org.apache.parquet.hadoop.metadata.StrictKeyValueMetadataMergeStrategy Maven / Gradle / Ivy
/*
* 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.parquet.hadoop.metadata;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
/**
* Strategy to throw errors if there are multiple values for a given key in metadata.
*/
public class StrictKeyValueMetadataMergeStrategy implements KeyValueMetadataMergeStrategy {
/**
* @param keyValueMetaData the merged app specific metadata
*/
public Map merge(Map> keyValueMetaData) {
Map mergedKeyValues = new HashMap();
for (Map.Entry> entry : keyValueMetaData.entrySet()) {
if (entry.getValue().size() > 1) {
throw new RuntimeException("could not merge metadata: key " + entry.getKey() + " has conflicting values: " + entry.getValue());
}
mergedKeyValues.put(entry.getKey(), entry.getValue().iterator().next());
}
return mergedKeyValues;
}
}