Difference between revisions of "ExistClient"

Revision as of 16:40, 23 May 2008

Introduction

The ExistClient is a Java library that implements the ISClient interface provided by the gCoreFramework. This library allow the developer to execute queries on the Information System.

Implementation Overview

The ExistClient implements all the query defined in the ISClient Interface:

Queries over GCUBEResource:

• GCUBECollectionQuery
• GCUBECSInstanceQuery
• GCUBECSQuery
• GCUBEExternalRIQuery
• GCUBEGenericResourceQuery
• GCUBEGHNQuery
• GCUBEMCollectionQuery
• GCUBERIQuery
• GCUBEServiceQuery
• GCUBETPQuery
• GCUBEVREQuery

Queries over GCUBEWSResource:

• WSResourceQuery

The ExistClient also offers the possibility to execute custom queries: GCUBEGenericQuery. GCUBEGenericQuery allows the developer to set the query expression to execute or to use a predefined set of queries which he should set some parameters on:

• GCUBEResourceQuery
• GCUBEWSResourceQuery
• RIEndpoint
• RIOnGHN
• RISpecificData
• GHNIDFromHostName
• InternalCollections
• UserCollectionIDsFromSchemaURI
• MCollectionIDForCollection
• MCollectionFormatsForCollection
• MCollectionIDFromCollectionIDAndRole
• MCollectionIDFromFormatLanguage
• MCollectionIDFromFormatLanguage
• MCollectionIDFromName
• MCollectionIDFromSchemaURI

Usage Examples

The ISclient reference implementation makes use of Xquery Technology to query over the underneath Exist database. Client/services can prepare a custom xQuery over the DB and use the Generic Query object to excecute it and going through the result with an XPath:

GCUBEGenericQuery query = client.getQuery(GCUBEGenericQuery.class);
query.setExpression("for $Profile in collection(\"/db/Profiles\")//Document/Data/child::*[local-name()='Profile']/Resource return $Profile/UniqueID");
List<XMLResult> result =client.execute(query, scope);
for (String resultItem :result ) {
System.out.println(resultItem.evaluate("an XPath ... ")); 
System.out.println(resultItem.toString());
}

You can use a predefined ISQuery Object as well:

GCUBEWSResourceEPRFromRPValuesAndNamespaceQuery query = client.getQuery(GCUBEWSResourceEPRFromRPValuesAndNamespaceQuery.class); 
GCUBEWSProperty property = new GCUBEWSProperty("IndexTypeName","index_type_string_string");

GCUBEWSProperty property2 = new GCUBEWSProperty("IndexID","999ba610-e9fb-11dc-b51b-84732c1e88f2");

ArrayList <GCUBEWSProperty> properties = new ArrayList();
properties.add(property);
properties.add(property2);
query.setPropertiesValuesAndNamespace(properties, "http://gcube-system.org/namespaces/index/ForwardIndexManagementService");
				
List<EndpointReferenceType> result = client.execute(query, scope);
				
for (EndpointReferenceType resultItem :result ) {
System.out.println(resultItem.toString());
	
}