/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2007, by Object Refinery Limited and Contributors.
 *
 * Project Info:  http://www.jfree.org/jfreechart/index.html
 *
 * This library is free software; you can redistribute it and/or modify it 
 * under the terms of the GNU Lesser General Public License as published by 
 * the Free Software Foundation; either version 2.1 of the License, or 
 * (at your option) any later version.
 *
 * This library 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 Lesser General Public 
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
 * USA.  
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
 * in the United States and other countries.]
 *
 * ---------------
 * TimeSeries.java
 * ---------------
 * (C) Copyright 2001-2007, by Object Refinery Limited.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   Bryan Scott;
 *                   Nick Guenther;
 *
 * Changes
 * -------
 * 11-Oct-2001 : Version 1 (DG);
 * 14-Nov-2001 : Added listener mechanism (DG);
 * 15-Nov-2001 : Updated argument checking and exceptions in add() method (DG);
 * 29-Nov-2001 : Added properties to describe the domain and range (DG);
 * 07-Dec-2001 : Renamed TimeSeries --> BasicTimeSeries (DG);
 * 01-Mar-2002 : Updated import statements (DG);
 * 28-Mar-2002 : Added a method add(TimePeriod, double) (DG);
 * 27-Aug-2002 : Changed return type of delete method to void (DG);
 * 04-Oct-2002 : Added itemCount and historyCount attributes, fixed errors 
 *               reported by Checkstyle (DG);
 * 29-Oct-2002 : Added series change notification to addOrUpdate() method (DG);
 * 28-Jan-2003 : Changed name back to TimeSeries (DG);
 * 13-Mar-2003 : Moved to com.jrefinery.data.time package and implemented 
 *               Serializable (DG);
 * 01-May-2003 : Updated equals() method (see bug report 727575) (DG);
 * 14-Aug-2003 : Added ageHistoryCountItems method (copied existing code for 
 *               contents) made a method and added to addOrUpdate.  Made a 
 *               public method to enable ageing against a specified time 
 *               (eg now) as opposed to lastest time in series (BS);
 * 15-Oct-2003 : Added fix for setItemCount method - see bug report 804425.  
 *               Modified exception message in add() method to be more 
 *               informative (DG);
 * 13-Apr-2004 : Added clear() method (DG);
 * 21-May-2004 : Added an extra addOrUpdate() method (DG);
 * 15-Jun-2004 : Fixed NullPointerException in equals() method (DG);
 * 29-Nov-2004 : Fixed bug 1075255 (DG);
 * 17-Nov-2005 : Renamed historyCount --> maximumItemAge (DG);
 * 28-Nov-2005 : Changed maximumItemAge from int to long (DG);
 * 01-Dec-2005 : New add methods accept notify flag (DG);
 * ------------- JFREECHART 1.0.x ---------------------------------------------
 * 24-May-2006 : Improved error handling in createCopy() methods (DG);
 * 01-Sep-2006 : Fixed bugs in removeAgedItems() methods - see bug report 
 *               1550045 (DG);
 * 22-Mar-2007 : Simplified getDataItem(RegularTimePeriod) - see patch 1685500 
 *               by Nick Guenther (DG);
 * 31-Oct-2007 : Implemented faster hashCode() (DG);
 * 
 */

package org.jfree.data.time;

import java.io.Serializable;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Collection;
import java.util.Collections;
import java.util.Date;
import java.util.List;
import java.util.TimeZone;

import org.jfree.data.general.Series;
import org.jfree.data.general.SeriesChangeEvent;
import org.jfree.data.general.SeriesException;
import org.jfree.util.ObjectUtilities;

/**
 * Represents a sequence of zero or more data items in the form (period, value).
 */
public class TimeSeries extends Series implements Cloneable, Serializable {

    /** For serialization. */
    private static final long serialVersionUID = -5032960206869675528L;
    
    /** Default value for the domain description. */
    protected static final String DEFAULT_DOMAIN_DESCRIPTION = "Time";

    /** Default value for the range description. */
    protected static final String DEFAULT_RANGE_DESCRIPTION = "Value";

    /** A description of the domain. */
    private String domain;

    /** A description of the range. */
    private String range;

    /** The type of period for the data. */
    protected Class timePeriodClass;

    /** The list of data items in the series. */
    protected List data;

    /** The maximum number of items for the series. */
    private int maximumItemCount;

