C++ XmlBeansxx / XmlBeanscxx

XML schema based data processing through auto-generated C++ code.

The XmlBeansxx (as named by its author) or the XmlBeanscxx (as named by the Apache group) framework was inspired by the Apache XML Beans Java framwork.

Related YoLinux Tutorials:

°C++ Info, links

°C++ String Class

°C++ Templates

°C++ STL vector, list

°C++ Log4cxx logging

°MS/Visual C++ Practices

°C++ Memory corruption and leaks

°YoLinux Tutorials Index

Free Information Technology Magazines and Document Downloads

Free Information Technology Software and Development Magazine Subscriptions and Document Downloads

The XmlBeansxx program and process is a C++ code generation program driven by an XSD XML schema definition. XmlBeansxx can read an XSD schema definition and auto-generate C++ classes to parse and access an XML file which meets the schema definition. XmlBeansxx will generate C++ classes and library which can be compiled in or linked into your C++ program.

Prerequisites:

• autoconf and automake (or cmake)
  • RHEL5 (autoconf: 2.59, automake: 1.9.6): yum install autoconf automake
  • Ubuntu 8.10 (autoconf: 2.61, automake: 1.10): apt-get install autoconf automake
• libtool:
  • RHEL5 (libtool: 1.5.22): yum install libtool
    (So old it leads to problems! See pitfalls below)
  • Ubuntu 8.10 (libtool: 2.2.4): apt-get install libtool
• gmp (http://swox.com/gmp/)
  • RHEL5 (gmp 4.1.4): yum install gmp gmp-devel
  • Ubuntu 8.10 (libgmpxx4 4.2.2, libgmp3-dev: 4.2.2): sudo apt-get install libgmpxx4 libgmp3-dev
• boost and boost-devel
  • RHEL6 (boost: 1.41.0): yum install boost boost-devel boost-test boost-date-time boost-thread boost-system boost-signals boost-filesystem boost-regex boost-program-options boost-wave boost-graph boost-python boost-serialization boost-iostreams
  • RHEL5 (boost: 1.33.1): yum install boost boost-devel
  • Ubuntu 8.10 (libboost-dev: 1.34.1): sudo apt-get install libboost-dev
• xerces-c: See the YoLInux.com Xerces-C 2.7.0 tutorial (Note that XmlBeansxx 0.9.8 works with Xerces-C 2.7.0 and not Xerces-C 3.0.1.)
  • RHEL5: Download source, compile and generate RPMs for installation: rpmbuild -ta xerces-c-2.7.0.tar.gz
    (Use RPMs as they install to /usr - required as XmlBeansxx does not allow one to specify an alternate path for Xerces)
  • Ubuntu: Compile from source and install to /usr
• Install Java (1.4.0+ including 1.6): (XmlBeans code generation requires Java and the Maven build tool is a Java program)
  See the YoLinux Java installation tutorial
• Install Maven (untar Java jar files. Java program and thus platform independent)
  (Called by XmlBeans configure script and Makefile)
  • Download compiled Java program: http://maven.apache.org/download.html
  • cd /opt
  • wget http://apache.opensourceresources.org/maven/binaries/apache-maven-2.2.1-bin.tar.gz
  • tar xzf apache-maven-2.2.1-bin.tar.gz
    This creates /opt/apache-maven-2.2.1
  • Configuration:
    • Add path to shell environment: export PATH=$PATH:/opt/apache-maven-2.2.1/bin
      This allows execution of the Maven build command mvn
    • If using a proxy, edit /opt/apache-maven-2.2.1/conf/settings.xml
      Set proxy: <proxies> <proxy> ...
  • Add mvn to path: export PATH=$PATH:/opt/apache-maven-2.2.1/bin
  Note: Maven will require an internet connection to download the appropriate plug-ins during operation.
  Ubuntu/Debian Note: Maven can also be installed using apt-get: sudo apt-get install maven2
• Log4cxx is an optional prerequisite (Version 0.9.7) See the YoLinux.com Log4cxx tutorial for Red Hat Enterprise Linux 5 (RHEL5) prerequisites and build instructions. Note that XmlBeansxx requires that Log4cxx be installed to /usr and is not recognised by the XmlBeans build in any other location such as /opt or /usr/local.

