org.lobid.lodmill.XmlEntitySplitter.java Source code

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Here is the source code for org.lobid.lodmill.XmlEntitySplitter.java

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/** Copyright 2013 hbz, Pascal Christoph.
 * Licensed under the Eclipse Public License 1.0 
 **/
package org.lobid.lodmill;

import java.util.HashSet;

import org.apache.commons.lang3.StringEscapeUtils;
import org.culturegraph.mf.framework.DefaultXmlPipe;
import org.culturegraph.mf.framework.StreamReceiver;
import org.culturegraph.mf.framework.XmlReceiver;
import org.culturegraph.mf.framework.annotations.Description;
import org.culturegraph.mf.framework.annotations.In;
import org.culturegraph.mf.framework.annotations.Out;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;

/**
 * An XML entity splitter.
 * 
 * @author Pascal Christoph
 * 
 */
@Description("Splits all entities (aka records) residing in one XML document into multiple single XML documents.")
@In(XmlReceiver.class)
@Out(StreamReceiver.class)
public final class XmlEntitySplitter extends DefaultXmlPipe<StreamReceiver> {

    private String entity;
    private StringBuilder builder = new StringBuilder();
    private HashSet<String> namespaces = new HashSet<String>();
    private boolean inEntity = false;
    private int recordCnt = 0;
    private String root;

    /**
     * Sets the name of the entity. All these entities in the XML stream will be
     * XML documents on their own.
     * 
     * @param name Identifies the entities
     */
    public void setEntityName(final String name) {
        this.entity = name;
    }

    /**
     * Sets the top-level XML document element.
     * 
     * @param name the element
     */
    public void setTopLevelElement(final String name) {
        this.root = name;
    }

    @Override
    public void startPrefixMapping(String prefix, String uri) throws SAXException {
        super.startPrefixMapping(prefix, uri);
        if (!prefix.isEmpty() && uri != null)
            namespaces.add(" xmlns:" + prefix + "=\"" + uri + "\"");
    }

    @Override
    public void startElement(final String uri, final String localName, final String qName,
            final Attributes attributes) throws SAXException {
        if (!inEntity) {
            if (entity.equals(localName)) {
                builder = new StringBuilder();
                getReceiver().startRecord(String.valueOf(this.recordCnt++));
                inEntity = true;
                appendValuesToEntity(qName, attributes);
            } else if (this.root == null)
                this.root = qName;
        } else
            appendValuesToEntity(qName, attributes);
    }

    private void appendValuesToEntity(final String qName, final Attributes attributes) {
        this.builder.append("<" + qName);
        if (attributes.getLength() > 0) {
            for (int i = 0; i < attributes.getLength(); i++) {
                builder.append(" " + attributes.getQName(i) + "=\""
                        + StringEscapeUtils.escapeXml(attributes.getValue(i)) + "\"");
            }
        }
        builder.append(">");
    }

    @Override
    public void endElement(final String uri, final String localName, final String qName) throws SAXException {
        if (inEntity) {
            builder.append("</" + qName + ">");
            if (entity.equals(localName)) {
                StringBuilder sb = new StringBuilder("<" + this.root);
                if (namespaces != null) {
                    for (String ns : namespaces) {
                        sb.append(ns);
                    }
                    sb.append(">");
                }
                builder.insert(0, sb.toString()).append("</" + this.root + ">");
                getReceiver().literal("entity", builder.toString());
                getReceiver().endRecord();
                inEntity = false;
                builder = new StringBuilder();
            }
        }
    }

    @Override
    public void characters(final char[] chars, final int start, final int length) throws SAXException {
        builder.append(StringEscapeUtils.escapeXml(new String(chars, start, length)));
    }
}