    /** 
     * The maximum age of items for the series, specified as a number of
     * time periods. 
     */
    private long maximumItemAge;
    
    /**
     * Creates a new (empty) time series.  By default, a daily time series is 
     * created.  Use one of the other constructors if you require a different 
     * time period.
     *
     * @param name  the series name (<code>null</code> not permitted).
     */
    public TimeSeries(Comparable name) {
        this(name, DEFAULT_DOMAIN_DESCRIPTION, DEFAULT_RANGE_DESCRIPTION, 
                Day.class);
    }

    /**
     * Creates a new (empty) time series with the specified name and class
     * of {@link RegularTimePeriod}.
     *
     * @param name  the series name (<code>null</code> not permitted).
     * @param timePeriodClass  the type of time period (<code>null</code> not 
     *                         permitted).
     */
    public TimeSeries(Comparable name, Class timePeriodClass) {
        this(name, DEFAULT_DOMAIN_DESCRIPTION, DEFAULT_RANGE_DESCRIPTION, 
                timePeriodClass);
    }

    /**
     * Creates a new time series that contains no data.
     * <P>
     * Descriptions can be specified for the domain and range.  One situation
     * where this is helpful is when generating a chart for the time series -
     * axis labels can be taken from the domain and range description.
     *
     * @param name  the name of the series (<code>null</code> not permitted).
     * @param domain  the domain description (<code>null</code> permitted).
     * @param range  the range description (<code>null</code> permitted).
     * @param timePeriodClass  the type of time period (<code>null</code> not 
     *                         permitted).
     */
    public TimeSeries(Comparable name, String domain, String range, 
                      Class timePeriodClass) {
        super(name);
        this.domain = domain;
        this.range = range;
        this.timePeriodClass = timePeriodClass;
        this.data = new java.util.ArrayList();
        this.maximumItemCount = Integer.MAX_VALUE;
        this.maximumItemAge = Long.MAX_VALUE;
    }

    /**
     * Returns the domain description.
     *
     * @return The domain description (possibly <code>null</code>).
     * 
     * @see #setDomainDescription(String)
     */
    public String getDomainDescription() {
        return this.domain;
    }

    /**
     * Sets the domain description and sends a <code>PropertyChangeEvent</code> 
     * (with the property name <code>Domain</code>) to all registered
     * property change listeners.
     *
     * @param description  the description (<code>null</code> permitted).
     * 
     * @see #getDomainDescription()
     */
    public void setDomainDescription(String description) {
        String old = this.domain;
        this.domain = description;
        firePropertyChange("Domain", old, description);
    }

    /**
     * Returns the range description.
     *
     * @return The range description (possibly <code>null</code>).
     * 
     * @see #setRangeDescription(String)
     */
    public String getRangeDescription() {
        return this.range;
    }

    /**
     * Sets the range description and sends a <code>PropertyChangeEvent</code> 
     * (with the property name <code>Range</code>) to all registered listeners.
     *
     * @param description  the description (<code>null</code> permitted).
     * 
     * @see #getRangeDescription()
     */
    public void setRangeDescription(String description) {
        String old = this.range;
        this.range = description;
        firePropertyChange("Range", old, description);
    }

    /**
     * Returns the number of items in the series.
     *
     * @return The item count.
     */
    public int getItemCount() {
        return this.data.size();
    }

    /**
     * Returns the list of data items for the series (the list contains 
     * {@link TimeSeriesDataItem} objects and is unmodifiable).
     *
     * @return The list of data items.
     */
    public List getItems() {
        return Collections.unmodifiableList(this.data);
    }

    /**
     * Returns the maximum number of items that will be retained in the series.
     * The default value is <code>Integer.MAX_VALUE</code>.
     *
     * @return The maximum item count.
     * 
     * @see #setMaximumItemCount(int)
     */
    public int getMaximumItemCount() {
        return this.maximumItemCount;
    }

    /**
     * Sets the maximum number of items that will be retained in the series.  
     * If you add a new item to the series such that the number of items will 
     * exceed the maximum item count, then the FIRST element in the series is 
     * automatically removed, ensuring that the maximum item count is not 
     * exceeded.
     *
     * @param maximum  the maximum (requires >= 0).
     * 
     * @see #getMaximumItemCount()
     */
    public void setMaximumItemCount(int maximum) {
        if (maximum < 0) {
            throw new IllegalArgumentException("Negative 'maximum' argument.");
        }
        this.maximumItemCount = maximum;
        int count = this.data.size();
        if (count > maximum) {
            delete(0, count - maximum - 1);
        }
    }

