CachedKeyPage.java

package net.bible.android.control.page;

import android.util.Log;

import net.bible.android.activity.R;
import net.bible.android.view.activity.base.Dialogs;
import net.bible.service.sword.SwordContentFacade;
import net.bible.service.sword.SwordDocumentFacade;

import org.apache.commons.lang3.StringUtils;
import org.crosswire.jsword.book.Book;
import org.crosswire.jsword.passage.Key;

import java.util.ArrayList;
import java.util.List;

/**
 * @author Martin Denham [mjdenham at gmail dot com]
 * @see gnu.lgpl.License for license details.<br>
 *      The copyright to this program is held by it's author.
 */
abstract public class CachedKeyPage extends CurrentPageBase  {

	private List<Key> mCachedGlobalKeyList;

	private static String TAG = "CachedKeyPage";
	
	CachedKeyPage(boolean shareKeyBetweenDocs, SwordContentFacade swordContentFacade, SwordDocumentFacade swordDocumentFacade) {
		super(shareKeyBetweenDocs, swordContentFacade, swordDocumentFacade);
	}

	@Override
	public void setCurrentDocument(Book doc) {
		// if doc changes then clear any caches from the previous doc
		if (doc!=null && !doc.equals(getCurrentDocument())) {
			mCachedGlobalKeyList = null;
		}
		super.setCurrentDocument(doc);
	}

	//TODO remove this and do binary search of globalkeylist
	/** make dictionary key lookup much faster
	 * 
	 * @return
	 */
	public List<Key> getCachedGlobalKeyList() {
		if (getCurrentDocument()!=null && mCachedGlobalKeyList==null) {
			try {
				Log.d(TAG, "Start to create cached key list for "+getCurrentDocument());
				// this cache is cleared in setCurrentDoc
		    	mCachedGlobalKeyList = new ArrayList<>();

		    	for (Key key : getCurrentDocument().getGlobalKeyList()) {
		    		// root key has no name and can be ignored but also check for any other keys with no name
		    		if (!StringUtils.isEmpty(key.getName())) {
						mCachedGlobalKeyList.add(key);
		    		}
		    	}

			} catch (OutOfMemoryError oom) {
				mCachedGlobalKeyList = null;
				System.gc();
				Log.e(TAG, "out of memory", oom);
				throw oom;
			} catch (Exception e) {
				mCachedGlobalKeyList = null;
				System.gc();
				Log.e(TAG, "Error getting keys for "+getCurrentDocument(), e);
				Dialogs.getInstance().showErrorMsg(R.string.error_occurred, e);
			}
			Log.d(TAG, "Finished creating cached key list len:"+mCachedGlobalKeyList.size());
		}
		return mCachedGlobalKeyList;
	}

	/** add or subtract a number of pages from the current position and return Verse
	 */
	public Key getKeyPlus(int num) {
		Key currentKey = getKey();
		int keyPos = findIndexOf(currentKey);
		// move forward or backward to new posn
		int newKeyPos = keyPos+num;
		// check bounds
		newKeyPos = Math.min(newKeyPos, getCachedGlobalKeyList().size()-1);
		newKeyPos = Math.max(newKeyPos, 0);
		// get the actual key at that posn
		return getCachedGlobalKeyList().get(newKeyPos);
	}
	
	/** find index of key in cached key list but cater for TreeKeys too
	 */
	protected int findIndexOf(Key key) {
		return getCachedGlobalKeyList().indexOf(key);
	}
}