Package db

Class Field

java.lang.Object
db.Field
All Implemented Interfaces:
Comparable<Field>
Direct Known Subclasses:
BinaryField, BooleanField, ByteField, IntField, LongField, ShortField, StringField
public abstract class Field extends Object implements Comparable<Field>

Field is an abstract data wrapper for use with Records. Note that when comparing two Field instances both must be of the same class.

Fields may take on a null state. In the case of FixedField and PrimitiveField this state is distinct from value and only applies when used for a sparse column within a SparseRecord. In this sparse column situation the SparseRecord.setField(int, Field) method may be passed a null Field argument. Sparse columns with a null value/state will not be indexed within a Table.

Stored Schema Field Type Encoding:

8-bit Legacy Field Type Encoding (I....FFF)

Supported encodings: 0x00..0x06 and 0x80..0x86, where: 
     FFF  - indexed field type (0..6)
     I    - index field indicator (only long primary keys were supported)

8-bit Field Type Encoding (PPPPFFFF)

(Reserved for future field extensions: 0x88 and 0xf0..0xff) 
     0xff - see Schema.FIELD_EXTENSION_INDICATOR
where: 
     FFFF - normal/indexed field type
     PPPP - indexed table primary key type (1000b: LegacyIndexField)

  • Field Details

    • EMPTY_ARRAY

      public static final Field[] EMPTY_ARRAY

  • Method Details

    • getLongValue

      public long getLongValue()
      Get field as a long value. All fixed-length field objects must implement this method
      Returns:
      long value
      Throws:
      IllegalFieldAccessException - thrown if method is not supported by specific Field instance.

    • setLongValue

      public void setLongValue(long value)
      Set field's long value. All fixed-length field objects must implement this method
      Parameters:
      value - long value
      Throws:
      IllegalFieldAccessException - thrown if method is not supported by specific Field instance.

    • getIntValue

      public int getIntValue()
      Get field as an integer value.
      Returns:
      integer value
      Throws:
      IllegalFieldAccessException - thrown if method is not supported by specific Field instance.

    • setIntValue

      public void setIntValue(int value)
      Set field's integer value.
      Parameters:
      value - integer value
      Throws:
      IllegalFieldAccessException - thrown if method is not supported by specific Field instance.

    • getShortValue

      public short getShortValue()
      Get field as a short value.
      Returns:
      short value
      Throws:
      IllegalFieldAccessException - thrown if method is not supported by specific Field instance.

    • setShortValue

      public void setShortValue(short value)
      Set field's short value.
      Parameters:
      value - short value
      Throws:
      IllegalFieldAccessException - thrown if method is not supported by specific Field instance.

    • getByteValue

      public byte getByteValue()
      Get field as a byte value.
      Returns:
      byte value
      Throws:
      IllegalFieldAccessException - thrown if method is not supported by specific Field instance.

    • setByteValue

      public void setByteValue(byte value)
      Set field's byte value.
      Parameters:
      value - byte value
      Throws:
      IllegalFieldAccessException - thrown if method is not supported by specific Field instance.

    • getBooleanValue

      public boolean getBooleanValue()
      Get field as a boolean value.
      Returns:
      boolean value
      Throws:
      IllegalFieldAccessException - thrown if method is not supported by specific Field instance.

    • setBooleanValue

      public void setBooleanValue(boolean value)
      Set field's boolean value.
      Parameters:
      value - boolean value
      Throws:
      IllegalFieldAccessException - thrown if method is not supported by specific Field instance.

    • getBinaryData

      public abstract byte[] getBinaryData()
      Get data as a byte array.
      Returns:
      byte[]

    • setBinaryData

      public abstract void setBinaryData(byte[] bytes)
      Set data from binary byte array. All variable-length fields must implement this method.
      Parameters:
      bytes - field data
      Throws:
      IllegalFieldAccessException - if error occurs while reading bytes into field which will generally be caused by the incorrect number of bytes provided to a fixed-length field.

    • getString

      public String getString()
      Get field as a String value.
      Returns:
      String value
      Throws:
      IllegalFieldAccessException - thrown if method is not supported by specific Field instance.

    • setString

      public void setString(String str)
      Set field's String value.
      Parameters:
      str - String value
      Throws:
      IllegalFieldAccessException - thrown if method is not supported by specific Field instance.

    • isVariableLength

      public boolean isVariableLength()
      Returns:
      true if a Field instance is variable length, else false.

    • isSameType

      public boolean isSameType(Field field)
      Determine if specified field is same type as this field
      Parameters:
      field - a Field instance
      Returns:
      true if field is same type as this field

    • copyField

      public abstract Field copyField()
      Create new instance of this field with the same value.
      Returns:
      new field instance with same value

    • newField

      public abstract Field newField()
      Create new instance of this field type.
      Returns:
      new field instance with undefined initial value

    • equals

      public abstract boolean equals(Object obj)
      Determine if the specified Object is another Field which has the same type and value as this Field. When comparing a PrimitiveField, with a null state, a value of zero (0) is used.
      Overrides:
      equals in class Object
      Parameters:
      obj - another object
      Returns:
      true if this field equals obj

    • hashCode

      public abstract int hashCode()
      Overrides:
      hashCode in class Object

    • getValueAsString

      public abstract String getValueAsString()
      Get field value as a formatted string
      Returns:
      field value string

    • isNull

      public abstract boolean isNull()
      Determine if the field has been set to a null-state or value.
      Returns:
      true if field has been set to a null state or value, else false

    • compareTo

      public abstract int compareTo(Field otherField)
      Compares this Field with another Field for order. Returns a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified Field.
      NOTE: Field objects do not fully comply with the Comparable interface. Only the same Field implementations may be compared. In addition, the null state is not considered when comparing PrimitiveFields which have a zero (0) value.
      Specified by:
      compareTo in interface Comparable<Field>
      Parameters:
      otherField - another Field which is the same type as this Field
      Returns:
      field comparison result (see Comparable.compareTo(Object)).
      Throws:
      ClassCastException - if an attempt to compare dissimilar Fields (e.g., an IntField may not be compared with a ShortField).

    • canIndex

      public static boolean canIndex(Field field)
      Determine if a specified field instance may be indexed
      Parameters:
      field - field to be checked
      Returns:
      true if field can be indexed