    /**
     * Returns the maximum item age (in time periods) for the series.
     *
     * @return The maximum item age.
     * 
     * @see #setMaximumItemAge(long)
     */
    public long getMaximumItemAge() {
        return this.maximumItemAge;
    }

    /**
     * Sets the number of time units in the 'history' for the series.  This 
     * provides one mechanism for automatically dropping old data from the
     * time series. For example, if a series contains daily data, you might set
     * the history count to 30.  Then, when you add a new data item, all data
     * items more than 30 days older than the latest value are automatically 
     * dropped from the series.
     *
     * @param periods  the number of time periods.
     * 
     * @see #getMaximumItemAge()
     */
    public void setMaximumItemAge(long periods) {
        if (periods < 0) {
            throw new IllegalArgumentException("Negative 'periods' argument.");
        }
        this.maximumItemAge = periods;
        removeAgedItems(true);  // remove old items and notify if necessary
    }

    /**
     * Returns the time period class for this series.
     * <p>
     * Only one time period class can be used within a single series (enforced).
     * If you add a data item with a {@link Year} for the time period, then all
     * subsequent data items must also have a {@link Year} for the time period.
     *
     * @return The time period class (never <code>null</code>).
     */
    public Class getTimePeriodClass() {
        return this.timePeriodClass;
    }

    /**
     * Returns a data item for the series.
     *
     * @param index  the item index (zero-based).
     *
     * @return The data item.
     * 
     * @see #getDataItem(RegularTimePeriod)
     */
    public TimeSeriesDataItem getDataItem(int index) {
        return (TimeSeriesDataItem) this.data.get(index);
    }

    /**
     * Returns the data item for a specific period.
     *
     * @param period  the period of interest (<code>null</code> not allowed).
     *
     * @return The data item matching the specified period (or 
     *         <code>null</code> if there is no match).
     *
     * @see #getDataItem(int)
     */
    public TimeSeriesDataItem getDataItem(RegularTimePeriod period) {
        int index = getIndex(period);
        if (index >= 0) {
            return (TimeSeriesDataItem) this.data.get(index);
        }
        else {
            return null;
        }
    }

    /**
     * Returns the time period at the specified index.
     *
     * @param index  the index of the data item.
     *
     * @return The time period.
     */
    public RegularTimePeriod getTimePeriod(int index) {
        return getDataItem(index).getPeriod();
    }

    /**
     * Returns a time period that would be the next in sequence on the end of
     * the time series.
     *
     * @return The next time period.
     */
    public RegularTimePeriod getNextTimePeriod() {
        RegularTimePeriod last = getTimePeriod(getItemCount() - 1);
        return last.next();
    }

    /**
     * Returns a collection of all the time periods in the time series.
     *
     * @return A collection of all the time periods.
     */
    public Collection getTimePeriods() {
        Collection result = new java.util.ArrayList();
        for (int i = 0; i < getItemCount(); i++) {
            result.add(getTimePeriod(i));
        }
        return result;
    }

    /**
     * Returns a collection of time periods in the specified series, but not in
     * this series, and therefore unique to the specified series.
     *
     * @param series  the series to check against this one.
     *
     * @return The unique time periods.
     */
    public Collection getTimePeriodsUniqueToOtherSeries(TimeSeries series) {

        Collection result = new java.util.ArrayList();
        for (int i = 0; i < series.getItemCount(); i++) {
            RegularTimePeriod period = series.getTimePeriod(i);
            int index = getIndex(period);
            if (index < 0) {
                result.add(period);
            }
        }
        return result;

    }

    /**
     * Returns the index for the item (if any) that corresponds to a time 
     * period.
     *
     * @param period  the time period (<code>null</code> not permitted).
     *
     * @return The index.
     */
    public int getIndex(RegularTimePeriod period) {
        if (period == null) {
            throw new IllegalArgumentException("Null 'period' argument.");
        } 
        TimeSeriesDataItem dummy = new TimeSeriesDataItem(
              period, Integer.MIN_VALUE);
        return Collections.binarySearch(this.data, dummy);
    }

    /**
     * Returns the value at the specified index.
     *
     * @param index  index of a value.
     *
     * @return The value (possibly <code>null</code>).
     */
    public Number getValue(int index) {
        return getDataItem(index).getValue();
    }

