org.apache.lucene.document

Class Field

public final class Field extends Object implements 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.
Nested Class Summary
static classField.Index
Specifies whether and how a field should be indexed.
static classField.Store
Specifies whether and how a field should be stored.
static classField.TermVector
Specifies whether and how a field should have term vectors.
Constructor Summary
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, 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 string, boolean store, boolean index, boolean token)
Create a field by specifying all parameters except for storeTermVector, which is set to false.
Field(String name, byte[] value, Field.Store store)
Create a stored field with binary value.
Field(String name, String string, boolean store, boolean index, boolean token, boolean storeTermVector)
Method Summary
byte[]binaryValue()
The value of the field in Binary, or null.
floatgetBoost()
Returns the boost factor for hits for this field.
booleangetOmitNorms()
True if norms are omitted for this indexed field
booleanisBinary()
True iff the value of the filed is stored as binary
booleanisCompressed()
True if the value of the field is stored and compressed within the index
booleanisIndexed()
True iff the value of the field is to be indexed, so that it may be searched on.
booleanisStored()
True iff the value of the field is to be stored in the index for return with search hits.
booleanisStoreOffsetWithTermVector()
True iff terms are stored as term vector together with their offsets (start and end positon in source text).
booleanisStorePositionWithTermVector()
True iff terms are stored as term vector together with their token positions.
booleanisTermVectorStored()
True iff the term or terms used to index this field are stored as a term vector, available from {@link IndexReader#getTermFreqVector(int,String)}.
booleanisTokenized()
True iff the value of the field should be tokenized as text prior to indexing.
static FieldKeyword(String name, String value)
Constructs a String-valued Field that is not tokenized, but is indexed and stored.
static FieldKeyword(String name, Date value)
Constructs a Date-valued Field that is not tokenized and is indexed, and stored in the index, for return with hits.
Stringname()
Returns the name of the field as an interned string.
ReaderreaderValue()
The value of the field as a Reader, or null.
voidsetBoost(float boost)
Sets the boost factor hits on this field.
voidsetOmitNorms(boolean omitNorms)
Expert: If set, omit normalization factors associated with this indexed field.
StringstringValue()
The value of the field as a String, or null.
StringtoString()
Prints a Field for human consumption.
static FieldText(String name, String value)
Constructs a String-valued Field that is tokenized and indexed, and is stored in the index, for return with hits.
static FieldText(String name, String value, boolean storeTermVector)
Constructs a String-valued Field that is tokenized and indexed, and is stored in the index, for return with hits.
static FieldText(String name, Reader value)
Constructs a Reader-valued Field that is tokenized and indexed, but is not stored in the index verbatim.
static FieldText(String name, Reader value, boolean storeTermVector)
Constructs a Reader-valued Field that is tokenized and indexed, but is not stored in the index verbatim.
static FieldUnIndexed(String name, String value)
Constructs a String-valued Field that is not tokenized nor indexed, but is stored in the index, for return with hits.
static FieldUnStored(String name, String value)
Constructs a String-valued Field that is tokenized and indexed, but that is not stored in the index.
static FieldUnStored(String name, String value, boolean storeTermVector)
Constructs a String-valued Field that is tokenized and indexed, but that is not stored in the index.

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:

Field

public Field(String name, Reader reader)
Create a tokenized and indexed field that is not stored. Term vectors will not be stored.

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.

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, String string, boolean store, boolean index, boolean token)

Deprecated: use {@link #Field(String, String, Field.Store, Field.Index)} instead

Create a field by specifying all parameters except for storeTermVector, which is set to false.

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

Field

public Field(String name, String string, boolean store, boolean index, boolean token, boolean storeTermVector)

Deprecated: use {@link #Field(String, String, Field.Store, Field.Index, Field.TermVector)} instead

Parameters: name The name of the field string The string to process store true if the field should store the string index true if the field should be indexed token true if the field should be tokenized storeTermVector true if we should store the Term Vector info

Method Detail

binaryValue

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

getBoost

public float getBoost()
Returns the boost factor for hits for this field.

The default value is 1.0.

Note: this value is not stored directly with the document in the index. Documents returned from {@link IndexReader#document(int)} and {@link Hits#doc(int)} may thus not have the same value present as when this field was indexed.

