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Common utility classes used by JSimpleDB.

There is a newer version: 3.6.1


/*
 * Copyright (C) 2015 Archie L. Cobbs. All rights reserved.
 */

package org.jsimpledb.index;

import java.util.NavigableMap;
import java.util.NavigableSet;

import org.jsimpledb.tuple.Tuple2;
import org.jsimpledb.tuple.Tuple3;

/**
 * An index on two fields.
 *
 * 
 * Indexes are read-only and "live", always reflecting the current transaction state.
 *
 * @param  first indexed value type
 * @param  second indexed value type
 * @param  index target type
 * @see org.jsimpledb.index
 */
public interface Index2 {

    /**
     * View this index as a {@link NavigableSet} of tuples.
     *
     * @return {@link NavigableSet} of tuples containing indexed values and target value
     */
    NavigableSet> asSet();

    /**
     * View this index as a {@link NavigableMap} of target values keyed by indexed value tuples.
     *
     * @return {@link NavigableMap} from indexed value tuple to the corresponding set of target objects
     */
    NavigableMap, NavigableSet> asMap();

    /**
     * View this index as a {@link NavigableMap} of {@link Index}s keyed by the first value.
     *
     * @return {@link NavigableMap} from first value to {@link Index}
     */
    NavigableMap> asMapOfIndex();

    /**
     * Get the prefix of this instance that only includes the first two indexed fields.
     *
     * @return prefix of this index
     */
    Index asIndex();
}