    /**
     * Returns the value for a time period.  If there is no data item with the 
     * specified period, this method will return <code>null</code>.
     *
     * @param period  time period (<code>null</code> not permitted).
     *
     * @return The value (possibly <code>null</code>).
     */
    public Number getValue(RegularTimePeriod period) {

        int index = getIndex(period);
        if (index >= 0) {
            return getValue(index);
        }
        else {
            return null;
        }

    }

    /**
     * Adds a data item to the series and sends a 
     * {@link org.jfree.data.general.SeriesChangeEvent} to all registered 
     * listeners.
     *
     * @param item  the (timeperiod, value) pair (<code>null</code> not 
     *              permitted).
     */
    public void add(TimeSeriesDataItem item) {
        add(item, true);
    }
        
    /**
     * Adds a data item to the series and sends a 
     * {@link org.jfree.data.general.SeriesChangeEvent} to all registered 
     * listeners.
     *
     * @param item  the (timeperiod, value) pair (<code>null</code> not 
     *              permitted).
     * @param notify  notify listeners?
     */
    public void add(TimeSeriesDataItem item, boolean notify) {
        if (item == null) {
            throw new IllegalArgumentException("Null 'item' argument.");
        }
        if (!item.getPeriod().getClass().equals(this.timePeriodClass)) {
            StringBuffer b = new StringBuffer();
            b.append("You are trying to add data where the time period class ");
            b.append("is ");
            b.append(item.getPeriod().getClass().getName());
            b.append(", but the TimeSeries is expecting an instance of ");
            b.append(this.timePeriodClass.getName());
            b.append(".");
            throw new SeriesException(b.toString());
        }

        // make the change (if it's not a duplicate time period)...
        boolean added = false;
        int count = getItemCount();
        if (count == 0) {
            this.data.add(item);
            added = true;
        }
        else {
            RegularTimePeriod last = getTimePeriod(getItemCount() - 1);
            if (item.getPeriod().compareTo(last) > 0) {
                this.data.add(item);
                added = true;
            }
            else {
                int index = Collections.binarySearch(this.data, item);
                if (index < 0) {
                    this.data.add(-index - 1, item);
                    added = true;
                }
                else {
                    StringBuffer b = new StringBuffer();
                    b.append("You are attempting to add an observation for ");
                    b.append("the time period ");
                    b.append(item.getPeriod().toString());
                    b.append(" but the series already contains an observation");
                    b.append(" for that time period. Duplicates are not ");
                    b.append("permitted.  Try using the addOrUpdate() method.");
                    throw new SeriesException(b.toString());
                }
            }
        }
        if (added) {
            // check if this addition will exceed the maximum item count...
            if (getItemCount() > this.maximumItemCount) {
                this.data.remove(0);
            }

            removeAgedItems(false);  // remove old items if necessary, but
                                     // don't notify anyone, because that
                                     // happens next anyway...
            if (notify) {
                fireSeriesChanged();
            }
        }

    }

    /**
     * Adds a new data item to the series and sends a {@link SeriesChangeEvent}
     * to all registered listeners.
     *
     * @param period  the time period (<code>null</code> not permitted).
     * @param value  the value.
     */
    public void add(RegularTimePeriod period, double value) {
        // defer argument checking...
        add(period, value, true);
    }

    /**
     * Adds a new data item to the series and sends a {@link SeriesChangeEvent}
     * to all registered listeners.
     *
     * @param period  the time period (<code>null</code> not permitted).
     * @param value  the value.
     * @param notify  notify listeners?
     */
    public void add(RegularTimePeriod period, double value, boolean notify) {
        // defer argument checking...
        TimeSeriesDataItem item = new TimeSeriesDataItem(period, value);
        add(item, notify);
    }

    /**
     * Adds a new data item to the series and sends 
     * a {@link org.jfree.data.general.SeriesChangeEvent} to all registered 
     * listeners.
     *
     * @param period  the time period (<code>null</code> not permitted).
     * @param value  the value (<code>null</code> permitted).
     */
    public void add(RegularTimePeriod period, Number value) {
        // defer argument checking...
        add(period, value, true);
    }

    /**
     * Adds a new data item to the series and sends 
     * a {@link org.jfree.data.general.SeriesChangeEvent} to all registered 
     * listeners.
     *
     * @param period  the time period (<code>null</code> not permitted).
     * @param value  the value (<code>null</code> permitted).
     * @param notify  notify listeners?
     */
    public void add(RegularTimePeriod period, Number value, boolean notify) {
        // defer argument checking...
        TimeSeriesDataItem item = new TimeSeriesDataItem(period, value);
        add(item, notify);
    }

