com.sleepycat.je

Enum Get

java.lang.Object

java.lang.Enum<Get>

com.sleepycat.je.Get

All Implemented Interfaces:

java.io.Serializable, java.lang.Comparable<Get>

public enum Get
extends java.lang.Enum<Get>

The operation type passed to "get" methods on databases and cursors.

Enum Constant Summary

Enum Constants

Enum Constant and Description
CURRENT Accesses the current record.
FIRST Finds the first record in the database.
LAST Finds the last record in the database.
NEXT Moves to the next record.
NEXT_DUP Moves to the next record with the same key.
NEXT_NO_DUP Moves to the next record with a different key.
PREV Moves to the previous record.
PREV_DUP Moves to the previous record with the same key.
PREV_NO_DUP Moves to the previous record with a different key.
SEARCH Searches using an exact match by key.
SEARCH_BOTH Searches using an exact match by key and data (or pKey).
SEARCH_BOTH_GTE Searches using an exact match by key and a GTE match by data (or pKey).
SEARCH_GTE Searches using a GTE match by key.

Method Summary

Modifier and Type	Method and Description
static Get	valueOf(java.lang.String name) Returns the enum constant of this type with the specified name.
static Get[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

SEARCH

public static final Get SEARCH

Searches using an exact match by key.

Returns, or moves the cursor to, the record having a key exactly matching the given key parameter.

If the database has duplicate keys, the record with the matching key and lowest data value (or the lowest primary key, for secondary databases) is selected.

The operation does not succeed if no record matches.

SEARCH_BOTH

public static final Get SEARCH_BOTH

Searches using an exact match by key and data (or pKey).

Returns, or moves the cursor to, the record having a key exactly matching the given key parameter, and having a data value (or primary key) exactly matching the given data (or pKey) parameter. The data is matched for Database and Cursor operations, while the primary key is matched for SecondaryDatabase and SecondaryCursor operations.

If the database has duplicate keys, the search is performed by key and data (or pKey) using the database Btree. If the database has does not have duplicate keys, the search is performed by key alone using the Btree, and then the data (or primary key) of the matching record is simply compared to the data (pKey) parameter. In other words, using this operation has no performance advantage over SEARCH when the database does not have duplicates.

The operation does not succeed (null is returned) if no record matches.

SEARCH_GTE

public static final Get SEARCH_GTE

Searches using a GTE match by key.

Returns, or moves the cursor to, the record with a key that is greater than or equal to (GTE) the given key parameter.

If the database has duplicate keys, the record with the lowest data value (or the lowest primary key, for a secondary database) is selected among the duplicates with the matching key.

The operation does not succeed (null is returned) if no record matches.

SEARCH_BOTH_GTE

public static final Get SEARCH_BOTH_GTE

Searches using an exact match by key and a GTE match by data (or pKey).

Returns, or moves the cursor to, the record with a key exactly matching the given key parameter, and having a data value (or primary key) that is greater than or equal to (GTE) the given data (or pKey) parameter. The data is matched for Database and Cursor operations, while the primary key is matched for SecondaryDatabase and SecondaryCursor operations.

If the database does not have duplicate keys, the data (or pKey) is matched exactly and this operation is equivalent to SEARCH_BOTH.

The operation does not succeed (null is returned) if no record matches.

CURRENT

public static final Get CURRENT

Accesses the current record.

Accesses the record at the current cursor position. If the cursor is uninitialized (not positioned on a record), IllegalStateException is thrown.

The operation does not succeed (null is returned) if the record at the current position has been deleted. This can occur in two cases: 1. If the record was deleted using this cursor and then accessed. 2. If the record was not locked by this cursor or transaction, and was deleted by another thread or transaction after this cursor was positioned on it.

FIRST

public static final Get FIRST

Finds the first record in the database.

Moves the cursor to the record in the database with the lowest valued key.

If the database has duplicate keys, the record with the lowest data value (or the lowest primary key, for a secondary database) is selected among the duplicates for the lowest key.

The operation does not succeed (null is returned) if the database is empty.

LAST

public static final Get LAST

Finds the last record in the database.

