Package com.sodius.oslc.server.process.query

Class QueryWhereHandler<C>

java.lang.Object
com.sodius.oslc.server.process.query.QueryWhereHandler<C>
Type Parameters:
C - the type of context, which is used by term handlers to report processing outputs
public class QueryWhereHandler<C> extends Object
Handles the terms found in an oslc.where expression. This is for visiting the terms, identifying the OSLC properties used and delegating to specific term handlers for a given context. The context is whatever provides information about the underlying application to term handlers and what may receive their processing output.

An naive example of handler can be: 

 private static class MyQueryWhereTermHandler<T> extends QueryWhereTermHandler<T, StringBuilder> {
      private MyQueryWhereTermHandler(String propertyDefinition, Class<T> type) {
          super(propertyDefinition, type);
      }
      protected void handle(String property, Operator operator, T value, StringBuilder buffer) {
          buffer.append("Found " + property + " using " + operator + " and " + value);
      }
 };
 ...
 QueryWhereHandler<StringBuilder> whereHandler = new QueryWhereHandler<>(Arrays.asList(
         new MyQueryWhereTermHandler<>(Dcterms.PROPERTY_TITLE, String.class),
         new MyQueryWhereTermHandler<>(Dcterms.PROPERTY_IDENTIFIER, String.class)));
 StringBuilder buffer = new StringBuilder();
 whereHandler.apply(whereClause, buffer);
 System.out.println(buffer.toString());
Since:
3.6.0

  • Constructor Details

    • QueryWhereHandler

      public QueryWhereHandler(Collection<QueryWhereTermHandler<?,C>> handlers)
      Creates a new instance using the given term handlers.
      Parameters:
      handlers - the term handlers

  • Method Details

    • handle

      public void handle(WhereClause whereClause, C context)
      Process an oslc.where expression in a given context.

      The context is whatever provides information about the underlying application to term handlers and what may receive their processing output.

      Parameters:
      whereClause - the parsed where expression
      context - the context that can receive where terms processing output
      Throws:
      WebApplicationException - if a term, property, operator or value is not supported
      See Also: