org.eclipse.smila.search.lucene.index.access.ExistsOperation.java Source code

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Here is the source code for org.eclipse.smila.search.lucene.index.access.ExistsOperation.java

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/***********************************************************************************************************************
 * Copyright (c) 2008 empolis GmbH and brox IT Solutions GmbH. All rights reserved. This program and the accompanying
 * materials are made available under the terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors: Ivan Churkin (brox IT Solutions GmbH) - initial creator
 **********************************************************************************************************************/
package org.eclipse.smila.search.lucene.index.access;

import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
import org.eclipse.smila.search.index.IndexException;

/**
 * The Class ExistsOperation.
 */
public class ExistsOperation implements ISynchronizedOperation<IndexReader, Boolean> {

    /**
     * The _term.
     */
    private final Term _term;

    /**
     * Instantiates a new exists operation.
     * 
     * @param term
     *          the term
     */
    public ExistsOperation(final Term term) {
        _term = term;
    }

    /**
     * {@inheritDoc}
     * 
     * @see org.eclipse.smila.search.lucene.index.access.ISynchronizedOperation#process(java.lang.Object)
     */
    public Boolean process(final IndexReader object) throws IndexException {
        boolean exists;
        try {
            exists = (object.docFreq(_term) > 0);
        } catch (final Exception e) {
            throw new IndexException("Unable to check wether document exists by term [" + _term.text() + "]", e);
        }
        return exists;
    }

}