javax.xml.transform.stream.StreamSource Maven / Gradle / Ivy
Show all versions of qbicc-rt-java.xml Show documentation
/*
* Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package javax.xml.transform.stream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
/**
* Acts as an holder for a transformation Source in the form
* of a stream of XML markup.
*
* Note: Due to their internal use of either a {@link Reader} or {@link InputStream} instance,
* StreamSource instances may only be used once.
*
* @author Jeff Suttor
* @since 1.4
*/
public class StreamSource implements Source {
/** If {@link javax.xml.transform.TransformerFactory#getFeature}
* returns true when passed this value as an argument,
* the Transformer supports Source input of this type.
*/
public static final String FEATURE =
"http://javax.xml.transform.stream.StreamSource/feature";
/**
* Zero-argument default constructor. If this constructor is used, and
* no Stream source is set using
* {@link #setInputStream(java.io.InputStream inputStream)} or
* {@link #setReader(java.io.Reader reader)}, then the
* Transformer will
* create an empty source {@link java.io.InputStream} using
* {@link java.io.InputStream#InputStream() new InputStream()}.
*
* @see javax.xml.transform.Transformer#transform(Source xmlSource, Result outputTarget)
*/
public StreamSource() { }
/**
* Construct a StreamSource from a byte stream. Normally,
* a stream should be used rather than a reader, so
* the XML parser can resolve character encoding specified
* by the XML declaration.
*
* If this constructor is used to process a stylesheet, normally
* setSystemId should also be called, so that relative URI references
* can be resolved.
*
* @param inputStream A valid InputStream reference to an XML stream.
*/
public StreamSource(InputStream inputStream) {
setInputStream(inputStream);
}
/**
* Construct a StreamSource from a byte stream. Normally,
* a stream should be used rather than a reader, so that
* the XML parser can resolve character encoding specified
* by the XML declaration.
*
* This constructor allows the systemID to be set in addition
* to the input stream, which allows relative URIs
* to be processed.
*
* @param inputStream A valid InputStream reference to an XML stream.
* @param systemId Must be a String that conforms to the URI syntax.
*/
public StreamSource(InputStream inputStream, String systemId) {
setInputStream(inputStream);
setSystemId(systemId);
}
/**
* Construct a StreamSource from a character reader. Normally,
* a stream should be used rather than a reader, so that
* the XML parser can resolve character encoding specified
* by the XML declaration. However, in many cases the encoding
* of the input stream is already resolved, as in the case of
* reading XML from a StringReader.
*
* @param reader A valid Reader reference to an XML character stream.
*/
public StreamSource(Reader reader) {
setReader(reader);
}
/**
* Construct a StreamSource from a character reader. Normally,
* a stream should be used rather than a reader, so that
* the XML parser may resolve character encoding specified
* by the XML declaration. However, in many cases the encoding
* of the input stream is already resolved, as in the case of
* reading XML from a StringReader.
*
* @param reader A valid Reader reference to an XML character stream.
* @param systemId Must be a String that conforms to the URI syntax.
*/
public StreamSource(Reader reader, String systemId) {
setReader(reader);
setSystemId(systemId);
}
/**
* Construct a StreamSource from a URL.
*
* @param systemId Must be a String that conforms to the URI syntax.
*/
public StreamSource(String systemId) {
this.systemId = systemId;
}
/**
* Construct a StreamSource from a File.
*
* @param f Must a non-null File reference.
*/
public StreamSource(File f) {
//convert file to appropriate URI, f.toURI().toASCIIString()
//converts the URI to string as per rule specified in
//RFC 2396,
setSystemId(f.toURI().toASCIIString());
}
/**
* Set the byte stream to be used as input. Normally,
* a stream should be used rather than a reader, so that
* the XML parser can resolve character encoding specified
* by the XML declaration.
*
* If this Source object is used to process a stylesheet, normally
* setSystemId should also be called, so that relative URL references
* can be resolved.
