001/**
002 * Copyright 2014 DuraSpace, Inc.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016package org.fcrepo.kernel.impl.rdf.impl.mappings;
017
018import com.google.common.collect.AbstractIterator;
019import com.google.common.collect.Iterators;
020import org.fcrepo.kernel.exception.RepositoryRuntimeException;
021
022import javax.jcr.Property;
023import javax.jcr.RepositoryException;
024import javax.jcr.Value;
025import java.util.Iterator;
026
027/**
028 * Iterate over all the values in a property or list of properties
029 *
030 * @author cabeer
031 */
032public class PropertyValueIterator extends AbstractIterator<Value> {
033    private Iterator<Property> properties;
034    private Iterator<Value> currentValues;
035
036    /**
037     * Iterate through a single property's values
038     * @param properties
039     */
040    public PropertyValueIterator(final Property properties) {
041        this(Iterators.singletonIterator(properties));
042    }
043
044    /**
045     * Iterate through multiple property's values
046     * @param properties
047     */
048    public PropertyValueIterator(final Iterator<Property> properties) {
049        this.properties = properties;
050        this.currentValues = null;
051    }
052
053    @Override
054    protected Value computeNext() {
055        try {
056            if (currentValues != null && currentValues.hasNext()) {
057                return currentValues.next();
058            }
059            if (properties.hasNext()) {
060                final Property property = properties.next();
061
062                if (property.isMultiple()) {
063                    currentValues = Iterators.forArray(property.getValues());
064                    return currentValues.next();
065                } else {
066                    currentValues = null;
067                    return property.getValue();
068                }
069            }
070
071            return endOfData();
072        } catch (final RepositoryException e) {
073            throw new RepositoryRuntimeException(e);
074        }
075    }
076}