DataSetFetcher.java

/*-
 *
 *  * Copyright 2015 Skymind,Inc.
 *  *
 *  *    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.
 *
 */

package org.deeplearning4j.datasets.iterator;

import org.nd4j.linalg.dataset.DataSet;

import java.io.Serializable;

/**
 * A low level interface for loading datasets in to memory.
 * 
 * This is used by an DataSetIterator to handle the specifics of loading data in to memory.
 * @author Adam Gibson
 *
 * @deprecated Retained for legacy purposes, will be removed in a future release
 */
@Deprecated
public interface DataSetFetcher extends Serializable {

    /**
     * Whether the dataset has more to load
     * @return whether the data applyTransformToDestination has more to load
     */
    boolean hasMore();

    /**
     * Returns the next data applyTransformToDestination
     * @return the next dataset
     */
    DataSet next();

    /**
     * Fetches the next dataset. You need to call this
     * to getFromOrigin a new dataset, otherwise {@link #next()}
     * just returns the last data applyTransformToDestination fetch
     * @param numExamples the number of examples to fetch
     */
    void fetch(int numExamples);

    /**
     * The number of labels for a dataset
     * @return the number of labels for a dataset
     */
    int totalOutcomes();

    /**
     * The length of a feature vector for an individual example
     * @return the length of a feature vector for an individual example
     */
    int inputColumns();

    /**
     * The total number of examples
     * @return the total number of examples
     */
    int totalExamples();

    /**
     * Returns the fetcher back to the beginning of the dataset
     */
    void reset();

    /**
     * Direct access to a number represenative of iterating through a dataset
     * @return a cursor similar to an index
     */
    int cursor();
}