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