org.apache.lucene.document

Class Document

public final class Document extends Object implements Serializable

Documents are the unit of indexing and search. A Document is a set of fields. Each field has a name and a textual value. A field may be {@link Field#isStored() stored} with the document, in which case it is returned with search hits on the document. Thus each document should typically contain one or more stored fields which uniquely identify it.

Note that fields which are not {@link Field#isStored() stored} are not available in documents retrieved from the index, e.g. with {@link Hits#doc(int)}, {@link Searcher#doc(int)} or {@link IndexReader#document(int)}.

Constructor Summary
Document()
Constructs a new document with no fields.
Method Summary
voidadd(Field field)

Adds a field to a document.

Enumerationfields()
Returns an Enumeration of all the fields in a document.
Stringget(String name)
Returns the string value of the field with the given name if any exist in this document, or null.
byte[]getBinaryValue(String name)
Returns an array of bytes for the first (or only) field that has the name specified as the method parameter.
byte[][]getBinaryValues(String name)
Returns an array of byte arrays for of the fields that have the name specified as the method parameter.
floatgetBoost()
Returns the boost factor for hits on any field of this document.
FieldgetField(String name)
Returns a field with the given name if any exist in this document, or null.
Field[]getFields(String name)
Returns an array of {@link Field}s with the given name.
String[]getValues(String name)
Returns an array of values of the field specified as the method parameter.
voidremoveField(String name)

Removes field with the specified name from the document.

voidremoveFields(String name)

Removes all fields with the given name from the document.

voidsetBoost(float boost)
Sets a boost factor for hits on any field of this document.
StringtoString()
Prints the fields of a document for human consumption.

Constructor Detail

Document

public Document()
Constructs a new document with no fields.

Method Detail

add

public final void add(Field field)

Adds a field to a document. Several fields may be added with the same name. In this case, if the fields are indexed, their text is treated as though appended for the purposes of search.

Note that add like the removeField(s) methods only makes sense prior to adding a document to an index. These methods cannot be used to change the content of an existing index! In order to achieve this, a document has to be deleted from an index and a new changed version of that document has to be added.

fields

public final Enumeration fields()
Returns an Enumeration of all the fields in a document.

get

public final String get(String name)
Returns the string value of the field with the given name if any exist in this document, or null. If multiple fields exist with this name, this method returns the first value added. If only binary fields with this name exist, returns null.

getBinaryValue

public final byte[] getBinaryValue(String name)
Returns an array of bytes for the first (or only) field that has the name specified as the method parameter. This method will return null if no binary fields with the specified name are available. There may be non-binary fields with the same name.

Parameters: name the name of the field.

Returns: a byte[] containing the binary field value.

getBinaryValues

public final byte[][] getBinaryValues(String name)
Returns an array of byte arrays for of the fields that have the name specified as the method parameter. This method will return null if no binary fields with the specified name are available.

Parameters: name the name of the field

Returns: a byte[][] of binary field values.

getBoost

public float getBoost()
Returns the boost factor for hits on any field of this document.

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 document was indexed.

See Also: Document

getField

public final Field getField(String name)
Returns a field with the given name if any exist in this document, or null. If multiple fields exists with this name, this method returns the first value added.

getFields

public final Field[] getFields(String name)
Returns an array of {@link Field}s with the given name. This method can return null.

Parameters: name the name of the field

Returns: a Field[] array

getValues

public final String[] getValues(String name)
Returns an array of values of the field specified as the method parameter. This method can return null.

Parameters: name the name of the field

Returns: a String[] of field values

removeField

public final void removeField(String name)

Removes field with the specified name from the document. If multiple fields exist with this name, this method removes the first field that has been added. If there is no field with the specified name, the document remains unchanged.

Note that the removeField(s) methods like the add method only make sense prior to adding a document to an index. These methods cannot be used to change the content of an existing index! In order to achieve this, a document has to be deleted from an index and a new changed version of that document has to be added.

removeFields

public final void removeFields(String name)

Removes all fields with the given name from the document. If there is no field with the specified name, the document remains unchanged.

Note that the removeField(s) methods like the add method only make sense prior to adding a document to an index. These methods cannot be used to change the content of an existing index! In order to achieve this, a document has to be deleted from an index and a new changed version of that document has to be added.

setBoost

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

Values are multiplied into the value of {@link Field#getBoost()} of each field in this document. Thus, this method in effect sets a default boost for the fields of this document.

See Also: Field

toString

public final String toString()
Prints the fields of a document for human consumption.
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