## org.apache.lucene.document
Class Field

    java.lang.Object
      org.apache.lucene.document.AbstractField
          org.apache.lucene.document.Field

All Implemented Interfaces:
  Serializable, Fieldable

    public final class Field

extends AbstractField
implements Fieldable, Serializable

A field is a section of a Document. Each field has two parts, a name and a value. Values may be free text, provided as a String or as a Reader, or they may be atomic keywords, which are not further processed. Such keywords may be used to represent dates, urls, etc. Fields are optionally stored in the index, so that they may be returned with hits on the document.

See Also:
  Serialized Form

Nested Class Summary
`static class` `Field.Index` Specifies whether and how a field should be indexed.
`static class` `Field.Store` Specifies whether and how a field should be stored.
`static class` `Field.TermVector` Specifies whether and how a field should have term vectors.

Field Summary

Fields inherited from class org.apache.lucene.document.AbstractField
`boost, fieldsData, isBinary, isCompressed, isIndexed, isStored, isTokenized, lazy, name, omitNorms, storeOffsetWithTermVector, storePositionWithTermVector, storeTermVector`

Constructor Summary
`Field(String name, byte[] value, Field.Store store)` Create a stored field with binary value.
`Field(String name, Reader reader)` Create a tokenized and indexed field that is not stored.
`Field(String name, Reader reader, Field.TermVector termVector)` Create a tokenized and indexed field that is not stored, optionally with storing term vectors.
`Field(String name, String value, Field.Store store, Field.Index index)` Create a field by specifying its name, value and how it will be saved in the index.
`Field(String name, String value, Field.Store store, Field.Index index, Field.TermVector termVector)` Create a field by specifying its name, value and how it will be saved in the index.
`Field(String name, TokenStream tokenStream)` Create a tokenized and indexed field that is not stored.
`Field(String name, TokenStream tokenStream, Field.TermVector termVector)` Create a tokenized and indexed field that is not stored, optionally with storing term vectors.

Method Summary
`byte[]` `binaryValue()` The value of the field in Binary, or null.
`Reader` `readerValue()` The value of the field as a Reader, or null.
`void` `setValue(byte[] value)` Expert: change the value of this field.
`void` `setValue(Reader value)` Expert: change the value of this field.
`void` `setValue(String value)` Expert: change the value of this field.
`void` `setValue(TokenStream value)` Expert: change the value of this field.
`String` `stringValue()` The value of the field as a String, or null.
`TokenStream` `tokenStreamValue()` The value of the field as a TokesStream, or null.

Methods inherited from class org.apache.lucene.document.AbstractField
`getBoost, getOmitNorms, isBinary, isCompressed, isIndexed, isLazy, isStored, isStoreOffsetWithTermVector, isStorePositionWithTermVector, isTermVectorStored, isTokenized, name, setBoost, setOmitNorms, setStoreTermVector, toString`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

Methods inherited from interface org.apache.lucene.document.Fieldable
`getBoost, getOmitNorms, isBinary, isCompressed, isIndexed, isLazy, isStored, isStoreOffsetWithTermVector, isStorePositionWithTermVector, isTermVectorStored, isTokenized, name, setBoost, setOmitNorms`

Constructor Detail

### Field

    public Field(String name,
                 String value,
                 Field.Store store,
                 Field.Index index)

  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

    public Field(String name,
                 String value,
                 Field.Store store,
                 Field.Index index,
                 Field.TermVector termVector)

  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

    public Field(String name,
                 Reader reader)

  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(Document)` 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

    public Field(String name,
                 Reader reader,
                 Field.TermVector termVector)

  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(Document)` 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

    public Field(String name,
                 TokenStream tokenStream)

  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(Document)` 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

    public Field(String name,
                 TokenStream tokenStream,
                 Field.TermVector termVector)

  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(Document)` 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

    public Field(String name,
                 byte[] value,
                 Field.Store store)

  Create a stored field with binary value. Optionally the value may be compressed.

  Parameters:
    `name` - The name of the field
    `value` - The binary value
    `store` - How `value` should be stored (compressed or not)
  Throws:
    `IllegalArgumentException` - if store is `Store.NO`

Method Detail

### stringValue

    public String stringValue()

  The value of the field as a String, or null. If null, the Reader value, binary value, or TokenStream value is used. Exactly one of stringValue(), readerValue(), binaryValue(), and tokenStreamValue() must be set.

  Specified by:
    `stringValue` in interface `Fieldable`

### readerValue

    public Reader readerValue()

  The value of the field as a Reader, or null. If null, the String value, binary value, or TokenStream value is used. Exactly one of stringValue(), readerValue(), binaryValue(), and tokenStreamValue() must be set.

  Specified by:
    `readerValue` in interface `Fieldable`

### binaryValue

    public byte[] binaryValue()

  The value of the field in Binary, or null. If null, the Reader value, String value, or TokenStream value is used. Exactly one of stringValue(), readerValue(), binaryValue(), and tokenStreamValue() must be set.

  Specified by:
    `binaryValue` in interface `Fieldable`

### tokenStreamValue

    public TokenStream tokenStreamValue()

  The value of the field as a TokesStream, or null. If null, the Reader value, String value, or binary value is used. Exactly one of stringValue(), readerValue(), binaryValue(), and tokenStreamValue() must be set.

  Specified by:
    `tokenStreamValue` in interface `Fieldable`

### setValue

    public void setValue(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.

  Note that you should only use this method after the Field has been consumed (ie, the `Document` containing this Field has been added to the index). Also, each Field instance should only be used once within a single `Document` instance. See ImproveIndexingSpeed for details.

### setValue

    public void setValue(Reader value)

  Expert: change the value of this field. See setValue(String).

### setValue

    public void setValue(byte[] value)

  Expert: change the value of this field. See setValue(String).

### setValue

    public void setValue(TokenStream value)

  Expert: change the value of this field. See setValue(String).

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