src/main/java/org/apache/sling/pipes/internal/slingquery/AbstractSlingQueryPipe.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.sling.pipes.internal.slingquery;

import org.apache.sling.api.resource.Resource;
import org.apache.sling.pipes.BasePipe;
import org.apache.sling.pipes.PipeBindings;
import org.apache.sling.pipes.Plumber;
import org.apache.sling.query.SlingQuery;
import java.util.Iterator;

/**
 * deals with common sling query pipe code
 */
public abstract class AbstractSlingQueryPipe extends BasePipe {

    public AbstractSlingQueryPipe(Plumber plumber, Resource resource, PipeBindings upperBindings) throws Exception {
        super(plumber, resource, upperBindings);
    }
    @Override
    public boolean modifiesContent() {
        return false;
    }

    /**
     * generates a sling query object out of a resource
     * @param resource input resource
     * @return SlingQuery object
     */
    protected abstract SlingQuery getQuery(Resource resource);

    /**
     * generate outputs out of input resource and abstract query
     * @return output's resource iterator, empty in case input is null
     */
    protected Iterator<Resource> computeOutput() throws Exception {
        Resource resource = getInput();
        if (resource != null) {
            SlingQuery query = getQuery(resource);
            return query.iterator();
        }
        return EMPTY_ITERATOR;
    }
}