net.sf.jsefa.xml.lowlevel.StaxBasedXmlLowLevelSerializer Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of jsefa-android Show documentation
JSefa (Java Simple exchange format api) is a simple library for stream-based serialization of java objects to XML, CSV, FLR or any other format and back again using an iterator-style interface independent of the serialization format. The mapping between java object types and types of the serialization format (e. g. xml complex element types) can be defined either by annotating the java classes or programmatically using a simple API. The current implementation supports XML, CSV and FLR - for XML it is based on JSR 173.
The newest version!
/*
 * Copyright 2007 the original author or authors.
 *
 * 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 net.sf.jsefa.xml.lowlevel;

import static net.sf.jsefa.xml.namespace.NamespaceConstants.DEFAULT_NAMESPACE_PREFIX;
import static net.sf.jsefa.xml.namespace.NamespaceConstants.NO_NAMESPACE_URI;

import java.io.Writer;

import javax.xml.stream.XMLOutputFactory;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamWriter;

import net.sf.jsefa.common.lowlevel.LowLevelSerializationException;
import net.sf.jsefa.xml.lowlevel.config.XmlLowLevelConfiguration;
import net.sf.jsefa.xml.namespace.NamespaceManager;
import net.sf.jsefa.xml.namespace.QName;

/**
 * Stax based implementation of {@link XmlLowLevelSerializer}.
 * 
 * @author Norman Lahme-Huetig
 * @author Matthias Derer
 */
public final class StaxBasedXmlLowLevelSerializer implements XmlLowLevelSerializer {
    private final XmlLowLevelConfiguration config;

    private Writer writer;

    private XMLStreamWriter streamWriter;

    private int depth = -1;

    private boolean lastWasStartElement;

    private NamespaceManager namespaceManager;

    /**
     * Constructs a new StaxBasedXmlLowLevelSerializer.
     * 
     * @param config the configuration object
     */
    public StaxBasedXmlLowLevelSerializer(XmlLowLevelConfiguration config) {
        this.config = config;
    }

    /**
     * {@inheritDoc}
     */
    public void open(Writer writer) {
        this.writer = writer;
        XMLOutputFactory factory = XMLOutputFactory.newInstance();
        if (factory.isPropertySupported("com.ctc.wstx.outputEscapeCr")) {
            factory.setProperty("com.ctc.wstx.outputEscapeCr", Boolean.FALSE);
        }
        try {
            this.streamWriter = factory.createXMLStreamWriter(writer);
        } catch (XMLStreamException e) {
            throw new LowLevelSerializationException("Error while opening the serialization stream", e);
        }
        this.depth = -1;
        this.namespaceManager = this.config.getNamespaceManager();
    }

    /**
     * {@inheritDoc}
     */
    public void writeXmlDeclaration(String version, String encoding) {
        try {
            this.streamWriter.writeStartDocument(encoding, version);
            writeLineBreak();
        } catch (XMLStreamException e) {
            throw new LowLevelSerializationException(e);
        }
    }

    /**
     * {@inheritDoc}
     */
    public void writeDocTypeDeclaration(QName rootElementName, String publicId, String systemId) {
        StringBuilder dtd = new StringBuilder(" 0) {
                dtd.append(prefix).append(":");
            }
            dtd.append(rootElementName.getLocalName());
        }
        if (publicId != null) {
            dtd.append(" PUBLIC \"").append(publicId).append("\" \"").append(systemId).append("\">");
        } else {
            dtd.append(" SYSTEM \"").append(systemId).append("\">");
        }
        try {
            this.streamWriter.writeDTD(dtd.toString());
            writeLineBreak();
        } catch (XMLStreamException e) {
            throw new LowLevelSerializationException(e);
        }
    }

    /**
     * {@inheritDoc}
     */
    public void writeStartElement(QName name) {
        writeStartElement(name, null);
    }

