org.springframework.ui.context.support.UiApplicationContextUtils.java Source code

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Here is the source code for org.springframework.ui.context.support.UiApplicationContextUtils.java

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/*
 * Copyright 2002-2012 the original author or authors.
 *
 * 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.
 */

package org.springframework.ui.context.support;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.context.ApplicationContext;
import org.springframework.ui.context.HierarchicalThemeSource;
import org.springframework.ui.context.ThemeSource;

/**
 * Utility class for UI application context implementations.
 * Provides support for a special bean named "themeSource",
 * of type {@link org.springframework.ui.context.ThemeSource}.
 *
 * @author Jean-Pierre Pawlak
 * @author Juergen Hoeller
 * @since 17.06.2003
 */
public abstract class UiApplicationContextUtils {

    /**
     * Name of the ThemeSource bean in the factory.
     * If none is supplied, theme resolution is delegated to the parent.
     * @see org.springframework.ui.context.ThemeSource
     */
    public static final String THEME_SOURCE_BEAN_NAME = "themeSource";

    private static final Log logger = LogFactory.getLog(UiApplicationContextUtils.class);

    /**
     * Initialize the ThemeSource for the given application context,
     * autodetecting a bean with the name "themeSource". If no such
     * bean is found, a default (empty) ThemeSource will be used.
     * @param context current application context
     * @return the initialized theme source (will never be {@code null})
     * @see #THEME_SOURCE_BEAN_NAME
     */
    public static ThemeSource initThemeSource(ApplicationContext context) {
        if (context.containsLocalBean(THEME_SOURCE_BEAN_NAME)) {
            ThemeSource themeSource = context.getBean(THEME_SOURCE_BEAN_NAME, ThemeSource.class);
            // Make ThemeSource aware of parent ThemeSource.
            if (context.getParent() instanceof ThemeSource && themeSource instanceof HierarchicalThemeSource) {
                HierarchicalThemeSource hts = (HierarchicalThemeSource) themeSource;
                if (hts.getParentThemeSource() == null) {
                    // Only set parent context as parent ThemeSource if no parent ThemeSource
                    // registered already.
                    hts.setParentThemeSource((ThemeSource) context.getParent());
                }
            }
            if (logger.isDebugEnabled()) {
                logger.debug("Using ThemeSource [" + themeSource + "]");
            }
            return themeSource;
        } else {
            // Use default ThemeSource to be able to accept getTheme calls, either
            // delegating to parent context's default or to local ResourceBundleThemeSource.
            HierarchicalThemeSource themeSource = null;
            if (context.getParent() instanceof ThemeSource) {
                themeSource = new DelegatingThemeSource();
                themeSource.setParentThemeSource((ThemeSource) context.getParent());
            } else {
                themeSource = new ResourceBundleThemeSource();
            }
            if (logger.isDebugEnabled()) {
                logger.debug("Unable to locate ThemeSource with name '" + THEME_SOURCE_BEAN_NAME
                        + "': using default [" + themeSource + "]");
            }
            return themeSource;
        }
    }

}