org.entirej.framework.plugin.preferences.FieldEditorOverlayPage.java Source code

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/*******************************************************************************
 * Copyright 2013 Mojave Innovations GmbH
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 * 
 * Contributors: Mojave Innovations GmbH - initial API and implementation
 ******************************************************************************/
package org.entirej.framework.plugin.preferences;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.eclipse.core.resources.IResource;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.core.runtime.QualifiedName;
import org.eclipse.jface.preference.FieldEditor;
import org.eclipse.jface.preference.FieldEditorPreferencePage;
import org.eclipse.jface.preference.IPreferenceNode;
import org.eclipse.jface.preference.IPreferencePage;
import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.preference.PreferenceDialog;
import org.eclipse.jface.preference.PreferenceManager;
import org.eclipse.jface.preference.PreferenceNode;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.BusyIndicator;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.ui.IWorkbenchPropertyPage;

public abstract class FieldEditorOverlayPage extends FieldEditorPreferencePage implements IWorkbenchPropertyPage {

    /***
     * Name of resource property for the selection of workbench or project
     * settings
     ***/
    public static final String USEPROJECTSETTINGS = "useProjectSettings"; //$NON-NLS-1$

    private static final String FALSE = "false"; //$NON-NLS-1$
    private static final String TRUE = "true"; //$NON-NLS-1$

    // Stores all created field editors
    private List<FieldEditor> editors = new ArrayList<FieldEditor>();

    // Stores owning element of properties
    private IAdaptable element;

    // Additional buttons for property pages
    private Button useWorkspaceSettingsButton, useProjectSettingsButton, configureButton;

    // Overlay preference store for property pages
    private IPreferenceStore overlayStore;

    // The image descriptor of this pages title image
    private ImageDescriptor image;

    // Cache for page id
    private String pageId;

    protected final boolean supportWorkspaceSettings;

    /**
     * Constructor
     * 
     * @param style
     *            - layout style
     */
    public FieldEditorOverlayPage(int style) {
        this(style, true);
    }

    public FieldEditorOverlayPage(int style, boolean supportWorkspaceSettings) {
        super(style);
        this.supportWorkspaceSettings = supportWorkspaceSettings;
    }

    /**
     * Returns the id of the current preference page as defined in plugin.xml
     * Subclasses must implement.
     * 
     * @return - the qualifier
     */
    protected abstract String getPageId();

    /**
     * Receives the object that owns the properties shown in this property page.
     * 
     * @see org.eclipse.ui.IWorkbenchPropertyPage#setElement(org.eclipse.core.runtime.IAdaptable)
     */
    public void setElement(IAdaptable element) {
        this.element = element;
    }

    /**
     * Delivers the object that owns the properties shown in this property page.
     * 
     * @see org.eclipse.ui.IWorkbenchPropertyPage#getElement()
     */
    public IAdaptable getElement() {
        return element;
    }

    /**
     * Returns true if this instance represents a property page
     * 
     * @return - true for property pages, false for preference pages
     */
    public boolean isPropertyPage() {
        return getElement() != null;
    }

    /**
     * We override the addField method. This allows us to store each field
     * editor added by subclasses in a list for later processing.
     * 
     * @see org.eclipse.jface.preference.FieldEditorPreferencePage#addField(org.eclipse.jface.preference.FieldEditor)
     */
    protected void addField(FieldEditor editor) {
        editors.add(editor);
        super.addField(editor);
    }

    /**
     * We override the createControl method. In case of property pages we create
     * a new PropertyStore as local preference store. After all control have
     * been create, we enable/disable these controls.
     * 
     * @see org.eclipse.jface.preference.PreferencePage#createControl()
     */
    public void createControl(Composite parent) {
        // Special treatment for property pages
        if (isPropertyPage()) {
            // Cache the page id
            pageId = getPageId();
            // Create an overlay preference store and fill it with properties
            overlayStore = new PropertyStore((IResource) getElement(), super.getPreferenceStore(), pageId);
            // Set overlay store as current preference store
        }
        super.createControl(parent);
        // Update state of all subclass controls
        if (isPropertyPage())
            updateFieldEditors();
    }

    /**
     * We override the createContents method. In case of property pages we
     * insert two radio buttons at the top of the page.
     * 
     * @see org.eclipse.jface.preference.PreferencePage#createContents(org.eclipse.swt.widgets.Composite)
     */
    protected Control createContents(Composite parent) {
        if (isPropertyPage())
            createSelectionGroup(parent);
        return super.createContents(parent);
    }

