Package com.healthmarketscience.jackcess.impl

Class IndexData

  • public class IndexData
extends Object
    Access table index data. This is the actual data which backs a logical Index, where one or more logical indexes can be backed by the same index data.
    Author:
    Tim McCune

    • Field Detail

      • FIRST_ENTRY

        public static final IndexData.Entry FIRST_ENTRY
        special entry which is less than any other entry

      • LAST_ENTRY

        public static final IndexData.Entry LAST_ENTRY
        special entry which is greater than any other entry

      • MAX_VALUE

        public static final Object MAX_VALUE
        special object which will always be greater than any other value, when searching for an index entry range in a multi-value index

      • MIN_VALUE

        public static final Object MIN_VALUE
        special object which will always be greater than any other value, when searching for an index entry range in a multi-value index

      • MAX_COLUMNS

        public static final int MAX_COLUMNS
        Max number of columns in an index
        See Also:
        Constant Field Values

      • IGNORE_NULLS_INDEX_FLAG

        public static final byte IGNORE_NULLS_INDEX_FLAG
        See Also:
        Constant Field Values

      • BYTE_CODE_COMPARATOR

        public static final Comparator<byte[]> BYTE_CODE_COMPARATOR

    • Method Detail

      • create

        public static IndexData create​(TableImpl table,
                               ByteBuffer tableBuffer,
                               int number,
                               JetFormat format)
        Creates an IndexData appropriate for the given table, using information from the given table definition buffer.

      • getName

        public String getName()

      • getPrimaryIndex

        public Index getPrimaryIndex()
        Returns:
        the "main" logical index which is backed by this data.

      • getIndexes

        public List<Index> getIndexes()
        Returns:
        All of the Indexes backed by this data (unmodifiable List)

      • getIndexFlags

        public byte getIndexFlags()

      • getIndexDataNumber

        public int getIndexDataNumber()

      • getUniqueEntryCount

        public int getUniqueEntryCount()

      • getUniqueEntryCountOffset

        public int getUniqueEntryCountOffset()

      • shouldIgnoreNulls

        public boolean shouldIgnoreNulls()
        Whether or not null values are actually recorded in the index.

      • isUnique

        public boolean isUnique()
        Whether or not index entries must be unique.

        Some notes about uniqueness:

        • Access does not seem to consider multiple null entries invalid for a unique index
        • text indexes collapse case, and Access seems to compare only the index entry bytes, therefore two strings which differ only in case will violate the unique constraint

      • isRequired

        public boolean isRequired()
        Whether or not values are required in the columns.

      • getColumnCount

        public int getColumnCount()

      • isInitialized

        public boolean isInitialized()
        Whether or not the complete index state has been read.

      • getOwnedPageCount

        public int getOwnedPageCount()
        Returns the number of database pages owned by this index data.
        Usage:
        Intermediate: This method requires moderate API knowledge.

      • validate

        public void validate​(boolean forceLoad)
              throws IOException
        Used by unit tests to validate the internal status of the index.
        Parameters:
        forceLoad - if false only validate currently loaded index data pages, otherwise, load and validate all index pages
        Throws:
        IOException
        Usage:
        Advanced: This method is for advanced/internal use.

      • getEntryCount

        public int getEntryCount()
                  throws IOException
        Returns the number of index entries in the index. Only called by unit tests.

        Forces index initialization.

        Throws:
        IOException
        Usage:
        Advanced: This method is for advanced/internal use.

      • initialize

        public void initialize()
                throws IOException
        Forces initialization of this index (actual parsing of index pages). normally, the index will not be initialized until the entries are actually needed.
        Throws:
        IOException

      • update

        public void update()
            throws IOException
        Writes the current index state to the database.

        Forces index initialization.

