Package org.apache.arrow.vector.complex

Class ListVector

java.lang.Object
org.apache.arrow.vector.BaseValueVector
org.apache.arrow.vector.complex.BaseRepeatedValueVector
org.apache.arrow.vector.complex.ListVector
All Implemented Interfaces:
Closeable, AutoCloseable, Iterable<ValueVector>, BaseListVector, PromotableVector, RepeatedValueVector, DensityAwareVector, FieldVector, ValueVector
Direct Known Subclasses:
MapVector
public class ListVector extends BaseRepeatedValueVector implements PromotableVector
A list vector contains lists of a specific type of elements. Its structure contains 3 elements.
  1. A validity buffer.
  2. An offset buffer, that denotes lists boundaries.
  3. A child data vector that contains the elements of lists.
The latter two are managed by its superclass.

  • Field Details

    • validityBuffer

      protected ArrowBuf validityBuffer

    • reader

      protected UnionListReader reader

    • field

      protected Field field

    • validityAllocationSizeInBytes

      protected int validityAllocationSizeInBytes

    • lastSet

      protected int lastSet
      The maximum index that is actually set.

  • Constructor Details

    • ListVector

      public ListVector(String name, BufferAllocator allocator, FieldType fieldType, CallBack callBack)
      Constructs a new instance.
      Parameters:
      name - The name of the instance.
      allocator - The allocator to use for allocating/reallocating buffers.
      fieldType - The type of this list.
      callBack - A schema change callback.

    • ListVector

      public ListVector(Field field, BufferAllocator allocator, CallBack callBack)
      Constructs a new instance.
      Parameters:
      field - The field materialized by this vector.
      allocator - The allocator to use for allocating/reallocating buffers.
      callBack - A schema change callback.

  • Method Details

    • empty

      public static ListVector empty(String name, BufferAllocator allocator)

    • initializeChildrenFromFields

      public void initializeChildrenFromFields(List<Field> children)
      Description copied from interface: FieldVector
      Initializes the child vectors to be later loaded with loadBuffers.
      Specified by:
      initializeChildrenFromFields in interface FieldVector
      Parameters:
      children - the schema

    • setInitialCapacity

      public void setInitialCapacity(int numRecords)
      Description copied from interface: ValueVector
      Set the initial record capacity.
      Specified by:
      setInitialCapacity in interface ValueVector
      Overrides:
      setInitialCapacity in class BaseRepeatedValueVector
      Parameters:
      numRecords - the initial record capacity.

    • setInitialCapacity

      public void setInitialCapacity(int numRecords, double density)
      Specialized version of setInitialCapacity() for ListVector. This is used by some callers when they want to explicitly control and be conservative about memory allocated for inner data vector. This is very useful when we are working with memory constraints for a query and have a fixed amount of memory reserved for the record batch. In such cases, we are likely to face OOM or related problems when we reserve memory for a record batch with value count x and do setInitialCapacity(x) such that each vector allocates only what is necessary and not the default amount but the multiplier forces the memory requirement to go beyond what was needed.
      Specified by:
      setInitialCapacity in interface DensityAwareVector
      Overrides:
      setInitialCapacity in class BaseRepeatedValueVector
      Parameters:
      numRecords - value count
      density - density of ListVector. Density is the average size of list per position in the List vector. For example, a density value of 10 implies each position in the list vector has a list of 10 values. A density value of 0.1 implies out of 10 positions in the list vector, 1 position has a list of size 1 and remaining positions are null (no lists) or empty lists. This helps in tightly controlling the memory we provision for inner data vector.

    • setInitialTotalCapacity

      public void setInitialTotalCapacity(int numRecords, int totalNumberOfElements)
      Specialized version of setInitialTotalCapacity() for ListVector. This is used by some callers when they want to explicitly control and be conservative about memory allocated for inner data vector. This is very useful when we are working with memory constraints for a query and have a fixed amount of memory reserved for the record batch. In such cases, we are likely to face OOM or related problems when we reserve memory for a record batch with value count x and do setInitialCapacity(x) such that each vector allocates only what is necessary and not the default amount but the multiplier forces the memory requirement to go beyond what was needed.
      Overrides:
      setInitialTotalCapacity in class BaseRepeatedValueVector
      Parameters:
      numRecords - value count
      totalNumberOfElements - the total number of elements to to allow for in this vector across all records.

