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The Kite Data HBase module provides integration with HBase.
/**
* Copyright 2013 Cloudera 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 org.kitesdk.data.hbase.impl;
import com.google.common.collect.Maps;
import java.util.List;
import java.util.Map;
import org.kitesdk.data.DatasetException;
import org.kitesdk.data.PartitionStrategy;
import org.kitesdk.data.impl.Accessor;
import org.kitesdk.data.spi.FieldPartitioner;
import org.kitesdk.data.spi.partition.IdentityFieldPartitioner;
/**
* The KeySchema type.
*/
public class KeySchema {
private final String rawSchema;
private final PartitionStrategy partitionStrategy;
private final Map fieldPositions;
public KeySchema(String rawSchema, PartitionStrategy partitionStrategy) {
this.rawSchema = rawSchema;
this.partitionStrategy = partitionStrategy;
this.fieldPositions = Maps.newHashMap();
List partitioners =
Accessor.getDefault().getFieldPartitioners(partitionStrategy);
for (int i = 0; i < partitioners.size(); i += 1) {
FieldPartitioner fp = partitioners.get(i);
if (fp instanceof IdentityFieldPartitioner) {
fieldPositions.put(fp.getSourceName(), i);
}
}
}
/**
* Method meant to determine if two KeySchemas are compatible with each other
* for schema migration purposes. Classes that inherit KeySchema should
* override this implementation, since this implementation isn't able to make
* that determination.
*
* TODO: Figure out a base set of properties that all key schema
* implementations should share in their implementation of determining
* compatibility and execute that here.
*
* @param keySchema
* The other KeySchema to determine compatible with
* @return
*/
public boolean compatible(KeySchema keySchema) {
// throw an exception if anyone calls this directly, as this should be
// overridden in derived classes.
throw new UnsupportedOperationException(
"KeySchema class can't determine if two key schemas are compatible.");
}
/**
* Get the raw schema
*
* @return The raw schema.
*/
public String getRawSchema() {
return rawSchema;
}
public PartitionStrategy getPartitionStrategy() {
return partitionStrategy;
}
/**
* Resolves the storage position of a field in keys with this KeySchema.
*
* @param fieldName
* The source field name.
* @return
* The position of the field in keys with this schema.
* @throws DatasetException
* If the field cannot be recovered from keys with this schema.
*/
public int position(String fieldName) {
if (fieldPositions.containsKey(fieldName)) {
return fieldPositions.get(fieldName);
} else {
throw new DatasetException("Cannot recover " + fieldName + " from key");
}
}
}