org.apache.parquet.hadoop.api.InitContext Maven / Gradle / Ivy
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* 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.api;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.Map.Entry;
import org.apache.hadoop.conf.Configuration;
import org.apache.parquet.schema.MessageType;
/**
*
* Context passed to ReadSupport when initializing for read
*/
public class InitContext {
private final Map> keyValueMetadata;
private Map mergedKeyValueMetadata;
private final Configuration configuration;
private final MessageType fileSchema;
/**
* @param configuration the hadoop configuration
* @param keyValueMetadata extra metadata from file footers
* @param fileSchema the merged schema from the files
*/
public InitContext(
Configuration configuration,
Map> keyValueMetadata,
MessageType fileSchema) {
super();
this.keyValueMetadata = keyValueMetadata;
this.configuration = configuration;
this.fileSchema = fileSchema;
}
/**
* If there is a conflicting value when reading from multiple files,
* an exception will be thrown
* @return the merged key values metadata form the file footers
*/
@Deprecated
public Map getMergedKeyValueMetaData() {
if (mergedKeyValueMetadata == null) {
Map mergedKeyValues = new HashMap();
for (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());
}
mergedKeyValueMetadata = mergedKeyValues;
}
return mergedKeyValueMetadata;
}
/**
* @return the configuration for this job
*/
public Configuration getConfiguration() {
return configuration;
}
/**
* this is the union of all the schemas when reading multiple files.
* @return the schema of the files being read
*/
public MessageType getFileSchema() {
return fileSchema;
}
/**
* each key is associated with the list of distinct values found in footers
* @return the merged metadata from the footer of the file
*/
public Map> getKeyValueMetadata() {
return keyValueMetadata;
}
}