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diff --git a/src/documentation/content/xdocs/0.94/embedding.xml b/src/documentation/content/xdocs/0.94/embedding.xml new file mode 100644 index 000000000..3e3c964f8 --- /dev/null +++ b/src/documentation/content/xdocs/0.94/embedding.xml @@ -0,0 +1,689 @@ +<?xml version="1.0" standalone="no"?> +<!-- + 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. +--> +<!-- $Id$ --> +<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V2.0//EN" "http://forrest.apache.org/dtd/document-v20.dtd"> +<!-- Embedding FOP --> +<document> + <header> + <title>Apache FOP: Embedding</title> + <subtitle>How to Embed FOP in a Java application</subtitle> + <version>$Revision$</version> + </header> + + <body> + <section id="overview"> + <title>Overview</title> + <p> + Review <a href="running.html">Running FOP</a> for important information that applies + to embedded applications as well as command-line use, such as options and performance. + </p> + <p> + To embed Apache FOP in your application, first create a new + org.apache.fop.apps.FopFactory instance. This object can be used to launch multiple + rendering runs. For each run, create a new org.apache.fop.apps.Fop instance through + one of the factory methods of FopFactory. In the method call you specify which output + format (i.e. Renderer) to use and, if the selected renderer requires an OutputStream, + which OutputStream to use for the results of the rendering. You can customize FOP's + behaviour in a rendering run by supplying your own FOUserAgent instance. The + FOUserAgent can, for example, be used to set your own Renderer instance (details + below). Finally, you retrieve a SAX DefaultHandler instance from the Fop object and + use that as the SAXResult of your transformation. + </p> + <note> + We recently changed FOP's outer API to what we consider the final API. This might require + some changes in your application. The main reasons for these changes were performance + improvements due to better reuse of reusable objects and reduced use of static variables + for added flexibility in complex environments. + </note> + </section> + <section id="basics"> + <title>Basic Usage Pattern</title> + <p> + Apache FOP relies heavily on JAXP. It uses SAX events exclusively to receive the XSL-FO + input document. It is therefore a good idea that you know a few things about JAXP (which + is a good skill anyway). Let's look at the basic usage pattern for FOP... + </p> + <p>Here is the basic pattern to render an XSL-FO file to PDF: + </p> + <source><![CDATA[ +import org.apache.fop.apps.FopFactory; +import org.apache.fop.apps.Fop; +import org.apache.fop.apps.MimeConstants; + +/*..*/ + +// Step 1: Construct a FopFactory +// (reuse if you plan to render multiple documents!) +FopFactory fopFactory = FopFactory.newInstance(); + +// Step 2: Set up output stream. +// Note: Using BufferedOutputStream for performance reasons (helpful with FileOutputStreams). +OutputStream out = new BufferedOutputStream(new FileOutputStream(new File("C:/Temp/myfile.pdf"))); + +try { + // Step 3: Construct fop with desired output format + Fop fop = fopFactory.newFop(MimeConstants.MIME_PDF, out); + + // Step 4: Setup JAXP using identity transformer + TransformerFactory factory = TransformerFactory.newInstance(); + Transformer transformer = factory.newTransformer(); // identity transformer + + // Step 5: Setup input and output for XSLT transformation + // Setup input stream + Source src = new StreamSource(new File("C:/Temp/myfile.fo")); + + // Resulting SAX events (the generated FO) must be piped through to FOP + Result res = new SAXResult(fop.getDefaultHandler()); + + // Step 6: Start XSLT transformation and FOP processing + transformer.transform(src, res); + +} finally { + //Clean-up + out.close(); +}]]></source> + <p> + Let's discuss these 5 steps in detail: + </p> + <ul> + <li> + <strong>Step 1:</strong> You create a new FopFactory instance. The FopFactory instance holds + references to configuration information and cached data. It's important to reuse this + instance if you plan to render multiple documents during a JVM's lifetime. + </li> + <li> + <strong>Step 2:</strong> You set up an OutputStream that the generated document + will be written to. It's a good idea to buffer the OutputStream as demonstrated + to improve performance. + </li> + <li> + <strong>Step 3:</strong> You create a new Fop instance through one of the factory + methods on the FopFactory. You tell the FopFactory what your desired output format + is. This is done by using the MIME type of the desired output format (ex. "application/pdf"). + You can use one of the MimeConstants.