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      1 /*
      2  * Copyright (C) 2010 Google Inc.
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  * http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.google.clearsilver.jsilver.compatibility;
     18 
     19 import com.google.clearsilver.jsilver.TemplateRenderer;
     20 import com.google.clearsilver.jsilver.template.Template;
     21 import com.google.clearsilver.jsilver.data.Data;
     22 import com.google.clearsilver.jsilver.exceptions.JSilverException;
     23 import com.google.clearsilver.jsilver.resourceloader.ResourceLoader;
     24 
     25 import org.clearsilver.CS;
     26 import org.clearsilver.CSFileLoader;
     27 import org.clearsilver.ClearsilverFactory;
     28 import org.clearsilver.HDF;
     29 import org.clearsilver.jni.JniClearsilverFactory;
     30 
     31 import java.io.FileNotFoundException;
     32 import java.io.IOException;
     33 import java.io.Reader;
     34 
     35 /**
     36  * A {@link TemplateRenderer} implemented using ClearSilver itself.
     37  */
     38 public class ClearsilverRenderer implements TemplateRenderer {
     39   private final ClearsilverFactory factory;
     40   private final ResourceLoader defaultResourceLoader;
     41 
     42   /**
     43    * Creates an implementation using the provided ClearSilver factory and JSilver resource loader.
     44    */
     45   public ClearsilverRenderer(ClearsilverFactory factory, ResourceLoader resourceLoader) {
     46     this.factory = factory;
     47     this.defaultResourceLoader = resourceLoader;
     48   }
     49 
     50   /**
     51    * Creates a JSilver implementation using the JNI ClearSilver factory and provided JSilver
     52    * resource loader.
     53    */
     54   public ClearsilverRenderer(ResourceLoader resourceLoader) {
     55     this(new JniClearsilverFactory(), resourceLoader);
     56   }
     57 
     58   @Override
     59   public void render(String templateName, Data data, Appendable output,
     60       final ResourceLoader resourceLoader) throws IOException, JSilverException {
     61     CSFileLoader fileLoader = new CSFileLoader() {
     62       @Override
     63       public String load(HDF hdf, String filename) throws IOException {
     64         return loadResource(filename, resourceLoader);
     65       }
     66     };
     67 
     68     HDF hdf = factory.newHdf();
     69     try {
     70       // Copy the Data into the HDF.
     71       hdf.readString(data.toString());
     72 
     73       CS cs = factory.newCs(hdf);
     74       try {
     75         cs.setFileLoader(fileLoader);
     76         cs.parseFile(templateName);
     77         output.append(cs.render());
     78       } finally {
     79         cs.close();
     80       }
     81     } finally {
     82       hdf.close();
     83     }
     84   }
     85 
     86   @Override
     87   public void render(String templateName, Data data, Appendable output) throws IOException,
     88       JSilverException {
     89     render(templateName, data, output, defaultResourceLoader);
     90   }
     91 
     92   @Override
     93   public String render(String templateName, Data data) throws IOException, JSilverException {
     94     Appendable output = new StringBuilder(8192);
     95     render(templateName, data, output);
     96     return output.toString();
     97   }
     98 
     99   @Override
    100   public void render(Template template, Data data, Appendable output, ResourceLoader resourceLoader)
    101       throws IOException, JSilverException {
    102     throw new UnsupportedOperationException("ClearsilverRenderer only expects "
    103         + "template names, not Templates");
    104   }
    105 
    106   @Override
    107   public void render(Template template, Data data, Appendable output) throws IOException,
    108       JSilverException {
    109     render(template, data, output, defaultResourceLoader);
    110   }
    111 
    112   @Override
    113   public String render(Template template, Data data) throws IOException, JSilverException {
    114     Appendable output = new StringBuilder(8192);
    115     render(template, data, output);
    116     return output.toString();
    117   }
    118 
    119   @Override
    120   public void renderFromContent(String content, Data data, Appendable output) throws IOException,
    121       JSilverException {
    122     throw new UnsupportedOperationException();
    123   }
    124 
    125   @Override
    126   public String renderFromContent(String content, Data data) throws IOException, JSilverException {
    127     Appendable output = new StringBuilder(8192);
    128     renderFromContent(content, data, output);
    129     return output.toString();
    130   }
    131 
    132   /**
    133    * @return the contents of a resource, or null if the resource was not found.
    134    */
    135   private String loadResource(String filename, ResourceLoader resourceLoader) throws IOException {
    136     Reader reader = resourceLoader.open(filename);
    137     if (reader == null) {
    138       throw new FileNotFoundException(filename);
    139     }
    140     StringBuilder sb = new StringBuilder();
    141     char buf[] = new char[4096];
    142     int count;
    143     while ((count = reader.read(buf)) != -1) {
    144       sb.append(buf, 0, count);
    145     }
    146     return sb.toString();
    147   }
    148 }
    149