// bdld_datummapbuilder.h -*-C++-*-
#ifndef INCLUDED_BDLD_DATUMMAPBUILDER
#define INCLUDED_BDLD_DATUMMAPBUILDER
#include <bsls_ident.h>
BSLS_IDENT("$Id$ $CSID$")
//@PURPOSE: Provide a utility to build a 'Datum' object holding a map.
//
//@CLASSES:
// bdld::DatumMapBuilder: utility to build a 'Datum' object holding a map
//
//@SEE_ALSO: bdld_datum, bdld_datummapowningkeysbuilder
//
//@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
// '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
///-----
// This section illustrates intended use of this component.
//
///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:
//..
// 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);
//..
// Next, we create an object of 'DatumMapBuilder' class with initial capacity
// sufficient for storing all our data:
//..
// DatumMapBuilder builder(DATA_SIZE, &ta);
//..
// Then, we load our builder with these data:
//..
// for (size_t i = 0; i < DATA_SIZE; ++i) {
// builder.pushBack(bartData[i].key(), bartData[i].value());
// }
//..
// Next, we adopt the map, held by our builder, by newly created 'Datum'
// object:
//..
// Datum bart = builder.commit();
//..
// Now, we can check that all data have been correctly added to the map at the
// required order:
//..
// 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());
//..
// Finally, we destroy the 'Datum' object to release all allocated memory
// correctly:
//..
// Datum::destroy(bart, &ta);
// assert(0 == ta.numBytesInUse());
//..
#include <bdlscm_version.h>
#include <bdld_datum.h>
#include <bslma_stdallocator.h>
#include <bslma_usesbslmaallocator.h>
#include <bslmf_nestedtraitdeclaration.h>
#include <bsls_types.h>
namespace BloombergLP {
namespace bdld {
// =====================
// class DatumMapBuilder
// =====================
class DatumMapBuilder {
// This 'class' provides a mechanism to build a 'Datum' object having a map
// value in an exception-safe manner.
public:
// TYPES
typedef bsls::Types::size_type SizeType;
// 'SizeType' is an alias for a unsigned integral value, representing
// the capacity or size of a datum map.
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
BSLMF_NESTED_TRAIT_DECLARATION(DatumMapBuilder, bslma::UsesBslmaAllocator);
// 'DatumMapBuilder' is allocator-aware.
// CREATORS
DatumMapBuilder();
explicit DatumMapBuilder(const allocator_type &allocator);
explicit DatumMapBuilder(
SizeType initialCapacity,
const allocator_type& allocator = allocator_type());
// 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.
~DatumMapBuilder();
// 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.
// MANIPULATORS
void append(const DatumMapEntry *entries, SizeType size);
// 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.
Datum commit();
// 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.
void pushBack(const bslstl::StringRef& key, const Datum& value);
// 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 setSorted(bool 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.
Datum sortAndCommit();
// 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.
// ACCESSORS
SizeType capacity() const;
// 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.
allocator_type get_allocator() 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.
SizeType size() const;
// Return the size of the held 'Datum' map. The behavior is undefined
// if 'commit' or 'sortAndCommit' has already been called on this
// object.
};
// ============================================================================
// 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
} // close enterprise 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 ----------------------------------