Package org.apache.lucene.document

Class Field

java.lang.Object
org.apache.lucene.document.Field
All Implemented Interfaces:
IndexableField
Direct Known Subclasses:
BinaryDocValuesField, DoubleField, FloatField, IntField, LongField, NumericDocValuesField, SortedDocValuesField, SortedSetDocValuesField, StoredField, StringField, TextField
public class Field extends Object implements IndexableField
Expert: directly create a field for a document. Most users should use one of the sugar subclasses: IntField, LongField, FloatField, DoubleField, BinaryDocValuesField, NumericDocValuesField, SortedDocValuesField, StringField, TextField, StoredField.

A field is a section of a Document. Each field has three parts: name, type and value. Values may be text (String, Reader or pre-analyzed TokenStream), binary (byte[]), or numeric (a Number). Fields are optionally stored in the index, so that they may be returned with hits on the document.

NOTE: the field type is an IndexableFieldType. Making changes to the state of the IndexableFieldType will impact any Field it is used in. It is strongly recommended that no changes be made after Field instantiation.

  • Field Details

    • type

      protected final FieldType type
      Field's type

    • name

      protected final String name
      Field's name

    • fieldsData

      protected Object fieldsData
      Field's value

    • tokenStream

      protected TokenStream tokenStream
      Pre-analyzed tokenStream for indexed fields; this is separate from fieldsData because you are allowed to have both; eg maybe field has a String value but you customize how it's tokenized

    • boost

      protected float boost
      Field's boost
      See Also:

  • Constructor Details

    • Field

      protected Field(String name, FieldType type)
      Expert: creates a field with no initial value. Intended only for custom Field subclasses.
      Parameters:
      name - field name
      type - field type
      Throws:
      IllegalArgumentException - if either the name or type is null.

    • Field

      public Field(String name, Reader reader, FieldType type)
      Create field with Reader value.
      Parameters:
      name - field name
      reader - reader value
      type - field type
      Throws:
      IllegalArgumentException - if either the name or type is null, or if the field's type is stored(), or if tokenized() is false.
      NullPointerException - if the reader is null

    • Field

      public Field(String name, TokenStream tokenStream, FieldType type)
      Create field with TokenStream value.
      Parameters:
      name - field name
      tokenStream - TokenStream value
      type - field type
      Throws:
      IllegalArgumentException - if either the name or type is null, or if the field's type is stored(), or if tokenized() is false, or if indexed() is false.
      NullPointerException - if the tokenStream is null

    • Field

      public Field(String name, byte[] value, FieldType type)
      Create field with binary value.

      NOTE: the provided byte[] is not copied so be sure not to change it until you're done with this field.

      Parameters:
      name - field name
      value - byte array pointing to binary content (not copied)
      type - field type
      Throws:
      IllegalArgumentException - if the field name is null, or the field's type is indexed()
      NullPointerException - if the type is null

    • Field

      public Field(String name, byte[] value, int offset, int length, FieldType type)
      Create field with binary value.

      NOTE: the provided byte[] is not copied so be sure not to change it until you're done with this field.

      Parameters:
      name - field name
      value - byte array pointing to binary content (not copied)
      offset - starting position of the byte array
      length - valid length of the byte array
      type - field type
      Throws:
      IllegalArgumentException - if the field name is null, or the field's type is indexed()
      NullPointerException - if the type is null

    • Field

      public Field(String name, BytesRef bytes, FieldType type)
      Create field with binary value.

      NOTE: the provided BytesRef is not copied so be sure not to change it until you're done with this field.

      Parameters:
      name - field name
      bytes - BytesRef pointing to binary content (not copied)
      type - field type
      Throws:
      IllegalArgumentException - if the field name is null, or the field's type is indexed()
      NullPointerException - if the type is null

    • Field

      public Field(String name, String value, FieldType type)
      Create field with String value.
      Parameters:
      name - field name
      value - string value
      type - field type
      Throws:
      IllegalArgumentException - if either the name or value is null, or if the field's type is neither indexed() nor stored(), or if indexed() is false but storeTermVectors() is true.
      NullPointerException - if the type is null

    • Field

      @Deprecated public Field(String name, String value, Field.Store store, Field.Index index)
      Deprecated.
      Use StringField, TextField instead.
      Create a field by specifying its name, value and how it will be saved in the index. Term vectors will not be stored in the index.
      Parameters:
      name - The name of the field
      value - The string to process
      store - Whether value should be stored in the index
      index - Whether the field should be indexed, and if so, if it should be tokenized before indexing
      Throws:
      NullPointerException - if name or value is null
      IllegalArgumentException - if the field is neither stored nor indexed

