Package org.apache.lucene.search

Class SortField

    • Field Detail

      • FIELD_SCORE

        public static final SortField FIELD_SCORE
        Represents sorting by document score (relevance).

      • FIELD_DOC

        public static final SortField FIELD_DOC
        Represents sorting by document number (index order).

      • field

        private java.lang.String field

      • reverse

        boolean reverse

      • missingValue

        protected java.lang.Object missingValue

      • canUsePoints

        private boolean canUsePoints

      • bytesComparator

        private java.util.Comparator<BytesRef> bytesComparator

    • Constructor Detail

      • SortField

        public SortField​(java.lang.String field,
                 SortField.Type type)
        Creates a sort by terms in the given field with the type of term values explicitly given.
        Parameters:
        field - Name of field to sort by. Can be null if type is SCORE or DOC.
        type - Type of values in the terms.

      • SortField

        public SortField​(java.lang.String field,
                 SortField.Type type,
                 boolean reverse)
        Creates a sort, possibly in reverse, by terms in the given field with the type of term values explicitly given.
        Parameters:
        field - Name of field to sort by. Can be null if type is SCORE or DOC.
        type - Type of values in the terms.
        reverse - True if natural order should be reversed.

      • SortField

        public SortField​(java.lang.String field,
                 FieldComparatorSource comparator)
        Creates a sort with a custom comparison function.
        Parameters:
        field - Name of field to sort by; cannot be null.
        comparator - Returns a comparator for sorting hits.

      • SortField

        public SortField​(java.lang.String field,
                 FieldComparatorSource comparator,
                 boolean reverse)
        Creates a sort, possibly in reverse, with a custom comparison function.
        Parameters:
        field - Name of field to sort by; cannot be null.
        comparator - Returns a comparator for sorting hits.
        reverse - True if natural order should be reversed.

    • Method Detail

      • readType

        protected static SortField.Type readType​(DataInput in)
                                  throws java.io.IOException
        Throws:
        java.io.IOException

      • serialize

        private void serialize​(DataOutput out)
                throws java.io.IOException
        Throws:
        java.io.IOException

      • getMissingValue

        public java.lang.Object getMissingValue()
        Return the value to use for documents that don't have a value. A value of null indicates that default should be used.

      • setMissingValue

        public void setMissingValue​(java.lang.Object missingValue)
        Set the value to use for documents that don't have a value.

      • initFieldType

        private void initFieldType​(java.lang.String field,
                           SortField.Type type)

      • getField

        public java.lang.String getField()
        Returns the name of the field. Could return null if the sort is by SCORE or DOC.
        Returns:
        Name of field, possibly null.

      • getType

        public SortField.Type getType()
        Returns the type of contents in the field.
        Returns:
        One of the constants SCORE, DOC, STRING, INT or FLOAT.

      • getReverse

        public boolean getReverse()
        Returns whether the sort should be reversed.
        Returns:
        True if natural order should be reversed.

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object

      • setCanUsePoints

        public void setCanUsePoints()
        For numeric sort fields, setting this field, indicates that the same numeric data has been indexed with two fields: doc values and points and that these fields have the same name. This allows to use sort optimization and skip non-competitive documents.

      • getCanUsePoints

        public boolean getCanUsePoints()

      • equals

        public boolean equals​(java.lang.Object o)
        Returns true if o is equal to this. If a FieldComparatorSource was provided, it must properly implement equals (unless a singleton is always used). canUsePoints field is not part of equals and hasCode intentionally, as it is only useful during search-time and using it in these functions prevents index sorting optimizations that rely on the equality of the index-time and search-time SortField instances.
        Overrides:
        equals in class java.lang.Object

      • hashCode

        public int hashCode()
        Returns a hash code for this SortField instance. If a FieldComparatorSource was provided, it must properly implement hashCode (unless a singleton is always used).
        Overrides:
        hashCode in class java.lang.Object

      • setBytesComparator

        public void setBytesComparator​(java.util.Comparator<BytesRef> b)

      • getBytesComparator

        public java.util.Comparator<BytesRef> getBytesComparator()

      • getComparator

        public FieldComparator<?> getComparator​(int numHits,
                                        int sortPos)
        Returns the FieldComparator to use for sorting.
        Parameters:
        numHits - number of top hits the queue will store
        sortPos - position of this SortField within Sort. The comparator is primary if sortPos==0, secondary if sortPos==1, etc. Some comparators can optimize themselves when they are the primary sort.
        Returns:
        FieldComparator to use when sorting

      • rewrite

        public SortField rewrite​(IndexSearcher searcher)
                  throws java.io.IOException
        Rewrites this SortField, returning a new SortField if a change is made. Subclasses should override this define their rewriting behavior when this SortField is of type SortField.Type.REWRITEABLE
        Parameters:
        searcher - IndexSearcher to use during rewriting
        Returns:
        New rewritten SortField, or this if nothing has changed.
        Throws:
        java.io.IOException - Can be thrown by the rewriting

      • needsScores

        public boolean needsScores()
        Whether the relevance score is needed to sort documents.

      • getIndexSorter

        public IndexSorter getIndexSorter()
        Returns an IndexSorter used for sorting index segments by this SortField. If the SortField cannot be used for index sorting (for example, if it uses scores or other query-dependent values) then this method should return null SortFields that implement this method should also implement a companion SortFieldProvider to serialize and deserialize the sort in index segment headers