/*
* org.openmicroscopy.shoola.util.concur.tasks.InvocationChainAdapter
*
*------------------------------------------------------------------------------
* Copyright (C) 2006 University of Dundee. All rights reserved.
*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
* 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.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
*------------------------------------------------------------------------------
*/
package org.openmicroscopy.shoola.util.concur.tasks;
//Java imports
//Third-party libraries
//Application-internal dependencies
/**
* Turns an {@link Invocation} chain into a {@link MultiStepTask}.
*
* @author Jean-Marie Burel
* <a href="mailto:j.burel@dundee.ac.uk">j.burel@dundee.ac.uk</a>
* @author <br>Andrea Falconi
* <a href="mailto:a.falconi@dundee.ac.uk">
* a.falconi@dundee.ac.uk</a>
* @version 2.2
* <small>
* (<b>Internal version:</b> $Revision$ $Date$)
* </small>
* @since OME2.2
*/
class InvocationChainAdapter
implements MultiStepTask
{
/** The adaptee. */
private Invocation[] chain;
/** Keeps track of how many times {@link #doStep()} has been invoked. */
private int step;
/**
* Creates a new adpter.
*
* @param chain The adaptee. Mustn't be <code>null</code> or
* <code>0</code>-length and none of its elements must be
* <code>null</code> either.
*/
InvocationChainAdapter(Invocation[] chain)
{
if (chain == null) throw new NullPointerException("No call.");
if (chain.length == 0)
throw new IllegalArgumentException("The chain has no elements.");
this.chain = new Invocation[chain.length];
for(int i = 0; i < chain.length; ++i)
if ((this.chain[i] = chain[i]) == null)
throw new NullPointerException("Null element: "+i+".");
step = 0;
}
/**
* Implemented as specified by the interface contract.
* @see org.openmicroscopy.shoola.util.concur.tasks.MultiStepTask#doStep()
*/
public Object doStep()
throws Exception
{
Object result = null;
if (!isDone())
result = chain[step++].call();
return result;
}
/**
* Implemented as specified by the interface contract.
* @see org.openmicroscopy.shoola.util.concur.tasks.MultiStepTask#isDone()
*/
public boolean isDone()
{
return (step == chain.length);
}
/*
* ==============================================================
* Follows code to enable testing.
* ==============================================================
*/
Invocation[] getChain()
{
Invocation[] c = new Invocation[chain.length];
for(int i = 0; i < chain.length; ++i) c[i] = chain[i];
return c;
}
}