Initiators.java

/* Initiators.java

	Purpose:
		
	Description:
		
	History:
		Wed Dec 14 09:02:20     2005, Created by tomyeh

Copyright (C) 2005 Potix Corporation. All Rights Reserved.

{{IS_RIGHT
	This program is distributed under LGPL Version 2.1 in the hope that
	it will be useful, but WITHOUT ANY WARRANTY.
}}IS_RIGHT
*/
package org.zkoss.zk.ui.impl;

import java.util.Collections;
import java.util.List;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.zkoss.zk.ui.Component;
import org.zkoss.zk.ui.Page;
import org.zkoss.zk.ui.UiException;
import org.zkoss.zk.ui.metainfo.PageDefinition;
import org.zkoss.zk.ui.util.Initiator;
import org.zkoss.zk.ui.util.InitiatorExt;

/**
 * A helper class used to handle {@link Initiator}.
 *
 * @author tomyeh
 * @see org.zkoss.zk.ui.sys.UiEngine
 */
/*package*/ class Initiators {
	/*package(inner)*/ static final Logger log = LoggerFactory.getLogger(Initiators.class);

	/** Invokes {@link Initiator#doInit}, if any, and returns
	 * an instance of{@link Initiators}.
	 * @param sysinits the system-level initiators
	 */
	@SuppressWarnings("unchecked")
	public static final Initiators doInit(PageDefinition pagedef, Page page, Initiator[] sysinits) {
		if (sysinits != null)
			try {
				for (int j = 0; j < sysinits.length; ++j)
					sysinits[j].doInit(page, Collections.EMPTY_MAP);
			} catch (Throwable ex) {
				throw UiException.Aide.wrap(ex);
			}

		final List<Initiator> inits = pagedef != null ? pagedef.doInit(page) : null;
		boolean sysinitEx = false;
		if (sysinits != null)
			for (int j = 0; j < sysinits.length; ++j)
				if (sysinits[j] instanceof InitiatorExt) {
					sysinitEx = true;
					break;
				}

		boolean initEx = false;
		if (inits != null)
			for (Initiator init : inits)
				if (init instanceof InitiatorExt) {
					initEx = true;
					break;
				}

		if (!sysinitEx && !initEx)
			return new Initiators();
		return new RealInits(sysinits, inits, sysinitEx, initEx);
	}

	protected Initiators() {
	}

	public void doAfterCompose(Page page, Component[] comps) throws Exception {
	}

	public boolean doCatch(Throwable t) {
		return false;
	}

	public void doFinally() {
	}

	private static class RealInits extends Initiators {
		private final Initiator[] _sysinits;
		private final List<Initiator> _inits;
		private boolean _sysinitEx, _initEx;

		/**
		 * @param inits a collection of {@link Initiator}.
		 * @param sysinitEx whether any of sysinits implements InitiatorExt
		 * @param initEx whether any of inits implements InitiatorExt
		 */
		private RealInits(Initiator[] sysinits, List<Initiator> inits, boolean sysinitEx, boolean initEx) {
			_sysinits = sysinits;
			_inits = inits;
			_sysinitEx = sysinitEx;
			_initEx = initEx;
		}

		/**
		 * Invokes {@link Initiator#doAfterCompose}.
		 * @param page
		 * @throws Exception
		 */
		public void doAfterCompose(Page page, Component[] comps) throws Exception {
			if (_sysinitEx)
				for (int j = 0; j < _sysinits.length; ++j) {
					final Initiator init = _sysinits[j];
					if (init instanceof InitiatorExt) {
						if (comps == null)
							comps = new Component[0];
						((InitiatorExt) init).doAfterCompose(page, comps);
					}
				}
			if (_initEx)
				for (Initiator init : _inits) {
					if (init instanceof InitiatorExt) {
						if (comps == null)
							comps = new Component[0];
						((InitiatorExt) init).doAfterCompose(page, comps);
					}
				}
		}

		/** Invokes {@link Initiator#doCatch}.
		 * It eats all exception without throwing one (but logging).
		 * Caller has to re-throw the exception.
		 */
		public boolean doCatch(Throwable t) {
			if (_sysinitEx)
				for (int j = 0; j < _sysinits.length; ++j) {
					final Initiator init = _sysinits[j];
					if (init instanceof InitiatorExt) {
						try {
							if (((InitiatorExt) init).doCatch(t))
								return true;
						} catch (Throwable ex) {
							Initiators.log.error("", ex);
						}
					}
				}
			if (_initEx)
				for (Initiator init : _inits) {
					if (init instanceof InitiatorExt) {
						try {
							if (((InitiatorExt) init).doCatch(t))
								return true; //ignore and skip all other initiators
						} catch (Throwable ex) {
							Initiators.log.error("", ex);
						}
					}
				}
			return false;
		}

		/** Invokes {@link Initiator#doFinally}.
		 */
		public void doFinally() {
			Throwable t = null;
			if (_sysinitEx)
				for (int j = 0; j < _sysinits.length; ++j) {
					final Initiator init = _sysinits[j];
					if (init instanceof InitiatorExt) {
						try {
							((InitiatorExt) init).doFinally();
						} catch (Throwable ex) {
							Initiators.log.error("", ex);
							if (t == null)
								t = ex;
						}
					}
				}
			if (_initEx)
				for (Initiator init : _inits) {
					if (init instanceof InitiatorExt) {
						try {
							((InitiatorExt) init).doFinally();
						} catch (Throwable ex) {
							Initiators.log.error("", ex);
							if (t == null)
								t = ex;
						}
					}
				}
			if (t != null)
				throw UiException.Aide.wrap(t);
		}
	}
}