com.coyotegulch.jisp
public class BTreeIterator extends Object implements IndexIterator
BTreeIterator
defines an object that references a specific object relative to other
objects in an ObjectIndex
. In many ways, a BTreeIterator
is analogous
to the "cursors" found in SQL-type databases; it is essentially a movable reference to elements
in an index, and it can be moved forward and backward through the list of keys.
See Also: ObjectIndex IndexedObjectDatabase
Constructor Summary | |
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BTreeIterator(BTreeIndex index)
Creates a new BTreeIterator for a given index and database.
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BTreeIterator(BTreeIterator iterator)
Creates a new BTreeIterator that points to the same location as an existing
BtreeIterator .
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Method Summary | |
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Object | getKey()
Returns the key Object currently associated with this iterator.
|
long | getRecPtr()
Returns the reference (usually a file pointer) currently associated with this iterator.
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void | invalidate()
Sets this iterator's state to invalid. |
boolean | isValid()
Checks to see if this iterator is valid.
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boolean | moveFirst()
Moves this iterator to the first key and reference in sequence.
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boolean | moveLast()
Moves this iterator to the last key and reference in sequence.
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boolean | moveNext()
Moves this iterator to the next key and reference in sequence.
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boolean | movePrevious()
Moves this iterator to the previous key and reference in sequence.
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boolean | moveTo(KeyObject key)
Moves this iterator to point to the given key .
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boolean | moveTo(KeyObject key, boolean acceptNext)
Moves this iterator to point to the given key .
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BTreeIterator
for a given index and database.
Parameters: index the index to which this iterator is attached.
Throws: IOException when an I/O exception is thrown by an underlying java.io.* class ClassNotFoundException for a casting error, usually when a persistent object or index does match the expected type
See Also: BTreeIndex
BTreeIterator
that points to the same location as an existing
BtreeIterator
.
Parameters: iterator the iterator to be copied.
Throws: IOException when an I/O exception is thrown by an underlying java.io.* class ClassNotFoundException for a casting error, usually when a persistent object or index does match the expected type
See Also: BTreeIndex
Object
currently associated with this iterator.
Returns: the key Object
currently referenced by this iterator, or null if the iterator is invalid
Throws: IOException when an I/O exception is thrown by an underlying java.io.* class
Returns: the record Object
currently referenced by this iterator, or -1 if the iterator is invalid
Returns: true
if the iterator is valid; false
if it is invalid.
Returns: true
if the operation was successful; false
otherwise.
Throws: IOException when an I/O exception is thrown by an underlying java.io.* class ClassNotFoundException for a casting error, usually when a persistent object or index does match the expected type BTreeException when an error occurs during B-Tree processing
Returns: true
if the operation was successful; false
otherwise.
Throws: IOException when an I/O exception is thrown by an underlying java.io.* class ClassNotFoundException for a casting error, usually when a persistent object or index does match the expected type BTreeException when an error occurs during B-Tree processing
Returns: true
if the operation was successful; false
otherwise.
Throws: IOException when an I/O exception is thrown by an underlying java.io.* class ClassNotFoundException for a casting error, usually when a persistent object or index does match the expected type
Returns: true
if the operation was successful; false
otherwise.
Throws: IOException when an I/O exception is thrown by an underlying java.io.* class ClassNotFoundException for a casting error, usually when a persistent object or index does match the expected type BTreeException when an error occurs during B-Tree processing
key
.
Parameters: key key identifier to find
Returns: true
if the operation was successful; false
otherwise.
Throws: IOException when an I/O exception is thrown by an underlying java.io.* class ClassNotFoundException for a casting error, usually when a persistent object or index does match the expected type BTreeException when an error occurs during B-Tree processing
key
.
Parameters: key key identifier to find acceptNext when true, allows the search to return the next record in sequence if an exact match is not found
Returns: true
if the operation was successful; false
otherwise.
Throws: IOException when an I/O exception is thrown by an underlying java.io.* class ClassNotFoundException for a casting error, usually when a persistent object or index does match the expected type BTreeException when an error occurs during B-Tree processing