org.apache.blur.utils.TermDocIterable.java Source code

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Here is the source code for org.apache.blur.utils.TermDocIterable.java

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package org.apache.blur.utils;

/**
 * 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.
 */
import java.io.IOException;
import java.util.Iterator;

import org.apache.lucene.document.Document;
import org.apache.lucene.index.AtomicReader;
import org.apache.lucene.index.DocsEnum;
import org.apache.lucene.index.MultiFields;
import org.apache.lucene.search.DocIdSetIterator;
import org.apache.lucene.util.Bits;

public class TermDocIterable implements Iterable<Document> {

    private DocsEnum docsEnum;
    private AtomicReader reader;
    private ResetableDocumentStoredFieldVisitor fieldSelector;

    public TermDocIterable(DocsEnum docsEnum, AtomicReader reader) {
        this(docsEnum, reader, new ResetableDocumentStoredFieldVisitor());
    }

    public TermDocIterable(DocsEnum docsEnum, AtomicReader reader,
            ResetableDocumentStoredFieldVisitor fieldSelector) {
        if (docsEnum == null) {
            throw new NullPointerException("docsEnum can not be null.");
        }
        this.docsEnum = docsEnum;
        this.reader = reader;
        this.fieldSelector = fieldSelector;
    }

    @Override
    public Iterator<Document> iterator() {
        return new Iterator<Document>() {
            private boolean hasNext = getNext();

            @Override
            public boolean hasNext() {
                return hasNext;
            }

            @Override
            public Document next() {
                Document doc;
                try {
                    doc = getDoc();
                    hasNext = getNext();
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
                return doc;
            }

            @Override
            public void remove() {

            }
        };
    }

    private Document getDoc() throws IOException {
        fieldSelector.reset();
        reader.document(docsEnum.docID(), fieldSelector);
        return fieldSelector.getDocument();
    }

    private boolean getNext() {
        try {
            int next = docsEnum.nextDoc();
            if (next == DocIdSetIterator.NO_MORE_DOCS) {
                return false;
            }
            Bits liveDocs = MultiFields.getLiveDocs(reader);
            if (liveDocs != null) {
                while (!liveDocs.get(docsEnum.docID())) {
                    next = docsEnum.nextDoc();
                }
            }
            return next == DocIdSetIterator.NO_MORE_DOCS ? false : true;
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

}