    /**
     * Updates (changes) the value for a time period.  Throws a 
     * {@link SeriesException} if the period does not exist.
     *
     * @param period  the period (<code>null</code> not permitted).
     * @param value  the value (<code>null</code> permitted).
     */
    public void update(RegularTimePeriod period, Number value) {
        TimeSeriesDataItem temp = new TimeSeriesDataItem(period, value);
        int index = Collections.binarySearch(this.data, temp);
        if (index >= 0) {
            TimeSeriesDataItem pair = (TimeSeriesDataItem) this.data.get(index);
            pair.setValue(value);
            fireSeriesChanged();
        }
        else {
            throw new SeriesException(
                "TimeSeries.update(TimePeriod, Number):  period does not exist."
            );
        }

    }

    /**
     * Updates (changes) the value of a data item.
     *
     * @param index  the index of the data item.
     * @param value  the new value (<code>null</code> permitted).
     */
    public void update(int index, Number value) {
        TimeSeriesDataItem item = getDataItem(index);
        item.setValue(value);
        fireSeriesChanged();
    }

    /**
     * Adds or updates data from one series to another.  Returns another series
     * containing the values that were overwritten.
     *
     * @param series  the series to merge with this.
     *
     * @return A series containing the values that were overwritten.
     */
    public TimeSeries addAndOrUpdate(TimeSeries series) {
        TimeSeries overwritten = new TimeSeries("Overwritten values from: " 
                + getKey(), series.getTimePeriodClass());
        for (int i = 0; i < series.getItemCount(); i++) {
            TimeSeriesDataItem item = series.getDataItem(i);
            TimeSeriesDataItem oldItem = addOrUpdate(item.getPeriod(), 
                    item.getValue());
            if (oldItem != null) {
                overwritten.add(oldItem);
            }
        }
        return overwritten;
    }

    /**
     * Adds or updates an item in the times series and sends a 
     * {@link org.jfree.data.general.SeriesChangeEvent} to all registered 
     * listeners.
     *
     * @param period  the time period to add/update (<code>null</code> not 
     *                permitted).
     * @param value  the new value.
     *
     * @return A copy of the overwritten data item, or <code>null</code> if no 
     *         item was overwritten.
     */
    public TimeSeriesDataItem addOrUpdate(RegularTimePeriod period, 
                                          double value) {
        return this.addOrUpdate(period, new Double(value));    
    }
    
    /**
     * Adds or updates an item in the times series and sends a 
     * {@link org.jfree.data.general.SeriesChangeEvent} to all registered 
     * listeners.
     *
     * @param period  the time period to add/update (<code>null</code> not 
     *                permitted).
     * @param value  the new value (<code>null</code> permitted).
     *
     * @return A copy of the overwritten data item, or <code>null</code> if no 
     *         item was overwritten.
     */
    public TimeSeriesDataItem addOrUpdate(RegularTimePeriod period, 
                                          Number value) {

        if (period == null) {
            throw new IllegalArgumentException("Null 'period' argument.");   
        }
        TimeSeriesDataItem overwritten = null;

        TimeSeriesDataItem key = new TimeSeriesDataItem(period, value);
        int index = Collections.binarySearch(this.data, key);
        if (index >= 0) {
            TimeSeriesDataItem existing 
                = (TimeSeriesDataItem) this.data.get(index);
            overwritten = (TimeSeriesDataItem) existing.clone();
            existing.setValue(value);
            removeAgedItems(false);  // remove old items if necessary, but
                                     // don't notify anyone, because that
                                     // happens next anyway...
            fireSeriesChanged();
        }
        else {
            this.data.add(-index - 1, new TimeSeriesDataItem(period, value));

            // check if this addition will exceed the maximum item count...
            if (getItemCount() > this.maximumItemCount) {
                this.data.remove(0);
            }

            removeAgedItems(false);  // remove old items if necessary, but
                                     // don't notify anyone, because that
                                     // happens next anyway...
            fireSeriesChanged();
        }
        return overwritten;