* constants. The second parameter is the + OutputStream you've setup up in step 2. + </li> + <li> + <strong>Step 4</strong> We recommend that you use JAXP Transformers even + if you don't do XSLT transformations to generate the XSL-FO file. This way + you can always use the same basic pattern. The example here sets up an + "identity transformer" which just passes the input (Source) unchanged to the + output (Result). You don't have to work with a SAXParser if you don't do any + XSLT transformations. + </li> + <li> + <strong>Step 5:</strong> Here you set up the input and output for the XSLT + transformation. The Source object is set up to load the "myfile.fo" file. + The Result is set up so the output of the XSLT transformation is sent to FOP. + The FO file is sent to FOP in the form of SAX events which is the most efficient + way. Please always avoid saving intermediate results to a file or a memory buffer + because that affects performance negatively. + </li> + <li> + <strong>Step 6:</strong> Finally, we start the XSLT transformation by starting + the JAXP Transformer. As soon as the JAXP Transformer starts to send its output + to FOP, FOP itself starts its processing in the background. When the + <code>transform()</code> method returns FOP will also have finished converting + the FO file to a PDF file and you can close the OutputStream. + <note label="Tip!"> + It's a good idea to enclose the whole conversion in a try..finally statement. If + you close the OutputStream in the finally section, this will make sure that the + OutputStream is properly closed even if an exception occurs during the conversion. + </note> + </li> + </ul> + <p> + If you're not totally familiar with JAXP Transformers, please have a look at the + <a href="#examples">Embedding examples</a> below. The section contains examples + for all sorts of use cases. If you look at all of them in turn you should be able + to see the patterns in use and the flexibility this approach offers without adding + too much complexity. + </p> + <p> + This may look complicated at first, but it's really just the combination of an + XSL transformation and a FOP run. It's also easy to comment out the FOP part + for debugging purposes, for example when you're tracking down a bug in your + stylesheet. You can easily write the XSL-FO output from the XSL transformation + to a file to check if that part generates the expected output. An example for that + can be found in the <a href="#examples">Embedding examples</a> (See "ExampleXML2FO"). + </p> + <section id="basic-logging"> + <title>Logging</title> + <p> + Logging is now a little different than it was in FOP 0.20.5. We've switched from + Avalon Logging to <a href="ext:jakarta/commons/logging">Jakarta Commons Logging</a>. + While with Avalon Logging the loggers were directly given to FOP, FOP now retrieves + its logger(s) through a statically available LogFactory. This is similar to the + general pattern that you use when you work with Apache Log4J directly, for example. + We call this "static logging" (Commons Logging, Log4J) as opposed to "instance logging" + (Avalon Logging). This has a consequence: You can't give FOP a logger for each + processing run anymore. The log output of multiple, simultaneously running FOP instances + is sent to the same logger. + </p> + <note> + We know this may be an issue in multi-threaded server environments if you'd like to + know what's going on in every single FOP processing run. We're planning to add an + additional feedback facility to FOP which can be used to obtain all sorts of specific + feedback (validation messages, layout problems etc.). "Static logging" is mainly + interesting for a developer working on FOP and for advanced users who are debugging + FOP. We don't consider the logging output to be useful to normal FOP users. Please + have some patience until we can add this feature or jump in and help us build it. We've + set up a <a href="http://wiki.apache.org/xmlgraphics-fop/ProcessingFeedback">Wiki page</a> + which documents what we're