package org.apache.lucene.search;
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 java.io.IOException;
import java.io.Serializable;
import java.util.Locale;
import org.apache.lucene.util.StringHelper;
/**
* Stores information about how to sort documents by terms in an individual
* field. Fields must be indexed in order to sort by them.
*
* <p>Created: Feb 11, 2004 1:25:29 PM
*
* @since lucene 1.4
* @see Sort
*/
public class SortField
implements Serializable {
/** Sort by document score (relevancy). Sort values are Float and higher
* values are at the front. */
public static final int SCORE = 0;
/** Sort by document number (index order). Sort values are Integer and lower
* values are at the front. */
public static final int DOC = 1;
// reserved, in Lucene 2.9, there was a constant: AUTO = 2;
/** Sort using term values as Strings. Sort values are String and lower
* values are at the front. */
public static final int STRING = 3;
/** Sort using term values as encoded Integers. Sort values are Integer and
* lower values are at the front. */
public static final int INT = 4;
/** Sort using term values as encoded Floats. Sort values are Float and
* lower values are at the front. */
public static final int FLOAT = 5;
/** Sort using term values as encoded Longs. Sort values are Long and
* lower values are at the front. */
public static final int LONG = 6;
/** Sort using term values as encoded Doubles. Sort values are Double and
* lower values are at the front. */
public static final int DOUBLE = 7;
/** Sort using term values as encoded Shorts. Sort values are Short and
* lower values are at the front. */
public static final int SHORT = 8;
/** Sort using a custom Comparator. Sort values are any Comparable and
* sorting is done according to natural order. */
public static final int CUSTOM = 9;
/** Sort using term values as encoded Bytes. Sort values are Byte and
* lower values are at the front. */
public static final int BYTE = 10;
/** Sort using term values as Strings, but comparing by
* value (using String.compareTo) for all comparisons.
* This is typically slower than {@link #STRING}, which
* uses ordinals to do the sorting. */
public static final int STRING_VAL = 11;
/** Represents sorting by document score (relevancy). */
public static final SortField FIELD_SCORE = new SortField (null, SCORE);
/** Represents sorting by document number (index order). */
public static final SortField FIELD_DOC = new SortField (null, DOC);
private String field;
private int type; // defaults to determining type dynamically
private Locale locale; // defaults to "natural order" (no Locale)
boolean reverse = false; // defaults to natural order
private FieldCache.Parser parser;
// Used for CUSTOM sort
private FieldComparatorSource comparatorSource;
/** Creates a sort by terms in the given field with the type of term
* values explicitly given.
* @param field Name of field to sort by. Can be <code>null</code> if
* <code>type</code> is SCORE or DOC.
* @param type Type of values in the terms.
*/
public SortField (String field, int type) {
initFieldType(field, type);
}
/** Creates a sort, possibly in reverse, by terms in the given field with the
* type of term values explicitly given.
* @param field Name of field to sort by. Can be <code>null</code> if
* <code>type</code> is SCORE or DOC.
* @param type Type of values in the terms.
* @param reverse True if natural order should be reversed.
*/
public SortField (String field, int type, boolean reverse) {
initFieldType(field, type);
this.reverse = reverse;
}
/** Creates a sort by terms in the given field, parsed
* to numeric values using a custom {@link FieldCache.Parser}.
* @param field Name of field to sort by. Must not be null.
* @param parser Instance of a {@link FieldCache.Parser},
* which must subclass one of the existing numeric
* parsers from {@link FieldCache}. Sort type is inferred
* by testing which numeric parser the parser subclasses.
* @throws IllegalArgumentException if the parser fails to
* subclass an existing numeric parser, or field is null
*/
public SortField (String field, FieldCache.Parser parser) {
this(field, parser, false);
}
/** Creates a sort, possibly in reverse, by terms in the given field, parsed
* to numeric values using a custom {@link FieldCache.Parser}.
* @param field Name of field to sort by. Must not be null.
* @param parser Instance of a {@link FieldCache.Parser},
* which must subclass one of the existing numeric
* parsers from {@link FieldCache}. Sort type is inferred
* by testing which numeric parser the parser subclasses.
* @param reverse True if natural order should be reversed.
