Java tutorial
/* * eXist Apache FOP Transformation Extension * Copyright (C) 2007 Craig Goodyer at the University of the West of England * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program 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 Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. * * $Id$ */ package org.exist.xquery.modules.xslfo; import java.io.ByteArrayInputStream; import java.util.Properties; import org.apache.commons.io.output.ByteArrayOutputStream; import org.apache.log4j.Logger; import org.exist.dom.QName; import org.exist.xquery.BasicFunction; import org.exist.xquery.Cardinality; import org.exist.xquery.FunctionSignature; import org.exist.xquery.XPathException; import org.exist.xquery.XQueryContext; import org.exist.xquery.modules.ModuleUtils; import org.exist.xquery.value.Base64BinaryValueType; import org.exist.xquery.value.BinaryValueFromInputStream; import org.exist.xquery.value.FunctionParameterSequenceType; import org.exist.xquery.value.Item; import org.exist.xquery.value.NodeValue; import org.exist.xquery.value.Sequence; import org.exist.xquery.value.SequenceType; import org.exist.xquery.value.Type; import org.xml.sax.ContentHandler; import org.xml.sax.SAXException; /** * @author Craig Goodyer <craiggoodyer@gmail.com> * @author Adam Retter <adam@exist-db.org> */ public class RenderFunction extends BasicFunction { @SuppressWarnings("unused") private static final Logger logger = Logger.getLogger(RenderFunction.class); public final static FunctionSignature signatures[] = { new FunctionSignature(new QName("render", XSLFOModule.NAMESPACE_URI, XSLFOModule.PREFIX), "Renders a given FO document. " + "Returns an xs:base64binary of the result. " + "Parameters are specified with the structure: " + "<parameters><param name=\"param-name1\" value=\"param-value1\"/>" + "</parameters>. " + "Recognised rendering parameters are: author, title, keywords and dpi.", new SequenceType[] { new FunctionParameterSequenceType("document", Type.NODE, Cardinality.EXACTLY_ONE, "FO document"), new FunctionParameterSequenceType("mime-type", Type.STRING, Cardinality.EXACTLY_ONE, ""), new FunctionParameterSequenceType("parameters", Type.NODE, Cardinality.ZERO_OR_ONE, "parameters for the transform") }, new FunctionParameterSequenceType("result", Type.BASE64_BINARY, Cardinality.ZERO_OR_ONE, "result")), new FunctionSignature(new QName("render", XSLFOModule.NAMESPACE_URI, XSLFOModule.PREFIX), "Renders a given FO document. " + "Returns an xs:base64binary of the result. " + "Parameters are specified with the structure: " + "<parameters><param name=\"param-name1\" value=\"param-value1\"/>" + "</parameters>. " + "Recognised rendering parameters are: author, title, keywords and dpi.", new SequenceType[] { new FunctionParameterSequenceType("document", Type.NODE, Cardinality.EXACTLY_ONE, "FO document"), new FunctionParameterSequenceType("mime-type", Type.STRING, Cardinality.EXACTLY_ONE, ""), new FunctionParameterSequenceType("parameters", Type.NODE, Cardinality.ZERO_OR_ONE, "parameters for the transform"), new FunctionParameterSequenceType("config-file", Type.NODE, Cardinality.ZERO_OR_ONE, "FOP Processor Configuration file") }, new FunctionParameterSequenceType("result", Type.BASE64_BINARY, Cardinality.ZERO_OR_ONE, "result")) }; /** * Constructor for RenderFunction, which returns a new instance of this * class. * * @param context * @param signature */ public RenderFunction(XQueryContext context, FunctionSignature signature) { super(context, signature); } /* * Actual implementation of the rendering process. When a function in this * module is called, this method is executed with the given inputs. @param * Sequence[] args (XSL-FO, mime-type, parameters) @param Sequence * contextSequence (default sequence) * * @see org.exist.xquery.BasicFunction#eval(org.exist.xquery.value.Sequence[], * org.exist.xquery.value.Sequence) */ @Override public Sequence eval(Sequence[] args, Sequence contextSequence) throws XPathException { // gather input XSL-FO document // if no input document (empty), return empty result as we need data to // process if (args[0].isEmpty()) { return Sequence.EMPTY_SEQUENCE; } Item inputNode = args[0].itemAt(0); // get mime-type String mimeType = args[1].getStringValue(); // get parameters Properties parameters = new Properties(); if (!args[2].isEmpty()) { parameters = ModuleUtils.parseParameters(((NodeValue) args[2].itemAt(0)).getNode()); } ProcessorAdapter adapter = null; try { adapter = ((XSLFOModule) getParentModule()).getProcessorAdapter(); NodeValue configFile = args.length == 4 ? (NodeValue) args[3].itemAt(0) : null; ByteArrayOutputStream baos = new ByteArrayOutputStream(); ContentHandler contentHandler = adapter.getContentHandler(context.getBroker(), configFile, parameters, mimeType, baos); // process the XSL-FO contentHandler.startDocument(); inputNode.toSAX(context.getBroker(), contentHandler, new Properties()); contentHandler.endDocument(); // return the result return BinaryValueFromInputStream.getInstance(context, new Base64BinaryValueType(), new ByteArrayInputStream(baos.toByteArray())); } catch (SAXException se) { throw new XPathException(this, se.getMessage(), se); } finally { if (adapter != null) { adapter.cleanup(); } } } }