going to build. + </note> + <p> + By default, <a href="ext:jakarta/commons/logging">Jakarta Commons Logging</a> uses + JDK logging (available in JDKs 1.4 or higher) as its backend. You can configure Commons + Logging to use an alternative backend, for example Log4J. Please consult the + <a href="ext:jakarta/commons/logging">documentation for Jakarta Commons Logging</a> on + how to configure alternative backends. + </p> + </section> + + <section id="render"> + <title>Processing XSL-FO</title> + <p> + Once the Fop instance is set up, call <code>getDefaultHandler()</code> to obtain a SAX + DefaultHandler instance to which you can send the SAX events making up the XSL-FO + document you'd like to render. FOP processing starts as soon as the DefaultHandler's + <code>startDocument()</code> method is called. Processing stops again when the + DefaultHandler's <code>endDocument()</code> method is called. Please refer to the basic + usage pattern shown above to render a simple XSL-FO document. + </p> + </section> + + <section id="render-with-xslt"> + <title>Processing XSL-FO generated from XML+XSLT</title> + <p> + If you want to process XSL-FO generated from XML using XSLT we recommend + again using standard JAXP to do the XSLT part and piping the generated SAX + events directly through to FOP. The only thing you'd change to do that + on the basic usage pattern above is to set up the Transformer differently: + </p> + <source><![CDATA[ + //without XSLT: + //Transformer transformer = factory.newTransformer(); // identity transformer + + //with XSLT: + Source xslt = new StreamSource(new File("mystylesheet.xsl")); + Transformer transformer = factory.newTransformer(xslt);]]></source> + </section> + </section> + <section id="input"> + <title>Input Sources</title> + <p> + The input XSL-FO document is always received by FOP as a SAX stream (see the + <a href="../dev/design/parsing.html">Parsing Design Document</a> for the rationale). + </p> + <p> + However, you may not always have your input document available as a SAX stream. + But with JAXP it's easy to convert different input sources to a SAX stream so you + can pipe it into FOP. That sounds more difficult than it is. You simply have + to set up the right Source instance as input for the JAXP transformation. + A few examples: + </p> + <ul> + <li> + <strong>URL:</strong> <code>Source src = new StreamSource("http://localhost:8080/testfile.xml");</code> + </li> + <li> + <strong>File:</strong> <code>Source src = new StreamSource(new File("C:/Temp/myinputfile.xml"));</code> + </li> + <li> + <strong>String:</strong> <code>Source src = new StreamSource(new StringReader(myString)); // myString is a String</code> + </li> + <li> + <strong>InputStream:</strong> <code>Source src = new StreamSource(new MyInputStream(something));</code> + </li> + <li> + <strong>Byte Array:</strong> <code>Source src = new StreamSource(new ByteArrayInputStream(myBuffer)); // myBuffer is a byte[] here</code> + </li> + <li> + <strong>DOM:</strong> <code>Source src = new DOMSource(myDocument); // myDocument is a Document or a Node</code> + </li> + <li> + <strong>Java Objects:</strong> Please have a look at the <a href="#examples">Embedding examples</a> which contain an example for this. + </li> + </ul> + <p> + There are a variety of upstream data manipulations possible. + For example, you may have a DOM and an XSL stylesheet; or you may want to + set variables in the stylesheet. Interface documentation and some cookbook + solutions to these situations are provided in + <a href="http://xml.apache.org/xalan-j/usagepatterns.html">Xalan Basic Usage Patterns</a>. + </p> + </section> + <section id="config-internal"> + <title>Configuring Apache FOP Programmatically</title> + <p> + Apache FOP provides two levels on which you can customize FOP's + behaviour: the FopFactory and the user agent. + </p> + <section id="fop-factory"> + <title>Customizing the FopFactory</title> + <p> + The FopFactory holds configuration data and references to objects which are reusable over + multiple rendering runs. It's important to instantiate it only once (except in special + environments) and reuse it every time to create new FOUserAgent and Fop instances. + </p> + <p> + You can set all sorts of things on the FopFactory: + </p> + <ul> + <li> + <p> + The <strong>font base URL</strong> to use when resolving