CountDirective.java

/**
 * Copyright (c)2010-2011 Enterprise Website Content Management System(EWCMS), All rights reserved.
 * EWCMS PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 * http://www.ewcms.com
 */

package com.ewcms.publication.freemarker.directive.component;

import java.io.IOException;
import java.util.Map;

//import org.slf4j.Logger;
//import org.slf4j.LoggerFactory;

import com.ewcms.content.document.model.Article;
import com.ewcms.publication.freemarker.FreemarkerUtil;
import com.ewcms.publication.freemarker.GlobalVariable;
import com.ewcms.publication.freemarker.directive.PropertyDirective;

import freemarker.core.Environment;
import freemarker.template.TemplateDirectiveBody;
import freemarker.template.TemplateException;
import freemarker.template.TemplateModel;

/**
 * 当使用callback参数时，elementId参数将失效。
 * 
 * @author wangwei
 */
// TODO 是否可以通过统计分析替代
public class CountDirective extends PropertyDirective {

//	private static final Logger logger = LoggerFactory.getLogger(CountDirective.class);

	private static final String PARAM_ELEMENT_ID_VALUE = "elementId";
	private static final String PARAM_CALLBACK_VALUE = "callback";
	private static final String PARAM_URL_VALUE = "url";
	private static final String DEFAULT_CALLBACK_NAME = "browse_count_callback";
	private static final String DEFAULT_ELEMENT_ID = "browse_count_element_id";
	private static final String DEFAULT_URL = "/component/counter";
	private String elementId;
	private String callback;
	private String url;

	@SuppressWarnings("rawtypes")
	@Override
	public void execute(final Environment env, final Map params, final TemplateModel[] loopVars, final TemplateDirectiveBody body)
			throws TemplateException, IOException {

		elementId = getParamValue(params, PARAM_ELEMENT_ID_VALUE);
		callback = getParamValue(params, PARAM_CALLBACK_VALUE);
		url = getParamValue(params, PARAM_URL_VALUE);
		body.render(env.getOut());
	}

    @SuppressWarnings("rawtypes")
	@Override
    protected String constructOut(Object objectValue,String propertyName,Environment env, Map params)throws TemplateException, NoSuchMethodException{

		StringBuilder builder = new StringBuilder();

		if (elementId == null && callback == null) {
			elementId = DEFAULT_ELEMENT_ID;
			builder.append("<span id='").append(DEFAULT_ELEMENT_ID)
					.append("'></span>");
		}

		if (callback == null) {
			callback = DEFAULT_CALLBACK_NAME;
			builder.append(createDefaultCallBackFunction(elementId));
		}
		
		Article article = (Article) FreemarkerUtil.getBean(env, defaultValueParamValue());
		 
		String src = getSrc(article, callback);
		builder.append("<script type='text/javascript' src='").append(src)
				.append("'>");
		builder.append("</script>");
		return builder.toString();
	}

	private String createDefaultCallBackFunction(final String elementId) {
		StringBuilder builder = new StringBuilder();
		builder.append("<script type=\"text/javascript\">\n");
		builder.append("function ").append(DEFAULT_CALLBACK_NAME)
				.append("(count){\n");
		builder.append("document.getElementById('").append(elementId)
				.append("').innerHTML = count;\n");
		builder.append("}\n");
		builder.append("</script>\n");

		return builder.toString();
	}

	@SuppressWarnings("rawtypes")
	private String getParamValue(final Map params, final String name) throws TemplateException {
		return FreemarkerUtil.getString(params, name);
	}

	private String getSrc(Article articleRmc, final String callback) {
		url = (url == null ? DEFAULT_URL : url);
		int id = articleRmc.getId().intValue();
		return String.format("%s?article_id=%d&callback=%s", url, id, callback);
	}
	
	@Override
    protected String defaultValueParamValue(){
        return GlobalVariable.ARTICLE.toString();
    }
}