    /**
     * Creates and initializes a selection group with two choice buttons and one
     * push button.
     * 
     * @param parent
     *            - the parent composite
     */
    private void createSelectionGroup(Composite parent) {
        Composite comp = new Composite(parent, SWT.NONE);
        GridLayout layout = new GridLayout(2, false);
        layout.marginHeight = 0;
        layout.marginWidth = 0;
        comp.setLayout(layout);
        comp.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
        if (supportWorkspaceSettings) {
            Composite radioGroup = new Composite(comp, SWT.NONE);
            radioGroup.setLayout(new GridLayout());
            radioGroup.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
            useWorkspaceSettingsButton = createRadioButton(radioGroup,
                    Messages.getString("OverlayPage.Use_Workspace_Settings")); //$NON-NLS-1$
            useProjectSettingsButton = createRadioButton(radioGroup,
                    Messages.getString("OverlayPage.Use_Project_Settings")); //$NON-NLS-1$
            configureButton = new Button(comp, SWT.PUSH);
            configureButton.setText(Messages.getString("OverlayPage.Configure_Workspace_Settings")); //$NON-NLS-1$
            configureButton.addSelectionListener(new SelectionAdapter() {
                public void widgetSelected(SelectionEvent e) {
                    configureWorkspaceSettings();
                }
            });

            // Set workspace/project radio buttons
            try {
                String use = ((IResource) getElement())
                        .getPersistentProperty(new QualifiedName(pageId, USEPROJECTSETTINGS));
                if (TRUE.equals(use)) {
                    useProjectSettingsButton.setSelection(true);
                    configureButton.setEnabled(false);
                } else
                    useWorkspaceSettingsButton.setSelection(true);
            } catch (CoreException e) {
                useWorkspaceSettingsButton.setSelection(true);
            }
        }

    }

    /**
     * Convenience method creating a radio button
     * 
     * @param parent
     *            - the parent composite
     * @param label
     *            - the button label
     * @return - the new button
     */
    private Button createRadioButton(Composite parent, String label) {
        final Button button = new Button(parent, SWT.RADIO);
        button.setText(label);
        button.addSelectionListener(new SelectionAdapter() {
            public void widgetSelected(SelectionEvent e) {
                configureButton.setEnabled(button == useWorkspaceSettingsButton);
                updateFieldEditors();
            }
        });
        return button;
    }

    /**
     * Returns in case of property pages the overlay store, in case of
     * preference pages the standard preference store
     * 
     * @see org.eclipse.jface.preference.PreferencePage#getPreferenceStore()
     */
    public IPreferenceStore getPreferenceStore() {
        if (isPropertyPage())
            return overlayStore;
        return super.getPreferenceStore();
    }

    /*
     * Enables or disables the field editors and buttons of this page
     */
    private void updateFieldEditors() {
        // We iterate through all field editors
        boolean enabled = !supportWorkspaceSettings || useProjectSettingsButton.getSelection();
        updateFieldEditors(enabled);
    }

    /**
     * Enables or disables the field editors and buttons of this page Subclasses
     * may override.
     * 
     * @param enabled
     *            - true if enabled
     */
    protected void updateFieldEditors(boolean enabled) {
        Composite parent = getFieldEditorParent();
        Iterator<FieldEditor> it = editors.iterator();
        while (it.hasNext()) {
            FieldEditor editor = it.next();
            editor.setEnabled(enabled, parent);
        }
    }

    /**
     * We override the performOk method. In case of property pages we copy the
     * values in the overlay store into the property values of the selected
     * project. We also save the state of the radio buttons.
     * 
     * @see org.eclipse.jface.preference.IPreferencePage#performOk()
     */
    public boolean performOk() {
        boolean result = super.performOk();
        if (result && isPropertyPage()) {
            // Save state of radiobuttons in project properties
            IResource resource = (IResource) getElement();
            try {
                String value = (!supportWorkspaceSettings || useProjectSettingsButton.getSelection()) ? TRUE
                        : FALSE;
                resource.setPersistentProperty(new QualifiedName(pageId, USEPROJECTSETTINGS), value);
            } catch (CoreException e) {
            }
        }
        return result;
    }

    /**
     * We override the performDefaults method. In case of property pages we
     * switch back to the workspace settings and disable the field editors.
     * 
     * @see org.eclipse.jface.preference.PreferencePage#performDefaults()
     */
    protected void performDefaults() {
        if (isPropertyPage()) {
            if (supportWorkspaceSettings) {
                useWorkspaceSettingsButton.setSelection(true);
                useProjectSettingsButton.setSelection(false);
                configureButton.setEnabled(true);
            }
            updateFieldEditors();
        }
        super.performDefaults();
    }

    /**
     * Creates a new preferences page and opens it
     */
    protected void configureWorkspaceSettings() {
        try {
            // create a new instance of the current class
            IPreferencePage page = (IPreferencePage) this.getClass().newInstance();
            page.setTitle(getTitle());
            page.setImageDescriptor(image);
            // and show it
            showPreferencePage(pageId, page);
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
    }

    /**
     * Show a single preference pages
     * 
     * @param id
     *            - the preference page identification
     * @param page
     *            - the preference page
     */
    protected void showPreferencePage(String id, IPreferencePage page) {
        final IPreferenceNode targetNode = new PreferenceNode(id, page);
        PreferenceManager manager = new PreferenceManager();
        manager.addToRoot(targetNode);
        final PreferenceDialog dialog = new PreferenceDialog(getControl().getShell(), manager);
        BusyIndicator.showWhile(getControl().getDisplay(), new Runnable() {
            public void run() {
                dialog.create();
                dialog.setMessage(targetNode.getLabelText());
                dialog.open();
            }
        });
    }

}