package com.cloudhopper.datastore.tokyo;
/*
* #%L
* ch-datastore
* %%
* Copyright (C) 2012 Cloudhopper by Twitter
* %%
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
* #L%
*/
import com.cloudhopper.datastore.DataStoreFatalException;
import com.cloudhopper.datastore.DataStoreIterator;
import tokyocabinet.BDB;
import tokyocabinet.BDBCUR;
/**
*
* @author joelauer
*/
public class TokyoDataStoreIterator implements DataStoreIterator {
private BDBCUR cursor;
private boolean firstNextCall;
public TokyoDataStoreIterator(BDB bdb) {
this.cursor = new BDBCUR(bdb);
// flag to indicate this is the first call to next()
this.firstNextCall = true;
}
public boolean next() throws DataStoreFatalException {
// tokyo cabinet does things a little different in that the first record
// is already selected by default -- our interface says that you need
// to call next() first, so we will only call next on calls after the
// first one
if (this.firstNextCall) {
this.firstNextCall = false;
// move to first record
return this.cursor.first();
} else {
return cursor.next();
}
}
public boolean jump(byte[] key) throws DataStoreFatalException {
if (this.firstNextCall) this.firstNextCall = false;
return this.cursor.jump(key);
}
public Record getRecord() throws DataStoreFatalException {
byte[] key = cursor.key();
byte[] value = cursor.val();
if (key == null || value == null) {
throw new DataStoreFatalException("Record key or value was null");
}
return new Record(key, value);
}
public void close() throws DataStoreFatalException {
// don't really have to do anything to close the cursor
cursor = null;
}
}