    • getDensity

      public double getDensity()
      Get the density of this ListVector.
      Returns:
      density

    • getChildrenFromFields

      public List<FieldVector> getChildrenFromFields()
      Description copied from interface: FieldVector
      The returned list is the same size as the list passed to initializeChildrenFromFields.
      Specified by:
      getChildrenFromFields in interface FieldVector
      Returns:
      the children according to schema (empty for primitive types)

    • loadFieldBuffers

      public void loadFieldBuffers(ArrowFieldNode fieldNode, List<ArrowBuf> ownBuffers)
      Load the buffers of this vector with provided source buffers. The caller manages the source buffers and populates them before invoking this method.
      Specified by:
      loadFieldBuffers in interface FieldVector
      Parameters:
      fieldNode - the fieldNode indicating the value count
      ownBuffers - the buffers for this Field (own buffers only, children not included)

    • getFieldBuffers

      public List<ArrowBuf> getFieldBuffers()
      Get the buffers belonging to this vector.
      Specified by:
      getFieldBuffers in interface FieldVector
      Returns:
      the inner buffers.

    • exportCDataBuffers

      public void exportCDataBuffers(List<ArrowBuf> buffers, ArrowBuf buffersPtr, long nullValue)
      Export the buffers of the fields for C Data Interface. This method traverse the buffers and export buffer and buffer's memory address into a list of buffers and a pointer to the list of buffers.
      Specified by:
      exportCDataBuffers in interface FieldVector

    • getFieldInnerVectors

      @Deprecated public List<BufferBacked> getFieldInnerVectors()
      Deprecated.
      This API will be removed as the current implementations no longer support inner vectors.
      Get the inner vectors.
      Specified by:
      getFieldInnerVectors in interface FieldVector
      Returns:
      the inner vectors for this field as defined by the TypeLayout

    • getWriter

      public UnionListWriter getWriter()

    • allocateNew

      public void allocateNew() throws OutOfMemoryException
      Same as allocateNewSafe().
      Specified by:
      allocateNew in interface ValueVector
      Throws:
      OutOfMemoryException - Thrown if no memory can be allocated.

    • allocateNewSafe

      public boolean allocateNewSafe()
      Allocate memory for the vector. We internally use a default value count of 4096 to allocate memory for at least these many elements in the vector.
      Specified by:
      allocateNewSafe in interface ValueVector
      Overrides:
      allocateNewSafe in class BaseRepeatedValueVector
      Returns:
      false if memory allocation fails, true otherwise.

    • allocateValidityBuffer

      protected void allocateValidityBuffer(long size)

    • reAlloc

      public void reAlloc()
      Resize the vector to increase the capacity. The internal behavior is to double the current value capacity.
      Specified by:
      reAlloc in interface ValueVector
      Overrides:
      reAlloc in class BaseRepeatedValueVector

    • reallocValidityAndOffsetBuffers

      protected void reallocValidityAndOffsetBuffers()

    • copyFromSafe

      public void copyFromSafe(int inIndex, int outIndex, ValueVector from)
      Same as copyFrom(int, int, ValueVector) except that it handles the case when the capacity of the vector needs to be expanded before copy.
      Specified by:
      copyFromSafe in interface ValueVector
      Overrides:
      copyFromSafe in class BaseValueVector
      Parameters:
      inIndex - position to copy from in source vector
      outIndex - position to copy to in this vector
      from - source vector

    • copyFrom

      public void copyFrom(int inIndex, int outIndex, ValueVector from)
      Copy a cell value from a particular index in source vector to a particular position in this vector.
      Specified by:
      copyFrom in interface ValueVector
      Overrides:
      copyFrom in class BaseValueVector
      Parameters:
      inIndex - position to copy from in source vector
      outIndex - position to copy to in this vector
      from - source vector

    • getDataVector

      public FieldVector getDataVector()
      Get the inner data vector for this list vector.
      Specified by:
      getDataVector in interface RepeatedValueVector
      Overrides:
      getDataVector in class BaseRepeatedValueVector
      Returns:
      data vector

    • getTransferPair

      public TransferPair getTransferPair(String ref, BufferAllocator allocator)
      Description copied from interface: ValueVector
      To transfer quota responsibility.
      Specified by:
      getTransferPair in interface ValueVector
      Parameters:
      ref - the name of the vector
      allocator - the target allocator
      Returns:
      a transfer pair, creating a new target vector of the same type.

    • getTransferPair

      public TransferPair getTransferPair(Field field, BufferAllocator allocator)
      Description copied from interface: ValueVector
      To transfer quota responsibility.
      Specified by:
      getTransferPair in interface ValueVector
      Parameters:
      field - the Field object used by the target vector
      allocator - the target allocator
      Returns:
      a transfer pair, creating a new target vector of the same type.

    • getTransferPair

      public TransferPair getTransferPair(String ref, BufferAllocator allocator, CallBack callBack)
      Description copied from interface: ValueVector
      To transfer quota responsibility.
      Specified by:
      getTransferPair in interface ValueVector
      Parameters:
      ref - the name of the vector
      allocator - the target allocator
      callBack - A schema change callback.
      Returns:
      a transfer pair, creating a new target vector of the same type.

