gate.creole.annic.apache.lucene.document
Class Document

java.lang.Object
  gate.creole.annic.apache.lucene.document.Document

All Implemented Interfaces:

Serializable

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 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 stored are not available in documents retrieved from the index, e.g. with Hits.doc(int), Searchable.doc(int) or IndexReader.document(int).

See Also:

Serialized Form

Constructor Summary

Document()
Constructs a new document with no fields.

Method Summary

void	add(Field field) Adds a field to a document.
Enumeration	fields() Returns an Enumeration of all the fields in a document.
String	get(String name) Returns the string value of the field with the given name if any exist in this document, or null.
float	getBoost() Returns the boost factor for hits on any field of this document.
Field	getField(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 Fields with the given name.
String[]	getValues(String name) Returns an array of values of the field specified as the method parameter.
void	removeField(String name) Removes field with the specified name from the document.
void	removeFields(String name) Removes all fields with the given name from the document.
void	setBoost(float boost) Sets a boost factor for hits on any field of this document.
String	toString() Prints the fields of a document for human consumption.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Document

public Document()

Constructs a new document with no fields.

Method Detail

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 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.setBoost(float)

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 IndexReader.document(int) and Hits.doc(int) may thus not have the same value present as when this document was indexed.

See Also:

setBoost(float)

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.

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.

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.

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.

fields

public final Enumeration fields()

Returns an Enumeration of all the fields in a document.

getFields

public final Field[] getFields(String name)

Returns an array of Fields 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

toString

public final String toString()

Prints the fields of a document for human consumption.

Overrides:

toString in class Object