*
* @param inputStream A valid InputStream reference to an XML stream.
*/
public void setInputStream(InputStream inputStream) {
this.inputStream = inputStream;
}
/**
* Get the byte stream that was set with setByteStream.
*
* @return The byte stream that was set with setByteStream, or null
* if setByteStream or the ByteStream constructor was not called.
*/
public InputStream getInputStream() {
return inputStream;
}
/**
* Set the input to be a character reader. Normally,
* a stream should be used rather than a reader, so that
* the XML parser can resolve character encoding specified
* by the XML declaration. However, in many cases the encoding
* of the input stream is already resolved, as in the case of
* reading XML from a StringReader.
*
* @param reader A valid Reader reference to an XML CharacterStream.
*/
public void setReader(Reader reader) {
this.reader = reader;
}
/**
* Get the character stream that was set with setReader.
*
* @return The character stream that was set with setReader, or null
* if setReader or the Reader constructor was not called.
*/
public Reader getReader() {
return reader;
}
/**
* Set the public identifier for this Source.
*
* The public identifier is always optional: if the application
* writer includes one, it will be provided as part of the
* location information.
*
* @param publicId The public identifier as a string.
*/
public void setPublicId(String publicId) {
this.publicId = publicId;
}
/**
* Get the public identifier that was set with setPublicId.
*
* @return The public identifier that was set with setPublicId, or null
* if setPublicId was not called.
*/
public String getPublicId() {
return publicId;
}
/**
* Set the system identifier for this Source.
*
* The system identifier is optional if there is a byte stream
* or a character stream, but it is still useful to provide one,
* since the application can use it to resolve relative URIs
* and can include it in error messages and warnings (the parser
* will attempt to open a connection to the URI only if
* there is no byte stream or character stream specified).
*
* @param systemId The system identifier as a URL string.
*/
@Override
public void setSystemId(String systemId) {
this.systemId = systemId;
}
/**
* Get the system identifier that was set with setSystemId.
*
* @return The system identifier that was set with setSystemId, or null
* if setSystemId was not called.
*/
@Override
public String getSystemId() {
return systemId;
}
/**
* Set the system ID from a File reference.
*
* @param f Must a non-null File reference.
*/
public void setSystemId(File f) {
//convert file to appropriate URI, f.toURI().toASCIIString()
//converts the URI to string as per rule specified in
//RFC 2396,
this.systemId = f.toURI().toASCIIString();
}
/**
* Indicates whether the {@code StreamSource} object is empty. Empty is
* defined as follows:
*
* - All of the input sources, including the public identifier, system
* identifier, byte stream, and character stream, are {@code null}.
*
* - The public identifier and system identifier are {@code null}, and
* byte and character stream are either {@code null} or contain no byte or
* character.
*
* Note that this method will reset the byte stream if it is provided, or
* the character stream if the byte stream is not provided.
*
*
*
* In case of error while checking the byte or character stream, the method
* will return false to allow the XML processor to handle the error.
*
* @return true if the {@code StreamSource} object is empty, false otherwise
*/
@Override
public boolean isEmpty() {
return (publicId == null && systemId == null && isStreamEmpty());
}
private boolean isStreamEmpty() {
boolean empty = true;
try {
if (inputStream != null) {
inputStream.reset();
int bytesRead = inputStream.available();
if (bytesRead > 0) {
return false;
}
}
if (reader != null) {
reader.reset();
int c = reader.read();
reader.reset();
if (c != -1) {
return false;
}
}
} catch (IOException ex) {
//in case of error, return false
return false;
}
return empty;
}
//////////////////////////////////////////////////////////////////////
// Internal state.
//////////////////////////////////////////////////////////////////////
/**
* The public identifier for this input source, or null.
*/
private String publicId;
/**
* The system identifier as a URL string, or null.
*/
private String systemId;
/**
* The byte stream for this Source, or null.
*/
private InputStream inputStream;
/**
* The character stream for this Source, or null.
*/
private Reader reader;
}