Description </a>
///   * <a href="#bdld_datummapbuilder-usage"> Usage </a>
///     * <a href="#bdld_datummapbuilder-example-1-basic-syntax"> Example 1: Basic Syntax </a>
///
/// # Purpose {#bdld_datummapbuilder-purpose}
/// Provide a utility to build a `Datum` object holding a map.
///
/// # Classes {#bdld_datummapbuilder-classes}
///
/// -  bdld::DatumMapBuilder: utility to build a `Datum` object holding a map
///
/// @see  bdld_datum, bdld_datummapowningkeysbuilder
///
/// # Description {#bdld_datummapbuilder-description}
/// This component defines a mechanism, `bdld::DatumMapBuilder`,
/// used to populate a `Datum` map value in an exception-safe manner.  In
/// addition to providing exception safety, a `DatumMapBuilder` is particularly
/// useful when the size of the map to be constructed is not known in advance.
/// The user can append elements to the datum map as needed, and when there are
/// no more elements to append the user calls `commit` or `sortAndCommit` and
/// ownership of the populated `Datum` object is transferred to the caller.
/// After calling `commit` or `sortAndCommit`, no additional elements can be
/// appended to the `Datum` map value.  Note that `sortAndCommit` method will
/// sort the populated map (by keys) and tag the resulting `Datum` map value as
/// sorted.  Also note that the user can insert elements in a (ascending) sorted
/// order and tag the map as sorted.  The behaviour is undefined if unsorted map
/// is tagged sorted.
///
/// The only difference between this component and
/// @ref bdld_datummapowningkeysbuilder  is that this component does not make a copy
/// of the map entries keys and the resulting `Datum` object does not own memory
/// for the map entries keys.
///
/// ## Usage {#bdld_datummapbuilder-usage}
///
///
/// This section illustrates intended use of this component.
///
/// ### Example 1: Basic Syntax {#bdld_datummapbuilder-example-1-basic-syntax}
///
///
/// Suppose we need a map for some personal data.  And the values in that map
/// can be different types.   The following code illustrates how to use
/// `bdld::DatumMapBuilder` to create such map easily.
///
/// First, we need data to fill our map:
/// @code
/// bslma::TestAllocator ta("test", veryVeryVerbose);
///
/// DatumMapEntry bartData[] = {
///     DatumMapEntry(StringRef("firstName"),
///                   Datum:: createStringRef("Bart", &ta)),
///     DatumMapEntry(StringRef("lastName"),
///                   Datum:: createStringRef("Simpson", &ta)),
///     DatumMapEntry(StringRef("gender"),
///                   Datum::createStringRef("male", &ta)),
///     DatumMapEntry(StringRef("age"), Datum::createInteger(10))
/// };
///
/// const size_t DATA_SIZE  = sizeof(bartData) / sizeof(DatumMapEntry);
/// @endcode
/// Next, we create an object of `DatumMapBuilder` class with initial capacity
/// sufficient for storing all our data:
/// @code
/// DatumMapBuilder builder(DATA_SIZE, &ta);
/// @endcode
/// Then, we load our builder with these data:
/// @code
/// for (size_t i = 0; i < DATA_SIZE; ++i) {
///     builder.pushBack(bartData[i].key(), bartData[i].value());
/// }
/// @endcode
/// Next, we adopt the map, held by our builder, by newly created `Datum`
/// object:
/// @code
/// Datum bart = builder.commit();
/// @endcode
/// Now, we can check that all data have been correctly added to the map at the
/// required order:
/// @code
/// assert(true == bart.isMap());
/// assert(DATA_SIZE == bart.theMap().size());
///
/// assert("firstName" == bart.theMap()[0].key());
/// assert(true        == bart.theMap()[0].value().isString());
/// assert("Bart"      == bart.theMap()[0].value().theString());
///
/// assert("lastName"  == bart.theMap()[1].key());
/// assert(true        == bart.theMap()[1].value().isString());
/// assert("Simpson"   == bart.theMap()[1].value().theString());
///
/// assert("gender"    == bart.theMap()[2].key());
/// assert(true        == bart.theMap()[2].value().isString());
/// assert("male"      == bart.theMap()[2].value().theString());
///
/// assert("age"       == bart.theMap()[3].key());
/// assert(true        == bart.theMap()[3].value().isInteger());
/// assert(10          == bart.theMap()[3].value().theInteger());
/// @endcode
/// Finally, we destroy the `Datum` object to release all allocated memory
/// correctly:
/// @code
/// Datum::destroy(bart, &ta);
/// assert(0 == ta.numBytesInUse());
/// @endcode
/// @}
/** @} */
/** @} */
 
/** @addtogroup bdl
 * @{
 */
/** @addtogroup bdld
 * @{
 */
/** @addtogroup bdld_datummapbuilder
 * @{
 */
 
#include <bdlscm_version.h>
 
#include <bdld_datum.h>
 
#include <bslma_bslallocator.h>
#include <bslma_usesbslmaallocator.h>
 
#include <bslmf_nestedtraitdeclaration.h>
 
#include <bsls_types.h>
 
 
namespace bdld {
 
                           // =====================
                           // class DatumMapBuilder
                           // =====================
 