relative URLs for fonts. Example: + </p> + <source>fopFactory.setFontBaseURL("file:///C:/Temp/fonts");</source> + </li> + <li> + <p> + The <strong>hyphenation base URL</strong> to use when resolving relative URLs for + hyphenation patterns. Example: + </p> + <source>fopFactory.setHyphenBaseURL("file:///C:/Temp/hyph");</source> + </li> + <li> + <p> + Disable <strong>strict validation</strong>. When disabled FOP is less strict about the rules + established by the XSL-FO specification. Example: + </p> + <source>fopFactory.setStrictValidation(false);</source> + </li> + <li> + <p> + Enable an <strong>alternative set of rules for text indents</strong> that tries to mimic the behaviour of many commercial + FO implementations, that chose to break the specification in this respect. The default of this option is + 'false', which causes Apache FOP to behave exactly as described in the specification. To enable the + alternative behaviour, call: + </p> + <source>fopFactory.setBreakIndentInheritanceOnReferenceAreaBoundary(true);</source> + </li> + <li> + <p> + Set the <strong>source resolution</strong> for the document. This is used internally to determine the pixel + size for SVG images and bitmap images without resolution information. Default: 72 dpi. Example: + </p> + <source>fopFactory.setSourceResolution(96); // =96dpi (dots/pixels per Inch)</source> + </li> + <li> + <p> + Manually add an <strong>ElementMapping instance</strong>. If you want to supply a special FOP extension + you can give the instance to the FOUserAgent. Normally, the FOP extensions can be automatically detected + (see the documentation on extension for more info). Example: + </p> + <source>fopFactory.addElementMapping(myElementMapping); // myElementMapping is a org.apache.fop.fo.ElementMapping</source> + </li> + <li> + <p> + Set a <strong>URIResolver</strong> for custom URI resolution. By supplying a JAXP URIResolver you can add + custom URI resolution functionality to FOP. For example, you can use + <a href="ext:xml.apache.org/commons/resolver">Apache XML Commons Resolver</a> to make use of XCatalogs. Example: + </p> + <source>fopFactory.setURIResolver(myResolver); // myResolver is a javax.xml.transform.URIResolver</source> + <note> + Both the FopFactory and the FOUserAgent have a method to set a URIResolver. The URIResolver on the FopFactory + is primarily used to resolve URIs on factory-level (hyphenation patterns, for example) and it is always used + if no other URIResolver (for example on the FOUserAgent) resolved the URI first. + </note> + </li> + </ul> + </section> + <section id="user-agent"> + <title>Customizing the User Agent</title> + <p> + The user agent is the entity that allows you to interact with a single rendering run, i.e. the processing of a single + document. If you wish to customize the user agent's behaviour, the first step is to create your own instance + of FOUserAgent using the appropriate factory method on FopFactory and pass that + to the factory method that will create a new Fop instance: + </p> + <source><![CDATA[ + FopFactory fopFactory = FopFactory.newInstance(); // Reuse the FopFactory if possible! + // do the following for each new rendering run + FOUserAgent userAgent = fopFactory.newFOUserAgent(); + // customize userAgent + Fop fop = fopFactory.newFop(MimeConstants.MIME_POSTSCRIPT, userAgent, out);]]></source> + <p> + You can do all sorts of things on the user agent: + </p> + <ul> + <li> + <p> + The <strong>base URL</strong> to use when resolving relative URLs. Example: + </p> + <source>userAgent.setBaseURL("file:///C:/Temp/");</source> + </li> + <li> + <p> + Set the <strong>producer</strong> of the document. This is metadata information that can be used for certain output formats such as PDF. The default producer is "Apache FOP". Example: + </p> + <source>userAgent.setProducer("MyKillerApplication");</source> + </li> + <li> + <p> + Set the <strong>creating user</strong> of the document. This is metadata information that can be used for certain output formats such as PDF. Example: + </p> + <source>userAgent.setCreator("John Doe");</source> + </li> + <li> + <p> + Set the <strong>author</strong> of the document. This is metadata information that can be used for certain output formats such as PDF. Example: + </p> + <source>userAgent.setAuthor("John Doe");</source> + </li> + <li> + <p> + Override