/*

 * Copyright 1998-2003 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package javax.swing.text;

import java.io.Serializable;

/**

 * A TabSet is comprised of many TabStops. It offers methods for locating the

 * closest TabStop to a given position and finding all the potential TabStops.

 * It is also immutable.

 * <p>

 * <strong>Warning:</strong>

 * Serialized objects of this class will not be compatible with

 * future Swing releases. The current serialization support is

 * appropriate for short term storage or RMI between applications running

 * the same version of Swing.  As of 1.4, support for long term storage

 * of all JavaBeans<sup><font size="-2">TM</font></sup>

 * has been added to the <code>java.beans</code> package.

 * Please see {@link java.beans.XMLEncoder}.

 *

 * @author  Scott Violet

 */

public class TabSet implements Serializable

{

    /** TabStops this TabSet contains. */

    private TabStop[]              tabs;

    /**

     * Since this class is immutable the hash code could be

     * calculated once. MAX_VALUE means that it was not initialized

     * yet. Hash code shouldn't has MAX_VALUE value.

     */

    private int hashCode = Integer.MAX_VALUE;

    /**

     * Creates and returns an instance of TabSet. The array of Tabs

     * passed in must be sorted in ascending order.

     */

    public TabSet(TabStop[] tabs) {

        // PENDING(sky): If this becomes a problem, make it sort.

        if(tabs != null) {

            int          tabCount = tabs.length;

            this.tabs = new TabStop[tabCount];

            System.arraycopy(tabs, 0, this.tabs, 0, tabCount);

        }

        else

            this.tabs = null;

    }

    /**

     * Returns the number of Tab instances the receiver contains.

     */

    public int getTabCount() {

        return (tabs == null) ? 0 : tabs.length;

    }

    /**

     * Returns the TabStop at index <code>index</code>. This will throw an

     * IllegalArgumentException if <code>index</code> is outside the range

     * of tabs.

     */

    public TabStop getTab(int index) {

        int          numTabs = getTabCount();

        if(index < 0 || index >= numTabs)

            throw new IllegalArgumentException(index +

                                              " is outside the range of tabs");

        return tabs[index];

    }

    /**

     * Returns the Tab instance after <code>location</code>. This will

     * return null if there are no tabs after <code>location</code>.

     */

    public TabStop getTabAfter(float location) {

        int     index = getTabIndexAfter(location);

        return (index == -1) ? null : tabs[index];

    }

    /**

     * @return the index of the TabStop <code>tab</code>, or -1 if

     * <code>tab</code> is not contained in the receiver.

     */

    public int getTabIndex(TabStop tab) {

        for(int counter = getTabCount() - 1; counter >= 0; counter--)

            // should this use .equals?

            if(getTab(counter) == tab)

                return counter;

        return -1;

    }

    /**

     * Returns the index of the Tab to be used after <code>location</code>.

     * This will return -1 if there are no tabs after <code>location</code>.

     */

    public int getTabIndexAfter(float location) {

        int     current, min, max;

        min = 0;

        max = getTabCount();

        while(min != max) {

            current = (max - min) / 2 + min;

            if(location > tabs[current].getPosition()) {

                if(min == current)

                    min = max;

                else

                    min = current;

            }

            else {

                if(current == 0 || location > tabs[current - 1].getPosition())

                    return current;

                max = current;

            }

        }

        // no tabs after the passed in location.

        return -1;

    }

    /**

     * Indicates whether this <code>TabSet</code> is equal to another one.

     * @param o the <code>TabSet</code> instance which this instance

     *  should be compared to.

     * @return <code>true</code> if <code>o</code> is the instance of

     * <code>TabSet</code>, has the same number of <code>TabStop</code>s

     * and they are all equal, <code>false</code> otherwise.

     *

     * @since 1.5

     */

    public boolean equals(Object o) {

        if (o == this) {

            return true;

        }

        if (o instanceof TabSet) {

            TabSet ts = (TabSet) o;

            int count = getTabCount();

            if (ts.getTabCount() != count) {

                return false;

            }

            for (int i=0; i < count; i++) {

                TabStop ts1 = getTab(i);

                TabStop ts2 = ts.getTab(i);

                if ((ts1 == null && ts2 != null) ||

                        (ts1 != null && !getTab(i).equals(ts.getTab(i)))) {

                    return false;

                }

            }

            return true;

        }

        return false;

    }

    /**

     * Returns a hashcode for this set of TabStops.

     * @return  a hashcode value for this set of TabStops.

     *

     * @since 1.5

     */

    public int hashCode() {

        if (hashCode == Integer.MAX_VALUE) {

            hashCode = 0;

            int len = getTabCount();

            for (int i = 0; i < len; i++) {

                TabStop ts = getTab(i);

                hashCode ^= ts != null ? getTab(i).hashCode() : 0;

            }

            if (hashCode == Integer.MAX_VALUE) {

                hashCode -= 1;

            }

        }

        return hashCode;

    }

    /**

     * Returns the string representation of the set of tabs.

     */

    public String toString() {

        int            tabCount = getTabCount();

        StringBuffer   buffer = new StringBuffer("[ ");

        for(int counter = 0; counter < tabCount; counter++) {

            if(counter > 0)

                buffer.append(" - ");

            buffer.append(getTab(counter).toString());

        }

        buffer.append(" ]");

        return buffer.toString();

    }

}