Build and install:

• Build and install Log4cxx to /usr (See the Log4cxx tutorial)
• Download xmlbeansxx-0.9.8.tar.gz
• tar xzf xmlbeansxx-0.9.8.tar.gz
• cd xmlbeansxx-0.9.8
• ./bootstrap
  [Potential Pitfall]: CppUnit errors

  + mkdir -p config m4
  + aclocal -I m4
  configure.ac:36: warning: macro `AM_PATH_CPPUNIT' not found in library
  + autoheader
  + libtoolize --automake --copy
  + automake --foreign --add-missing --copy
  tests/Makefile.am:7: HAVE_CPPUNIT does not appear in AM_CONDITIONAL
  + autoconf 

  Fix by installing cppunit and cppunit-devel packages (RPMs)

• ./configure --prefix=/usr --disable-log4cxx (or with log4cxx if you plan to use its' logging facility.)
  Typically I would specify /opt or /usr/local but execution of xmlbeansxx scompxx command requires /usr in order to fuction. (As Far As I Can Tell)
  [Potential Pitfall]: RHEL6.3 configure boost error:

  ...
  checking for main in -lboost_thread... no
  configure: error: boost_thread library not found. Please install it.
      

  Check dependency: rpm -qa|grep boost-thread
    boost-thread-1.41.0-11.el6_1.2.x86_64
    boost-thread-1.41.0-11.el6_1.2.i686
  Note that the libraries are now named:
    /usr/lib/libboost_thread-mt.so.5
    /usr/lib64/libboost_thread-mt.so
    /usr/lib64/libboost_thread-mt.so.5
  Thus edit the file xmlbeansxx-0.9.8/configure: Edit lines 16758 and 16816 from:
    LIBS="-lboost_thread $LIBS"
  to:
    LIBS="-lboost_thread-mt $LIBS"
• make
  [Potential Pitfall]: RHEL5: If you get the error (and you will):

  ../../libtool: line 466: CDPATH: command not found
  ../../libtool: line 1144: func_opt_split: command not found
      

  This due to the file ./libtool which is created by ./configure is for the newer version of libtool 2.2.4 while RHEL5 has libtool version 1.5.22 /usr/bin/libtool which does not have these functions.
  Thus fix by:
  • mv libtool NoGood-libtool
  • ln -s /usr/bin/libtool ./
  Then try make again.
  Note Ubuntu 8.10 uses libtool 2.2.4 and does not have this problem.
• make check
  This requires cppunit to be installed before executing "configure".
  (Note: "CalendarTest" failed for me, the rest was Ok)
  [Potential Pitfall]: Library error

  xmlbeansxx-0.9.8/tests/.libs/lt-XXXTest: error while loading shared libraries: liblog4cxx.so.10: cannot open shared object file: No such file or directory

  Fix: Register the newly generated libraries with the command (as root): ldconfig -n /usr/lib
• make install
  Installs to /usr/include/xmlbeansxx/, /usr/lib, /usr/bin and /usr/share/xmlbeansxx/ for configure "--prefix=/usr".

Links:

• XMLBeans/C++ - Apache xmlbeanscxx Home Page
• download (Sourceforge)

The first example is using a variation of the Apache XML Beans sample XSD and XML
The second is our own YoLinux.com example using a more complex XSD and XmlBeansxx compiled with Log4cxx.

The following schema example is based on the Apache XML Beans example.