the <strong>creation date and time</strong> of the document. This is metadata information that can be used for certain output formats such as PDF. Example: + </p> + <source>userAgent.setCreationDate(new Date());</source> + </li> + <li> + <p> + Set the <strong>title</strong> of the document. This is metadata information that can be used for certain output formats such as PDF. Example: + </p> + <source>userAgent.setTitle("Invoice No 138716847");</source> + </li> + <li> + <p> + Set the <strong>keywords</strong> of the document. This is metadata information that can be used for certain output formats such as PDF. Example: + </p> + <source>userAgent.setKeywords("XML XSL-FO");</source> + </li> + <li> + <p> + Set the <strong>target resolution</strong> for the document. This is used to + specify the output resolution for bitmap images generated by bitmap renderers + (such as the TIFF renderer) and by bitmaps generated by Apache Batik for filter + effects and such. Default: 72 dpi. Example: + </p> + <source>userAgent.setTargetResolution(300); // =300dpi (dots/pixels per Inch)</source> + </li> + <li> + <p> + Set <strong>your own Renderer instance</strong>. If you want to supply your own renderer or + configure a Renderer in a special way you can give the instance to the FOUserAgent. Normally, + the Renderer instance is created by FOP. Example: + </p> + <source>userAgent.setRendererOverride(myRenderer); // myRenderer is an org.apache.fop.render.Renderer</source> + </li> + <li> + <p> + Set <strong>your own FOEventHandler instance</strong>. If you want to supply your own FOEventHandler or + configure an FOEventHandler subclass in a special way you can give the instance to the FOUserAgent. Normally, + the FOEventHandler instance is created by FOP. Example: + </p> + <source>userAgent.setFOEventHandlerOverride(myFOEventHandler); // myFOEventHandler is an org.apache.fop.fo.FOEventHandler</source> + </li> + <li> + <p> + Set a <strong>URIResolver</strong> for custom URI resolution. By supplying a JAXP URIResolver you can add + custom URI resolution functionality to FOP. For example, you can use + <a href="ext:xml.apache.org/commons/resolver">Apache XML Commons Resolver</a> to make use of XCatalogs. Example: + </p> + <source>userAgent.setURIResolver(myResolver); // myResolver is a javax.xml.transform.URIResolver</source> + <note> + Both the FopFactory and the FOUserAgent have a method to set a URIResolver. The URIResolver on the FOUserAgent is + used for resolving URIs which are document-related. If it's not set or cannot resolve a URI, the URIResolver + from the FopFactory is used. + </note> + </li> + </ul> + <note> + You should not reuse an FOUserAgent instance between FOP rendering runs although you can. Especially + in multi-threaded environment, this is a bad idea. + </note> + </section> + </section> + <section id="config-external"> + <title>Using a Configuration File</title> + <p> + Instead of setting the parameters manually in code as shown above you can also set + many values from an XML configuration file: + </p> + <source><![CDATA[ +import org.apache.avalon.framework.configuration.Configuration; +import org.apache.avalon.framework.configuration.DefaultConfigurationBuilder; + +/*..*/ + +DefaultConfigurationBuilder cfgBuilder = new DefaultConfigurationBuilder(); +Configuration cfg = cfgBuilder.buildFromFile(new File("C:/Temp/mycfg.xml")); +fopFactory.setUserConfig(cfg); + +/* ..or.. */ + +fopFactory.setUserConfig(new File("C:/Temp/mycfg.xml"));]]></source> + <p> + The layout of the configuration file is described on the <a href="configuration.html">Configuration page</a>. + </p> + </section> + <section id="hints"> + <title>Hints</title> + <section id="object-reuse"> + <title>Object reuse</title> + <p> + Fop instances shouldn't (and can't) be reused. Please recreate + Fop and FOUserAgent instances for each rendering run using the FopFactory. + This is a cheap operation as all reusable information is held in the + FopFactory. That's why it's so important to reuse the FopFactory instance. + </p> + </section> + <section id="awt"> + <title>AWT issues</title> + <p> + If your XSL-FO files contain SVG then Apache Batik will be used. When Batik is + initialised it uses certain classes in <code>java.awt</code> that + intialise the Java AWT classes. This means that a daemon thread + is created by the JVM