org.apache.xmlgraphics.io.XmlSourceUtil 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.
*/
package org.apache.xmlgraphics.io;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import javax.xml.transform.Source;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.sax.SAXSource;
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.stream.StreamSource;
import org.xml.sax.InputSource;
import org.apache.commons.io.IOUtils;
import org.apache.xmlgraphics.image.loader.ImageSource;
import org.apache.xmlgraphics.image.loader.util.ImageInputStreamAdapter;
import org.apache.xmlgraphics.image.loader.util.ImageUtil;
/**
* A utility class for handling {@link Source} objects, more specficially the streams that back
* the {@link Source}.
*/
public final class XmlSourceUtil {
private XmlSourceUtil() {
}
/**
* Returns the {@link InputStream} that is backing the given {@link Source} object.
*
* @param src is backed by an {@link InputStream}
* @return the input stream
*/
public static InputStream getInputStream(Source src) {
try {
if (src instanceof StreamSource) {
return ((StreamSource) src).getInputStream();
} else if (src instanceof DOMSource) {
ByteArrayOutputStream outStream = new ByteArrayOutputStream();
StreamResult xmlSource = new StreamResult(outStream);
TransformerFactory.newInstance().newTransformer().transform(src, xmlSource);
return new ByteArrayInputStream(outStream.toByteArray());
} else if (src instanceof SAXSource) {
return ((SAXSource) src).getInputSource().getByteStream();
} else if (src instanceof ImageSource) {
return new ImageInputStreamAdapter(((ImageSource) src).getImageInputStream());
}
} catch (Exception e) {
// TODO: How do we want to handle these? They all come from the TransformerFactory
}
return null;
}
/**
* Returns the InputStream of a Source object. This method throws an IllegalArgumentException
* if there's no InputStream instance available from the Source object.
* @param src the Source object
* @return the InputStream
*/
public static InputStream needInputStream(Source src) {
InputStream in = getInputStream(src);
if (in != null) {
return in;
} else {
throw new IllegalArgumentException("Source must be a StreamSource with an InputStream"
+ " or an ImageSource");
}
}
/**
* Indicates whether the Source object has a Reader instance.
* @param src the Source object
* @return true if an Reader is available
*/
public static boolean hasReader(Source src) {
if (src instanceof StreamSource) {
Reader reader = ((StreamSource) src).getReader();
return (reader != null);
} else if (src instanceof SAXSource) {
InputSource is = ((SAXSource) src).getInputSource();
if (is != null) {
return (is.getCharacterStream() != null);
}
}
return false;
}
/**
* Removes any references to InputStreams or Readers from the given Source to prohibit
* accidental/unwanted use by a component further downstream.
* @param src the Source object
*/
public static void removeStreams(Source src) {
if (src instanceof ImageSource) {
ImageSource isrc = (ImageSource) src;
isrc.setImageInputStream(null);
} else if (src instanceof StreamSource) {
StreamSource ssrc = (StreamSource) src;
ssrc.setInputStream(null);
ssrc.setReader(null);
} else if (src instanceof SAXSource) {
InputSource is = ((SAXSource) src).getInputSource();
if (is != null) {
is.setByteStream(null);
is.setCharacterStream(null);
}
}
}
/**
* Closes the InputStreams or ImageInputStreams of Source objects. Any exception occurring
* while closing the stream is ignored.
* @param src the Source object
*/
public static void closeQuietly(Source src) {
if (src instanceof StreamSource) {
StreamSource streamSource = (StreamSource) src;
IOUtils.closeQuietly(streamSource.getReader());
} else if (src instanceof ImageSource) {
if (ImageUtil.getImageInputStream(src) != null) {
try {
ImageUtil.getImageInputStream(src).close();
} catch (IOException ioe) {
// ignore
}
}
} else if (src instanceof SAXSource) {
InputSource is = ((SAXSource) src).getInputSource();
if (is != null) {
IOUtils.closeQuietly(is.getByteStream());
IOUtils.closeQuietly(is.getCharacterStream());
}
}
removeStreams(src);
}
/**
* Indicates whether the Source object has an InputStream instance.
* @param src the Source object
* @return true if an InputStream is available
*/
public static boolean hasInputStream(Source src) {
return getInputStream(src) != null;
}
}