    • getTransferPair

      public TransferPair getTransferPair(Field field, BufferAllocator allocator, CallBack callBack)
      Description copied from interface: ValueVector
      To transfer quota responsibility.
      Specified by:
      getTransferPair in interface ValueVector
      Parameters:
      field - the Field object used by the target vector
      allocator - the target allocator
      callBack - A schema change callback.
      Returns:
      a transfer pair, creating a new target vector of the same type.

    • makeTransferPair

      public TransferPair makeTransferPair(ValueVector target)
      Description copied from interface: ValueVector
      Makes a new transfer pair used to transfer underlying buffers.
      Specified by:
      makeTransferPair in interface ValueVector
      Parameters:
      target - the target for the transfer
      Returns:
      a new transfer pair that is used to transfer underlying buffers into the target vector.

    • getValidityBufferAddress

      public long getValidityBufferAddress()
      Description copied from interface: FieldVector
      Gets the starting address of the underlying buffer associated with validity vector.
      Specified by:
      getValidityBufferAddress in interface FieldVector
      Returns:
      buffer address

    • getDataBufferAddress

      public long getDataBufferAddress()
      Description copied from interface: FieldVector
      Gets the starting address of the underlying buffer associated with data vector.
      Specified by:
      getDataBufferAddress in interface FieldVector
      Returns:
      buffer address

    • getOffsetBufferAddress

      public long getOffsetBufferAddress()
      Description copied from interface: FieldVector
      Gets the starting address of the underlying buffer associated with offset vector.
      Specified by:
      getOffsetBufferAddress in interface FieldVector
      Returns:
      buffer address

    • getValidityBuffer

      public ArrowBuf getValidityBuffer()
      Description copied from interface: ValueVector
      Gets the underlying buffer associated with validity vector.
      Specified by:
      getValidityBuffer in interface ValueVector
      Returns:
      buffer

    • getDataBuffer

      public ArrowBuf getDataBuffer()
      Description copied from interface: ValueVector
      Gets the underlying buffer associated with data vector.
      Specified by:
      getDataBuffer in interface ValueVector
      Returns:
      buffer

    • getOffsetBuffer

      public ArrowBuf getOffsetBuffer()
      Description copied from interface: ValueVector
      Gets the underlying buffer associated with offset vector.
      Specified by:
      getOffsetBuffer in interface ValueVector
      Returns:
      buffer

    • hashCode

      public int hashCode(int index)
      Description copied from interface: ValueVector
      Returns hashCode of element in index with the default hasher.
      Specified by:
      hashCode in interface ValueVector

    • hashCode

      public int hashCode(int index, ArrowBufHasher hasher)
      Description copied from interface: ValueVector
      Returns hashCode of element in index with the given hasher.
      Specified by:
      hashCode in interface ValueVector

    • accept

      public <OUT, IN> OUT accept(VectorVisitor<OUT,IN> visitor, IN value)
      Description copied from interface: ValueVector
      Accept a generic VectorVisitor and return the result.
      Specified by:
      accept in interface ValueVector
      Type Parameters:
      OUT - the output result type.
      IN - the input data together with visitor.

    • getReaderImpl

      protected FieldReader getReaderImpl()
      Description copied from class: BaseValueVector
      Each vector has a different reader that implements the FieldReader interface. Overridden methods must make sure to return the correct concrete reader implementation.
      Specified by:
      getReaderImpl in class BaseValueVector
      Returns:
      Returns a lambda that initializes a reader when called.

    • getReader

      public UnionListReader getReader()
      Description copied from class: BaseValueVector
      Default implementation to create a reader for the vector. Depends on the individual vector class' implementation of BaseValueVector.getReaderImpl() to initialize the reader appropriately.
      Specified by:
      getReader in interface ValueVector
      Overrides:
      getReader in class BaseValueVector
      Returns:
      Concrete instance of FieldReader by using double-checked locking.

    • addOrGetVector

      public <T extends ValueVector> AddOrGetResult<T> addOrGetVector(FieldType fieldType)
      Initialize the child data vector to field type.
      Specified by:
      addOrGetVector in interface PromotableVector
      Overrides:
      addOrGetVector in class BaseRepeatedValueVector

    • getBufferSize

      public int getBufferSize()
      Get the size (number of bytes) of underlying buffers used by this vector.
      Specified by:
      getBufferSize in interface ValueVector
      Overrides:
      getBufferSize in class BaseRepeatedValueVector
      Returns:
      size of underlying buffers.

