net.bpelunit.framework.client.eclipse.preferences.ComboFieldEditor.java Source code

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Here is the source code for net.bpelunit.framework.client.eclipse.preferences.ComboFieldEditor.java

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/**
 * This file belongs to the BPELUnit utility and Eclipse plugin set. See enclosed
 * license file for more information.
 * 
 */
package net.bpelunit.framework.client.eclipse.preferences;

import org.eclipse.jface.preference.FieldEditor;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.widgets.Combo;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;

/**
 * A field editor for a combo box that allows the drop-down selection of one of a list of items.
 * 
 * Taken from org.eclipse.jdt.internal.debug.ui.launcher.ComboFieldEditor and extended to allow
 * external reactions to selections.
 * 
 * @version $Id$
 * @author Philip Mayer
 */
public class ComboFieldEditor extends FieldEditor {

    /**
     * The Combo widget.
     */
    private Combo fCombo;

    /**
     * The value (not the name) of the currently selected item in the Combo widget.
     */
    private String fValue;

    /**
     * The names (labels) and underlying values to populate the combo widget. These should be
     * arranged as: { {name1, value1}, {name2, value2}, ...}
     */
    private String[][] fEntryNamesAndValues;

    public ComboFieldEditor(String name, String labelText, String[][] entryNamesAndValues, Composite parent) {
        init(name, labelText);
        fEntryNamesAndValues = entryNamesAndValues;
        createControl(parent);
    }

    /**
     * @see FieldEditor#adjustForNumColumns(int)
     */
    @Override
    protected void adjustForNumColumns(int numColumns) {
        if (numColumns > 1) {
            Control control = getLabelControl();
            int left = numColumns;
            if (control != null) {
                ((GridData) control.getLayoutData()).horizontalSpan = 1;
                left = left - 1;
            }
            ((GridData) fCombo.getLayoutData()).horizontalSpan = left;
        } else {
            Control control = getLabelControl();
            if (control != null) {
                ((GridData) control.getLayoutData()).horizontalSpan = 1;
            }
            ((GridData) fCombo.getLayoutData()).horizontalSpan = 1;
        }
    }

    /**
     * @see FieldEditor#doFillIntoGrid(Composite, int)
     */
    @Override
    protected void doFillIntoGrid(Composite parent, int numColumns) {
        int comboC = 1;
        if (numColumns > 1) {
            comboC = numColumns - 1;
        }
        Control control = getLabelControl(parent);
        GridData gd = new GridData();
        gd.horizontalSpan = 1;
        control.setLayoutData(gd);
        control = getComboBoxControl(parent);
        gd = new GridData();
        gd.horizontalSpan = comboC;
        gd.horizontalAlignment = GridData.FILL;
        control.setLayoutData(gd);
        control.setFont(parent.getFont());
    }

    /**
     * @see FieldEditor#doLoad()
     */
    @Override
    protected void doLoad() {
        updateComboForValue(getPreferenceStore().getString(getPreferenceName()));
    }

    /**
     * @see FieldEditor#doLoadDefault()
     */
    @Override
    protected void doLoadDefault() {
        updateComboForValue(getPreferenceStore().getDefaultString(getPreferenceName()));
    }

    /**
     * @see FieldEditor#doStore()
     */
    @Override
    protected void doStore() {
        if (fValue == null) {
            getPreferenceStore().setToDefault(getPreferenceName());
            return;
        }

        getPreferenceStore().setValue(getPreferenceName(), fValue);
    }

    /**
     * @see FieldEditor#getNumberOfControls()
     */
    @Override
    public int getNumberOfControls() {
        return 1;
    }

    /**
     * Lazily create and return the Combo control.
     */
    public Combo getComboBoxControl(Composite parent) {
        if (fCombo == null) {
            fCombo = new Combo(parent, SWT.READ_ONLY);
            fCombo.setFont(parent.getFont());
            for (int i = 0; i < fEntryNamesAndValues.length; i++) {
                fCombo.add(fEntryNamesAndValues[i][0], i);
            }

            fCombo.addSelectionListener(new SelectionAdapter() {
                @Override
                public void widgetSelected(SelectionEvent evt) {
                    String oldValue = fValue;
                    String name = fCombo.getText();
                    fValue = getValueForName(name);
                    setPresentsDefaultValue(false);
                    fireValueChanged(VALUE, oldValue, fValue);
                }
            });
        }
        return fCombo;
    }

    /**
     * Given the name (label) of an entry, return the corresponding value.
     */
    protected String getValueForName(String name) {
        for (String[] entry : fEntryNamesAndValues) {
            if (name.equals(entry[0])) {
                return entry[1];
            }
        }
        return fEntryNamesAndValues[0][0];
    }

    /**
     * Set the name in the combo widget to match the specified value.
     */
    protected void updateComboForValue(String value) {
        fValue = value;
        for (String[] element : fEntryNamesAndValues) {
            if (value.equals(element[1])) {
                fCombo.setText(element[0]);
                return;
            }
        }
        if (fEntryNamesAndValues.length > 0) {
            fValue = fEntryNamesAndValues[0][1];
        }
    }

    public String getCurrentSelectionString() {
        return fValue;
    }
}