    • Field

      @Deprecated public Field(String name, String value, Field.Store store, Field.Index index, Field.TermVector termVector)
      Deprecated.
      Use StringField, TextField instead.
      Create a field by specifying its name, value and how it will be saved in the index.
      Parameters:
      name - The name of the field
      value - The string to process
      store - Whether value should be stored in the index
      index - Whether the field should be indexed, and if so, if it should be tokenized before indexing
      termVector - Whether term vector should be stored
      Throws:
      NullPointerException - if name or value is null
      IllegalArgumentException - in any of the following situations:
      • the field is neither stored nor indexed
      • the field is not indexed but termVector is TermVector.YES

    • Field

      @Deprecated public Field(String name, Reader reader)
      Deprecated.
      Use TextField instead.
      Create a tokenized and indexed field that is not stored. Term vectors will not be stored. The Reader is read only when the Document is added to the index, i.e. you may not close the Reader until IndexWriter.addDocument(java.lang.Iterable<? extends org.apache.lucene.index.IndexableField>) has been called.
      Parameters:
      name - The name of the field
      reader - The reader with the content
      Throws:
      NullPointerException - if name or reader is null

    • Field

      @Deprecated public Field(String name, Reader reader, Field.TermVector termVector)
      Deprecated.
      Use TextField instead.
      Create a tokenized and indexed field that is not stored, optionally with storing term vectors. The Reader is read only when the Document is added to the index, i.e. you may not close the Reader until IndexWriter.addDocument(java.lang.Iterable<? extends org.apache.lucene.index.IndexableField>) has been called.
      Parameters:
      name - The name of the field
      reader - The reader with the content
      termVector - Whether term vector should be stored
      Throws:
      NullPointerException - if name or reader is null

    • Field

      @Deprecated public Field(String name, TokenStream tokenStream)
      Deprecated.
      Use TextField instead
      Create a tokenized and indexed field that is not stored. Term vectors will not be stored. This is useful for pre-analyzed fields. The TokenStream is read only when the Document is added to the index, i.e. you may not close the TokenStream until IndexWriter.addDocument(java.lang.Iterable<? extends org.apache.lucene.index.IndexableField>) has been called.
      Parameters:
      name - The name of the field
      tokenStream - The TokenStream with the content
      Throws:
      NullPointerException - if name or tokenStream is null

    • Field

      @Deprecated public Field(String name, TokenStream tokenStream, Field.TermVector termVector)
      Deprecated.
      Use TextField instead
      Create a tokenized and indexed field that is not stored, optionally with storing term vectors. This is useful for pre-analyzed fields. The TokenStream is read only when the Document is added to the index, i.e. you may not close the TokenStream until IndexWriter.addDocument(java.lang.Iterable<? extends org.apache.lucene.index.IndexableField>) has been called.
      Parameters:
      name - The name of the field
      tokenStream - The TokenStream with the content
      termVector - Whether term vector should be stored
      Throws:
      NullPointerException - if name or tokenStream is null

    • Field

      @Deprecated public Field(String name, byte[] value)
      Deprecated.
      Use StoredField instead.
      Create a stored field with binary value. Optionally the value may be compressed.
      Parameters:
      name - The name of the field
      value - The binary value

    • Field

      @Deprecated public Field(String name, byte[] value, int offset, int length)
      Deprecated.
      Use StoredField instead.
      Create a stored field with binary value. Optionally the value may be compressed.
      Parameters:
      name - The name of the field
      value - The binary value
      offset - Starting offset in value where this Field's bytes are
      length - Number of bytes to use for this Field, starting at offset

  • Method Details

    • stringValue

      public String stringValue()
      The value of the field as a String, or null. If null, the Reader value or binary value is used. Exactly one of stringValue(), readerValue(), and getBinaryValue() must be set.
      Specified by:
      stringValue in interface IndexableField

    • readerValue

      public Reader readerValue()
      The value of the field as a Reader, or null. If null, the String value or binary value is used. Exactly one of stringValue(), readerValue(), and getBinaryValue() must be set.
      Specified by:
      readerValue in interface IndexableField

    • tokenStreamValue

      public TokenStream tokenStreamValue()
      The TokenStream for this field to be used when indexing, or null. If null, the Reader value or String value is analyzed to produce the indexed tokens.