<!-- Copyright 2004 The Apache Software Foundation 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. --> <xs:schema targetNamespace="http://xmlbeans.apache.org/samples/enumeration/schemaenum/easypo" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:po="http://xmlbeans.apache.org/samples/enumeration/schemaenum/easypo" elementFormDefault="qualified"> <xs:element name="purchase-order"> <xs:complexType> <xs:sequence> <xs:element name="customer" type="po:customer"/> <xs:element name="date" type="xs:dateTime" /> <xs:element name="line-item" type="po:line-item" minOccurs="0" maxOccurs="unbounded"/> <xs:element name="shipper" type="po:shipper" minOccurs="0"/> </xs:sequence> </xs:complexType> </xs:element> <xs:complexType name="customer"> <xs:sequence> <xs:element name="name" type="xs:string"/> <xs:element name="address" type="xs:string"/> </xs:sequence> </xs:complexType> <xs:complexType name="line-item"> <xs:sequence> <xs:element name="description" type="xs:string"/> <xs:element name="per-unit-ounces" type="xs:decimal"/> <xs:element name="price" type="xs:double"/> <xs:element name="quantity" type="xs:int"/> </xs:sequence> </xs:complexType> <xs:complexType name="shipper"> <xs:sequence> <xs:element name="name" type="xs:string"/> <xs:element name="per-ounce-rate" type="xs:decimal"/> </xs:sequence> </xs:complexType> </xs:schema>

Note:

• The "xs:" prefix refers to XML built-in type definitions defined by the w3.org (World Wide Web consortium).
• The "po:" prefix refers to "Purchase Order" schema defined by the enumerations in http://xmlbeans.apache.org/samples/enumeration/schemaenum/easypo

Generate C++ classes from XSD: /usr/bin/scompxx EasyPO.xsd

[Potential Pitfall]: scompxx on RHEL6 runtime error:

    libtoolize: `COPYING.LIB' not found in `/usr/share/libtool/libltdl'

The scompxx command is a bash shell script which performs many operations including the generation and execution of a configure script. This error can be fixed by installing two packages not included with the RHEL6.3 workstation DVD but can be found on pkgs.org as CentOS RPM packages:

• libtool-ltdl-devel-2.2.6-15.5.el6.x86_64.rpm
• libtool-ltdl-devel-2.2.6-15.5.el6.i686.rpm

#include "EasyPO.h" #include <iostream> #include <fstream> using namespace std; using namespace xmlbeansxx; using namespace xmlbeansxx::samples::enumeration::schemaenum::easypo; int main() { try { fstream in("easypo.xml", ios::in); PurchaseOrderDocument pDoc(PurchaseOrderDocument::Factory::parse(in)); xmlbeansxx::XmlOptions opts; opts.setValidation(true); vector<LineItem> arr = pDoc.getPurchaseOrder().getLineItemArray(); for(int i=0; i < arr.size() ; i++) { cout << "item: " << i << endl; cout << " - description: " << arr[i].getDescription() << endl; cout << " - quantity: " << arr[i].getQuantity() << endl; cout << " - price: " << arr[i].getPrice() << endl; cout << " - amount: " << arr[i].getQuantity() * arr[i].getPrice() << endl; } // Debug line cout << "Xml:" << endl << pDoc.toString() << endl; } catch (BeansException &ex) { cout << "BeansException: " << ex.getMessage() << endl; } return 0; }

Compile and link: g++ -g -o test testEasyPO.cpp src/EasyPO.cpp -Isrc/ -lxerces-c -lgmp -lgmpxx -pthread -lxmlbeansxx /usr/lib/libxmlbeansxx.a
(Static link)

[Potential Pitfall]: RHEL6.3 Compiling errors due to missing include files. For some unknown reason some installations are incomplete and do not copy all of the required include files to /usr/include/xmlbeansxx/ (in my case five were missing). This will then have to be performed manually:

cd xmlbeansxx-0.9.8/src/xmlbeansxx
sudo /usr/bin/install -c -m 644 configLibxml2.h configLog4cxx.h configGmpxx.h XmlTypesGen.h xml-fragment.h '/usr/include/xmlbeansxx'

