org.apache.myfaces.custom.graphicimagedynamic.util.GraphicsImageDynamicHelper.java Source code

Introduction

Here is the source code for org.apache.myfaces.custom.graphicimagedynamic.util.GraphicsImageDynamicHelper.java

Source

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.myfaces.custom.graphicimagedynamic.util;

import java.util.Map;

import javax.faces.FacesException;
import javax.faces.context.ExternalContext;
import javax.faces.context.FacesContext;

import org.apache.commons.logging.Log;
import org.apache.myfaces.custom.graphicimagedynamic.GraphicImageDynamic;
import org.apache.myfaces.shared_tomahawk.util.ClassUtils;

/**
 * This class is a utility class used by the 
 * GraphicsImageDynamic component.
 */
public class GraphicsImageDynamicHelper {

    /**
     * This method is used for getting the ImageRenderer
     * from the image render class.
     * @param imageRendererClassName
     * @return the image renderer
     */
    public static ImageRenderer getImageRendererFromClassName(String imageRendererClassName) {
        ImageRenderer imageRenderer;
        try {
            Class rendererClass = ClassUtils.classForName(imageRendererClassName);
            if (!ImageRenderer.class.isAssignableFrom(rendererClass)) {
                throw new FacesException("Image renderer class [" + imageRendererClassName + "] does not implement "
                        + ImageRenderer.class.getName());
            }
            try {
                imageRenderer = (ImageRenderer) rendererClass.newInstance();
            } catch (InstantiationException e) {
                throw new FacesException("could not instantiate image renderer class " + imageRendererClassName
                        + " : " + e.getMessage(), e);
            } catch (IllegalAccessException e) {
                throw new FacesException("could not instantiate image renderer class " + imageRendererClassName
                        + " : " + e.getMessage(), e);
            }
        } catch (ClassNotFoundException e) {
            throw new FacesException("image renderer class not found: " + e.getMessage(), e);
        }
        return imageRenderer;
    }

    /**
     * This method gets the image renderer from the ValueBinding.
     * @param facesContext
     * @param rendererValueBinding
     * @return the ImageRenderer.
     */
    public static ImageRenderer getImageRendererFromValueBinding(FacesContext facesContext,
            String rendererValueBinding) {
        return (ImageRenderer) facesContext.getApplication().createValueBinding(rendererValueBinding)
                .getValue(facesContext);
    }

    /**
     * This method is used for creating the image context.
     * @param facesContext
     * @return the imageContext.
     */
    public static ImageContext createImageContext(FacesContext facesContext, Log log) {

        ExternalContext externalContext = facesContext.getExternalContext();
        final Map requestMap = externalContext.getRequestParameterMap();
        Object value = requestMap.get(GraphicImageDynamic.WIDTH_PARAM);
        Integer height = null;
        Integer width = null;

        if (value != null) {
            try {
                width = Integer.valueOf(value.toString());
            } catch (NumberFormatException e) {
                log.error("Invalid value for image width : " + value + ", " + e.getMessage(), e);
            }
        }

        value = requestMap.get(GraphicImageDynamic.HEIGHT_PARAM);
        if (value != null) {
            try {
                height = Integer.valueOf(value.toString());
            } catch (NumberFormatException e) {
                log.error("Invalid value for image height : " + value + ", " + e.getMessage(), e);
            }
        }

        return new SimpleImageContext(requestMap, width, height);
    }
}