de.metas.procurement.webui.ui.component.MFNavigator.java Source code

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Here is the source code for de.metas.procurement.webui.ui.component.MFNavigator.java

Source

package de.metas.procurement.webui.ui.component;

import java.util.HashSet;
import java.util.Set;

import com.google.gwt.thirdparty.guava.common.base.Objects;
import com.google.gwt.thirdparty.guava.common.base.Preconditions;
import com.google.gwt.thirdparty.guava.common.base.Supplier;
import com.vaadin.navigator.Navigator;
import com.vaadin.navigator.View;
import com.vaadin.navigator.ViewChangeListener;
import com.vaadin.navigator.ViewChangeListener.ViewChangeEvent;
import com.vaadin.server.Page;
import com.vaadin.ui.Notification;
import com.vaadin.ui.UI;

/*
 * #%L
 * de.metas.procurement.webui
 * %%
 * Copyright (C) 2016 metas GmbH
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as
 * published by the Free Software Foundation, either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program 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 for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program.  If not, see
 * <http://www.gnu.org/licenses/gpl-2.0.html>.
 * #L%
 */

@SuppressWarnings("serial")
public class MFNavigator extends Navigator {
    public static final MFNavigator createAndBind(final UI ui) {
        return new MFNavigator(ui);
    }

    public static final MFNavigator cast(final Navigator navigator) {
        return (MFNavigator) navigator;
    }

    public static final String createURIFragment(final String viewName) {
        final String parameters = null;
        return createURIFragment(viewName, parameters);
    }

    public static final String createURIFragment(final String viewName, final String parameters) {
        final StringBuilder uriFragment = new StringBuilder();
        uriFragment.append("!");
        if (viewName != null) {
            uriFragment.append(viewName.trim());
        }

        if (parameters != null && !parameters.trim().isEmpty()) {
            uriFragment.append("/").append(parameters.trim());
        }
        return uriFragment.toString();
    }

    /** Default view name to be used with {@link com.vaadin.navigator.View} */
    public static final String VIEWNAME_DEFAULT = "";
    /** Default login view name */
    public static final String VIEWNAME_DEFAULT_LOGIN = "login";

    private String loginViewName;
    private Supplier<Boolean> isLoggedInSupplier;

    private final Set<String> noLoginRequiredViewNames = new HashSet<>();

    private Notification nextViewNotification;

    private MFNavigator(final UI ui) {
        super(ui, ui);

        addViewChangeListener(new ViewChangeListener() {

            @Override
            public boolean beforeViewChange(final ViewChangeEvent event) {
                return checkLoggedInAndRedirect(event);
            }

            @Override
            public void afterViewChange(final ViewChangeEvent event) {
                showNextViewNotification();
            }
        });

    }

    public MFNavigator setLoginView(final String loginViewName, final Class<? extends View> loginViewClass,
            final Supplier<Boolean> isLoggedInSupplier) {
        Preconditions.checkNotNull(loginViewName, "loginViewName is null");
        Preconditions.checkArgument(!Objects.equal(VIEWNAME_DEFAULT, loginViewClass),
                "loginViewName cannot be the default view");
        Preconditions.checkNotNull(isLoggedInSupplier, "isLoggedInSupplier is null");
        Preconditions.checkNotNull(loginViewClass, "loginViewClass is null");

        this.loginViewName = loginViewName;
        this.isLoggedInSupplier = isLoggedInSupplier;

        addView(loginViewName, loginViewClass);

        return this;
    }

    public MFNavigator setLoginView(final Class<? extends View> loginViewClass,
            final Supplier<Boolean> isLoggedInSupplier) {
        return setLoginView(VIEWNAME_DEFAULT_LOGIN, loginViewClass, isLoggedInSupplier);
    }

    public MFNavigator setView(final String viewName, final Class<? extends View> viewClass) {
        addView(viewName, viewClass);
        return this;
    }

    public MFNavigator setViewNoLoginRequired(final String viewName, final Class<? extends View> viewClass) {
        addView(viewName, viewClass);
        noLoginRequiredViewNames.add(viewName);
        return this;
    }

    public MFNavigator setDefaultView(final Class<? extends View> viewClass) {
        setView(VIEWNAME_DEFAULT, viewClass);
        return this;
    }

    public MFNavigator navigateToDefaultView() {
        navigateTo(VIEWNAME_DEFAULT);
        return this;
    }

    public MFNavigator navigateToLoginView() {
        Preconditions.checkNotNull(loginViewName, "loginViewName is set");
        navigateTo(loginViewName);
        return this;
    }

    private final boolean checkLoggedInAndRedirect(final ViewChangeEvent event) {
        // If no login view was configured then we don't need the login functionality,
        // so allow the navigation to go on.
        if (loginViewName == null) {
            return true;
        }

        final String viewName = event.getViewName();

        // Check if a user has logged in
        final boolean isLoggedIn = isLoggedIn();
        final boolean isLoginView = loginViewName.equals(viewName);

        if (!isLoggedIn && !isLoginView) {
            if (!isLoginRequired(viewName)) {
                return true;
            }

            // Redirect to login view always if a user has not yet logged in
            navigateTo(loginViewName);
            return false;

        } else if (isLoggedIn && isLoginView) {
            // If someone tries to access to login view while logged in, then cancel
            return false;
        }

        return true;
    }

    private boolean isLoggedIn() {
        if (isLoggedInSupplier == null) {
            return false;
        }
        final Boolean loggedIn = isLoggedInSupplier.get();
        return loggedIn != null && loggedIn;
    }

    private boolean isLoginRequired(final String viewName) {
        if (noLoginRequiredViewNames.contains(viewName)) {
            return false;
        }
        return true;
    }

    public MFNavigator setNextViewNotification(final Notification notification) {
        this.nextViewNotification = notification;
        return this;
    }

    private final void showNextViewNotification() {
        final Notification notification = this.nextViewNotification;
        this.nextViewNotification = null;

        if (notification == null) {
            return;
        }

        notification.show(Page.getCurrent());
    }

}