org.dlese.dpc.index.reader
Class LazyDocumentMap

java.lang.Object
  org.dlese.dpc.index.reader.LazyDocumentMap

All Implemented Interfaces:

Map

public class LazyDocumentMap
extends Object
implements Map

A Map for accessing the data stored in a Lucene Document as field/value pairs. The data is loaded from the index only when requested via the Map accessor methods (e.g. lazy loading), making access to very large Documents possible in an efficient manner. Each stored field in the Document corresponds to a key in the Map. For example documentMap.get("title") gets the text that was indexed and stored under the field name "title" for the Document. Supports read operations only. A LazyDocumentMap is available from search results by calling ResultDoc.getDocMap().

Example that uses JSTL inside a JSP page (assumes result is an instance of ResultDoc):

The title is: ${result.docMap["title"]}.

Author:

John Weatherley

See Also:

Document, ResultDoc, DocumentMap

Nested Class Summary

class	LazyDocumentMap.FieldMapEntry A Map entry containing lucene fieldName/fieldValues
class	LazyDocumentMap.FieldNameList A List for field names in a Lucene Document.
class	LazyDocumentMap.FieldValuesList A List for field values in a Lucene Document.

Nested classes/interfaces inherited from interface java.util.Map

Map.Entry<K,V>

Constructor Summary

LazyDocumentMap()
Constructor for the LazyDocumentMap object.

LazyDocumentMap(org.apache.lucene.document.Document doc)
Constructor for the LazyDocumentMap object.

Method Summary

void	clear() Method not supported.
boolean	containsKey(Object fieldName) Determines whether a given field exists in the Lucene Document.
boolean	containsValue(Object value) Determines whether the given field value is present in the Lucene Document.
Set	entrySet() Gets the Set of field/value entries for the Lucene Document.
Object	get(Object fieldName) Gets the text content of the given Lucene field as a String or null if the given field is not available or was not stored in the index.
LazyDocumentMap.FieldNameList	getFieldNames() Gets the names of all fields in the document as Strings.
LazyDocumentMap.FieldValuesList	getFieldValues() Gets the values for all fields in the document as Map.Entry Objects.
String	getFirstTextValue(String fieldName) Returns the string value of the field with the given name if any exist in this document, or null.
boolean	isEmpty() Determines whether there are no fields in this Document.
Set	keySet() Gets the field names in the Lucene Document.
Object	put(Object key, Object value) Method not supported.
void	putAll(Map t) Method not supported.
Object	remove(Object key) Method not supported.
int	size() Gets the number of fields in the Document.
Collection	values() Gets all field values that are present in the Lucene Document.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Map

equals, hashCode

Constructor Detail

LazyDocumentMap

public LazyDocumentMap(org.apache.lucene.document.Document doc)

Constructor for the LazyDocumentMap object.

Parameters:

doc - The Lucene Document that is exposed by this Map.

LazyDocumentMap

public LazyDocumentMap()

Constructor for the LazyDocumentMap object.

Method Detail

getFieldNames

public LazyDocumentMap.FieldNameList getFieldNames()

Gets the names of all fields in the document as Strings. This is similar to #keySet, but does not load all field/values into the Map and is therefore more efficient if only some fields are needed.

Returns:

The fieldNames value

See Also:

keySet()

getFieldValues

public LazyDocumentMap.FieldValuesList getFieldValues()

Gets the values for all fields in the document as Map.Entry Objects.

Returns:

The fieldNames value

getFirstTextValue

public String getFirstTextValue(String fieldName)

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.

Parameters:

fieldName - Name of the field

Returns:

The text value or null if none

get

public Object get(Object fieldName)

Gets the text content of the given Lucene field as a String or null if the given field is not available or was not stored in the index. Text includes all values stored in the index for the given field.

Specified by:

get in interface Map

Parameters:

fieldName - A Lucene Document field name

Returns:

The text of the field as a String, a Date, or null if not available.

keySet

public Set keySet()

Gets the field names in the Lucene Document. This is similar to #getFieldNames but it also loads all field/values into the Map and is therfore more expensive than #getFieldNames, especially for large Documents.

Specified by:

keySet in interface Map

Returns:

The field names

See Also:

getFieldNames()

entrySet

public Set entrySet()

Gets the Set of field/value entries for the Lucene Document. Each Map.Entry Object in the Set contains the field name (key) and corresponding field value. The field value will be an empty String if the given field was not set to be stored in the index.

Specified by:

entrySet in interface Map

Returns:

The Set of field/value entries for the Lucene Document

See Also:

Map.Entry

containsKey

public boolean containsKey(Object fieldName)

Determines whether a given field exists in the Lucene Document.

Specified by:

containsKey in interface Map

Parameters:

fieldName - A field name

Returns:

True if the field exists in the Lucene Document

values

public Collection values()

Gets all field values that are present in the Lucene Document.

Specified by:

values in interface Map

Returns:

The field values

containsValue

public boolean containsValue(Object value)

Determines whether the given field value is present in the Lucene Document.

Specified by:

containsValue in interface Map

Parameters:

value - A field value

Returns:

True if the field value is present in this Document

isEmpty

public boolean isEmpty()

Determines whether there are no fields in this Document.

Specified by:

isEmpty in interface Map

Returns:

True if there are no fields in the Document.

size

public int size()

Gets the number of fields in the Document.

Specified by:

size in interface Map

Returns:

The number of fields in the Document

putAll

public void putAll(Map t)

Method not supported.

Specified by:

putAll in interface Map

Parameters:

t - Not supported.

put

public Object put(Object key,
                  Object value)

Method not supported.

Specified by:

put in interface Map

Parameters:

key - Not supported.

value - Not supported.

Returns:

Not supported.

remove

public Object remove(Object key)

Method not supported.

Specified by:

remove in interface Map

Parameters:

key - Not supported.

Returns:

Not supported.

clear

public void clear()

Method not supported.

Specified by:

clear in interface Map