    }

    /**
     * Age items in the series.  Ensure that the timespan from the youngest to 
     * the oldest record in the series does not exceed maximumItemAge time 
     * periods.  Oldest items will be removed if required.
     * 
     * @param notify  controls whether or not a {@link SeriesChangeEvent} is 
     *                sent to registered listeners IF any items are removed.
     */
    public void removeAgedItems(boolean notify) {
        // check if there are any values earlier than specified by the history 
        // count...
        if (getItemCount() > 1) {
            long latest = getTimePeriod(getItemCount() - 1).getSerialIndex();
            boolean removed = false;
            while ((latest - getTimePeriod(0).getSerialIndex()) 
                    > this.maximumItemAge) {
                this.data.remove(0);
                removed = true;
            }
            if (removed && notify) {
                fireSeriesChanged();
            }
        }
    }

    /**
     * Age items in the series.  Ensure that the timespan from the supplied 
     * time to the oldest record in the series does not exceed history count.  
     * oldest items will be removed if required.
     *
     * @param latest  the time to be compared against when aging data 
     *     (specified in milliseconds).
     * @param notify  controls whether or not a {@link SeriesChangeEvent} is 
     *                sent to registered listeners IF any items are removed.
     */
    public void removeAgedItems(long latest, boolean notify) {
        
        // find the serial index of the period specified by 'latest'
        long index = Long.MAX_VALUE; 
        try {
            Method m = RegularTimePeriod.class.getDeclaredMethod(
                    "createInstance", new Class[] {Class.class, Date.class, 
                    TimeZone.class});
            RegularTimePeriod newest = (RegularTimePeriod) m.invoke(
                    this.timePeriodClass, new Object[] {this.timePeriodClass,
                            new Date(latest), TimeZone.getDefault()});
            index = newest.getSerialIndex();
        }
        catch (NoSuchMethodException e) {
            e.printStackTrace();
        }
        catch (IllegalAccessException e) {
            e.printStackTrace();
        }
        catch (InvocationTargetException e) {
            e.printStackTrace();
        }
        
        // check if there are any values earlier than specified by the history 
        // count...
        boolean removed = false;
        while (getItemCount() > 0 && (index 
                - getTimePeriod(0).getSerialIndex()) > this.maximumItemAge) {
            this.data.remove(0);
            removed = true;
        }
        if (removed && notify) {
            fireSeriesChanged();
        }
    }

    /**
     * Removes all data items from the series and sends a 
     * {@link SeriesChangeEvent} to all registered listeners.
     */
    public void clear() {
        if (this.data.size() > 0) {
            this.data.clear();
            fireSeriesChanged();
        }
    }

    /**
     * Deletes the data item for the given time period and sends a 
     * {@link SeriesChangeEvent} to all registered listeners.  If there is no
     * item with the specified time period, this method does nothing.
     *
     * @param period  the period of the item to delete (<code>null</code> not 
     *                permitted).
     */
    public void delete(RegularTimePeriod period) {
        int index = getIndex(period);
        if (index >= 0) {
            this.data.remove(index);
            fireSeriesChanged();
        }
    }

    /**
     * Deletes data from start until end index (end inclusive).
     *
     * @param start  the index of the first period to delete.
     * @param end  the index of the last period to delete.
     */
    public void delete(int start, int end) {
        if (end < start) {
            throw new IllegalArgumentException("Requires start <= end.");
        }
        for (int i = 0; i <= (end - start); i++) {
            this.data.remove(start);
        }
        fireSeriesChanged();
    }

    /**
     * Returns a clone of the time series.
     * <P>
     * Notes:
     * <ul>
     *   <li>no need to clone the domain and range descriptions, since String 
     *     object is immutable;</li>
     *   <li>we pass over to the more general method clone(start, end).</li>
     * </ul>
     *
     * @return A clone of the time series.
     * 
     * @throws CloneNotSupportedException not thrown by this class, but 
     *         subclasses may differ.
     */
    public Object clone() throws CloneNotSupportedException {
        Object clone = createCopy(0, getItemCount() - 1);
        return clone;
    }

