/*
 * Copyright (c) 2006 Stiftung Deutsches Elektronen-Synchroton,
 * Member of the Helmholtz Association, (DESY), HAMBURG, GERMANY.
 *
 * THIS SOFTWARE IS PROVIDED UNDER THIS LICENSE ON AN "../AS IS" BASIS.
 * WITHOUT WARRANTY OF ANY KIND, EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR PARTICULAR PURPOSE AND
 * NON-INFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
 * FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR
 * THE USE OR OTHER DEALINGS IN THE SOFTWARE. SHOULD THE SOFTWARE PROVE DEFECTIVE
 * IN ANY RESPECT, THE USER ASSUMES THE COST OF ANY NECESSARY SERVICING, REPAIR OR
 * CORRECTION. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS LICENSE.
 * NO USE OF ANY SOFTWARE IS AUTHORIZED HEREUNDER EXCEPT UNDER THIS DISCLAIMER.
 * DESY HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS,
 * OR MODIFICATIONS.
 * THE FULL LICENSE SPECIFYING FOR THE SOFTWARE THE REDISTRIBUTION, MODIFICATION,
 * USAGE AND OTHER RIGHTS AND OBLIGATIONS IS INCLUDED WITH THE DISTRIBUTION OF THIS
 * PROJECT IN THE FILE LICENSE.HTML. IF THE LICENSE IS NOT INCLUDED YOU MAY FIND A COPY
 * AT HTTP://WWW.DESY.DE/LEGAL/LICENSE.HTM
 */

package org.csstudio.dal;

import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Iterator;

import com.cosylab.util.ArrayHelper;


/**
 * <p>
 * <code>HistoryHolder</code> iterates trough history iterator and stores
 * retrived data in two arrays: array of timestamps and values. Array of
 * values should have same type as array returned by iterator.
 * Thisimplementation should work with all by datatypes supported types with
 * reasonable performance for short history arrays.
 * </p>
 * <p>
 * Note that this implamintation is not optimized for long history arrays.
 * If returned history is very long, use directly iterator instead and fill
 * data models directly. E.g. series of points in history chart.
 * </p>
 *
 * @author <a href="mailto:igor.kriznar@cosylab.com">Igor Kriznar</a>)
 *
 * @since Oct 1, 2003.
 */
public class HistoryHolder
{
	/** Iterator for which data was extracted. */
	public HistoryIterator iterator;

	/**
	 * Array of values. Should have same type as array returned by iterator.
	 * E.g. for double iterator values can be casted to <code>double[].</code>
	 */
	public Object values = new Object[0];

	/** Array of timestamps. */
	public long[] timestamps = new long[0];

	/** <code>true</code> if order extracted data was reversed. */
	public boolean reversed = false;

	/**
	 * Constructor that iterates through history and stores the retrieved data in two arrays
	 */
	public HistoryHolder(HistoryIterator it, boolean rev)
		throws DataExchangeException
	{
		reversed = rev;
		iterator = it;

		ArrayList<long[]> times = new ArrayList<long[]>(3);
		ArrayList<Object> val = new ArrayList<Object>(3);

		// get all values
		while (iterator.hasNext()) {
			iterator.next(0);

			long[] t = iterator.getTimestamps();

			// end loop if iterator accidently run out of history
			if (t == null || t.length == 0) {
				break;
			}

			times.add(t);

			Object o = iterator.getValuesAsObject();
			val.add(o);
		}

		if (val.size() == 0) {
			return;
		}

		if (val.size() == 1) {
			timestamps = (long[])times.get(0);
			values = val.get(0);
		}

		// get length and type of data
		Iterator<Object> i = val.iterator();

		int l = 0;

		while (i.hasNext()) {
			l += Array.getLength(i.next());
		}

		Class<?> c = Array.get(val.get(0), 0).getClass();

		if (c.equals(Double.class)) {
			values = new double[l];
		} else if (c.equals(Long.class)) {
			values = new long[l];
		} else if (c.equals(Long.class)) {
			values = new long[l];
		} else {
			values = (Object[])Array.newInstance(Array.get(val.get(0), 0)
				    .getClass(), l);
		}

		int index = 0;
		i = val.iterator();

		while (i.hasNext()) {
			Object o = i.next();
			l = Array.getLength(o);
			System.arraycopy(o, 0, values, index, l);
			index += l;
		}

		if (reversed) {
			ArrayHelper.flip(values);
			ArrayHelper.flip(timestamps);
		}
	}
}

/* __oOo__ */