/*
* Copyright © 2014 Cask Data, Inc.
*
* 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.
*/
package co.cask.cdap.explore.service.datasets;
import co.cask.cdap.api.common.Bytes;
import co.cask.cdap.api.data.batch.RecordScannable;
import co.cask.cdap.api.data.batch.RecordScanner;
import co.cask.cdap.api.data.batch.RecordWritable;
import co.cask.cdap.api.data.batch.Scannables;
import co.cask.cdap.api.data.batch.Split;
import co.cask.cdap.api.dataset.DatasetAdmin;
import co.cask.cdap.api.dataset.DatasetContext;
import co.cask.cdap.api.dataset.DatasetDefinition;
import co.cask.cdap.api.dataset.DatasetProperties;
import co.cask.cdap.api.dataset.DatasetSpecification;
import co.cask.cdap.api.dataset.lib.AbstractDataset;
import co.cask.cdap.api.dataset.lib.AbstractDatasetDefinition;
import co.cask.cdap.api.dataset.module.DatasetDefinitionRegistry;
import co.cask.cdap.api.dataset.module.DatasetModule;
import co.cask.cdap.api.dataset.table.Row;
import co.cask.cdap.api.dataset.table.Table;
import com.google.common.base.Objects;
import com.google.gson.Gson;
import java.io.IOException;
import java.lang.reflect.Type;
import java.util.List;
import java.util.Map;
/**
*
*/
public class KeyValueTableDefinition
extends AbstractDatasetDefinition<KeyValueTableDefinition.KeyValueTable, DatasetAdmin> {
private static final Gson GSON = new Gson();
private final DatasetDefinition<? extends Table, ?> tableDef;
public KeyValueTableDefinition(String name, DatasetDefinition<? extends Table, ?> orderedTableDefinition) {
super(name);
this.tableDef = orderedTableDefinition;
}
@Override
public DatasetSpecification configure(String instanceName, DatasetProperties properties) {
return DatasetSpecification.builder(instanceName, getName())
.properties(properties.getProperties())
.datasets(tableDef.configure("key-value-table", properties))
.build();
}
@Override
public DatasetAdmin getAdmin(DatasetContext datasetContext, DatasetSpecification spec,
ClassLoader classLoader) throws IOException {
return tableDef.getAdmin(datasetContext, spec.getSpecification("key-value-table"), classLoader);
}
@Override
public KeyValueTable getDataset(DatasetContext datasetContext, DatasetSpecification spec,
Map<String, String> arguments, ClassLoader classLoader) throws IOException {
Table table = tableDef.getDataset(datasetContext, spec.getSpecification("key-value-table"), arguments, classLoader);
return new KeyValueTable(spec.getName(), table);
}
/**
* KeyStructValueTable
*/
public static class KeyValueTable extends AbstractDataset
implements RecordScannable<KeyValue>, RecordWritable<KeyValue> {
static final byte[] COL = new byte[] {'c', 'o', 'l', '1'};
private final Table table;
public KeyValueTable(String instanceName, Table table) {
super(instanceName, table);
this.table = table;
}
public void put(int key, String value) throws Exception {
table.put(Bytes.toBytes(key), COL, Bytes.toBytes(value));
}
public String get(int key) throws Exception {
return Bytes.toString(table.get(Bytes.toBytes(key), COL));
}
@Override
public Type getRecordType() {
return KeyValue.class;
}
@Override
public List<Split> getSplits() {
return table.getSplits();
}
@Override
public RecordScanner<KeyValue> createSplitRecordScanner(Split split) {
return Scannables.splitRecordScanner(table.createSplitReader(split), KEY_VALUE_ROW_MAKER);
}
@Override
public void write(KeyValue keyValue) throws IOException {
try {
put(keyValue.getKey(), keyValue.getValue());
} catch (Exception e) {
throw new IOException(e);
}
}
}
public static class KeyValue {
private final int key;
private final String value;
public KeyValue(Integer key, String value) {
this.key = key;
this.value = value;
}
@SuppressWarnings("UnusedDeclaration")
public int getKey() {
return key;
}
@SuppressWarnings("UnusedDeclaration")
public String getValue() {
return value;
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
KeyValue that = (KeyValue) o;
return Objects.equal(this.key, that.key) &&
Objects.equal(this.value, that.value);
}
@Override
public int hashCode() {
return Objects.hashCode(key, value);
}
}
/**
* KeyValueTableModule
*/
public static class KeyValueTableModule implements DatasetModule {
@Override
public void register(DatasetDefinitionRegistry registry) {
DatasetDefinition<Table, DatasetAdmin> table = registry.get("table");
KeyValueTableDefinition keyValueTable = new KeyValueTableDefinition("kvTable", table);
registry.add(keyValueTable);
}
}
private static final Scannables.RecordMaker<byte[], Row, KeyValue> KEY_VALUE_ROW_MAKER =
new Scannables.RecordMaker<byte[], Row, KeyValue>() {
@Override
public KeyValue makeRecord(byte[] key, Row row) {
return new KeyValue(Bytes.toInt(key),
GSON.fromJson(Bytes.toString(row.get(KeyValueTable.COL)), String.class));
}
};
}