com.esri.gpt.control.search.browse.TocIndexAdapter.java Source code

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Here is the source code for com.esri.gpt.control.search.browse.TocIndexAdapter.java

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/* See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * Esri Inc. 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 com.esri.gpt.control.search.browse;

import com.esri.gpt.catalog.lucene.LuceneIndexAdapter;
import com.esri.gpt.catalog.lucene.Storeables;
import com.esri.gpt.framework.util.Val;

import java.io.IOException;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.MapFieldSelector;
import org.apache.lucene.index.CorruptIndexException;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.TermDocs;
import org.apache.lucene.search.IndexSearcher;

/**
 * Provides utilities for querying a Lucene index during TOC construction.
 */
public class TocIndexAdapter {

    /** instance variables ====================================================== */
    private LuceneIndexAdapter baseAdapter;
    private IndexSearcher searcher;

    /** constructors ============================================================ */

    /** Default constructor */
    public TocIndexAdapter() {
    }

    /** methods ================================================================= */

    /**
     * Closes any open resources.
     */
    public void close() {
        if ((this.baseAdapter != null) && (this.searcher != null)) {
            this.baseAdapter.closeSearcher(this.searcher);
        }
    }

    /**
     * Gets the index searcher.
     * @param context the operation context
     * @return the index searcher
     * @throws CorruptIndexException if the index is corrupt 
     * @throws IOException if an I/O exception occurs
     */
    public IndexSearcher getSearcher(TocContext context) throws CorruptIndexException, IOException {
        if (this.searcher != null) {
            return this.searcher;
        } else {
            if (this.baseAdapter == null) {
                this.baseAdapter = new LuceneIndexAdapter(context.getRequestContext());
            }
            this.searcher = this.baseAdapter.newSearcher();
            return this.searcher;
        }
    }

    /**
     * Returns the field values associated with a document
     * @param context the operation context
     * @param fieldName the field name
     * @param uuid the document uuid
     * @return the field values (null if not found)
     * @throws CorruptIndexException if the index is corrupt
     * @throws IOException if an I/O exception occurs
     */
    public String[] queryFieldByUuid(TocContext context, String fieldName, String uuid)
            throws CorruptIndexException, IOException {
        TermDocs termDocs = null;
        try {
            uuid = Val.chkStr(uuid);
            if (uuid.length() > 0) {
                IndexSearcher searcher = this.getSearcher(context);
                IndexReader reader = searcher.getIndexReader();
                MapFieldSelector selector = new MapFieldSelector(new String[] { fieldName });
                termDocs = reader.termDocs();
                termDocs.seek(new Term(Storeables.FIELD_UUID, uuid));
                if (termDocs.next()) {
                    Document document = reader.document(termDocs.doc(), selector);
                    return document.getValues(fieldName);
                }
            }
        } finally {
            try {
                if (termDocs != null)
                    termDocs.close();
            } catch (Exception ef) {
            }
        }
        return null;
    }

}