Dictionary/src/java/org/thdl/lex/Global.java

package org.thdl.lex;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.Date;
import java.util.List;

import org.thdl.lex.component.ITerm;

/**
 * Description of the Class
 * 
 * @author travis
 * @created October 20, 2003
 */
public class Global {
	private static long refreshDelay;

	private static int recentTermsCount;

	private static long lastRefresh;

	private int entryCount;

	private List recentTerms;

	/**
	 * Gets the lastUpdateAsDate attribute of the LexComponentRepository class
	 * 
	 * @return The lastUpdateAsDate value
	 * @exception LexRepositoryException
	 *                Description of the Exception
	 */
	public Date getLastUpdate() throws LexRepositoryException {
		Date date = null;
		if (null != getRecentTerms() && getRecentTerms().size() > 0) {
			ITerm term = (ITerm) getRecentTerms().get(0);
			date = term.getMeta().getModifiedOn();
		}
		return date;
	}

	/**
	 * Sets the recentTermsCount attribute of the Global object
	 * 
	 * @param recentTermsCount
	 *            The new recentTermsCount value
	 */
	public void setRecentTermsCount(int recentTermsCount) {
		this.recentTermsCount = recentTermsCount;
	}

	/**
	 * Sets the refreshDelay attribute of the Global object
	 * 
	 * @param refreshDelay
	 *            The new refreshDelay value
	 */
	public void setRefreshDelay(long refreshDelay) {
		this.refreshDelay = refreshDelay;
	}

	/**
	 * Gets the recentTermsCount attribute of the Global object
	 * 
	 * @return The recentTermsCount value
	 */
	public int getRecentTermsCount() {
		return recentTermsCount;
	}

	/**
	 * Gets the refreshDelay attribute of the Global object
	 * 
	 * @return The refreshDelay value
	 */
	public long getRefreshDelay() {
		return refreshDelay;
	}

	/**
	 * Sets the entryCount attribute of the Global object
	 * 
	 * @param entryCount
	 *            The new entryCount value
	 */
	public void setEntryCount(int entryCount) {
		this.entryCount = entryCount;
	}

	/**
	 * Sets the lastRefresh attribute of the Global object
	 * 
	 * @param lastRefresh
	 *            The new lastRefresh value
	 */
	public void setLastRefresh(long lastRefresh) {
		this.lastRefresh = lastRefresh;
	}

	/**
	 * Sets the recentTerms attribute of the Global object
	 * 
	 * @param recentTerms
	 *            The new recentTerms value
	 */
	public void setRecentTerms(List recentTerms) {
		this.recentTerms = recentTerms;
		setLastRefresh(System.currentTimeMillis());
	}

	/**
	 * Gets the lastRefresh attribute of the Global object
	 * 
	 * @return The lastRefresh value
	 */
	public long getLastRefresh() {
		return lastRefresh;
	}

	/**
	 * Gets the recentTerms attribute of the Global object
	 * 
	 * @return The recentTerms value
	 * @exception LexRepositoryException
	 *                Description of the Exception
	 */
	public List getRecentTerms() throws LexRepositoryException {
		if (null == recentTerms || requiresRefresh()) {
			refresh();
		}
		return recentTerms;
	}

	//helpers

	/**
	 * Description of the Method
	 * 
	 * @return Description of the Return Value
	 */
	public boolean requiresRefresh() {
		boolean requiresRefresh = false;
		long now = System.currentTimeMillis();
		long lastUpdate = LexComponentRepository.getLastUpdate();
		long sinceLastRefresh = now - getLastRefresh();

		//LexLogger.debug( "Requires Refresh Logic: if " + sinceLastRefresh + "
		// > " + getRefreshDelay() + " && " + lastUpdate + " > " +
		// getLastRefresh() );
		if (sinceLastRefresh > getRefreshDelay()
				&& lastUpdate > getLastRefresh()) {
			requiresRefresh = true;
			LexLogger.debug("Refresh Required at: "
					+ System.currentTimeMillis());
		}
		return requiresRefresh;
	}

	/**
	 * Description of the Method
	 */
	public void refresh() {
		try {
			int limit = getRecentTermsCount();
			LexLogger.debug("GlobalRefresher is starting a refresh for the "
					+ limit + " most recent terms.");
			setRecentTerms(LexComponentRepository.getRecentTerms(limit));
			LexLogger.debug("GlobalRefresher is finished refreshing...");
			LexLogger.debug("Here's the new recent terms list: "
					+ getRecentTerms().toString());
			LexComponentRepository.cleanup();
			LexLogger.info("GlobalRefresher finished a refresh...");
		} catch (Exception e) {
			StringWriter writer = new StringWriter();
			e.printStackTrace(new PrintWriter(writer));
			String stackTrace = writer.getBuffer().toString();
			LexLogger.error("GlobalRefresher Thread caught an Exception: "
					+ stackTrace);
		}

	}

	/**
	 * Constructor for the Global object
	 */
	public Global() {
	}

	/**
	 * Constructor for the Global object
	 * 
	 * @param refreshDelay
	 *            Description of the Parameter
	 * @param recentItems
	 *            Description of the Parameter
	 */
	public Global(int recentItems, long refreshDelay) {
		setRecentTermsCount(recentItems);
		setRefreshDelay(refreshDelay);
	}

}