Package org.apache.lucene.index

Class SegmentInfo

  • public final class SegmentInfo
extends Object
    Information about a segment such as its name, directory, and files related to the segment.
    WARNING: This API is experimental and might change in incompatible ways in the next release.

    • Field Detail

      • NO

        public static final int NO
        Used by some member fields to mean not present (e.g., norms, deletions).
        See Also:
        Constant Field Values

      • YES

        public static final int YES
        Used by some member fields to mean present (e.g., norms, deletions).
        See Also:
        Constant Field Values

      • name

        public final String name
        Unique segment name in the directory.

      • dir

        public final Directory dir
        Where this segment resides.

    • Constructor Detail

      • SegmentInfo

        public SegmentInfo​(Directory dir,
                   Version version,
                   Version minVersion,
                   String name,
                   int maxDoc,
                   boolean isCompoundFile,
                   Codec codec,
                   Map<String,​String> diagnostics,
                   byte[] id,
                   Map<String,​String> attributes,
                   Sort indexSort)
        Construct a new complete SegmentInfo instance from input.

        Note: this is public only to allow access from the codecs package.

    • Method Detail

      • addDiagnostics

        public void addDiagnostics​(Map<String,​String> diagnostics)
        Adds or modifies this segment's diagnostics.

        Entries in the given map whose keys are not present in the current diagnostics are added. Otherwise, existing entries are modified with the given map's value.

        Parameters:
        diagnostics - the additional diagnostics

      • getDiagnostics

        public Map<String,​String> getDiagnostics()
        Returns diagnostics saved into the segment when it was written. The map is immutable.

      • getUseCompoundFile

        public boolean getUseCompoundFile()
        Returns true if this segment is stored as a compound file; else, false.

      • setCodec

        public void setCodec​(Codec codec)
        Can only be called once.

      • getCodec

        public Codec getCodec()
        Return Codec that wrote this segment.

      • maxDoc

        public int maxDoc()
        Returns number of documents in this segment (deletions are not taken into account).

      • files

        public Set<String> files()
        Return all files referenced by this SegmentInfo.

      • toString

        public String toString​(int delCount)
        Used for debugging. Format may suddenly change.

        Current format looks like _a(3.1):c45/4:[sorter=<long: "timestamp">!], which means the segment's name is _a; it was created with Lucene 3.1 (or '?' if it's unknown); it's using compound file format (would be C if not compound); it has 45 documents; it has 4 deletions (this part is left off when there are no deletions); it is sorted by the timestamp field in descending order (this part is omitted for unsorted segments).

      • equals

        public boolean equals​(Object obj)
        We consider another SegmentInfo instance equal if it has the same dir and same name.
        Overrides:
        equals in class Object

      • hashCode

        public int hashCode()
        Overrides:
        hashCode in class Object

      • getVersion

        public Version getVersion()
        Returns the version of the code which wrote the segment.

      • getMinVersion

        public Version getMinVersion()
        Return the minimum Lucene version that contributed documents to this segment, or null if it is unknown.

      • getId

        public byte[] getId()
        Return the id that uniquely identifies this segment.

      • setFiles

        public void setFiles​(Collection<String> files)
        Sets the files written for this segment.

      • addFiles

        public void addFiles​(Collection<String> files)
        Add these files to the set of files written for this segment.

      • addFile

        public void addFile​(String file)
        Add this file to the set of files written for this segment.

      • getAttribute

        public String getAttribute​(String key)
        Get a codec attribute value, or null if it does not exist

      • putAttribute

        public String putAttribute​(String key,
                           String value)
        Puts a codec attribute value.

        This is a key-value mapping for the field that the codec can use to store additional metadata, and will be available to the codec when reading the segment via getAttribute(String)

        If a value already exists for the field, it will be replaced with the new value. This method make a copy on write for every attribute change.

      • getAttributes

        public Map<String,​String> getAttributes()
        Returns the internal codec attributes map.
        Returns:
        internal codec attributes map.

      • getIndexSort

        public Sort getIndexSort()
        Return the sort order of this segment, or null if the index has no sort.