<?xml version="1.0" encoding="UTF-8"?> <purchase-order xmlns="http://xmlbeans.apache.org/samples/enumeration/schemaenum/easypo" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <customer> <name>Larry Kowalski</name> <address>ul. Anytown, PA</address> </customer> <date>2005-01-01T12:00:00</date> <line-item> <description>Burnham's Celestial Handbook Vol 1</description> <per-unit-ounces>10</per-unit-ounces> <price>23</price> <quantity>1</quantity> </line-item> <line-item> <description>Burnham's Celestial Handbook Vol 2</description> <per-unit-ounces>7</per-unit-ounces> <price>22</price> <quantity>1</quantity> </line-item> <line-item> <description>Introduction to Linux</description> <per-unit-ounces>7</per-unit-ounces> <price>27</price> <quantity>1</quantity> </line-item> <shipper> <name>Zip Ship</name> <per-ounce-rate>0.65</per-ounce-rate> </shipper> </purchase-order>

Test by running the resulting program: ./test

Locale: en_US.UTF-8
item: 0
 - description:     Burnham's Celestial Handbook Vol 1
 - quantity:        1
 - price:           23
 - amount:          23
item: 1
 - description:     Burnham's Celestial Handbook Vol 2
 - quantity:        1
 - price:           22
 - amount:          22
item: 2
 - description:     Introduction to Linux
 - quantity:        1
 - price:           27
 - amount:          27

Sample XSD schema to define a corporation, employees and their data.

XML Schema File: corporation.xsd

<?xml version="1.0" encoding="UTF-8"?> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified" attributeFormDefault="unqualified"> <xs:element name="root"> <xs:complexType> <xs:sequence> <xs:element name="Corporation"> <xs:complexType> <xs:sequence> <xs:element name="Name" type="xs:string"/> <xs:element name="Phone" type="xs:string"/> <xs:element name="Fax" type="xs:string"/> <xs:element name="Address" type="xs:string"/> </xs:sequence> </xs:complexType> </xs:element> <xs:element name="People"> <xs:complexType> <xs:sequence> <xs:element name="Employee" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="Name" type="xs:string"/> <xs:choice> <xs:element name="US-W2"> <xs:complexType mixed="true"> <xs:sequence> <xs:element name="EmpNumber" type="xs:int"/> <xs:element name="Manager" type="xs:string"/> <xs:element name="YearStart" type="xs:string"/> </xs:sequence> </xs:complexType> </xs:element> <xs:element name="US-1099"> <xs:complexType mixed="true"> <xs:sequence> <xs:element name="SsnNumber" type="xs:string"/> <xs:element name="Phone" type="xs:string" default="1-800-555-1212"/> <xs:element name="CorpName" type="xs:string"/> <xs:element name="CorpAddress" type="xs:string"/> <xs:element name="Relationship" type="ERelation"/> </xs:sequence> </xs:complexType> </xs:element> </xs:choice> <xs:element name="Data"> <xs:annotation> <xs:documentation>Data: personel data.</xs:documentation> </xs:annotation> <xs:complexType mixed="false"> <xs:sequence> <xs:element name="WorkPhone" type="xs:string" default="1-800-555-1212"/> <xs:element name="CellPhone" type="xs:string" default="1-800-555-1212"/> <xs:element name="Address" type="xs:string" default="NULL"/> </xs:sequence> </xs:complexType> </xs:element> </xs:sequence> <xs:attribute name="TaxStatus" type="ETaxStatus" use="required"/> <xs:attribute name="Gender" type="EGender" use="required"/> <xs:attribute name="Desc" type="ELocation" use="required"/> </xs:complexType> </xs:element> </xs:sequence> </xs:complexType> </xs:element> </xs:sequence> </xs:complexType> </xs:element> <xs:simpleType name="EGender"> <xs:restriction base="xs:string"> <xs:enumeration value="Male"/> <xs:enumeration value="Female"/> </xs:restriction> </xs:simpleType> <xs:simpleType name="ELocation"> <xs:restriction base="xs:string"> <xs:enumeration value="OnSite"/> <xs:enumeration value="OffSite"/> </xs:restriction> </xs:simpleType> <xs:simpleType name="ETaxStatus"> <xs:restriction base="xs:string"> <xs:enumeration value="US-W2"/> <xs:enumeration value="US-1099"/> </xs:restriction> </xs:simpleType> <xs:simpleType name="ERelation"> <xs:restriction base="xs:string"> <xs:enumeration value="CorpToCorp"/> <xs:enumeration value="CorpToIndividual"/> </xs:restriction> </xs:simpleType> </xs:schema>

