Env.java

/**
 * Copyright (c) 2011-2017, James Zhan 詹波 (jfinal@126.com).
 *
 * 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 com.jfinal.template;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import com.jfinal.template.stat.Location;
import com.jfinal.template.stat.ParseException;
import com.jfinal.template.stat.ast.Define;

/**
 * Env
 * 
 * 1：解析时存放 #define 定义的模板函数
 * 2：运行时提供 #define 定义的模板函数
 * 3：每个 Template 对象持有一个 Env 对象
 */
public class Env {
	
	protected EngineConfig engineConfig;
	protected Map<String, Define> functionMap = new HashMap<String, Define>();
	
	// 代替 Template 持有该属性，便于在 #include 指令中调用 Env.addStringSource()
	protected List<IStringSource> stringSourceList = null;
	
	public Env(EngineConfig engineConfig) {
		this.engineConfig = engineConfig;
	}
	
	public EngineConfig getEngineConfig() {
		return engineConfig;
	}
	
	/**
	 * Add template function
	 */
	public void addFunction(Define function) {
		String fn = function.getFunctionName();
		if (functionMap.containsKey(fn)) {
			Define previous = functionMap.get(fn);
			throw new ParseException(
				"Template function \"" + fn + "\" already defined in " + 
				getAlreadyDefinedLocation(previous.getLocation()),
				function.getLocation()
			);
		}
		functionMap.put(fn, function);
	}
	
	private String getAlreadyDefinedLocation(Location loc) {
		StringBuilder buf = new StringBuilder();
		if (loc.getTemplateFile() != null) {
			buf.append(loc.getTemplateFile()).append(", line ").append(loc.getRow());
		} else {
			buf.append("string template line ").append(loc.getRow());
		}
		return buf.toString();
	}
	
	/**
	 * Get function of current template first, getting shared function if null before
	 */
	public Define getFunction(String functionName) {
		Define func = functionMap.get(functionName);
		return func != null ? func : engineConfig.getSharedFunction(functionName);
	}
	
	/**
	 * For EngineConfig.addSharedFunction(...) only
	 */
	Map<String, Define> getFunctionMap() {
		return functionMap;
	}
	
	/**
	 * 本方法用于在 devMode 之下，判断当前 Template 以及其下 #include 指令
	 * 所涉及的所有 IStringSource 对象是否被修改，以便于在 devMode 下重新加载
	 * 
	 * stringSourceList 属性用于存放主模板以及 #include 进来的模板所对应的
	 * IStringSource 对象
	 */
	public boolean isStringSourceListModified() {
		if (stringSourceList != null) {
			for (int i = 0, size = stringSourceList.size(); i < size; i++) {
				if (stringSourceList.get(i).isModified()) {
					return true;
				}
			}
		}
		return false;
	}
	
	/**
	 * 添加本 Template 的 IStringSource，以及该 Template 使用 include 包含进来的所有 IStringSource
	 * 以便于在 devMode 之下判断该 Template 是否被 modified，进而 reload 该 Template
	 */
	public void addStringSource(IStringSource stringSource) {
		if (stringSourceList == null) {
			stringSourceList = new ArrayList<IStringSource>();
		}
		stringSourceList.add(stringSource);
	}
}