and on Unix it will need to connect to a + DISPLAY. + </p> + <p> + The thread means that the Java application may not automatically quit + when finished, you will need to call <code>System.exit()</code>. These + issues should be fixed in the JDK 1.4. + </p> + <p> + If you run into trouble running FOP on a head-less server, please see the + <a href="graphics.html#batik">notes on Batik</a>. + </p> + </section> + <section id="render-info"> + <title>Getting information on the rendering process</title> + <p> + To get the number of pages that were rendered by FOP you can call + <code>Fop.getResults()</code>. This returns a <code>FormattingResults</code> object + where you can look up the number of pages produced. It also gives you the + page-sequences that were produced along with their id attribute and their + numbers of pages. This is particularly useful if you render multiple + documents (each enclosed by a page-sequence) and have to know the number of + pages of each document. + </p> + </section> + </section> + <section id="performance"> + <title>Improving performance</title> + <p> + There are several options to consider: + </p> + <ul> + <li> + Whenever possible, try to use SAX to couple the individual components involved + (parser, XSL transformer, SQL datasource etc.). + </li> + <li> + Depending on the target OutputStream (in case of a FileOutputStream, but not + for a ByteArrayOutputStream, for example) it may improve performance considerably + if you buffer the OutputStream using a BufferedOutputStream: + <code>out = new java.io.BufferedOutputStream(out);</code> + <br/> + Make sure you properly close the OutputStream when FOP is finished. + </li> + <li> + Cache the stylesheet. If you use the same stylesheet multiple times + you can set up a JAXP <code>Templates</code> object and reuse it each time you do + the XSL transformation. (More information can be found + <a class="fork" href="http://www.javaworld.com/javaworld/jw-05-2003/jw-0502-xsl.html">here</a>.) + </li> + <li> + Use an XSLT compiler like <a class="fork" href="http://xml.apache.org/xalan-j/xsltc_usage.html">XSLTC</a> + that comes with Xalan-J. + </li> + <li> + Fine-tune your stylesheet to make the XSLT process more efficient and to create XSL-FO that can + be processed by FOP more efficiently. Less is more: Try to make use of property inheritance where possible. + </li> + </ul> + </section> + <section id="multithreading"> + <title>Multithreading FOP</title> + <p> + Apache FOP may currently not be completely thread safe. + The code has not been fully tested for multi-threading issues, yet. + If you encounter any suspicious behaviour, please notify us. + </p> + <p> + There is also a known issue with fonts being jumbled between threads when using + the Java2D/AWT renderer (which is used by the -awt and -print output options). + In general, you cannot safely run multiple threads through the AWT renderer. + </p> + </section> +<section id="examples"> + <title>Examples</title> + <p> + The directory "{fop-dir}/examples/embedding" contains several working examples. + </p> + <section id="ExampleFO2PDF"> + <title>ExampleFO2PDF.java</title> + <p>This + <a href="http://svn.apache.org/viewcvs.cgi/xmlgraphics/fop/trunk/examples/embedding/java/embedding/ExampleFO2PDF.java?view=markup"> + example</a> +demonstrates the basic usage pattern to transform an XSL-FO +file to PDF using FOP. + </p> + <figure src="images/EmbeddingExampleFO2PDF.png" alt="Example XSL-FO to PDF"/> + </section> + <section id="ExampleXML2FO"> + <title>ExampleXML2FO.java</title> + <p>This + <a href="http://svn.apache.org/viewcvs.cgi/xmlgraphics/fop/trunk/examples/embedding/java/embedding/ExampleXML2FO.java?view=markup"> + example</a> +has nothing to do with FOP. It is there to show you how an XML +file can be converted to XSL-FO using XSLT. The JAXP API is used to do the +transformation. Make sure you've got a JAXP-compliant XSLT processor in your +classpath (ex. <a href="http://xml.apache.org/xalan-j">Xalan</a>). + </p> + <figure src="images/EmbeddingExampleXML2FO.png" alt="Example XML to XSL-FO"/> + </section> + <section id="ExampleXML2PDF"> + <title>ExampleXML2PDF.java</title> + <p>This + <a href="http://svn.apache.org/viewcvs.cgi/xmlgraphics/fop/trunk/examples/embedding/java/embedding/ExampleXML2PDF.java?view=markup"> + example</a> +demonstrates how you can convert