001// License: GPL. For details, see LICENSE file.
002package org.openstreetmap.josm.gui.widgets;
003
004import java.util.ArrayList;
005import java.util.Iterator;
006import java.util.List;
007
008import javax.swing.DefaultComboBoxModel;
009
010import org.openstreetmap.josm.gui.tagging.ac.AutoCompletionListItem;
011
012public class ComboBoxHistory extends DefaultComboBoxModel<AutoCompletionListItem> implements Iterable<AutoCompletionListItem> {
013
014    private int maxSize = 10;
015
016    private List<HistoryChangedListener> listeners = new ArrayList<>();
017
018    public ComboBoxHistory(int size) {
019        maxSize = size;
020    }
021
022    public void addElement(String s) {
023        addElement(new AutoCompletionListItem(s));
024    }
025
026    /**
027     * Adds or moves an element to the top of the history
028     */
029    @Override
030    public void addElement(AutoCompletionListItem o) {
031        String newEntry = o.getValue();
032
033        // if history contains this object already, delete it,
034        // so that it looks like a move to the top
035        for (int i = 0; i < getSize(); i++) {
036            String oldEntry = getElementAt(i).getValue();
037            if(oldEntry.equals(newEntry)) {
038                removeElementAt(i);
039            }
040        }
041
042        // insert element at the top
043        insertElementAt(o, 0);
044
045        // remove an element, if the history gets too large
046        if(getSize()> maxSize) {
047            removeElementAt(getSize()-1);
048        }
049
050        // set selected item to the one just added
051        setSelectedItem(o);
052
053        fireHistoryChanged();
054    }
055
056    @Override
057    public Iterator<AutoCompletionListItem> iterator() {
058        return new Iterator<AutoCompletionListItem>() {
059
060            private int position = -1;
061
062            @Override
063            public void remove() {
064                removeElementAt(position);
065            }
066
067            @Override
068            public boolean hasNext() {
069                if(position < getSize()-1 && getSize()>0)
070                    return true;
071                return false;
072            }
073
074            @Override
075            public AutoCompletionListItem next() {
076                position++;
077                return getElementAt(position);
078            }
079        };
080    }
081
082    public void setItemsAsString(List<String> items) {
083        removeAllElements();
084        for (int i = items.size()-1; i>=0; i--) {
085            addElement(new AutoCompletionListItem(items.get(i)));
086        }
087    }
088
089    public List<String> asStringList() {
090        List<String> list = new ArrayList<>(maxSize);
091        for (AutoCompletionListItem item : this) {
092            list.add(item.getValue());
093        }
094        return list;
095    }
096
097    public void addHistoryChangedListener(HistoryChangedListener l) {
098        listeners.add(l);
099    }
100
101    public void removeHistoryChangedListener(HistoryChangedListener l) {
102        listeners.remove(l);
103    }
104
105    private void fireHistoryChanged() {
106        for (HistoryChangedListener l : listeners) {
107            l.historyChanged(asStringList());
108        }
109    }
110}