org.apache.bookkeeper.mledger.ReadOnlyCursor Maven / Gradle / Ivy
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*/
package org.apache.bookkeeper.mledger;
import java.util.List;
import com.google.common.base.Predicate;
import com.google.common.collect.Range;
import org.apache.bookkeeper.mledger.AsyncCallbacks.ReadEntriesCallback;
import org.apache.bookkeeper.mledger.impl.PositionImpl;
public interface ReadOnlyCursor {
/**
* Read entries from the ManagedLedger, up to the specified number. The returned list can be smaller.
*
* @param numberOfEntriesToRead maximum number of entries to return
* @return the list of entries
* @throws ManagedLedgerException
*/
List readEntries(int numberOfEntriesToRead) throws InterruptedException, ManagedLedgerException;
/**
* Asynchronously read entries from the ManagedLedger.
*
* @param numberOfEntriesToRead maximum number of entries to return
* @param callback callback object
* @param ctx opaque context
* @see #readEntries(int)
*/
void asyncReadEntries(int numberOfEntriesToRead, ReadEntriesCallback callback, Object ctx);
/**
* Get the read position. This points to the next message to be read from the cursor.
*
* @return the read position
*/
Position getReadPosition();
/**
* Tells whether this cursor has already consumed all the available entries.
*
*
* This method is not blocking.
*
* @return true if there are pending entries to read, false otherwise
*/
boolean hasMoreEntries();
/**
* Return the number of messages that this cursor still has to read.
*
*
* This method has linear time complexity on the number of ledgers included in the managed ledger.
*
* @return the number of entries
*/
long getNumberOfEntries();
/**
* Skip n entries from the read position of this cursor.
*
* @param numEntriesToSkip number of entries to skip
*/
void skipEntries(int numEntriesToSkip);
/**
* Find the newest entry that matches the given predicate.
*
* @param constraint search only active entries or all entries
* @param condition predicate that reads an entry an applies a condition
* @return Position of the newest entry that matches the given predicate
* @throws InterruptedException
* @throws ManagedLedgerException
*/
Position findNewestMatching(ManagedCursor.FindPositionConstraint constraint, Predicate condition) throws InterruptedException, ManagedLedgerException;
/**
* Return the number of messages that this cursor still has to read.
*
* This method has linear time complexity on the number of ledgers included in the managed ledger.
*
* @param range the range between two positions
* @return the number of entries in range
*/
long getNumberOfEntries(Range range);
/**
* Close the cursor and releases the associated resources.
*
* @throws InterruptedException
* @throws ManagedLedgerException
*/
void close() throws InterruptedException, ManagedLedgerException;
/**
* Close the cursor asynchronously and release the associated resources.
*
* @param callback callback object
* @param ctx opaque context
*/
void asyncClose(AsyncCallbacks.CloseCallback callback, Object ctx);
}