/*
    * 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.giraph.aggregators.matrix.sparse;
  
  import org.apache.giraph.aggregators.AggregatorUsage;
  import org.apache.giraph.aggregators.matrix.MatrixSumAggregator;
  import org.apache.giraph.master.MasterAggregatorUsage;
  import org.apache.giraph.worker.WorkerAggregatorUsage;
  
  /**
   * The long matrix aggregator is used to register and aggregate long matrices.
   */
  public class LongSparseMatrixSumAggregator extends MatrixSumAggregator {
    /** sparse vector with single entry */
    private LongSparseVector singletonVector = new LongSparseVector();
  
    /**
     * Create a new matrix aggregator with the given prefix name for the vector
     * aggregators.
     *
     * @param name the prefix for the row vector aggregators
     */
    public LongSparseMatrixSumAggregator(String name) {
      super(name);
    }
  
    /**
     * Register the long vector aggregators, one for each row of the matrix.
     *
     * @param numRows the number of rows
     * @param master the master to register the aggregators
     */
    public void register(int numRows, MasterAggregatorUsage master)
      throws InstantiationException, IllegalAccessException {
      for (int i = 0; i < numRows; ++i) {
        master.registerAggregator(getRowAggregatorName(i),
            LongSparseVectorSumAggregator.class);
      }
    }
  
    /**
     * Add the given value to the entry specified.
     *
     * @param i the row
     * @param j the column
     * @param v the value
     * @param worker the worker to aggregate
     */
    public void aggregate(int i, int j, long v, WorkerAggregatorUsage worker) {
      singletonVector.clear();
      singletonVector.set(j, v);
      worker.aggregate(getRowAggregatorName(i), singletonVector);
    }
  
    /**
     * Set the values of the matrix to the master specified. This is typically
     * used in the master, to build an external LongMatrix and only set it at
     * the end.
     *
     * @param matrix the matrix to set the values
     * @param master the master
     */
    public void setMatrix(LongSparseMatrix matrix,
        MasterAggregatorUsage master) {
      int numRows = matrix.getNumRows();
      for (int i = 0; i < numRows; ++i) {
        master.setAggregatedValue(getRowAggregatorName(i), matrix.getRow(i));
      }
    }
  
    /**
     * Read the aggregated values of the matrix.
     *
     * @param numRows the number of rows
     * @param aggUser the master or worker
     * @return the long matrix
     */
    public LongSparseMatrix getMatrix(int numRows, AggregatorUsage aggUser) {
      LongSparseMatrix matrix = new LongSparseMatrix(numRows);
      for (int i = 0; i < numRows; ++i) {
        LongSparseVector vec = aggUser.getAggregatedValue(
            getRowAggregatorName(i));
        matrix.setRow(i, vec);
     }
     return matrix;
   }
 }