XSD Notes:

• XSD requires that element attributes are defined at the end of the element definition.
• Multiple occurances of an element type is permitted when the following is specified:
  • element attribute maxOccurs="unbounded" is specified. or maxOccurs="10" is specified as a specific value greater than one.
  • element attribute minOccurs="3" is specified as a value greater than one.
  XML Beans will generate a method to return an array to handle multiple occurances.
• Indicate that any one of the elements may be specified: <xs:choice>
• Indicate that the elements must be specified in the order given: <xs:sequence>

Generate C++ classes from XSD: /usr/bin/scompxx corporation.xsd
This will generate the files src/corporation.h and src/corporation.cpp

This is a hand cleanup script for all of the extra files you probably will not need:

rm -Rf config.h.in stamp-h1 config.log config.h Makefile config.status libtool configure rm -Rf Makefile.in config autom4te.cache aclocal.m4 bootstrap configure.ac m4 Makefile.am rm src/*.o src/xmltypes src/xsd.txt src/Makefile.am src/Makefile.in src/Makefile rm -Rf src/*.lo src/libxmltypes.la src/xmltypes_headers.h src/.deps src/.libs

#include "corporation.h" #include <iostream> #include <fstream> #include <string> #include <vector> #include <log4cxx/logger.h> #include <log4cxx/xml/domconfigurator.h> using namespace std; using namespace xmlbeansxx; using namespace log4cxx; using namespace log4cxx::xml; using namespace log4cxx::helpers; LoggerPtr testProgramMain(log4cxx::Logger::getLogger("TestProgramMain")); int main() { DOMConfigurator::configure("Log4cxxConfig.xml"); // XMLBeans initialization try { fstream xmlData("CorporationMegaX.xml", ios::in); noNamespace::RootDocument_Root *pDoc = new noNamespace::RootDocument_Root(noNamespace::RootDocument_Root::Factory::parse(xmlData)); xmlbeansxx::XmlOptions opts; opts.setValidation(true); cout << "Corporation Name: " << pDoc->getCorporation().getName() << endl; cout << "Corporation Address: " << pDoc->getCorporation().getAddress() << endl << endl; // Load "Employee" data into STL vector vector<noNamespace::RootDocument_Root_People_Employee> arr = pDoc->getPeople().getEmployeeArray(); // For each "Employee", get tax info and data info. for(int i=0; i < arr.size() ; i++) { cout << "Employee name: " << arr[i].getName() << endl; switch (arr[i].getTaxStatus()) { case 0: // US-W2 cout << " Employee number: " << arr[i].getUSW2().getEmpNumber() << endl; break; case 1: // US-1099 cout << " Employee SSN number: " << arr[i].getUS1099().getSsnNumber() << endl; break; default: break; } cout << " Work phone: " << arr[i].getData().getWorkPhone() << endl; } // Debug line cout << "Xml:" << endl << pDoc.toString() << endl; } catch (BeansException &ex) { cout << "BeansException: " << ex.getMessage() << endl; } return 0; }

Compile and link: g++ -g -o test testProgramMain.cpp src/corporation.cpp -Isrc/ -I/opt/include -lxerces-c -lgmp -lgmpxx -pthread -lxmlbeansxx /usr/lib/libxmlbeansxx.a /usr/lib/liblog4cxx.a -lapr-1 -laprutil-1
(Static link)

