PaimonTableDecorators.java

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package org.apache.doris.datasource.paimon;

import org.apache.paimon.table.ChainGroupReadTable;
import org.apache.paimon.table.DelegatedFileStoreTable;
import org.apache.paimon.table.FallbackReadFileStoreTable;
import org.apache.paimon.table.FileStoreTable;
import org.apache.paimon.table.Table;

import java.util.Map;

/** Utilities for preserving Paimon's planning decorator invariants. */
public final class PaimonTableDecorators {

    private PaimonTableDecorators() {
    }

    public static FileStoreTable unwrapToFallbackOrBase(FileStoreTable table) {
        FileStoreTable current = table;
        // Fallback dispatch requires the pair to be the system wrapper's immediate child. Paimon
        // does not privilege-wrap system tables, so peeling privilege-only delegates matches its
        // catalog semantics while retaining the one decorator that changes read routing.
        while (current instanceof DelegatedFileStoreTable
                && !(current instanceof FallbackReadFileStoreTable)) {
            current = ((DelegatedFileStoreTable) current).wrapped();
        }
        return current;
    }

    static FileStoreTable rebuildFallbackPair(FallbackReadFileStoreTable pair, FileStoreTable wrapped,
            FileStoreTable other) {
        if (pair instanceof ChainGroupReadTable) {
            return new ChainGroupReadTable(wrapped, other);
        }
        return new FallbackReadFileStoreTable(wrapped, other, PaimonReaderOptions.isWrappedFirst(pair));
    }

    static Map<String, String> otherOptions(FallbackReadFileStoreTable pair, Map<String, String> options) {
        return new FallbackOptions(pair).rewriteOtherOptions(options);
    }

    private static final class FallbackOptions extends FallbackReadFileStoreTable {
        private FallbackOptions(FallbackReadFileStoreTable pair) {
            super(pair.wrapped(), pair.other(), PaimonReaderOptions.isWrappedFirst(pair));
        }

        @Override
        public Map<String, String> rewriteOtherOptions(Map<String, String> options) {
            return super.rewriteOtherOptions(options);
        }
    }

    static boolean isChainTable(Table table) {
        if (!(table instanceof FileStoreTable)) {
            return false;
        }
        FileStoreTable unwrapped = unwrapToFallbackOrBase((FileStoreTable) table);
        return unwrapped instanceof FallbackReadFileStoreTable
                && ((FallbackReadFileStoreTable) unwrapped).other() instanceof ChainGroupReadTable;
    }
}