* @throws IllegalArgumentException if the parser fails to
* subclass an existing numeric parser, or field is null
*/
public SortField (String field, FieldCache.Parser parser, boolean reverse) {
if (parser instanceof FieldCache.IntParser) initFieldType(field, INT);
else if (parser instanceof FieldCache.FloatParser) initFieldType(field, FLOAT);
else if (parser instanceof FieldCache.ShortParser) initFieldType(field, SHORT);
else if (parser instanceof FieldCache.ByteParser) initFieldType(field, BYTE);
else if (parser instanceof FieldCache.LongParser) initFieldType(field, LONG);
else if (parser instanceof FieldCache.DoubleParser) initFieldType(field, DOUBLE);
else
throw new IllegalArgumentException("Parser instance does not subclass existing numeric parser from FieldCache (got " + parser + ")");
this.reverse = reverse;
this.parser = parser;
}
/** Creates a sort by terms in the given field sorted
* according to the given locale.
* @param field Name of field to sort by, cannot be <code>null</code>.
* @param locale Locale of values in the field.
*/
public SortField (String field, Locale locale) {
initFieldType(field, STRING);
this.locale = locale;
}
/** Creates a sort, possibly in reverse, by terms in the given field sorted
* according to the given locale.
* @param field Name of field to sort by, cannot be <code>null</code>.
* @param locale Locale of values in the field.
*/
public SortField (String field, Locale locale, boolean reverse) {
initFieldType(field, STRING);
this.locale = locale;
this.reverse = reverse;
}
/** Creates a sort with a custom comparison function.
* @param field Name of field to sort by; cannot be <code>null</code>.
* @param comparator Returns a comparator for sorting hits.
*/
public SortField (String field, FieldComparatorSource comparator) {
initFieldType(field, CUSTOM);
this.comparatorSource = comparator;
}
/** Creates a sort, possibly in reverse, with a custom comparison function.
* @param field Name of field to sort by; cannot be <code>null</code>.
* @param comparator Returns a comparator for sorting hits.
* @param reverse True if natural order should be reversed.
*/
public SortField (String field, FieldComparatorSource comparator, boolean reverse) {
initFieldType(field, CUSTOM);
this.reverse = reverse;
this.comparatorSource = comparator;
}
// Sets field & type, and ensures field is not NULL unless
// type is SCORE or DOC
private void initFieldType(String field, int type) {
this.type = type;
if (field == null) {
if (type != SCORE && type != DOC)
throw new IllegalArgumentException("field can only be null when type is SCORE or DOC");
} else {
this.field = StringHelper.intern(field);
}
}
/** Returns the name of the field. Could return <code>null</code>
* if the sort is by SCORE or DOC.
* @return Name of field, possibly <code>null</code>.
*/
public String getField() {
return field;
}
/** Returns the type of contents in the field.
* @return One of the constants SCORE, DOC, STRING, INT or FLOAT.
*/
public int getType() {
return type;
}
/** Returns the Locale by which term values are interpreted.
* May return <code>null</code> if no Locale was specified.
* @return Locale, or <code>null</code>.
*/
public Locale getLocale() {
return locale;
}
/** Returns the instance of a {@link FieldCache} parser that fits to the given sort type.
* May return <code>null</code> if no parser was specified. Sorting is using the default parser then.
* @return An instance of a {@link FieldCache} parser, or <code>null</code>.
*/
public FieldCache.Parser getParser() {
return parser;
}
/** Returns whether the sort should be reversed.
* @return True if natural order should be reversed.
