| /* |
| * 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.apache.accumulo.core.client; |
| |
| import org.apache.accumulo.core.data.Range; |
| |
| /** |
| * Scans a table over a given range. |
| * |
| * "Clients can iterate over multiple column families, and there are several mechanisms for limiting the rows, columns, and timestamps traversed by a scan. For |
| * example, we could restrict [a] scan ... to only produce anchors whose columns match [a] regular expression ..., or to only produce anchors whose timestamps |
| * fall within ten days of the current time." |
| */ |
| public interface Scanner extends ScannerBase { |
| |
| /** |
| * Sets the range of keys to scan over. |
| * |
| * @param range |
| * key range to begin and end scan |
| */ |
| void setRange(Range range); |
| |
| /** |
| * Returns the range of keys to scan over. |
| * |
| * @return the range configured for this scanner |
| */ |
| Range getRange(); |
| |
| /** |
| * Sets the number of Key/Value pairs that will be fetched at a time from a tablet server. |
| * |
| * @param size |
| * the number of Key/Value pairs to fetch per call to Accumulo |
| */ |
| void setBatchSize(int size); |
| |
| /** |
| * Returns the batch size (number of Key/Value pairs) that will be fetched at a time from a tablet server. |
| * |
| * @return the batch size configured for this scanner |
| */ |
| int getBatchSize(); |
| |
| /** |
| * Enables row isolation. Writes that occur to a row after a scan of that row has begun will not be seen if this option is enabled. |
| */ |
| void enableIsolation(); |
| |
| /** |
| * Disables row isolation. Writes that occur to a row after a scan of that row has begun may be seen if this option is enabled. |
| */ |
| void disableIsolation(); |
| |
| /** |
| * The number of batches of Key/Value pairs returned before the {@link Scanner} will begin to prefetch the next batch |
| * |
| * @return Number of batches before read-ahead begins |
| * @since 1.6.0 |
| */ |
| long getReadaheadThreshold(); |
| |
| /** |
| * Sets the number of batches of Key/Value pairs returned before the {@link Scanner} will begin to prefetch the next batch |
| * |
| * @param batches |
| * Non-negative number of batches |
| * @since 1.6.0 |
| */ |
| void setReadaheadThreshold(long batches); |
| } |