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the jfinal enjoy plugin for normal java program to use sql management function.
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/**
 * Copyright (c) 2011-2017, James Zhan 詹波 ([email protected]).
 *
 * 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.io.OutputStream;
import java.io.Writer;
import java.util.Map;

import com.jfinal.template.io.ByteWriter;
import com.jfinal.template.io.CharWriter;
import com.jfinal.template.io.FastStringWriter;
import com.jfinal.template.stat.Scope;
import com.jfinal.template.stat.ast.Stat;

/**
 * Template
 * 
 * 用法：
 * Template template = Engine.use().getTemplate(...);
 * template.render(data, writer);
 * template.renderToString(data);
 */
public class Template {
	
	private Env env;
	private Stat ast;
	
	public Template(Env env, Stat ast) {
		if (env == null || ast == null) {
			throw new IllegalArgumentException("env and ast can not be null");
		}
		this.env = env;
		this.ast = ast;
	}
	
	/**
	 * 渲染到 OutputStream 中去
	 */
	public void render(Map data, OutputStream outputStream) {
		ByteWriter byteWriter = env.engineConfig.writerBuffer.getByteWriter(outputStream);
		try {
			ast.exec(env, new Scope(data, env.engineConfig.sharedObjectMap), byteWriter);
		} finally {
			byteWriter.close();
		}
	}
	
	/**
	 * 支持无 data 参数，渲染到 OutputStream 中去 

	 * 适用于数据在模板中通过表达式和语句直接计算得出等等应用场景
	 */
	public void render(OutputStream outputStream) {
		render(null, outputStream);
	}
	
	/**
	 * 渲染到 Writer 中去
	 */
	public void render(Map data, Writer writer) {
		CharWriter charWriter = env.engineConfig.writerBuffer.getCharWriter(writer);
		try {
			ast.exec(env, new Scope(data, env.engineConfig.sharedObjectMap), charWriter);
		} finally {
			charWriter.close();
		}
	}
	
	/**
	 * 支持无 data 参数，渲染到 Writer 中去 

	 * 适用于数据在模板中通过表达式和语句直接计算得出等等应用场景
	 */
	public void render(Writer writer) {
		render(null, writer);
	}
	
	/**
	 * 渲染到 String 中去
	 */
	public String renderToString(Map data) {
		FastStringWriter fsw = env.engineConfig.writerBuffer.getFastStringWriter();
		try {
			render(data, fsw);
			return fsw.toString();
		} finally {
			fsw.close();
		}
	}
	
	/**
	 * 渲染到 StringBuilder 中去
	 */
	public StringBuilder renderToStringBuilder(Map data) {
		FastStringWriter fsw = new FastStringWriter();
		render(data, fsw);
		return fsw.getBuffer();
	}
	
	public boolean isModified() {
		return env.isSourceListModified();
	}
}