        Throws:
        IOException

      • read

        public void read​(ByteBuffer tableBuffer,
                 List<ColumnImpl> availableColumns)
          throws IOException
        Read the rest of the index info from a tableBuffer
        Parameters:
        tableBuffer - table definition buffer to read from initial info
        availableColumns - Columns that this index may use
        Throws:
        IOException

      • prepareAddRow

        public IndexData.PendingChange prepareAddRow​(Object[] row,
                                             RowIdImpl rowId,
                                             IndexData.PendingChange nextChange)
                                      throws IOException
        Prepares to add a row to this index. All constraints are checked before this method returns.

        Forces index initialization.

        Parameters:
        row - Row to add
        rowId - rowId of the row to be added
        Returns:
        a PendingChange which can complete the addition or roll it back
        Throws:
        IOException

      • prepareUpdateRow

        public IndexData.PendingChange prepareUpdateRow​(Object[] oldRow,
                                                RowIdImpl rowId,
                                                Object[] newRow,
                                                IndexData.PendingChange nextChange)
                                         throws IOException
        Prepares to update a row in this index. All constraints are checked before this method returns.

        Forces index initialization.

        Parameters:
        oldRow - Row to be removed
        newRow - Row to be added
        rowId - rowId of the row to be updated
        Returns:
        a PendingChange which can complete the update or roll it back
        Throws:
        IOException

      • deleteRow

        public void deleteRow​(Object[] row,
                      RowIdImpl rowId)
               throws IOException
        Removes a row from this index

        Forces index initialization.

        Parameters:
        row - Row to remove
        rowId - rowId of the row to be removed
        Throws:
        IOException

      • cursor

        public IndexData.EntryCursor cursor​(Object[] startRow,
                                    boolean startInclusive,
                                    Object[] endRow,
                                    boolean endInclusive)
                             throws IOException
        Gets a new cursor for this index, narrowed to the range defined by the given startRow and endRow.

        Forces index initialization.

        Parameters:
        startRow - the first row of data for the cursor, or null for the first entry
        startInclusive - whether or not startRow is inclusive or exclusive
        endRow - the last row of data for the cursor, or null for the last entry
        endInclusive - whether or not endRow is inclusive or exclusive
        Throws:
        IOException

      • constructIndexRowFromEntry

        public Object[] constructIndexRowFromEntry​(Object... values)
        Constructs an array of values appropriate for this index from the given column values, expected to match the columns for this index.
        Returns:
        the appropriate sparse array of data
        Throws:
        IllegalArgumentException - if the wrong number of values are provided

      • constructPartialIndexRowFromEntry

        public Object[] constructPartialIndexRowFromEntry​(Object filler,
                                                  Object... values)
        Constructs an array of values appropriate for this index from the given column values, possibly only providing a prefix subset of the index columns (at least one value must be provided). If a prefix entry is provided, any missing, trailing index entry values will use the given filler value.
        Returns:
        the appropriate sparse array of data
        Throws:
        IllegalArgumentException - if at least one value is not provided

      • constructIndexRow

        public Object[] constructIndexRow​(String colName,
                                  Object value)
        Constructs an array of values appropriate for this index from the given column value.
        Returns:
        the appropriate sparse array of data or null if not all columns for this index were provided

      • constructPartialIndexRow

        public Object[] constructPartialIndexRow​(Object filler,
                                         String colName,
                                         Object value)
        Constructs an array of values appropriate for this index from the given column value, which must be the first column of the index. Any missing, trailing index entry values will use the given filler value.
        Returns:
        the appropriate sparse array of data or null if no prefix list of columns for this index were provided

      • constructIndexRow

        public Object[] constructIndexRow​(Map<String,​?> row)
        Constructs an array of values appropriate for this index from the given column values.
        Returns:
        the appropriate sparse array of data or null if not all columns for this index were provided

      • constructPartialIndexRow

        public Object[] constructPartialIndexRow​(Object filler,
                                         Map<String,​?> row)
        Constructs an array of values appropriate for this index from the given column values, possibly only using a subset of the given values. A partial row can be created if one or more prefix column values are provided. If a prefix can be found, any missing, trailing index entry values will use the given filler value.
        Returns:
        the appropriate sparse array of data or null if no prefix list of columns for this index were provided