See Also: Field

getOmitNorms

public boolean getOmitNorms()
True if norms are omitted for this indexed field

isBinary

public final boolean isBinary()
True iff the value of the filed is stored as binary

isCompressed

public final boolean isCompressed()
True if the value of the field is stored and compressed within the index

isIndexed

public final boolean isIndexed()
True iff the value of the field is to be indexed, so that it may be searched on.

isStored

public final boolean isStored()
True iff the value of the field is to be stored in the index for return with search hits. It is an error for this to be true if a field is Reader-valued.

isStoreOffsetWithTermVector

public boolean isStoreOffsetWithTermVector()
True iff terms are stored as term vector together with their offsets (start and end positon in source text).

isStorePositionWithTermVector

public boolean isStorePositionWithTermVector()
True iff terms are stored as term vector together with their token positions.

isTermVectorStored

public final boolean isTermVectorStored()
True iff the term or terms used to index this field are stored as a term vector, available from {@link IndexReader#getTermFreqVector(int,String)}. These methods do not provide access to the original content of the field, only to terms used to index it. If the original content must be preserved, use the stored attribute instead.

See Also: IndexReader

isTokenized

public final boolean isTokenized()
True iff the value of the field should be tokenized as text prior to indexing. Un-tokenized fields are indexed as a single word and may not be Reader-valued.

Keyword

public static final Field Keyword(String name, String value)

Deprecated: use {@link #Field(String, String, Field.Store, Field.Index) Field(name, value, Field.Store.YES, Field.Index.UN_TOKENIZED)} instead

Constructs a String-valued Field that is not tokenized, but is indexed and stored. Useful for non-text fields, e.g. date or url.

Keyword

public static final Field Keyword(String name, Date value)

Deprecated: use {@link #Field(String, String, Field.Store, Field.Index) Field(name, value, Field.Store.YES, Field.Index.UN_TOKENIZED)} instead

Constructs a Date-valued Field that is not tokenized and is indexed, and stored in the index, for return with hits.

name

public String name()
Returns the name of the field as an interned string. For example "date", "title", "body", ...

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 binaryValue() must be set.

setBoost

public void setBoost(float boost)
Sets the boost factor hits on this field. This value will be multiplied into the score of all hits on this this field of this document.

The boost is multiplied by {@link Document#getBoost()} of the document containing this field. If a document has multiple fields with the same name, all such values are multiplied together. This product is then multipled by the value {@link Similarity#lengthNorm(String,int)}, and rounded by {@link Similarity#encodeNorm(float)} before it is stored in the index. One should attempt to ensure that this product does not overflow the range of that encoding.

See Also: Document Similarity Similarity

setOmitNorms

public void setOmitNorms(boolean omitNorms)
Expert: If set, omit normalization factors associated with this indexed field. This effectively disables indexing boosts and length normalization for this field.

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 binaryValue() must be set.

toString

public final String toString()
Prints a Field for human consumption.

Text

public static final Field Text(String name, String value)

Deprecated: use {@link #Field(String, String, Field.Store, Field.Index) Field(name, value, Field.Store.YES, Field.Index.TOKENIZED)} instead

Constructs a String-valued Field that is tokenized and indexed, and is stored in the index, for return with hits. Useful for short text fields, like "title" or "subject". Term vector will not be stored for this field.

Text

public static final Field Text(String name, String value, boolean storeTermVector)

Deprecated: use {@link #Field(String, String, Field.Store, Field.Index, Field.TermVector) Field(name, value, Field.Store.YES, Field.Index.TOKENIZED, storeTermVector)} instead

Constructs a String-valued Field that is tokenized and indexed, and is stored in the index, for return with hits. Useful for short text fields, like "title" or "subject".

Text

public static final Field Text(String name, Reader value)

Deprecated: use {@link #Field(String, Reader) Field(name, value)} instead

Constructs a Reader-valued Field that is tokenized and indexed, but is not stored in the index verbatim. Useful for longer text fields, like "body". Term vector will not be stored for this field.

Text

public static final Field Text(String name, Reader value, boolean storeTermVector)

Deprecated: use {@link #Field(String, Reader, Field.TermVector) Field(name, value, storeTermVector)} instead

Constructs a Reader-valued Field that is tokenized and indexed, but is not stored in the index verbatim. Useful for longer text fields, like "body".

UnIndexed

public static final Field UnIndexed(String name, String value)

Deprecated: use {@link #Field(String, String, Field.Store, Field.Index) Field(name, value, Field.Store.YES, Field.Index.NO)} instead

Constructs a String-valued Field that is not tokenized nor indexed, but is stored in the index, for return with hits.

UnStored

public static final Field UnStored(String name, String value)

Deprecated: use {@link #Field(String, String, Field.Store, Field.Index) Field(name, value, Field.Store.NO, Field.Index.TOKENIZED)} instead

Constructs a String-valued Field that is tokenized and indexed, but that is not stored in the index. Term vector will not be stored for this field.

UnStored

public static final Field UnStored(String name, String value, boolean storeTermVector)

Deprecated: use {@link #Field(String, String, Field.Store, Field.Index, Field.TermVector) Field(name, value, Field.Store.NO, Field.Index.TOKENIZED, storeTermVector)} instead

Constructs a String-valued Field that is tokenized and indexed, but that is not stored in the index.
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