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// Copyright 2014 The Bazel Authors. All rights reserved.
//
// 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.google.devtools.build.docgen;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.VelocityEngine;
import org.apache.velocity.exception.MethodInvocationException;
import org.apache.velocity.exception.ParseErrorException;
import org.apache.velocity.exception.ResourceNotFoundException;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.StringWriter;
/**
* Class that represents a page to be generated using the {@link TemplateEngine}.
*/
class Page {
private final VelocityEngine engine;
private final VelocityContext context;
private final String template;
/**
* Creates a new Page instance using the reference to the VelocityEngine and the .vm
* template file path.
*/
public Page(VelocityEngine engine, String template) {
this.engine = engine;
this.template = template;
this.context = new VelocityContext();
}
/**
* Sets a Velocity variable in the template with the given value.
*/
public void add(String var, Object value) {
context.put(var, value);
}
/**
* Renders the template and writes the output to the given file.
*
* Strips all trailing whitespace before writing to file.
*/
public void write(File outputFile) throws IOException {
StringWriter stringWriter = new StringWriter();
try {
engine.mergeTemplate(template, "UTF-8", context, stringWriter);
} catch (ResourceNotFoundException|ParseErrorException|MethodInvocationException e) {
throw new IOException(e);
}
stringWriter.close();
String[] lines = stringWriter.toString().split(System.getProperty("line.separator"));
try (FileWriter fileWriter = new FileWriter(outputFile)) {
for (String line : lines) {
// Strip trailing whitespace then append newline before writing to file.
fileWriter.write(line.replaceFirst("\\s+$", "") + "\n");
}
}
}
}