Package com.univocity.parsers.common.processor.core

Class AbstractBatchedColumnProcessor<T extends Context>

java.lang.Object
com.univocity.parsers.common.processor.core.AbstractBatchedColumnProcessor<T>
All Implemented Interfaces:
BatchedColumnReader<String>, ColumnReader<String>, Processor<T>
Direct Known Subclasses:
BatchedColumnProcessor
public abstract class AbstractBatchedColumnProcessor<T extends Context> extends Object implements Processor<T>, BatchedColumnReader<String>
A Processor implementation that stores values of columns in batches. Use this implementation in favor of AbstractColumnProcessor when processing large inputs to avoid running out of memory. Values parsed in each row will be split into columns of Strings. Each column has its own list of values.

During the execution of the process, the batchProcessed(int) method will be invoked after a given number of rows has been processed.

The user can access the lists with values parsed for all columns using the methods getColumnValuesAsList(), getColumnValuesAsMapOfIndexes() and getColumnValuesAsMapOfNames().

After batchProcessed(int) is invoked, all values will be discarded and the next batch of column values will be accumulated. This process will repeat until there's no more rows in the input.

See Also:

  • Field Details

    • splitter

      private final ColumnSplitter<String> splitter

    • rowsPerBatch

      private final int rowsPerBatch

    • batchCount

      private int batchCount

    • batchesProcessed

      private int batchesProcessed

  • Constructor Details

    • AbstractBatchedColumnProcessor

      public AbstractBatchedColumnProcessor(int rowsPerBatch)
      Constructs a batched column processor configured to invoke the batchesProcessed method after a given number of rows has been processed.
      Parameters:
      rowsPerBatch - the number of rows to process in each batch.

  • Method Details

    • processStarted

      public void processStarted(T context)
      Description copied from interface: Processor
      This method will by invoked by the parser once, when it is ready to start processing the input.
      Specified by:
      processStarted in interface Processor<T extends Context>
      Parameters:
      context - A contextual object with information and controls over the current state of the parsing process

    • rowProcessed

      public void rowProcessed(String[] row, T context)
      Description copied from interface: Processor
      Invoked by the parser after all values of a valid record have been processed.
      Specified by:
      rowProcessed in interface Processor<T extends Context>
      Parameters:
      row - the data extracted by the parser for an individual record. Note that:
      context - A contextual object with information and controls over the current state of the parsing process

    • processEnded

      public void processEnded(T context)
      Description copied from interface: Processor
      This method will by invoked by the parser once, after the parsing process stopped and all resources were closed.

      It will always be called by the parser: in case of errors, if the end of the input us reached, or if the user stopped the process manually using Context.stop().

      Specified by:
      processEnded in interface Processor<T extends Context>
      Parameters:
      context - A contextual object with information and controls over the state of the parsing process

    • getHeaders

      public final String[] getHeaders()
      Description copied from interface: ColumnReader
      Returns the column headers. This can be either the headers defined in CommonSettings.getHeaders() or the headers parsed in the input when CommonSettings.getHeaders() equals to true
      Specified by:
      getHeaders in interface ColumnReader<T extends Context>
      Returns:
      the headers of all column parsed.

    • getColumnValuesAsList

      public final List<List<String>> getColumnValuesAsList()
      Description copied from interface: ColumnReader
      Returns the values processed for each column
      Specified by:
      getColumnValuesAsList in interface ColumnReader<T extends Context>
      Returns:
      a list of lists. The stored lists correspond to the position of the column processed from the input; Each list contains the corresponding values parsed for a column, across multiple rows.

    • putColumnValuesInMapOfNames

      public final void putColumnValuesInMapOfNames(Map<String,List<String>> map)
      Description copied from interface: ColumnReader
      Fills a given map associating each column name to its list o values
      Specified by:
      putColumnValuesInMapOfNames in interface ColumnReader<T extends Context>
      Parameters:
      map - the map to hold the values of each column

    • putColumnValuesInMapOfIndexes

      public final void putColumnValuesInMapOfIndexes(Map<Integer,List<String>> map)
      Description copied from interface: ColumnReader
      Fills a given map associating each column index to its list of values
      Specified by:
      putColumnValuesInMapOfIndexes in interface ColumnReader<T extends Context>
      Parameters:
      map - the map to hold the values of each column

    • getColumnValuesAsMapOfNames

      public final Map<String,List<String>> getColumnValuesAsMapOfNames()
      Description copied from interface: ColumnReader
      Returns a map of column names and their respective list of values parsed from the input.
      Specified by:
      getColumnValuesAsMapOfNames in interface ColumnReader<T extends Context>
      Returns:
      a map of column names and their respective list of values.

    • getColumnValuesAsMapOfIndexes

      public final Map<Integer,List<String>> getColumnValuesAsMapOfIndexes()
      Description copied from interface: ColumnReader
      Returns a map of column indexes and their respective list of values parsed from the input.
      Specified by:
      getColumnValuesAsMapOfIndexes in interface ColumnReader<T extends Context>
      Returns:
      a map of column indexes and their respective list of values.

    • getColumn

      public List<String> getColumn(String columnName)
      Description copied from interface: ColumnReader
      Returns the values of a given column.
      Specified by:
      getColumn in interface ColumnReader<T extends Context>
      Parameters:
      columnName - the name of the column in the input.
      Returns:
      a list with all data stored in the given column

    • getColumn

      public List<String> getColumn(int columnIndex)
      Description copied from interface: ColumnReader
      Returns the values of a given column.
      Specified by:
      getColumn in interface ColumnReader<T extends Context>
      Parameters:
      columnIndex - the position of the column in the input (0-based).
      Returns:
      a list with all data stored in the given column

    • getRowsPerBatch

      public int getRowsPerBatch()
      Description copied from interface: BatchedColumnReader
      Returns the number of rows processed in each batch
      Specified by:
      getRowsPerBatch in interface BatchedColumnReader<T extends Context>
      Returns:
      the number of rows per batch

    • getBatchesProcessed

      public int getBatchesProcessed()
      Description copied from interface: BatchedColumnReader
      Returns the number of batches already processed
      Specified by:
      getBatchesProcessed in interface BatchedColumnReader<T extends Context>
      Returns:
      the number of batches already processed

    • batchProcessed

      public abstract void batchProcessed(int rowsInThisBatch)
      Description copied from interface: BatchedColumnReader
      Callback to the user, where the lists with values parsed for all columns can be accessed using the methods ColumnReader.getColumnValuesAsList(), ColumnReader.getColumnValuesAsMapOfIndexes() and ColumnReader.getColumnValuesAsMapOfNames().
      Specified by:
      batchProcessed in interface BatchedColumnReader<T extends Context>
      Parameters:
      rowsInThisBatch - the number of rows processed in the current batch. This corresponds to the number of elements of each list of each column.