/**
* 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.camel.component.hbase.mapping;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;
import org.apache.camel.Exchange;
import org.apache.camel.Message;
import org.apache.camel.component.hbase.HbaseAttribute;
import org.apache.camel.component.hbase.model.HBaseCell;
import org.apache.camel.component.hbase.model.HBaseData;
import org.apache.camel.component.hbase.model.HBaseRow;
/**
* A default {@link CellMappingStrategy} implementation.
* It distinguishes between multiple cell, by reading headers with index suffix.
* <p/>
* In case of multiple headers:
* <ul>
* <li>First header is expected to have no suffix</li>
* <li>Suffixes start from number 2</li>
* <li>Suffixes need to be sequential</li>
* </ul>
*/
public class HeaderMappingStrategy implements CellMappingStrategy {
/**
* Resolves the cell that the {@link Exchange} refers to.
*/
private HBaseRow resolveRow(Message message, int index) {
HBaseRow hRow = new HBaseRow();
HBaseCell hCell = new HBaseCell();
if (message != null) {
Object id = message.getHeader(HbaseAttribute.HBASE_ROW_ID.asHeader(index));
String rowClassName = message.getHeader(HbaseAttribute.HBASE_ROW_TYPE.asHeader(index), String.class);
Class<?> rowClass = rowClassName == null || rowClassName.isEmpty() ? String.class : message.getExchange().getContext().getClassResolver().resolveClass(rowClassName);
String columnFamily = (String) message.getHeader(HbaseAttribute.HBASE_FAMILY.asHeader(index));
String columnName = (String) message.getHeader(HbaseAttribute.HBASE_QUALIFIER.asHeader(index));
Object value = message.getHeader(HbaseAttribute.HBASE_VALUE.asHeader(index));
String valueClassName = message.getHeader(HbaseAttribute.HBASE_VALUE_TYPE.asHeader(index), String.class);
Class<?> valueClass = valueClassName == null || valueClassName.isEmpty() ? String.class : message.getExchange().getContext().getClassResolver().resolveClass(valueClassName);
//Id can be accepted as null when using get, scan etc.
if (id == null && columnFamily == null && columnName == null) {
return null;
}
hRow.setId(id);
hRow.setRowType(rowClass);
hCell.setQualifier(columnName);
hCell.setFamily(columnFamily);
hCell.setValue(value);
hCell.setValueType(valueClass);
hRow.getCells().add(hCell);
}
return hRow;
}
/**
* Resolves the cells that the {@link org.apache.camel.Exchange} refers to.
*/
@Override
public HBaseData resolveModel(Message message) {
int index = 1;
HBaseData data = new HBaseData();
//We use a LinkedHashMap to preserve the order.
Map<Object, HBaseRow> rows = new LinkedHashMap<Object, HBaseRow>();
HBaseRow hRow = new HBaseRow();
while (hRow != null) {
hRow = resolveRow(message, index++);
if (hRow != null) {
if (rows.containsKey(hRow.getId())) {
rows.get(hRow.getId()).getCells().addAll(hRow.getCells());
} else {
rows.put(hRow.getId(), hRow);
}
}
}
for (Map.Entry<Object, HBaseRow> rowEntry : rows.entrySet()) {
data.getRows().add(rowEntry.getValue());
}
return data;
}
/**
* Applies the cells to the {@link org.apache.camel.Exchange}.
*/
public void applyGetResults(Message message, HBaseData data) {
int index = 1;
if (data == null || data.getRows() == null) {
return;
}
for (HBaseRow hRow : data.getRows()) {
if (hRow.getId() != null) {
Set<HBaseCell> cells = hRow.getCells();
for (HBaseCell cell : cells) {
message.setHeader(HbaseAttribute.HBASE_VALUE.asHeader(index++), getValueForColumn(cells, cell.getFamily(), cell.getQualifier()));
}
}
}
}
/**
* Applies the cells to the {@link org.apache.camel.Exchange}.
*/
public void applyScanResults(Message message, HBaseData data) {
int index = 1;
if (data == null || data.getRows() == null) {
return;
}
for (HBaseRow hRow : data.getRows()) {
Set<HBaseCell> cells = hRow.getCells();
for (HBaseCell cell : cells) {
message.setHeader(HbaseAttribute.HBASE_ROW_ID.asHeader(index), hRow.getId());
message.setHeader(HbaseAttribute.HBASE_FAMILY.asHeader(index), cell.getFamily());
message.setHeader(HbaseAttribute.HBASE_QUALIFIER.asHeader(index), cell.getQualifier());
message.setHeader(HbaseAttribute.HBASE_VALUE.asHeader(index), cell.getValue());
}
index++;
}
}
/**
* Searches a list of cells and returns the value, if family/column matches with the specified.
*/
private Object getValueForColumn(Set<HBaseCell> cells, String family, String qualifier) {
if (cells != null) {
for (HBaseCell cell : cells) {
if (cell.getQualifier().equals(qualifier) && cell.getFamily().equals(family)) {
return cell.getValue();
}
}
}
return null;
}
}