IBM WebSphere Everyplace Access V5 Handbook for Developers and Administrators Volume IV: Advanced Topics

Chapter 6. Location Aware Services application development 213

6.3 Location Aware Services Java application

development

Location Aware Services is not limited to portlet development Everyplace Toolkit

for WebSphere Studio can also be used to develop Java applications that use

the Location Aware Services API.

6.3.1 Summary of Java application development

Developing a Java Location Aware Services application involves these steps:

1. Add all the JAR files in <WebSphere>LAS/las/lib into your project.

2. Find the atlas.properties file and add it to your project.

3. Modify the atlas.properties file (Example 6-1 on page 214). This is a global

file for the Atlas Location Aware Services middleware. By default, Atlas loads

this file from com.ibm.atlas.properties file, but may be pointed to directly by

the system property ATLAS_PROPERTIES.

4. Modify the servicePropertiesRoot to point to the folder where the Location

Aware Services adapter properties files are located. Location Aware Services

adapter properties files are located in the directory

<WebSphere>/LAS/las/service_properties.

5. Modify the trace and log level accordingly. Setting trace on and to high will

slow down the system performances.

6. Set useConsoleLog or useConsoleTrace to true causes the log and trace

messages to be written to the Portal server log and trace file, or the

messages will be written in the file specified by logFileName and

traceFileName properties.

7. ClientName and Password are clear text values used to gain access to

services when no corresponding properties are provided in individual service

properties file.

8. Atlas gives a default service failover policy file. But you could write your own

service failover policy class, which implements the ServiceFailoverPolicy

interface to define how the system should behave when a service fails. If you

define your own service failover class for a particular service, this should be

specified by the <service-type>FailoverPolicyClass.

9. Specify the proxy the service adapters have to use by the HTTPProxy

property.

214 IBM WebSphere Everyplace Access V5, Volume IV: Advanced Topics

Example 6-1 Sample atlas.properties file

logDirectory=C:\\WebSphere\\LAS\\logs

logFileName=atlas.log traceFileName=atlas.trace

registryClassname=com.ibm.atlas.system.PropertiesFileServiceRegistry

servicePropertiesRoot=C:\\WebSphere\\LAS\\las\\service_properties

useConsoleLog=false

useConsoleTrace=false

# Set to one of 'warn', 'info' or 'error'.

logLevel = warn

#Set to one of "high", "medium", "low", or "none".

traceLevel = none

clientName = dummy

clientPassword = dummy

defaultUserLanguagePreference = en

#<service-type>FailoverPolicyClass =

#

# Specifies the default failover policy class. If not set, defaults to

# com.ibm.atlas.system.DefaultServiceFailoverPolicy.

#

#defaultFailoverPolicyClass =

#Coordinate reference system classes

CRS.WGS84.className = com.ibm.atlas.geometry.WGS84ReferenceSystem

CRS.EPSG:4326.className = com.ibm.atlas.geometry.WGS84ReferenceSystem

HTTPProxy=

10.Modify the service properties and the properties file of the service provider.

The properties file must be located in the directory as specified in the

atlas.properties file. For the adapters provided along with Location Aware

Services, the properties file are under the directory

<WebSphere>/LAS/las/service_properties.

11.The properties file is used by the Location Aware Services Engine to select

the appropriate adapter depending on the serviceType and serviceName

(service provider). Also, this properties file specifies the location of the

initPropertiesFile. Example 6-2 shows the service properties file for the

mapping service provided by Webraska.

12.The service provider properties file contains information required by the

adapter. The parameters in the properties file depend on the service provider.

Example 6-3 on page 215 shows the Webraska adapter’s properties file.

Example 6-2 Mapping Service properties

serviceType = mapping

className = com.ibm.atlas.adapters.webraska.WebraskaMappingService

serviceName = webraska-na.MappingService

initPropertiesFile = webraska-na/init.properties

Chapter 6. Location Aware Services application development 215

Example 6-3 Webraska service init properties

server = dummy.webraska.com

path = /gns

clientName = demo clientPassword = demo

connectionTimeout = -1

#geolang = en

13.Initialize the service as shown in Example 6-4.

Example 6-4 Initializing the service

GeocodingService geocodingService = new GeocodingService(geoProps);

MappingService mappingService = new MappingService(mapProps);

This command invokes the Atlas core components, which connects to the

appropriate service provider using the property files. The code allocates two

Location Aware Services that are used in the application: geocoding and

mapping. The Location Aware Services provide access to multiple providers

of the location services. Location Aware Services searches among the

registered services for the one that fits the specifications provided in the

properties file, such as the geography, and returns the first match.

GeocodingService is defined in the package com.ibm.atlas.Geocoding.

GeocodingService determines the location of the given address.

MappingService is defined in the package com.ibm.atlas.Mapping.

MappingService returns a map of the given location.

14.The Construct and Address object is used by GeocodingService to obtain the

location. The address is defined in the package com.ibm.atlas.GeoCoding.

This class represents an address and is loosely based on RFC 2426 and

ISO/ISE 11180.

Note: To learn about the different parameters that are required by the

adapters that are provided by WebSphere Everyplace Access, see the

InfoCenter (select Location Aware Services

→ Managing →

Administrative Services

→ Properties for Service Provider

Configuration Profile).