org.apache.parquet.column.values.RequiresFallback Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
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* 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
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* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.parquet.column.values;
import org.apache.parquet.column.values.fallback.FallbackValuesWriter;
/**
* Used to add extra behavior to a ValuesWriter that requires fallback
*
* @see FallbackValuesWriter
*/
public interface RequiresFallback {
/**
* In the case of a dictionary based encoding we will fallback if the dictionary becomes too big
*
* @return true to notify the parent that we should fallback to another encoding
*/
boolean shouldFallBack();
/**
* Before writing the first page we will verify if the encoding is worth it.
* and fall back if a simpler encoding would be better in that case
*
* @param rawSize the size if encoded with plain
* @param encodedSize the size as encoded by the current encoding
* @return true if we keep this encoding
*/
boolean isCompressionSatisfying(long rawSize, long encodedSize);
/**
* When falling back to a different encoding we must re-encode all the values seen so far
*
* @param writer the new encoder to write the current values to
*/
void fallBackAllValuesTo(ValuesWriter writer);
}