/// This `class` provides a mechanism to build a `Datum` object having a map
/// value in an exception-safe manner.
///
/// See @ref bdld_datummapbuilder 
class DatumMapBuilder {
 
  public:
    // TYPES
 
    /// `SizeType` is an alias for a unsigned integral value, representing
    /// the capacity or size of a datum map.
    typedef bsls::Types::size_type SizeType;
 
    typedef bsl::allocator<char> allocator_type;
 
  private:
    // DATA
    DatumMutableMapRef d_mapping;    // mutable access to the datum map
    SizeType           d_capacity;   // capacity of the datum map
    bool               d_sorted;     // underlying map is sorted or not
    allocator_type     d_allocator;  // allocator for memory
 
  private:
    // NOT IMPLEMENTED
    DatumMapBuilder(const DatumMapBuilder&);
    DatumMapBuilder& operator=(const DatumMapBuilder&);
 
  public:
    // TRAITS
 
    /// `DatumMapBuilder` is allocator-aware.
    BSLMF_NESTED_TRAIT_DECLARATION(DatumMapBuilder, bslma::UsesBslmaAllocator);
 
    // CREATORS
 
    DatumMapBuilder();
    explicit DatumMapBuilder(const allocator_type &allocator);
    /// Create a `DatumMapBuilder` object that will administer the process
    /// of building a `Datum` map.  Optionally specify an `initialCapacity`
    /// for the map.  If `initialCapacity` is not supplied, the initial
    /// capacity of the map is 0.  Optionally specify an `allocator` (e.g.,
    /// the address of a `bslma::Allocator` object) to supply memory;
    /// otherwise, the default allocator is used.
    explicit DatumMapBuilder(
                           SizeType              initialCapacity,
                           const allocator_type& allocator = allocator_type());
 
    /// Destroy this object.  If this object is holding a datum map that has
    /// not been adopted, then the datum map is disposed after destroying
    /// each of its elements.
    ~DatumMapBuilder();
 
    // MANIPULATORS
 
    /// Append the specified array `entries` having the specified `size` to
    /// the `Datum` map being build by this object.  The behavior is
    /// undefined unless `0 != entries && 0 != size` and each element in
    /// `entries` that needs dynamic memory, is allocated with the same
    /// allocator that was used to construct this object.  The behavior is
    /// undefined if `commit` or `sortAndCommit` has already been called on
    /// this object.
    void append(const DatumMapEntry *entries, SizeType size);
 
    /// Return a `Datum` map value holding the elements supplied to
    /// `pushBack` or `append`.  The caller is responsible for releasing the
    /// resources of the returned `Datum` object.  Calling this method
    /// indicates that the caller is finished building the `Datum` map and
    /// no further values shall be appended.  The behavior is undefined if
    /// any method of this object, other than its destructor, is called
    /// after `commit` invocation.
    Datum commit();
 
    /// Append the entry with the specified `key` and the specified `value`
    /// to the `Datum` map being build by this object.  The behavior is
    /// undefined if `value` needs dynamic memory and was allocated using a
    /// different allocator than the one used to construct this object.  The
    /// behavior is also undefined if `commit` or `sortAndCommit` has
    /// already been called on this object.
    void pushBack(const bslstl::StringRef& key, const Datum& value);
 
    /// Mark the Datum map being built by this object as sorted if the
    /// specified `value` is `true` and mark it unsorted otherwise.  This
    /// function does not sort the map entries, or mark them to be sorted
    /// later; the function should be used to indicate if the entries are
    /// being appended in sorted order.  The behavior is undefined if
    /// `commit` or `sortAndCommit` has already been called on this object.
    /// The behavior is also undefined if the map being constructed is
    /// marked sorted, but the entries are not appended in sorted order.
    /// Note also that the map being constructed is marked unsorted by
    /// default.
    void setSorted(bool value);
 
    /// Return a `Datum` map value holding the elements supplied to
    /// `pushBack` or `append` sorted by their keys.  The caller is
    /// responsible for releasing the resources of the returned `Datum`
    /// object.  Calling this method indicates that the caller is finished
    /// building the `Datum` map and no further values shall be appended.
    /// The behavior is undefined if any method of this object, other than
    /// its destructor, is called after `sortAndCommit` invocation.
    Datum sortAndCommit();
 
    // ACCESSORS
 
    /// Return the capacity of the held `Datum` map.  The behavior is
    /// undefined if `commit` or `sortAndCommit` has already been called on
    /// this object.  Note that similar to the capacity of a `vector`, the
    /// returned capacity has no bearing on the value of the `Datum` being
    /// constructed, but does indicate at which point additional memory will
    /// be required to grow the `Datum` map being built.
    SizeType capacity() const;
 
    /// 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;
 
    /// Return the size of the held `Datum` map.  The behavior is undefined
    /// if `commit` or `sortAndCommit` has already been called on this
    /// object.
    SizeType size() const;
};
 
// ============================================================================
//                               INLINE DEFINITIONS
// ============================================================================
 
                      // ---------------------
                      // class DatumMapBuilder
                      // ---------------------
 
// ACCESSORS
inline
DatumMapBuilder::SizeType DatumMapBuilder::capacity() const
{
    return d_capacity;
}
 
inline
DatumMapBuilder::allocator_type DatumMapBuilder::get_allocator() const
{
    return d_allocator;
}
 
inline
DatumMapBuilder::SizeType DatumMapBuilder::size() const
{
    if (d_capacity) {
        return *d_mapping.size();                                     // RETURN
    }
    return 0;
}
 
}  // close package namespace
 
 
#endif
 
// ----------------------------------------------------------------------------
// Copyright 2014 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 ----------------------------------
 
/** @} */
/** @} */
/** @} */