org.apache.fop.render.bitmap.MultiFileRenderingUtil Maven / Gradle / Ivy
/*
* 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.
*/
/* $Id: MultiFileRenderingUtil.java 820637 2009-10-01 12:56:26Z jeremias $ */
package org.apache.fop.render.bitmap;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
/**
* This utility class helps renderers who generate one file per page,
* like the PNG renderer.
*/
public class MultiFileRenderingUtil {
/** The file syntax prefix, eg. "page" will output "page1.png" etc */
private String filePrefix;
private String fileExtension;
/** The output directory where images are to be written */
private File outputDir;
/**
* Creates a new instance.
*
* The file name must not have an extension, or must have extension "png",
* and its last period must not be at the start (empty file prefix).
* @param ext the extension to be used
* @param outputFile the output file or null if there's no such information
*/
public MultiFileRenderingUtil(String ext, File outputFile) {
this.fileExtension = ext;
// the file provided on the command line
if (outputFile == null) {
//No filename information available. Only the first page will be rendered.
outputDir = null;
filePrefix = null;
} else {
outputDir = outputFile.getParentFile();
// extracting file name syntax
String s = outputFile.getName();
int i = s.lastIndexOf(".");
if (i > 0) {
// Make sure that the file extension was "png"
String extension = s.substring(i + 1).toLowerCase();
if (!ext.equals(extension)) {
throw new IllegalArgumentException("Invalid file extension ('"
+ extension + "') specified");
}
} else if (i == -1) {
i = s.length();
} else { // i == 0
throw new IllegalArgumentException("Invalid file name ('"
+ s + "') specified");
}
if (s.charAt(i - 1) == '1') {
i--; // getting rid of the "1"
}
filePrefix = s.substring(0, i);
}
}
/**
* Creates a new {@link OutputStream} for the given page number.
* @param pageNumber the page number (zero-based)
* @return the output stream for the page
* @throws IOException if there's an I/O error while setting up the output stream
*/
public OutputStream createOutputStream(int pageNumber) throws IOException {
if (filePrefix == null) {
return null;
} else {
File f = new File(outputDir,
filePrefix + (pageNumber + 1) + "." + fileExtension);
OutputStream os = new BufferedOutputStream(new FileOutputStream(f));
return os;
}
}
}