generator.java

velocity官方工具包 包括各种JAR包 示例 文档等

package org.apache.velocity.texen;

/*
 * 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.    
 */

import java.io.File;
import java.io.InputStream;
import java.io.FileInputStream;
import java.io.BufferedInputStream;
import java.io.Writer;
import java.io.FileWriter;
import java.io.IOException;
import java.io.StringWriter;
import java.io.OutputStreamWriter;
import java.io.BufferedWriter;
import java.io.FileOutputStream;

import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.Properties;

import org.apache.velocity.Template;
import org.apache.velocity.context.Context;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.VelocityEngine;
import org.apache.velocity.util.ClassUtils;

/**
 * A text/code generator class
 *
 * @author <a href="mailto:[e-mail]">Leon Messerschmidt</a>
 * @author <a href="mailto:[e-mail]">Jason van Zyl</a>
 * @version $Id: Generator.java 463298 2006-10-12 16:10:32Z henning $
 */
public class Generator
{
    /**
     * Where the texen output will placed.
     */
    public static final String OUTPUT_PATH = "output.path";

    /**
     * Where the velocity templates live.
     */
    public static final String TEMPLATE_PATH = "template.path";

    /**
     * Default properties file used for controlling the
     * tools placed in the context.
     */
    private static final String DEFAULT_TEXEN_PROPERTIES =
        "org/apache/velocity/texen/defaults/texen.properties";

    /**
     * Default properties used by texen.
     */
    private Properties props = new Properties();

    /**
     * Context used for generating the texen output.
     */
    private Context controlContext;

    /**
     * Keep track of the file writers used for outputting
     * to files. If we come across a file writer more
     * then once then the additional output will be
     * appended to the file instead of overwritting
     * the contents.
     */
    private Hashtable writers = new Hashtable();

    /**
     * The generator tools used for creating additional
     * output withing the control template. This could
     * use some cleaning up.
     */
    private static Generator instance = new Generator();

    /**
     * This is the encoding for the output file(s).
     */
    protected String outputEncoding;

    /**
     * This is the encoding for the input file(s)
     * (templates).
     */
    protected String inputEncoding;

    /**
     * Velocity engine.
     */
    protected VelocityEngine ve;

    /**
     * Default constructor.
     */
    private Generator()
    {
        setDefaultProps();
    }

    /**
     * Create a new generator object with default properties.
     *
     * @return Generator generator used in the control context.
     */
    public static Generator getInstance()
    {
        return instance;
    }

    /**
     * Set the velocity engine.
     * @param ve
     */
    public void setVelocityEngine(VelocityEngine ve)
    {
        this.ve = ve;
    }

    /**
     * Create a new generator object with properties loaded from
     * a file.  If the file does not exist or any other exception
     * occurs during the reading operation the default properties
     * are used.
     *
     * @param propFile properties used to help populate the control context.
     */
    public Generator (String propFile)
    {
        try
        {
            BufferedInputStream bi = null;
            try
            {
                bi = new BufferedInputStream (new FileInputStream (propFile));
                props.load (bi);
            }
            finally
            {
                if (bi != null)
                {
                    bi.close();
                }
            }
        }
        catch (IOException e)
        {
            System.err.println("Could not load " + propFile
                    + ", falling back to defaults. ("
                    + e.getMessage() + ")");
            /*
             * If something goes wrong we use default properties
             */
            setDefaultProps();
        }
    }

    /**
     * Create a new Generator object with a given property
     * set. The property set will be duplicated.
     *
     * @param props properties object to help populate the control context.
     */
    public Generator (Properties props)
    {
        this.props = (Properties)props.clone();
    }

    /**
     * Set default properties.
     */
    protected void setDefaultProps()
    {
        ClassLoader classLoader = VelocityEngine.class.getClassLoader();
        try
        {
            InputStream inputStream = null;
            try
            {
                inputStream = classLoader.getResourceAsStream(
                    DEFAULT_TEXEN_PROPERTIES);

                props.load( inputStream );
            }
            finally
            {
                if (inputStream != null)
                {
                    inputStream.close();
                }
            }
        }
        catch (IOException ioe)
        {
            System.err.println("Cannot get default properties: " + ioe.getMessage());
        }
    }

    /**
     * Set the template path, where Texen will look
     * for Velocity templates.
     *
     * @param templatePath template path for velocity templates.
     */
    public void setTemplatePath(String templatePath)
    {
        props.put(TEMPLATE_PATH, templatePath);
    }

    /**
     * Get the template path.
     *
     * @return String template path for velocity templates.
     */
    public String getTemplatePath()
    {
        return props.getProperty(TEMPLATE_PATH);
    }

    /**
     * Set the output path for the generated
     * output.
     * @param outputPath
     */
    public void setOutputPath(String outputPath)
    {
        props.put(OUTPUT_PATH, outputPath);
    }

    /**
     * Get the output path for the generated
     * output.
     *
     * @return String output path for texen output.
     */
    public String getOutputPath()
    {
        return props.getProperty(OUTPUT_PATH);
    }

    /**
     * Set the output encoding.
     * @param outputEncoding
     */
    public void setOutputEncoding(String outputEncoding)
    {
        this.outputEncoding = outputEncoding;
    }

    /**
     * Set the input (template) encoding.
     * @param inputEncoding
     */
    public void setInputEncoding(String inputEncoding)
    {
        this.inputEncoding = inputEncoding;
    }

    /**
     * Returns a writer, based on encoding and path.
     *