*/
public boolean getReverse() {
return reverse;
}
/** Returns the {@link FieldComparatorSource} used for
* custom sorting
*/
public FieldComparatorSource getComparatorSource() {
return comparatorSource;
}
@Override
public String toString() {
StringBuilder buffer = new StringBuilder();
switch (type) {
case SCORE:
buffer.append("<score>");
break;
case DOC:
buffer.append("<doc>");
break;
case STRING:
buffer.append("<string: \"").append(field).append("\">");
break;
case STRING_VAL:
buffer.append("<string_val: \"").append(field).append("\">");
break;
case BYTE:
buffer.append("<byte: \"").append(field).append("\">");
break;
case SHORT:
buffer.append("<short: \"").append(field).append("\">");
break;
case INT:
buffer.append("<int: \"").append(field).append("\">");
break;
case LONG:
buffer.append("<long: \"").append(field).append("\">");
break;
case FLOAT:
buffer.append("<float: \"").append(field).append("\">");
break;
case DOUBLE:
buffer.append("<double: \"").append(field).append("\">");
break;
case CUSTOM:
buffer.append("<custom:\"").append(field).append("\": ").append(comparatorSource).append('>');
break;
default:
buffer.append("<???: \"").append(field).append("\">");
break;
}
if (locale != null) buffer.append('(').append(locale).append(')');
if (parser != null) buffer.append('(').append(parser).append(')');
if (reverse) buffer.append('!');
return buffer.toString();
}
/** Returns true if <code>o</code> is equal to this. If a
* {@link FieldComparatorSource} or {@link
* FieldCache.Parser} was provided, it must properly
* implement equals (unless a singleton is always used). */
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (!(o instanceof SortField)) return false;
final SortField other = (SortField)o;
return (
other.field == this.field // field is always interned
&& other.type == this.type
&& other.reverse == this.reverse
&& (other.locale == null ? this.locale == null : other.locale.equals(this.locale))
&& (other.comparatorSource == null ? this.comparatorSource == null : other.comparatorSource.equals(this.comparatorSource))
&& (other.parser == null ? this.parser == null : other.parser.equals(this.parser))
);
}
/** Returns true if <code>o</code> is equal to this. If a
* {@link FieldComparatorSource} or {@link
* FieldCache.Parser} was provided, it must properly
* implement hashCode (unless a singleton is always
* used). */
@Override
public int hashCode() {
int hash=type^0x346565dd + Boolean.valueOf(reverse).hashCode()^0xaf5998bb;
if (field != null) hash += field.hashCode()^0xff5685dd;
if (locale != null) hash += locale.hashCode()^0x08150815;
if (comparatorSource != null) hash += comparatorSource.hashCode();
if (parser != null) hash += parser.hashCode()^0x3aaf56ff;
return hash;
}
// field must be interned after reading from stream
private void readObject(java.io.ObjectInputStream in) throws java.io.IOException, ClassNotFoundException {
in.defaultReadObject();
if (field != null)
field = StringHelper.intern(field);
}
/** Returns the {@link FieldComparator} to use for
* sorting.
*
* @lucene.experimental
*
* @param numHits number of top hits the queue will store
* @param sortPos position of this SortField within {@link
* Sort}. The comparator is primary if sortPos==0,
* secondary if sortPos==1, etc. Some comparators can
* optimize themselves when they are the primary sort.
* @return {@link FieldComparator} to use when sorting
*/
public FieldComparator getComparator(final int numHits, final int sortPos) throws IOException {
if (locale != null) {
// TODO: it'd be nice to allow FieldCache.getStringIndex
// to optionally accept a Locale so sorting could then use
// the faster StringComparator impls
return new FieldComparator.StringComparatorLocale(numHits, field, locale);
}
switch (type) {
case SortField.SCORE:
return new FieldComparator.RelevanceComparator(numHits);
case SortField.DOC:
return new FieldComparator.DocComparator(numHits);
case SortField.INT:
return new FieldComparator.IntComparator(numHits, field, parser);
case SortField.FLOAT:
return new FieldComparator.FloatComparator(numHits, field, parser);
case SortField.LONG:
return new FieldComparator.LongComparator(numHits, field, parser);
case SortField.DOUBLE:
return new FieldComparator.DoubleComparator(numHits, field, parser);
case SortField.BYTE:
return new FieldComparator.ByteComparator(numHits, field, parser);
case SortField.SHORT:
return new FieldComparator.ShortComparator(numHits, field, parser);
case SortField.CUSTOM:
assert comparatorSource != null;
return comparatorSource.newComparator(field, numHits, sortPos, reverse);
case SortField.STRING:
return new FieldComparator.TermOrdValComparator(numHits, field, sortPos, reverse);
case SortField.STRING_VAL:
return new FieldComparator.TermValComparator(numHits, field);
default:
throw new IllegalStateException("Illegal sort type: " + type);
}
}
}