<?xml version="1.0" encoding="UTF-8"?> <root xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="corporation.xsd"> <Corporation> <Name>Corporation MegaX</Name> <Phone>1-800-555-1212</Phone> <Fax>1-877-555-1212</Fax> <Address>512 Megacorp Way, Gotham City</Address> </Corporation> <People> <!-- The Boss --> <Employee TaxStatus="US-W2" Gender="Male" Desc="OnSite"> <Name>Mr Grand Kahuna</Name> <US-W2> <EmpNumber>1</EmpNumber> <Manager>None</Manager> <YearStart>1998</YearStart> </US-W2> <Data> <WorkPhone>1-800-555-1213</WorkPhone> <CellPhone>1-800-555-1214</CellPhone> <Address>100 Cherry Hill Lane, Gotham City</Address> </Data> </Employee> <!-- The Consultant --> <Employee TaxStatus="US-1099" Gender="Male" Desc="OnSite"> <Name>Mr Special Tee</Name> <US-1099> <SsnNumber>123-45-6788</SsnNumber> <Phone>1-817-555-1212</Phone> <CorpName>ABC Consulting</CorpName> <CorpAddress>3 Mockingbird Lane, Smallville AK</CorpAddress> <Relationship>CorpToIndividual</Relationship> </US-1099> <Data> <WorkPhone>1-800-555-1215</WorkPhone> <CellPhone>1-800-555-1216</CellPhone> <Address>200 Lookout Hill, Gotham City</Address> </Data> </Employee> <!-- The Secratary --> <Employee TaxStatus="US-W2" Gender="Female" Desc="OnSite"> <Name>Mrs Jenny Reliable</Name> <US-W2> <EmpNumber>2</EmpNumber> <Manager>Mr Grand Kahuna</Manager> <YearStart>1999</YearStart> </US-W2> <Data> <WorkPhone>1-800-555-1217</WorkPhone> <CellPhone>1-800-555-1218</CellPhone> <Address>300 Riverside View, Gotham City</Address> </Data> </Employee> </People> </root>

Test by running the resulting program: ./test

Locale: en_US.UTF-8
Corporation Name:    Corporation MegaX
Corporation Address: 512 Megacorp Way, Gotham City

Employee name: Mr Grand Kahuna
   Employee number: 1
   Work phone: 1-800-555-1213
Employee name: Mr Special Tee
   Employee SSN number: 123-45-6788
   Work phone: 1-800-555-1215
Employee name: Mrs Jenny Reliable
   Employee number: 2
   Work phone: 1-800-555-1217

<?xml version="1.0" encoding="UTF-8" ?> <log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/"> <!-- Output the log message to system console. --> <appender name="testConsoleAppender" class="org.apache.log4j.ConsoleAppender"> <param name="Target" value="System.out"/> <layout class="org.apache.log4j.PatternLayout"> <param name="ConversionPattern" value="%-5p %c{1} - %m%n"/> </layout> </appender> <root> <priority value="error" /> <appender-ref ref="testConsoleAppender"/> </root> <!-- Specify the level for some specific categories --> <category name="TestProgramMain" > <priority value ="all" /> <!-- appender-ref ref="testConsoleAppender"/ --> </category> <category name="xmlbeansxx" > <priority value ="warn" /> </category> </log4j:configuration>

For more on Apache Log4cxx, see the YoLinux.com Log4cxx tutorial

Books:

	C++ How to Program by Harvey M. Deitel, Paul J. Deitel ISBN #0131857576, Prentice Hall Fifth edition. The first edition of this book (and Professor Sheely at UTA) taught me to program C++. It is complete and covers all the nuances of the C++ language. It also has good code examples. Good for both learning and reference.
	Professional XML Development with Apache Tools : Xerces, Xalan, FOP, Cocoon, Axis, Xindice by Theodore W. Leung ISBN #0764543555, Wrox Press