| /* |
| * 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.impl; |
| |
| import static com.google.common.base.Preconditions.checkArgument; |
| |
| import java.util.Iterator; |
| import java.util.Map.Entry; |
| import java.util.concurrent.TimeUnit; |
| |
| import org.apache.accumulo.core.Constants; |
| import org.apache.accumulo.core.client.Scanner; |
| import org.apache.accumulo.core.data.Key; |
| import org.apache.accumulo.core.data.Range; |
| import org.apache.accumulo.core.data.Value; |
| import org.apache.accumulo.core.security.Authorizations; |
| |
| /** |
| * provides scanner functionality |
| * |
| * "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 class ScannerImpl extends ScannerOptions implements Scanner { |
| |
| // keep a list of columns over which to scan |
| // keep track of the last thing read |
| // hopefully, we can track all the state in the scanner on the client |
| // and just query for the next highest row from the tablet server |
| |
| private final ClientContext context; |
| private Authorizations authorizations; |
| private String tableId; |
| |
| private int size; |
| |
| private Range range; |
| private boolean isolated = false; |
| private long readaheadThreshold = Constants.SCANNER_DEFAULT_READAHEAD_THRESHOLD; |
| |
| public ScannerImpl(ClientContext context, String tableId, Authorizations authorizations) { |
| checkArgument(context != null, "context is null"); |
| checkArgument(tableId != null, "tableId is null"); |
| checkArgument(authorizations != null, "authorizations is null"); |
| this.context = context; |
| this.tableId = tableId; |
| this.range = new Range((Key) null, (Key) null); |
| this.authorizations = authorizations; |
| |
| this.size = Constants.SCAN_BATCH_SIZE; |
| } |
| |
| @Override |
| public synchronized void setRange(Range range) { |
| checkArgument(range != null, "range is null"); |
| this.range = range; |
| } |
| |
| @Override |
| public synchronized Range getRange() { |
| return range; |
| } |
| |
| @Override |
| public synchronized void setBatchSize(int size) { |
| if (size > 0) |
| this.size = size; |
| else |
| throw new IllegalArgumentException("size must be greater than zero"); |
| } |
| |
| @Override |
| public synchronized int getBatchSize() { |
| return size; |
| } |
| |
| @Override |
| public synchronized Iterator<Entry<Key,Value>> iterator() { |
| return new ScannerIterator(context, tableId, authorizations, range, size, getTimeout(TimeUnit.SECONDS), this, isolated, readaheadThreshold); |
| } |
| |
| @Override |
| public Authorizations getAuthorizations() { |
| return authorizations; |
| } |
| |
| @Override |
| public synchronized void enableIsolation() { |
| this.isolated = true; |
| } |
| |
| @Override |
| public synchronized void disableIsolation() { |
| this.isolated = false; |
| } |
| |
| @Override |
| public synchronized void setReadaheadThreshold(long batches) { |
| if (0 > batches) { |
| throw new IllegalArgumentException("Number of batches before read-ahead must be non-negative"); |
| } |
| |
| readaheadThreshold = batches; |
| } |
| |
| @Override |
| public synchronized long getReadaheadThreshold() { |
| return readaheadThreshold; |
| } |
| } |