Package org.terrier.realtime.memory

Class MemoryMetaIndexMap

  • All Implemented Interfaces:
    java.io.Closeable, java.io.Serializable, java.lang.AutoCloseable, MetaIndexMap, MetaIndex
    public class MemoryMetaIndexMap
extends MemoryMetaIndex
implements MetaIndexMap
    A memory meta index structure that supports fast look-ups via a map. It stores additional information about each document, e.g. the docno or title. Access to the memory versions of the meta index are faster than the on-disk versions, but can use up large amounts of RAM to store.

    Properties

    • indexer.meta.forward.keys - key names to store in the meta index
    • indexer.meta.forward.keylens - max key lengths for keys to store (this is ignored unless metaindex.crop is set)
    • metaindex.compressed.crop.long - should the content to store be cropped down to the length specified in indexer.meta.forward.keylens?
    Since:
    4.0
    Author:
    Richard McCreadie, Stuart Mackie
    See Also:
    Serialized Form

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void close()
      Delete contents of metadata index (but keep keys).
      java.lang.String[] getAllItems​(int docid)
      Obtain all metadata for specified document.
      int getDocument​(java.lang.String key, java.lang.String value)
      Not implemented.
      java.lang.String getItem​(java.lang.String key, int docid)
      Obtain metadata of specified type for specified document.
      java.lang.String[] getItems​(java.lang.String[] keys, int docid)
      Obtain metadata of specified types for specified document.
      java.lang.String[][] getItems​(java.lang.String[] keys, int[] docids)
      Obtain metadata of specified types for specified documents.
      java.lang.String[] getItems​(java.lang.String key, int[] docids)
      Obtain metadata of specified type for specified documents.
      java.lang.String[] getKeys()
      Returns the keys of this meta index
      java.util.Iterator<java.lang.String[]> iterator()
      Return iterator over meta-data index.
      void writeDocumentEntry​(int docid, java.lang.String[] data)  
      void writeDocumentEntry​(int docid, java.util.Map<java.lang.String,​java.lang.String> data)
      Write meta-data for document.

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • MemoryMetaIndexMap

        public MemoryMetaIndexMap​(java.lang.String[] keys,
                          int[] keylengths)

      • MemoryMetaIndexMap

        public MemoryMetaIndexMap()
        Constructor.

    • Method Detail

      • getItem

        public java.lang.String getItem​(java.lang.String key,
                                int docid)
                         throws java.io.IOException
        Obtain metadata of specified type for specified document.
        Specified by:
        getItem in interface MetaIndex
        Overrides:
        getItem in class MemoryMetaIndex
        Throws:
        java.io.IOException

      • getAllItems

        public java.lang.String[] getAllItems​(int docid)
                               throws java.io.IOException
        Obtain all metadata for specified document.
        Specified by:
        getAllItems in interface MetaIndex
        Overrides:
        getAllItems in class MemoryMetaIndex
        Throws:
        java.io.IOException

      • getItems

        public java.lang.String[] getItems​(java.lang.String key,
                                   int[] docids)
                            throws java.io.IOException
        Obtain metadata of specified type for specified documents.
        Specified by:
        getItems in interface MetaIndex
        Overrides:
        getItems in class MemoryMetaIndex
        Throws:
        java.io.IOException

      • getItems

        public java.lang.String[] getItems​(java.lang.String[] keys,
                                   int docid)
                            throws java.io.IOException
        Obtain metadata of specified types for specified document.
        Specified by:
        getItems in interface MetaIndex
        Overrides:
        getItems in class MemoryMetaIndex
        Throws:
        java.io.IOException

      • getItems

        public java.lang.String[][] getItems​(java.lang.String[] keys,
                                     int[] docids)
                              throws java.io.IOException
        Obtain metadata of specified types for specified documents. Return array is indexed by documents, then by metakeys.
        Specified by:
        getItems in interface MetaIndex
        Overrides:
        getItems in class MemoryMetaIndex
        Throws:
        java.io.IOException

      • writeDocumentEntry

        public void writeDocumentEntry​(int docid,
                               java.util.Map<java.lang.String,​java.lang.String> data)
                        throws java.lang.Exception
        Write meta-data for document.
        Throws:
        java.lang.Exception

      • writeDocumentEntry

        public void writeDocumentEntry​(int docid,
                               java.lang.String[] data)
        Specified by:
        writeDocumentEntry in interface MetaIndexMap

      • getDocument

        public int getDocument​(java.lang.String key,
                       java.lang.String value)
                throws java.io.IOException
        Not implemented.
        Specified by:
        getDocument in interface MetaIndex
        Overrides:
        getDocument in class MemoryMetaIndex
        Throws:
        java.io.IOException

      • close

        public void close()
           throws java.io.IOException
        Delete contents of metadata index (but keep keys).
        Specified by:
        close in interface java.lang.AutoCloseable
        Specified by:
        close in interface java.io.Closeable
        Overrides:
        close in class MemoryMetaIndex
        Throws:
        java.io.IOException

      • iterator

        public java.util.Iterator<java.lang.String[]> iterator()
        Return iterator over meta-data index.
        Overrides:
        iterator in class MemoryMetaIndex