Package org.apache.calcite.adapter.csv

Class CsvEnumerator<E>

  • Type Parameters:
    E - Row type
    All Implemented Interfaces:
    java.lang.AutoCloseable, Enumerator<E>
    class CsvEnumerator<E>
extends java.lang.Object
implements Enumerator<E>
    Enumerator that reads from a CSV file.

    • Field Detail

      • reader

        private final au.com.bytecode.opencsv.CSVReader reader

      • filterValues

        private final java.lang.String[] filterValues

      • cancelFlag

        private final java.util.concurrent.atomic.AtomicBoolean cancelFlag

      • current

        private E current

      • TIME_FORMAT_DATE

        private static final org.apache.commons.lang3.time.FastDateFormat TIME_FORMAT_DATE

      • TIME_FORMAT_TIME

        private static final org.apache.commons.lang3.time.FastDateFormat TIME_FORMAT_TIME

      • TIME_FORMAT_TIMESTAMP

        private static final org.apache.commons.lang3.time.FastDateFormat TIME_FORMAT_TIMESTAMP

    • Constructor Detail

      • CsvEnumerator

        CsvEnumerator​(Source source,
              java.util.concurrent.atomic.AtomicBoolean cancelFlag,
              java.util.List<CsvFieldType> fieldTypes)

      • CsvEnumerator

        CsvEnumerator​(Source source,
              java.util.concurrent.atomic.AtomicBoolean cancelFlag,
              java.util.List<CsvFieldType> fieldTypes,
              int[] fields)

      • CsvEnumerator

        CsvEnumerator​(Source source,
              java.util.concurrent.atomic.AtomicBoolean cancelFlag,
              boolean stream,
              java.lang.String[] filterValues,
              CsvEnumerator.RowConverter<E> rowConverter)

    • Method Detail

      • deduceRowType

        static RelDataType deduceRowType​(JavaTypeFactory typeFactory,
                                 Source source,
                                 java.util.List<CsvFieldType> fieldTypes)
        Deduces the names and types of a table's columns by reading the first line of a CSV file.

      • deduceRowType

        static RelDataType deduceRowType​(JavaTypeFactory typeFactory,
                                 Source source,
                                 java.util.List<CsvFieldType> fieldTypes,
                                 java.lang.Boolean stream)
        Deduces the names and types of a table's columns by reading the first line of a CSV file.

      • openCsv

        public static au.com.bytecode.opencsv.CSVReader openCsv​(Source source)
                                                 throws java.io.IOException
        Throws:
        java.io.IOException

      • current

        public E current()
        Description copied from interface: Enumerator
        Gets the current element in the collection.

        After an enumerator is created or after the Enumerator.reset() method is called, the Enumerator.moveNext() method must be called to advance the enumerator to the first element of the collection before reading the value of the current property; otherwise, current is undefined.

        This method also throws NoSuchElementException if the last call to moveNext returned false, which indicates the end of the collection.

        This method does not move the position of the enumerator, and consecutive calls to current return the same object until either moveNext or reset is called.

        An enumerator remains valid as long as the collection remains unchanged. If changes are made to the collection, such as adding, modifying, or deleting elements, the enumerator is irrecoverably invalidated. The next call to moveNext or reset may, at the discretion of the implementation, throw a ConcurrentModificationException. If the collection is modified between moveNext and current, current returns the element that it is set to, even if the enumerator is already invalidated.

        Specified by:
        current in interface Enumerator<E>
        Returns:
        Current element

      • moveNext

        public boolean moveNext()
        Description copied from interface: Enumerator
        Advances the enumerator to the next element of the collection.

        After an enumerator is created or after the reset method is called, an enumerator is positioned before the first element of the collection, and the first call to the moveNext method moves the enumerator over the first element of the collection.

        If moveNext passes the end of the collection, the enumerator is positioned after the last element in the collection and moveNext returns false. When the enumerator is at this position, subsequent calls to moveNext also return false until #reset is called.

        An enumerator remains valid as long as the collection remains unchanged. If changes are made to the collection, such as adding, modifying, or deleting elements, the enumerator is irrecoverably invalidated. The next call to moveNext or Enumerator.reset() may, at the discretion of the implementation, throw a ConcurrentModificationException.

        Specified by:
        moveNext in interface Enumerator<E>
        Returns:
        true if the enumerator was successfully advanced to the next element; false if the enumerator has passed the end of the collection

      • reset

        public void reset()
        Description copied from interface: Enumerator
        Sets the enumerator to its initial position, which is before the first element in the collection.

        An enumerator remains valid as long as the collection remains unchanged. If changes are made to the collection, such as adding, modifying, or deleting elements, the enumerator is irrecoverably invalidated. The next call to Enumerator.moveNext() or reset may, at the discretion of the implementation, throw a ConcurrentModificationException.

        This method is optional; it may throw UnsupportedOperationException.

        Notes to Implementers

        All calls to Reset must result in the same state for the enumerator. The preferred implementation is to move the enumerator to the beginning of the collection, before the first element. This invalidates the enumerator if the collection has been modified since the enumerator was created, which is consistent with Enumerator.moveNext() and Enumerator.current().

        Specified by:
        reset in interface Enumerator<E>

      • close

        public void close()
        Description copied from interface: Enumerator
        Closes this enumerable and releases resources.

        This method is idempotent. Calling it multiple times has the same effect as calling it once.

        Specified by:
        close in interface java.lang.AutoCloseable
        Specified by:
        close in interface Enumerator<E>

      • identityList

        static int[] identityList​(int n)
        Returns an array of integers {0, ..., n - 1}.