jena-arq/src/main/java/org/apache/jena/sparql/core/describe/DescribeHandler.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */

package org.apache.jena.sparql.core.describe;

import org.apache.jena.rdf.model.Model;
import org.apache.jena.rdf.model.Resource;
import org.apache.jena.sparql.util.Context;

/**
 * A DescribeHandler provides the description of a resource. DESCRIBE queries return
 * RDF that describes the resource found, either from the query pattern or explicitly
 * named in the DESCRIBE clause. For each resource, any handlers are called to builds
 * the RDF model that is to be the result of the query.
 */

public interface DescribeHandler {
    /**
     * Start the describe process, passing in the result model.
     *
     * @param accumulateResultModel
     * @param qContext Query execution context
     */
    public void start(Model accumulateResultModel, Context qContext);

    /**
     * Called on everything resource found by a query. Can add more RDF to the model
     * provided. May choose to add nothing.
     *
     * @param resource resource to describe
     */

    public void describe(Resource resource);

    /**
     * Finish the description process for this query execution
     */
    public void finish();
}