    • getBufferSizeFor

      public int getBufferSizeFor(int valueCount)
      Description copied from interface: ValueVector
      Returns the number of bytes that is used by this vector if it holds the given number of values. The result will be the same as if setValueCount() were called, followed by calling getBufferSize(), but without any of the closing side-effects that setValueCount() implies wrt finishing off the population of a vector. Some operations might wish to use this to determine how much memory has been used by a vector so far, even though it is not finished being populated.
      Specified by:
      getBufferSizeFor in interface ValueVector
      Overrides:
      getBufferSizeFor in class BaseRepeatedValueVector
      Parameters:
      valueCount - the number of values to assume this vector contains
      Returns:
      the buffer size if this vector is holding valueCount values

    • getField

      public Field getField()
      Description copied from interface: ValueVector
      Get information about how this field is materialized.
      Specified by:
      getField in interface ValueVector
      Returns:
      the field corresponding to this vector

    • getMinorType

      public Types.MinorType getMinorType()
      Specified by:
      getMinorType in interface ValueVector

    • clear

      public void clear()
      Description copied from interface: ValueVector
      Release any owned ArrowBuf and reset the ValueVector to the initial state. If the vector has any child vectors, they will also be cleared.
      Specified by:
      clear in interface ValueVector
      Overrides:
      clear in class BaseRepeatedValueVector

    • reset

      public void reset()
      Description copied from interface: ValueVector
      Reset the ValueVector to the initial state without releasing any owned ArrowBuf. Buffer capacities will remain unchanged and any previous data will be zeroed out. This includes buffers for data, validity, offset, etc. If the vector has any child vectors, they will also be reset.
      Specified by:
      reset in interface ValueVector
      Overrides:
      reset in class BaseRepeatedValueVector

    • getBuffers

      public ArrowBuf[] getBuffers(boolean clear)
      Return the underlying buffers associated with this vector. Note that this doesn't impact the reference counts for this buffer so it only should be used for in-context access. Also note that this buffer changes regularly thus external classes shouldn't hold a reference to it (unless they change it).
      Specified by:
      getBuffers in interface ValueVector
      Overrides:
      getBuffers in class BaseRepeatedValueVector
      Parameters:
      clear - Whether to clear vector before returning; the buffers will still be refcounted but the returned array will be the only reference to them
      Returns:
      The underlying buffers that is used by this vector instance.

    • promoteToUnion

      public UnionVector promoteToUnion()
      Specified by:
      promoteToUnion in interface PromotableVector

    • invalidateReader

      protected void invalidateReader()

    • getObject

      public List<?> getObject(int index)
      Get the element in the list vector at a particular index.
      Specified by:
      getObject in interface ValueVector
      Parameters:
      index - position of the element
      Returns:
      Object at given position

    • isNull

      public boolean isNull(int index)
      Check if element at given index is null.
      Specified by:
      isNull in interface ValueVector
      Parameters:
      index - position of element
      Returns:
      true if element at given index is null, false otherwise

    • isEmpty

      public boolean isEmpty(int index)
      Check if element at given index is empty list.
      Specified by:
      isEmpty in class BaseRepeatedValueVector
      Parameters:
      index - position of element
      Returns:
      true if element at given index is empty list or NULL, false otherwise

    • isSet

      public int isSet(int index)
      Same as isNull(int).
      Parameters:
      index - position of element
      Returns:
      1 if element at given index is not null, 0 otherwise

    • getNullCount

      public int getNullCount()
      Get the number of elements that are null in the vector.
      Specified by:
      getNullCount in interface ValueVector
      Returns:
      the number of null elements.

    • getValueCapacity

      public int getValueCapacity()
      Get the current value capacity for the vector.
      Specified by:
      getValueCapacity in interface ValueVector
      Overrides:
      getValueCapacity in class BaseRepeatedValueVector
      Returns:
      number of elements that vector can hold.

    • setNotNull

      public void setNotNull(int index)
      Sets the list at index to be not-null. Reallocates validity buffer if index is larger than current capacity.

    • setNull

      public void setNull(int index)
      Sets list at index to be null.
      Specified by:
      setNull in interface FieldVector
      Parameters:
      index - position in vector

    • startNewValue

      public int startNewValue(int index)
      Start a new value in the list vector.
      Overrides:
      startNewValue in class BaseRepeatedValueVector
      Parameters:
      index - index of the value to start

    • endValue

      public void endValue(int index, int size)
      End the current value.
      Parameters:
      index - index of the value to end
      size - number of elements in the list that was written

    • setValueCount

      public void setValueCount(int valueCount)
      Sets the value count for the vector.
      Specified by:
      setValueCount in interface ValueVector
      Overrides:
      setValueCount in class BaseRepeatedValueVector
      Parameters:
      valueCount - value count

    • setLastSet

      public void setLastSet(int value)

    • getLastSet

      public int getLastSet()

    • getElementStartIndex

      public int getElementStartIndex(int index)
      Description copied from interface: BaseListVector
      Get data vector start index with the given list index.
      Specified by:
      getElementStartIndex in interface BaseListVector

    • getElementEndIndex

      public int getElementEndIndex(int index)
      Description copied from interface: BaseListVector
      Get data vector end index with the given list index.
      Specified by:
      getElementEndIndex in interface BaseListVector