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com.eireneh.bible.book.raw
Class WordItemsMem
java.lang.Objectcom.eireneh.bible.book.raw.Mem
- All Implemented Interfaces:
- Items
- public class WordItemsMem
- extends ItemsMem
The WordItemsMem stores words in a dictionary for a Bible.
The single method that will be of use 99% of the time is the
getWord(int) method. This method will be called once for
each word every time we display a verse (Assuming that we have not
implemented any caches).
The getIndex(String) method is the reverse of this, and
is used in creating the index in the first place.
The class has an underlying File however this is transarent to the user, since calls to getIndex(String) have any disk changes automatically written to disk, and the implementation of this class must be free to choose whatever cacheing scheme it needs.
The index file size will be roughly n*(a+v) where:
- n is the number of words. (=~16,000)
- a is the average word length. (=~8)
- v is the overhead per word. (=~1)
Index File Structure
I expect that the general layout will be something like:0 -. \ 1 -+. ! 2 -++. ! index area . !!! ! . !!! / a <'!! \ a !! ! r !! ! o !! ! text area n !! ! a <-'! ! b ! ! . ! /For this layout we can use the index of word (n+1) to calculate the length of word (n) (so long as the words are in index order in the text area. This would make v=1 (for the index). We could even use upper case letters to mark new words - this would mean we could have an out of order text area, or no index area (i.e. v=0) However having v=0 would force us to do in memory cacheing.
The OLB v8 seems to do some form of (offset,length) indexing to compress files sizes further (or is it simply to obfusticate the file format?) I'd rather use .zip technology for compression.
Consider whether and to what extent this class should be static and public. I think that it should be package scope - Use of this class does not make sense outside of the RawBible package. There should only ever be one WordIndex for a given file, but if we can instansiate this class for several sets of files - it does not make sense to make it static.
How can we extend this class in the future?
- Various different cacheing methods, so that we can work in low memory conditions. This is totally internal to this class, and does not affect the interface at all.
- Inheritance. There are various classes that do a similar job of reading from files from similar locations.
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Distribution Licence: Project B is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License, version 2 as published by the Free Software Foundation. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. The License is available on the internet here, by writing to Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA, Or locally at the Licence link below. The copyright to this program is held by it's authors. |
- Version:
- D0.I0.T0
| Field Summary | |
protected static com.eireneh.util.Logger |
log
The log stream |
| Fields inherited from class com.eireneh.bible.book.raw.ItemsMem |
array, count, hash |
| Fields inherited from class com.eireneh.bible.book.raw.Mem |
create, leafname, raw |
| Constructor Summary | |
WordItemsMem(RawBible raw,
boolean create)
Create a WordMemResourceIndex from a File that contains the dictionary. |
|
| Method Summary | |
int |
getIndex(java.lang.String data)
This is a specialization of IndexedResource.getIndex(String) that ensures that the word is lower case before we insert it. |
int |
getMaxItems()
How many items are there in this index? |
java.lang.String[] |
getStartsWith(java.lang.String word)
Find a list of words that start with the given word |
void |
load(java.io.InputStream in)
Load the Resource from a stream |
void |
save(java.io.OutputStream out)
Ensure that all changes to the index of words are written to a stream |
| Methods inherited from class com.eireneh.bible.book.raw.ItemsMem |
defaultLoad, defaultSave, getEnumeration, getIndex, getItem, init, size |
| Methods inherited from class com.eireneh.bible.book.raw.Mem |
load, save |
| Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Methods inherited from interface com.eireneh.bible.book.raw.Items |
save |
| Field Detail |
log
protected static com.eireneh.util.Logger log
- The log stream
| Constructor Detail |
WordItemsMem
public WordItemsMem(RawBible raw, boolean create) throws java.lang.Exception
- Create a WordMemResourceIndex from a File that contains the dictionary.
| Method Detail |
getIndex
public int getIndex(java.lang.String data)
- This is a specialization of IndexedResource.getIndex(String) that
ensures that the word is lower case before we insert it.
getMaxItems
public int getMaxItems()
- How many items are there in this index?
- Specified by:
getMaxItemsin classItemsMem
getStartsWith
public java.lang.String[] getStartsWith(java.lang.String word) throws com.eireneh.bible.book.BookException
- Find a list of words that start with the given word
load
public void load(java.io.InputStream in) throws java.io.IOException, java.lang.ClassNotFoundException
save
public void save(java.io.OutputStream out) throws java.io.IOException
- Ensure that all changes to the index of words are written to a
stream
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SUMMARY: JAVADOC | SOURCE | DOWNLOAD | NESTED | FIELD | CONSTR | METHOD |
DETAIL: FIELD | CONSTR | METHOD | ||||||||