    /**
     * {@inheritDoc}
     */
    public void writeStartElement(QName name, QName dataTypeName) {
        this.depth++;
        this.namespaceManager = NamespaceManager.createWithParent(this.namespaceManager);
        try {
            if (this.lastWasStartElement) {
                writeLineBreak();
            } else {
                this.lastWasStartElement = true;
            }
            writeIdent();
            if (!hasNamespace(name)) {
                this.streamWriter.writeStartElement(name.getLocalName());
                if (defaultNamespaceExists()) {
                    this.namespaceManager.registerPrefix(DEFAULT_NAMESPACE_PREFIX, NO_NAMESPACE_URI);
                    this.streamWriter.writeNamespace(DEFAULT_NAMESPACE_PREFIX, NO_NAMESPACE_URI);
                }
            } else {
                String prefix = this.namespaceManager.getPrefix(name.getUri(), true);
                boolean createNamespace = (prefix == null);
                if (prefix == null) {
                    prefix = this.namespaceManager.createPrefix(name.getUri(), true);
                    this.namespaceManager.registerPrefix(prefix, name.getUri());
                }
                this.streamWriter.writeStartElement(prefix, name.getLocalName(), name.getUri());
                if (createNamespace) {
                    this.streamWriter.writeNamespace(prefix, name.getUri());
                }
            }
            if (dataTypeName != null) {
                String value = dataTypeName.getLocalName();
                if (hasNamespace(dataTypeName)) {
                    String prefix = this.namespaceManager.getPrefix(dataTypeName.getUri(), true);
                    if (prefix == null) {
                        prefix = this.namespaceManager.createPrefix(dataTypeName.getUri(), true);
                        this.namespaceManager.registerPrefix(prefix, dataTypeName.getUri());
                        this.streamWriter.writeNamespace(prefix, dataTypeName.getUri());
                    }
                    if (prefix.length() > 0) {
                        value = prefix + ":" + value;
                    }
                }
                writeAttribute(this.config.getDataTypeAttributeName(), value);
            }
        } catch (XMLStreamException e) {
            throw new LowLevelSerializationException("Unable to write element " + name, e);
        }
    }

    /**
     * {@inheritDoc}
     */
    public void writeAttribute(QName name, String value) {
        if (value == null) {
            return;
        }
        try {
            if (!hasNamespace(name)) {
                this.streamWriter.writeAttribute(name.getLocalName(), value);
            } else {
                String prefix = this.namespaceManager.getPrefix(name.getUri(), false);
                if (prefix == null) {
                    prefix = this.namespaceManager.createPrefix(name.getUri(), false);
                    this.namespaceManager.registerPrefix(prefix, name.getUri());
                    this.streamWriter.writeNamespace(prefix, name.getUri());
                }
                this.streamWriter.writeAttribute(prefix, name.getUri(), name.getLocalName(), value);
            }
        } catch (XMLStreamException e) {
            throw new LowLevelSerializationException("Unable to write attribute " + name, e);
        }
    }

    /**
     * {@inheritDoc}
     */
    public void writeText(String text, TextMode textMode) {
        if (text != null && text.length() != 0) {
            try {
                if (TextMode.CDATA.equals(textMode)) {
                    int index = text.indexOf("]]>");
                    int lastIndex = 0;
                    while (index > -1) {
                        this.streamWriter.writeCData(text.substring(lastIndex, index + 2));
                        lastIndex = index + 2;
                        index = text.indexOf("]]>", index + 1);
                    }
                    this.streamWriter.writeCData(text.substring(lastIndex));
                } else {
                    this.streamWriter.writeCharacters(text);
                }
            } catch (XMLStreamException e) {
                throw new LowLevelSerializationException("Unable to write text", e);
            }
        }
    }

    /**
     * {@inheritDoc}
     */
    public void writeEndElement() {
        try {
            if (!this.lastWasStartElement) {
                writeIdent();
            }
            this.lastWasStartElement = false;
            this.streamWriter.writeEndElement();
            writeLineBreak();
        } catch (XMLStreamException e) {
            throw new LowLevelSerializationException("Unable to finish element", e);
        }
        this.namespaceManager = this.namespaceManager.getParent();
        this.depth--;
    }

    /**
     * {@inheritDoc}
     */
    public void flush() {
        try {
            this.streamWriter.flush();
        } catch (Exception e) {
            throw new LowLevelSerializationException("Error while flushing the serialization stream", e);
        }
    }

    /**
     * {@inheritDoc}
     */
    public void close(boolean closeWriter) {
        try {
            this.streamWriter.close();
            if (closeWriter) {
                this.writer.close();
            }
        } catch (Exception e) {
            throw new LowLevelSerializationException("Error while closing the serialization stream", e);
        }
    }

    private void writeLineBreak() throws XMLStreamException {
        this.streamWriter.writeCharacters(this.config.getLineBreak());
    }

    private void writeIdent() throws XMLStreamException {
        String lineIndentation = this.config.getLineIndentation();
        if (lineIndentation.length() > 0) {
            for (int i = 0; i < this.depth; i++) {
                this.streamWriter.writeCharacters(lineIndentation);
            }
        }
    }

    private boolean hasNamespace(QName name) {
        return !NO_NAMESPACE_URI.equals(name.getUri());
    }

    private boolean defaultNamespaceExists() {
        String registeredUri = this.namespaceManager.getUri(DEFAULT_NAMESPACE_PREFIX);
        return registeredUri != null && !registeredUri.equals(NO_NAMESPACE_URI);
    }

}