    • setStringValue

      public void setStringValue(String value)

      Expert: change the value of this field. This can be used during indexing to re-use a single Field instance to improve indexing speed by avoiding GC cost of new'ing and reclaiming Field instances. Typically a single Document instance is re-used as well. This helps most on small documents.

      Each Field instance should only be used once within a single Document instance. See ImproveIndexingSpeed for details.

    • setReaderValue

      public void setReaderValue(Reader value)
      Expert: change the value of this field. See setStringValue(String).

    • setBytesValue

      public void setBytesValue(byte[] value)
      Expert: change the value of this field. See setStringValue(String).

    • setBytesValue

      public void setBytesValue(BytesRef value)
      Expert: change the value of this field. See setStringValue(String).

      NOTE: the provided BytesRef is not copied so be sure not to change it until you're done with this field.

    • setByteValue

      public void setByteValue(byte value)
      Expert: change the value of this field. See setStringValue(String).

    • setShortValue

      public void setShortValue(short value)
      Expert: change the value of this field. See setStringValue(String).

    • setIntValue

      public void setIntValue(int value)
      Expert: change the value of this field. See setStringValue(String).

    • setLongValue

      public void setLongValue(long value)
      Expert: change the value of this field. See setStringValue(String).

    • setFloatValue

      public void setFloatValue(float value)
      Expert: change the value of this field. See setStringValue(String).

    • setDoubleValue

      public void setDoubleValue(double value)
      Expert: change the value of this field. See setStringValue(String).

    • setTokenStream

      public void setTokenStream(TokenStream tokenStream)
      Expert: sets the token stream to be used for indexing and causes isIndexed() and isTokenized() to return true. May be combined with stored values from stringValue() or getBinaryValue()

    • name

      public String name()
      Description copied from interface: IndexableField
      Field name
      Specified by:
      name in interface IndexableField

    • boost

      public float boost()
      Returns the field's index-time boost.

      Only fields can have an index-time boost, if you want to simulate a "document boost", then you must pre-multiply it across all the relevant fields yourself.

      The boost is used to compute the norm factor for the field. By default, in the Similarity.computeNorm(FieldInvertState) method, the boost value is multiplied by the length normalization factor and then rounded by DefaultSimilarity.encodeNormValue(float) before it is stored in the index. One should attempt to ensure that this product does not overflow the range of that encoding.

      It is illegal to return a boost other than 1.0f for a field that is not indexed (IndexableFieldType.indexed() is false) or omits normalization values (IndexableFieldType.omitNorms() returns true).

      The default value is 1.0f (no boost).

      Specified by:
      boost in interface IndexableField
      See Also:

    • setBoost

      public void setBoost(float boost)
      Sets the boost factor on this field.
      Throws:
      IllegalArgumentException - if this field is not indexed, or if it omits norms.
      See Also:

    • numericValue

      public Number numericValue()
      Description copied from interface: IndexableField
      Non-null if this field has a numeric value
      Specified by:
      numericValue in interface IndexableField

    • binaryValue

      public BytesRef binaryValue()
      Description copied from interface: IndexableField
      Non-null if this field has a binary value
      Specified by:
      binaryValue in interface IndexableField

    • toString

      public String toString()
      Prints a Field for human consumption.
      Overrides:
      toString in class Object

    • fieldType

      public FieldType fieldType()
      Returns the FieldType for this field.
      Specified by:
      fieldType in interface IndexableField

    • tokenStream

      public TokenStream tokenStream(Analyzer analyzer) throws IOException
      Description copied from interface: IndexableField
      Creates the TokenStream used for indexing this field. If appropriate, implementations should use the given Analyzer to create the TokenStreams.
      Specified by:
      tokenStream in interface IndexableField
      Parameters:
      analyzer - Analyzer that should be used to create the TokenStreams from
      Returns:
      TokenStream value for indexing the document. Should always return a non-null value if the field is to be indexed
      Throws:
      IOException - Can be thrown while creating the TokenStream

    • translateFieldType

      @Deprecated public static final FieldType translateFieldType(Field.Store store, Field.Index index, Field.TermVector termVector)
      Deprecated.
      This is here only to ease transition from the pre-4.0 APIs.
      Translates the pre-4.0 enums for specifying how a field should be indexed into the 4.0 FieldType approach.