phoenix-core/src/main/java/org/apache/phoenix/schema/tuple/Tuple.java

/*
 * 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.phoenix.schema.tuple;

import java.util.List;

import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;

/**
 * 
 * Interface representing an ordered list of KeyValues returned as the
 * result of a query. Each tuple represents a row (i.e. all its KeyValues
 * will have the same key), and each KeyValue represents a column value.
 *
 * 
 * @since 0.1
 */
public interface Tuple {
    /**
     * @return Number of KeyValues contained by the Tuple.
     */
    public int size();
    
    /**
     * Determines whether or not the Tuple is immutable (the typical case)
     * or will potentially have additional KeyValues added to it (the case
     * during filter evaluation when we see one KeyValue at a time).
     * @return true if Tuple is immutable and false otherwise.
     */
    public boolean isImmutable();
    
    /**
     * Get the row key for the Tuple
     * @param ptr the bytes pointer that will be updated to point to
     * the key buffer.
     */
    public void getKey(ImmutableBytesWritable ptr);
    
    /**
     * Get the KeyValue at the given index.
     * @param index the zero-based KeyValue index between 0 and {@link #size()} exclusive
     * @return the KeyValue at the given index
     * @throws IndexOutOfBoundsException if an invalid index is used
     */
    public Cell getValue(int index);
    
    /**
     * Get the KeyValue contained by the Tuple with the given family and
     * qualifier name.
     * @param family the column family of the KeyValue being retrieved
     * @param qualifier the column qualify of the KeyValue being retrieved
     * @return the KeyValue with the given family and qualifier name or
     * null if not found.
     */
    public Cell getValue(byte [] family, byte [] qualifier);
    
    /**
     * Get the value byte array of the KeyValue contained by the Tuple with 
     * the given family and qualifier name.
     * @param family the column family of the KeyValue being retrieved
     * @param qualifier the column qualify of the KeyValue being retrieved
     * @param ptr the bytes pointer that will be updated to point to the 
     * value buffer.
     * @return true if the KeyValue with the given family and qualifier name
     * exists; otherwise false.
     */
    public boolean getValue(byte [] family, byte [] qualifier, ImmutableBytesWritable ptr);
    
    /**
     * Get the sequence value given the sequence index. May only be evaluated
     * on the client-side.
     * @param index
     * @return the current or next sequence value
     */
    public long getSequenceValue(int index);
    
    public void setKeyValues(List<Cell> values);
}