CmisReader.java

package fr.acxio.tools.agia.cmis;

/*
 * Copyright 2014 Acxio
 * 
 * Licensed 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.util.Calendar;
import java.util.Iterator;

import org.apache.chemistry.opencmis.client.api.ItemIterable;
import org.apache.chemistry.opencmis.client.api.OperationContext;
import org.apache.chemistry.opencmis.client.api.QueryResult;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.batch.item.ExecutionContext;
import org.springframework.batch.item.ItemStreamException;
import org.springframework.batch.item.ItemStreamReader;
import org.springframework.batch.item.NonTransientResourceException;
import org.springframework.batch.item.ParseException;
import org.springframework.batch.item.UnexpectedInputException;

import fr.acxio.tools.agia.convert.DateToStringConverter;

public class CmisReader implements ItemStreamReader<QueryResult> {

    private static final Logger LOGGER = LoggerFactory.getLogger(CmisReader.class);

    private static final String CONTEXT_KEY_LASTTIMESTAMP = "cmis.reader.lastTimestamp";
    private static final DateToStringConverter CONVERTER_TIMESTAMP = new DateToStringConverter("yyyy-MM-dd'T'HH:mm:ss.SSSZZ");

    private CmisService cmisService;
    private String query;
    private OperationContext operationContext;

    private String lastTimestamp;

    private ItemIterable<QueryResult> currentQueryResult;
    private Iterator<QueryResult> unreadObjects;

    public void setCmisService(CmisService sCmisService) {
        cmisService = sCmisService;
    }

    public void setQuery(String sQuery) {
        query = sQuery;
    }

    public void setOperationContext(OperationContext sOperationContext) {
        operationContext = sOperationContext;
    }

    @Override
    public void open(ExecutionContext sExecutionContext) throws ItemStreamException {
        cmisService.startSession();

        lastTimestamp = sExecutionContext.getString(CONTEXT_KEY_LASTTIMESTAMP, null);

        executeQuery();
    }

    @Override
    public void update(ExecutionContext sExecutionContext) throws ItemStreamException {
        sExecutionContext.putString(CONTEXT_KEY_LASTTIMESTAMP, lastTimestamp);
    }

    @Override
    public void close() throws ItemStreamException {
        unreadObjects = null;
        lastTimestamp = null;
        currentQueryResult = null;
    }

    @Override
    public QueryResult read() throws Exception, UnexpectedInputException, ParseException, NonTransientResourceException {
        QueryResult aResult = null;

        if (unreadObjects.hasNext()) {
            aResult = unreadObjects.next();
            if (aResult != null) {
                lastTimestamp = CONVERTER_TIMESTAMP.convert((Calendar) aResult.getPropertyByQueryName("cmis:creationDate").getFirstValue()).get(0);
            } else {
                executeQuery();
                aResult = read();
            }
        } else if (currentQueryResult.getHasMoreItems()) {
            executeQuery();
            aResult = read();
        }

        return aResult;
    }

    private void executeQuery() {
        StringBuilder aQuery = new StringBuilder(query);
        if (lastTimestamp != null) {
            aQuery.append(" and cmis:creationDate > TIMESTAMP '");
            aQuery.append(lastTimestamp);
            aQuery.append("'");
        }
        aQuery.append("order by cmis:creationDate");

        if (LOGGER.isDebugEnabled()) {
            LOGGER.debug("Execute query : " + aQuery.toString());
        }

        currentQueryResult = cmisService.getSession().query(aQuery.toString(), false, operationContext);
        unreadObjects = currentQueryResult.iterator();
    }

}