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<title>Berkeley DB: DbLogc.get</title>
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import com.sleepycat.db.*;
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public int get(DbLsn lsn, Dbt data, int flags)
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<p>The DbLogc.get method retrieve records from the log according to the
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<b>lsn</b> and <b>flags</b> arguments.
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<p>The data field of the <b>data</b> structure is set to the record
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retrieved, and the size field indicates the number of bytes in the
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record. See <a href="../api_java/dbt_class.html">Dbt</a> for a description of other fields in the
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<b>data</b> structure. The <a href="../api_java/dbt_class.html#DB_DBT_MALLOC">Db.DB_DBT_MALLOC</a>,
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<a href="../api_java/dbt_class.html#DB_DBT_REALLOC">Db.DB_DBT_REALLOC</a> and <a href="../api_java/dbt_class.html#DB_DBT_USERMEM">Db.DB_DBT_USERMEM</a> flags may be specified
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for any <a href="../api_java/dbt_class.html">Dbt</a> used for data retrieval.
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<p>The <b>flags</b> value must be set to one of the following values:
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<p><dt><a name="Db.DB_FIRST">Db.DB_FIRST</a><dd>The first record from any of the log files found in the log directory
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is returned in the <b>data</b> argument.
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The <b>lsn</b> argument is overwritten with the <a href="../api_java/lsn_class.html">DbLsn</a> of the
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If the log is empty, the DbLogc.get method will return Db.DB_NOTFOUND.
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<p><dt><a name="Db.DB_LAST">Db.DB_LAST</a><dd>The last record in the log is returned in the <b>data</b> argument.
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The <b>lsn</b> argument is overwritten with the <a href="../api_java/lsn_class.html">DbLsn</a> of the
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If the log is empty, the DbLogc.get method will return Db.DB_NOTFOUND.
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<p><dt><a name="Db.DB_NEXT">Db.DB_NEXT</a>, <a name="Db.DB_PREV">Db.DB_PREV</a><dd>The current log position is advanced to the next (previous) record in
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the log, and that record is returned in the <b>data</b> argument. The
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<b>lsn</b> argument is overwritten with the <a href="../api_java/lsn_class.html">DbLsn</a> of the record
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<p>If the cursor has not been initialized via DB_FIRST, DB_LAST, DB_SET,
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DB_NEXT, or DB_PREV, DbLogc.get will return the first (last) record
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If the last (first) log record has already been returned or the log is
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empty, the DbLogc.get method will return Db.DB_NOTFOUND.
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If the log was opened with the DB_THREAD flag set, calls to
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DbLogc.get with the DB_NEXT (DB_PREV) flag set, the DbLogc.get method throws an exception that encapsulates Db.EINVAL.
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<p><dt><a name="Db.DB_CURRENT">Db.DB_CURRENT</a><dd>Return the log record to which the log currently refers.
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If the log cursor has not been initialized via DB_FIRST, DB_LAST,
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DB_SET, DB_NEXT, or DB_PREV, or if the log was opened with the DB_THREAD
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flag set, the DbLogc.get method throws an exception that encapsulates Db.EINVAL.
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<p><dt><a name="Db.DB_SET">Db.DB_SET</a><dd>Retrieve the record specified by the <b>lsn</b> argument.
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If the specified <a href="../api_java/lsn_class.html">DbLsn</a> is invalid (for example, it does not
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appear in the log), the DbLogc.get method throws an exception that encapsulates Db.EINVAL.
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Otherwise, the DbLogc.get method throws an exception that encapsulates a non-zero error value on
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<p>The DbLogc.get method may fail and throw an exception encapsulating a non-zero error for the following conditions:
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<p><dt>EINVAL<dd>An invalid flag value or parameter was specified.
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<p>The DB_CURRENT flag was set and the log pointer had not yet been
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<p>The DB_SET flag was set and the specified log sequence number does not
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<p>The DbLogc.get method may fail and throw an exception for errors specified for other Berkeley DB and C library or system methods.
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If a catastrophic error has occurred, the DbLogc.get method may fail and
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throw a <a href="../api_java/runrec_class.html">DbRunRecoveryException</a>,
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in which case all subsequent Berkeley DB calls will fail in the same way.
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<a href="../api_java/env_class.html">DbEnv</a>, <a href="../api_java/logc_class.html">DbLogc</a>, <a href="../api_java/lsn_class.html">DbLsn</a>
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<a href="../api_java/log_list.html">Logging Subsystem and Related Methods</a>
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