    /**
     * Creates a new timeseries by copying a subset of the data in this time
     * series.
     *
     * @param start  the index of the first time period to copy.
     * @param end  the index of the last time period to copy.
     *
     * @return A series containing a copy of this times series from start until
     *         end.
     * 
     * @throws CloneNotSupportedException if there is a cloning problem.
     */
    public TimeSeries createCopy(int start, int end) 
        throws CloneNotSupportedException {

        if (start < 0) {
            throw new IllegalArgumentException("Requires start >= 0.");
        }
        if (end < start) {
            throw new IllegalArgumentException("Requires start <= end.");
        }
        TimeSeries copy = (TimeSeries) super.clone();

        copy.data = new java.util.ArrayList();
        if (this.data.size() > 0) {
            for (int index = start; index <= end; index++) {
                TimeSeriesDataItem item 
                    = (TimeSeriesDataItem) this.data.get(index);
                TimeSeriesDataItem clone = (TimeSeriesDataItem) item.clone();
                try {
                    copy.add(clone);
                }
                catch (SeriesException e) {
                    e.printStackTrace();
                }
            }
        }
        return copy;
    }

    /**
     * Creates a new timeseries by copying a subset of the data in this time 
     * series.
     *
     * @param start  the first time period to copy.
     * @param end  the last time period to copy.
     *
     * @return A time series containing a copy of this time series from start 
     *         until end.
     * 
     * @throws CloneNotSupportedException if there is a cloning problem.
     */
    public TimeSeries createCopy(RegularTimePeriod start, RegularTimePeriod end)
        throws CloneNotSupportedException {

        if (start == null) {
            throw new IllegalArgumentException("Null 'start' argument.");
        }
        if (end == null) {
            throw new IllegalArgumentException("Null 'end' argument.");
        }
        if (start.compareTo(end) > 0) {
            throw new IllegalArgumentException(
                    "Requires start on or before end.");
        }
        boolean emptyRange = false;
        int startIndex = getIndex(start);
        if (startIndex < 0) {
            startIndex = -(startIndex + 1);
            if (startIndex == this.data.size()) {
                emptyRange = true;  // start is after last data item
            }
        }
        int endIndex = getIndex(end);
        if (endIndex < 0) {             // end period is not in original series
            endIndex = -(endIndex + 1); // this is first item AFTER end period
            endIndex = endIndex - 1;    // so this is last item BEFORE end 
        }
        if (endIndex < 0) {
            emptyRange = true;
        }
        if (emptyRange) {
            TimeSeries copy = (TimeSeries) super.clone();
            copy.data = new java.util.ArrayList();
            return copy;
        }
        else {
            return createCopy(startIndex, endIndex);
        }

    }

    /**
     * Tests the series for equality with an arbitrary object.
     *
     * @param object  the object to test against (<code>null</code> permitted).
     *
     * @return A boolean.
     */
    public boolean equals(Object object) {
        if (object == this) {
            return true;
        }
        if (!(object instanceof TimeSeries) || !super.equals(object)) {
            return false;
        }
        TimeSeries s = (TimeSeries) object;
        if (!ObjectUtilities.equal(
            getDomainDescription(), s.getDomainDescription()
        )) {
            return false;
        }

        if (!ObjectUtilities.equal(
            getRangeDescription(), s.getRangeDescription()
        )) {
            return false;
        }

        if (!getClass().equals(s.getClass())) {
            return false;
        }

        if (getMaximumItemAge() != s.getMaximumItemAge()) {
            return false;
        }

        if (getMaximumItemCount() != s.getMaximumItemCount()) {
            return false;
        }

        int count = getItemCount();
        if (count != s.getItemCount()) {
            return false;
        }
        for (int i = 0; i < count; i++) {
            if (!getDataItem(i).equals(s.getDataItem(i))) {
                return false;
            }
        }
        return true;
    }

    /**
     * Returns a hash code value for the object.
     *
     * @return The hashcode
     */
    public int hashCode() {
        int result = super.hashCode();
        result = 29 * result + (this.domain != null ? this.domain.hashCode() 
                : 0);
        result = 29 * result + (this.range != null ? this.range.hashCode() : 0);
        result = 29 * result + (this.timePeriodClass != null 
                ? this.timePeriodClass.hashCode() : 0);
        // it is too slow to look at every data item, so let's just look at
        // the first, middle and last items...
        int count = getItemCount();
        if (count > 0) {
            TimeSeriesDataItem item = getDataItem(0);
            result = 29 * result + item.hashCode();
        }
        if (count > 1) {
            TimeSeriesDataItem item = getDataItem(count - 1);
            result = 29 * result + item.hashCode();
        }
        if (count > 2) {
            TimeSeriesDataItem item = getDataItem(count / 2);
            result = 29 * result + item.hashCode();
        }
        result = 29 * result + this.maximumItemCount;
        result = 29 * result + (int) this.maximumItemAge;
        return result;
    }

}