presto-parquet/src/main/java/io/prestosql/parquet/dictionary/FloatDictionary.java/FloatDictionary/FloatDictionary
class FloatDictionary:    public FloatDictionary(DictionaryPage dictionaryPage)
            throws IOException
    {
        super(dictionaryPage.getEncoding());
        content = new float[dictionaryPage.getDictionarySize()];
        FloatPlainValuesReader floatReader = new FloatPlainValuesReader();
        floatReader.initFromPage(dictionaryPage.getDictionarySize(), toInputStream(dictionaryPage));
        for (int i = 0; i < content.length; i++) {
            content[i] = floatReader.readFloat();
        }
    }