an arbitrary XML file to PDF +using XSLT and XSL-FO/FOP. It is a combination of the first two examples +above. The example uses JAXP to transform the XML file to XSL-FO and FOP to +transform the XSL-FO to PDF. + </p> + <figure src="images/EmbeddingExampleXML2PDF.png" alt="Example XML to PDF (via XSL-FO)"/> + <p> +The output (XSL-FO) from the XSL transformation is piped through to FOP using +SAX events. This is the most efficient way to do this because the +intermediate result doesn't have to be saved somewhere. Often, novice users +save the intermediate result in a file, a byte array or a DOM tree. We +strongly discourage you to do this if it isn't absolutely necessary. The +performance is significantly higher with SAX. + </p> + </section> + <section id="ExampleObj2XML"> + <title>ExampleObj2XML.java</title> + <p>This + <a href="http://svn.apache.org/viewcvs.cgi/xmlgraphics/fop/trunk/examples/embedding/java/embedding/ExampleObj2XML.java?view=markup"> + example</a> +is a preparatory example for the next one. It's an example that +shows how an arbitrary Java object can be converted to XML. It's an often +needed task to do this. Often people create a DOM tree from a Java object and +use that. This is pretty straightforward. The example here, however, shows how +to do this using SAX, which will probably be faster and not even more +complicated once you know how this works. + </p> + <figure src="images/EmbeddingExampleObj2XML.png" alt="Example Java object to XML"/> + <p> +For this example we've created two classes: ProjectTeam and ProjectMember +(found in xml-fop/examples/embedding/java/embedding/model). They represent +the same data structure found in +xml-fop/examples/embedding/xml/xml/projectteam.xml. We want to serialize to XML a +project team with several members which exist as Java objects. +Therefore we created the two classes: ProjectTeamInputSource and +ProjectTeamXMLReader (in the same place as ProjectTeam above). + </p> + <p> +The XMLReader implementation (regard it as a special kind of XML parser) is +responsible for creating SAX events from the Java object. The InputSource +class is only used to hold the ProjectTeam object to be used. + </p> + <p> +Have a look at the source of ExampleObj2XML.java to find out how this is +used. For more detailed information see other resources on JAXP (ex. +<a class="fork" href="http://java.sun.com/xml/jaxp/dist/1.1/docs/tutorial/xslt/3_generate.html">An older JAXP tutorial</a>). + </p> + </section> + <section id="ExampleObj2PDF"> + <title>ExampleObj2PDF.java</title> + <p>This + <a href="http://svn.apache.org/viewcvs.cgi/xmlgraphics/fop/trunk/examples/embedding/java/embedding/ExampleObj2PDF.java?view=markup"> + example</a> +combines the previous and the third to demonstrate +how you can transform a Java object to a PDF directly in one smooth run +by generating SAX events from the Java object that get fed to an XSL +transformation. The result of the transformation is then converted to PDF +using FOP as before. + </p> + <figure src="images/EmbeddingExampleObj2PDF.png" alt="Example Java object to PDF (via XML and XSL-FO)"/> + </section> + <section id="ExampleDOM2PDF"> + <title>ExampleDOM2PDF.java</title> + <p>This + <a href="http://svn.apache.org/viewcvs.cgi/xmlgraphics/fop/trunk/examples/embedding/java/embedding/ExampleDOM2PDF.java?view=markup"> + example</a> +has FOP use a DOMSource instead of a StreamSource in order to +use a DOM tree as input for an XSL transformation. + </p> + </section> + <section id="ExampleSVG2PDF"> + <title>ExampleSVG2PDF.java (PDF Transcoder example)</title> + <p>This + <a href="http://svn.apache.org/viewcvs.cgi/xmlgraphics/fop/trunk/examples/embedding/java/embedding/ExampleSVG2PDF.java?view=markup"> + example</a> +shows the usage of the PDF Transcoder, a sub-application within FOP. +It is used to generate a PDF document from an SVG file. + </p> + </section> + <section id="example-notes"> + <title>Final notes</title> + <p> +These examples should give you an idea of what's possible. It should be easy +to adjust these examples to your needs. Also, if you have other examples that you +think should be added here, please let us know via either the fop-users or fop-dev +mailing lists. Finally, for more help please send your questions to the fop-users +mailing list. + </p> + </section> +</section> + </body> +</document> + |