org.cloudata.core.client.scanner.AbstractTableScanner.java Source code

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Here is the source code for org.cloudata.core.client.scanner.AbstractTableScanner.java

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/**
 * 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.
 */
package org.cloudata.core.client.scanner;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.cloudata.core.client.Row;
import org.cloudata.core.client.ScanCell;

abstract class AbstractTableScanner implements TableScanner {
    private static final Log LOG = LogFactory.getLog(AbstractTableScanner.class.getName());

    private ScanCell lastCell;

    protected String columnName;

    protected abstract boolean isEnd();

    protected abstract void setEnd(boolean end);

    protected void setLastCell(ScanCell lastCell) {
        this.lastCell = lastCell;
    }

    @Override
    public Row nextRow() throws IOException {
        try {
            if (isEnd()) {
                return null;
            }

            List<ScanCell> result = new ArrayList<ScanCell>();
            while (true) {
                ScanCell cell = next();
                if (cell == null) {
                    if (lastCell != null) {
                        result.add(lastCell);
                        lastCell = cell;
                    }
                    setEnd(true);
                    break;
                }

                if (lastCell != null && !cell.getRowKey().equals(lastCell.getRowKey())) {
                    result.add(lastCell);
                    lastCell = cell;
                    break;
                }

                if (lastCell != null) {
                    result.add(lastCell);
                }

                lastCell = cell;
            }

            if (result.size() == 0) {
                setEnd(true);
                return null;
            }

            Row row = new Row(result.get(0).getRowKey());

            ScanCell.addCells(row, columnName, result);

            return row;
        } catch (IOException e) {
            throw e;
        } catch (Exception e) {
            LOG.error(e.getMessage(), e);
            IOException err = new IOException(e.getMessage());
            err.initCause(e);
            throw err;
        }
    }
}