package org.apache.lucene.document;
/**
* Copyright 2004 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.index.FieldInvertState; // for javadocs
import org.apache.lucene.search.PhraseQuery; // for javadocs
import org.apache.lucene.search.spans.SpanQuery; // for javadocs
import java.io.Reader;
import java.io.Serializable;
/**
* Synonymous with {@link Field}.
*
* <p><bold>WARNING</bold>: This interface may change within minor versions, despite Lucene's backward compatibility requirements.
* This means new methods may be added from version to version. This change only affects the Fieldable API; other backwards
* compatibility promises remain intact. For example, Lucene can still
* read and write indices created within the same major version.
* </p>
*
**/
public interface Fieldable extends Serializable {
/** 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.
*
* <p>The boost is multiplied by {@link org.apache.lucene.document.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
* used to compute the norm factor for the field. By
* default, in the {@link
* org.apache.lucene.search.Similarity#computeNorm(String,
* FieldInvertState)} method, the boost value is multiplied
* by the {@link
* org.apache.lucene.search.Similarity#lengthNorm(String,
* int)} and then rounded by {@link org.apache.lucene.search.Similarity#encodeNormValue(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 org.apache.lucene.document.Document#setBoost(float)
* @see org.apache.lucene.search.Similarity#computeNorm(String, FieldInvertState)
* @see org.apache.lucene.search.Similarity#encodeNormValue(float)
*/
void setBoost(float boost);
/** Returns the boost factor for hits for this field.
*
* <p>The default value is 1.0.
*
* <p>Note: this value is not stored directly with the document in the index.
* Documents returned from {@link org.apache.lucene.index.IndexReader#document(int)} and
* {@link org.apache.lucene.search.Searcher#doc(int)} may thus not have the same value present as when
* this field was indexed.
*
* @see #setBoost(float)
*/
float getBoost();
/** Returns the name of the field as an interned string.
* For example "date", "title", "body", ...
*/
String name();
/** The value of the field as a String, or null.
* <p>
* For indexing, if isStored()==true, the stringValue() will be used as the stored field value
* unless isBinary()==true, in which case getBinaryValue() will be used.
*
* If isIndexed()==true and isTokenized()==false, this String value will be indexed as a single token.
* If isIndexed()==true and isTokenized()==true, then tokenStreamValue() will be used to generate indexed tokens if not null,
* else readerValue() will be used to generate indexed tokens if not null, else stringValue() will be used to generate tokens.
*/
public String stringValue();
/** The value of the field as a Reader, which can be used at index time to generate indexed tokens.
* @see #stringValue()
*/
public Reader readerValue();
/** The TokenStream for this field to be used when indexing, or null.
* @see #stringValue()
*/
public TokenStream tokenStreamValue();
/** True if the value of the field is to be stored in the index for return
with search hits. */
boolean isStored();
/** True if the value of the field is to be indexed, so that it may be
searched on. */
boolean isIndexed();
/** True if 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. */
boolean isTokenized();
/** True if the term or terms used to index this field are stored as a term
* vector, available from {@link org.apache.lucene.index.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 <code>stored</code> attribute instead.
*
* @see org.apache.lucene.index.IndexReader#getTermFreqVector(int, String)
*/
boolean isTermVectorStored();
/**
* True if terms are stored as term vector together with their offsets
* (start and end positon in source text).
*/
boolean isStoreOffsetWithTermVector();
/**
* True if terms are stored as term vector together with their token positions.
*/
boolean isStorePositionWithTermVector();
/** True if the value of the field is stored as binary */
boolean isBinary();
/** True if norms are omitted for this indexed field */
boolean getOmitNorms();
/** Expert:
*
* If set, omit normalization factors associated with this indexed field.
* This effectively disables indexing boosts and length normalization for this field.
*/
void setOmitNorms(boolean omitNorms);
/**
* Indicates whether a Field is Lazy or not. The semantics of Lazy loading are such that if a Field is lazily loaded, retrieving
* it's values via {@link #stringValue()} or {@link #getBinaryValue()} is only valid as long as the {@link org.apache.lucene.index.IndexReader} that
* retrieved the {@link Document} is still open.
*
* @return true if this field can be loaded lazily
*/
boolean isLazy();
/**
* Returns offset into byte[] segment that is used as value, if Field is not binary
* returned value is undefined
* @return index of the first character in byte[] segment that represents this Field value
*/
abstract int getBinaryOffset();
/**
* Returns length of byte[] segment that is used as value, if Field is not binary
* returned value is undefined
* @return length of byte[] segment that represents this Field value
*/
abstract int getBinaryLength();
/**
* Return the raw byte[] for the binary field. Note that
* you must also call {@link #getBinaryLength} and {@link
* #getBinaryOffset} to know which range of bytes in this
* returned array belong to the field.
* @return reference to the Field value as byte[].
*/
abstract byte[] getBinaryValue();
/**
* Return the raw byte[] for the binary field. Note that
* you must also call {@link #getBinaryLength} and {@link
* #getBinaryOffset} to know which range of bytes in this
* returned array belong to the field.<p>
* About reuse: if you pass in the result byte[] and it is
* used, likely the underlying implementation will hold
* onto this byte[] and return it in future calls to
* {@link #getBinaryValue()}.
* So if you subsequently re-use the same byte[] elsewhere
* it will alter this Fieldable's value.
* @param result User defined buffer that will be used if
* possible. If this is null or not large enough, a new
* buffer is allocated
* @return reference to the Field value as byte[].
*/
abstract byte[] getBinaryValue(byte[] result);
/** @see #setOmitTermFreqAndPositions */
boolean getOmitTermFreqAndPositions();
/** Expert:
*
* If set, omit term freq, positions and payloads from
* postings for this field.
*
* <p><b>NOTE</b>: While this option reduces storage space
* required in the index, it also means any query
* requiring positional information, such as {@link
* PhraseQuery} or {@link SpanQuery} subclasses will
* silently fail to find results.
*/
void setOmitTermFreqAndPositions(boolean omitTermFreqAndPositions);
}