Moves the cursor to the record in the database with the highest valued key.

If the database has duplicate keys, the record with the highest data value (or the highest primary key, for a secondary database) is selected among the duplicates for the highest key.

The operation does not succeed (null is returned) if the database is empty.

NEXT

public static final Get NEXT

Moves to the next record.

Moves the cursor to the record following the record at the current cursor position. If the cursor is uninitialized (not positioned on a record), moves to the first record and this operation is equivalent to FIRST.

If the database does not have duplicate keys, the following record is defined as the record with the next highest key. If the database does have duplicate keys, the following record is defined as the record with the same key and the next highest data value (or the next highest primary key, for a secondary database) among the duplicates for that key; or if there are no more records with the same key, the following record is the record with the next highest key and the lowest data value (or the lowest primary key, for a secondary database) among the duplicates for that key.

The operation does not succeed (null is returned) if the record at the cursor position is the last record in the database.

NEXT_DUP

public static final Get NEXT_DUP

Moves to the next record with the same key.

Moves the cursor to the record following the record at the current cursor position and having the same key. If the cursor is uninitialized (not positioned on a record), IllegalStateException is thrown.

If the database has duplicate keys, moves to the record with the same key and the next highest data value (or the next highest primary key, for a secondary database) among the duplicates for that key.

The operation does not succeed (null is returned) if there are no following records with the same key. This is always the case when database does not have duplicate keys.

NEXT_NO_DUP

public static final Get NEXT_NO_DUP

Moves to the next record with a different key.

Moves the cursor to the record following the record at the current cursor position and having the next highest key. If the cursor is uninitialized (not positioned on a record), moves to the first record and this operation is equivalent to FIRST.

If the database has duplicate keys, moves to the record with the next highest key and the lowest data value (or the lowest primary key, for a secondary database) among the duplicates for that key; this effectively skips over records having the same key and a higher data value (or a higher primary key, for a secondary database). If the database does not have duplicate keys, this operation is equivalent to NEXT.

The operation does not succeed (null is returned) if there are no following records with a different key.

PREV

public static final Get PREV

Moves to the previous record.

Moves the cursor to the record preceding the record at the current cursor position. If the cursor is uninitialized (not positioned on a record), moves to the last record and this operation is equivalent to LAST.

If the database does not have duplicate keys, the preceding record is defined as the record with the next lowest key. If the database does have duplicate keys, the preceding record is defined as the record with the same key and the next lowest data value (or the next lowest primary key, for a secondary database) among the duplicates for that key; or if there are no preceding records with the same key, the preceding record is the record with the next lowest key and the highest data value (or the highest primary key, for a secondary database) among the duplicates for that key.

The operation does not succeed (null is returned) if the record at the cursor position is the first record in the database.

PREV_DUP

public static final Get PREV_DUP

Moves to the previous record with the same key.

Moves the cursor to the record preceding the record at the current cursor position and having the same key. If the cursor is uninitialized (not positioned on a record), IllegalStateException is thrown.

If the database has duplicate keys, moves to the record with the same key and the next lowest data value (or the next lowest primary key, for a secondary database) among the duplicates for that key.

The operation does not succeed (null is returned) if there are no preceding records with the same key. This is always the case when database does not have duplicate keys.

PREV_NO_DUP

public static final Get PREV_NO_DUP

Moves to the previous record with a different key.

Moves the cursor to the record preceding the record at the current cursor position and having the next lowest key. If the cursor is uninitialized (not positioned on a record), moves to the last record and this operation is equivalent to LAST.

If the database has duplicate keys, moves to the record with the next lowest key and the highest data value (or the highest primary key, for a secondary database) among the duplicates for that key; this effectively skips over records having the same key and a lower data value (or a lower primary key, for a secondary database). If the database does not have duplicate keys, this operation is equivalent to PREV.

The operation does not succeed (null is returned) if there are no preceding records with a different key.

Method Detail

values

public static Get[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (Get c : Get.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static Get valueOf(java.lang.String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

java.lang.IllegalArgumentException - if this enum type has no constant with the specified name

java.lang.NullPointerException - if the argument is null