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

Class 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 Detail

      • QueryWhereHandler

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

    • Method Detail

      • 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:
        QueryParameters.getWhere()