/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 2002, 2015 Oracle and/or its affiliates. All rights reserved.
*
* $Id$
*/
package com.sleepycat.db;
import com.sleepycat.db.internal.DbConstants;
import com.sleepycat.db.internal.DbUtil;
/**
A DatabaseEntry that holds multiple key/data pairs returned by a single
{@link com.sleepycat.db.Database Database} or {@link com.sleepycat.db.Cursor Cursor} get call.
*/
public class MultipleKeyDataEntry extends MultipleEntry {
/**
Construct an entry with no data. The object must be configured
before use with the {@link com.sleepycat.db.MultipleEntry#setUserBuffer MultipleEntry.setUserBuffer} method.
*/
public MultipleKeyDataEntry() {
super(null, 0, 0);
}
/**
Construct an entry with a given byte array. The offset is
set to zero; the size is set to the length of the array. If null
is passed, the object must be configured before use with the
{@link com.sleepycat.db.MultipleEntry#setUserBuffer MultipleEntry.setUserBuffer} method.
<p>
@param data
Byte array wrapped by the entry.
*/
public MultipleKeyDataEntry(final byte[] data) {
super(data, 0, (data == null) ? 0 : data.length);
}
/**
Constructs a DatabaseEntry with a given byte array, offset and size.
<p>
@param data
Byte array wrapped by the DatabaseEntry.
@param offset
Offset in the first byte in the byte array to be included.
@param size
Number of bytes in the byte array to be included.
*/
public MultipleKeyDataEntry(final byte[] data,
final int offset,
final int size) {
super(data, offset, size);
}
/**
* Return the bulk retrieval flag and reset the entry position so that the
* next set of key/data can be returned.
*/
/* package */
int getMultiFlag() {
pos = 0;
return DbConstants.DB_MULTIPLE_KEY;
}
/**
Get the next key/data pair in the returned set. This method may only
be called after a successful call to a {@link com.sleepycat.db.Database Database} or
{@link com.sleepycat.db.Cursor Cursor} get method with this object as the data parameter.
<p>
@param key
an entry that is set to refer to the next key element in the returned
set.
<p>
@param data
an entry that is set to refer to the next data element in the returned
set.
<p>
@return
indicates whether a value was found. A return of <code>false</code>
indicates that the end of the set was reached.
*/
public boolean next(final DatabaseEntry key, final DatabaseEntry data) {
if (pos == 0)
pos = ulen - INT32SZ;
final int keyoff = DbUtil.array2int(this.data, pos);
// crack out the key and data offsets and lengths.
if (keyoff < 0)
return false;
pos -= INT32SZ;
final int keysz = DbUtil.array2int(this.data, pos);
pos -= INT32SZ;
final int dataoff = DbUtil.array2int(this.data, pos);
pos -= INT32SZ;
final int datasz = DbUtil.array2int(this.data, pos);
pos -= INT32SZ;
key.setData(this.data);
key.setOffset(keyoff);
key.setSize(keysz);
data.setData(this.data);
data.setOffset(dataoff);
data.setSize(datasz);
return true;
}
/**
Append an entry to the bulk buffer.
<p>
@param key
an array containing the key to be added.
@param koff
the position in the <b>key</b> array where the record starts.
@param klen
the length of the record, in bytes, to be copied from the <b>key</b> array.
@param data
an array containing the value to be added.
@param doff
the position in the <b>data</b> array where the record starts.
@param dlen
the length of the record, in bytes, to be copied from the <b>data</b> array.
<p>
@return
indicates whether there was space. A return of <code>false</code>
indicates that the specified entry could not fit in the buffer.
*/
public boolean append(final byte[] key, int koff, int klen,
final byte[] data, int doff, int dlen)
throws DatabaseException {
return append_internal(key, koff, klen) &&
this.append_internal(data, doff, dlen);
}
/**
Append an entry to the bulk buffer.
<p>
@param key
the key to be appended, using the offset and size specified in the
{@link com.sleepycat.db.DatabaseEntry DatabaseEntry}.
@param data
the value to be appended, using the offset and size specified in the
{@link com.sleepycat.db.DatabaseEntry DatabaseEntry}.
<p>
@return
indicates whether there was space. A return of <code>false</code>
indicates that the specified entry could not fit in the buffer.
*/
public boolean append(final DatabaseEntry key, final DatabaseEntry data)
throws DatabaseException {
return append(key.data, key.offset, key.size,
data.data, data.offset, data.size);
}
/**
Append an entry to the bulk buffer.
<p>
@param key
an array containing the key to be added.
@param data
an array containing the value to be added.
<p>
@return
indicates whether there was space. A return of <code>false</code>
indicates that the specified entry could not fit in the buffer.
*/
public boolean append(final byte[] key, final byte[] data)
throws DatabaseException {
return append(key, 0, key.length, data, 0, data.length);
}
}