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Posted to fop-commits@xmlgraphics.apache.org by ga...@apache.org on 2012/07/05 21:15:15 UTC
svn commit: r1357814 [2/7] - in /xmlgraphics/fop/branches/fop-1_1: ./
src/documentation/content/ src/documentation/content/xdocs/
src/documentation/content/xdocs/1.1rc1/
src/documentation/content/xdocs/1.1rc1/fotree/
src/documentation/content/xdocs/1.1...
Added: xmlgraphics/fop/branches/fop-1_1/src/documentation/content/xdocs/1.1rc1/configuration.xml
URL: http://svn.apache.org/viewvc/xmlgraphics/fop/branches/fop-1_1/src/documentation/content/xdocs/1.1rc1/configuration.xml?rev=1357814&view=auto
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--- xmlgraphics/fop/branches/fop-1_1/src/documentation/content/xdocs/1.1rc1/configuration.xml (added)
+++ xmlgraphics/fop/branches/fop-1_1/src/documentation/content/xdocs/1.1rc1/configuration.xml Thu Jul 5 19:15:13 2012
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+<?xml version="1.0" encoding="UTF-8" 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">
+<document>
+ <header>
+ <title>Apache⢠FOP: Configuration</title>
+ <version>$Revision$</version>
+ </header>
+
+ <body>
+ <section id="general">
+ <title>Configuration File Basics</title>
+ <p>
+ The Apache⢠FOP configuration file is an XML file containing a variety of settings that are useful
+ for controlling FOP's behavior, and for helping it find resources that you wish it to use.
+ </p>
+ <p>
+ The easiest way to get started using a FOP configuration file is to copy the sample found
+ at <code>{fop-dir}/conf/fop.xconf</code> to a location of your choice, and then to
+ edit it according to your needs.
+ It contains templates for the various configuration options, most of which are commented
+ out. Remove the comments and change the settings for entries that you wish to use.
+ Be sure to follow any instructions, including comments which specify the value range.
+ Also, since the configuration file is XML, be sure to keep it well-formed.
+ </p>
+ <section id="general-available">
+ <title>Making Configuration Available to FOP</title>
+ <p>After creating your configuration file, you must tell FOP how to find it:</p>
+ <ul>
+ <li>
+ If running FOP from the command-line, see the "-c" command-line option in
+ <a href="running.html">Running FOP</a>.
+ </li>
+ <li>
+ If running FOP as an embedded application, see
+ <a href="embedding.html#config-external">Embedding, Using a Configuration File</a>.
+ </li>
+ </ul>
+ <p>
+ See <a href="embedding.html#config-internal">Setting the Configuration Programmatically</a>
+ for instructions on how to do so in an embedded environment.
+ </p>
+ </section>
+ </section>
+ <section id="general-elements">
+ <title>Summary of the General Configuration Options</title>
+ <table>
+ <tr>
+ <th>Element</th>
+ <th>Data Type (for the value)</th>
+ <th>Description</th>
+ <th>Default Value</th>
+ </tr>
+ <tr>
+ <td>base</td>
+ <td>URL or directory</td>
+ <td>Specifies the base URL based on which relative URL will be resolved.</td>
+ <td>current directory</td>
+ </tr>
+ <tr>
+ <td>font-base</td>
+ <td>URL or directory</td>
+ <td>Specifies the base URL based on which relative font URLs will be resolved.
+ </td>
+ <td>base URL/directory (above)</td>
+ </tr>
+ <tr>
+ <td>hyphenation-base</td>
+ <td>URL or directory</td>
+ <td>Specifies the base URL based on which relative URLs to hyphenation pattern
+ files will be resolved. If not specified, support for user-supplied hyphenation
+ patterns remains disabled.
+ </td>
+ <td>disabled</td>
+ </tr>
+ <tr>
+ <td colspan="4">Relative URIs for the above three properties are evaluated relative to the base URI of the configuration file. If the configuration is provided programmatically, the base URI can be set with <code>FopFactory.setUserConfigBaseURI</code>; default is the current working directory.</td>
+ </tr>
+ <tr>
+ <td>hyphenation-pattern</td>
+ <td>String, attribute lang, attribute country (optional)</td>
+ <td>Register a file name for the hyphenation pattern for the mentioned language and country. Language ll and country CC must both consist of two letters.</td>
+ <td>ll_CC</td>
+ </tr>
+ <tr>
+ <td>source-resolution</td>
+ <td>Integer, dpi</td>
+ <td>
+ Resolution in dpi (dots per inch) which is used internally to determine the pixel
+ size for SVG images and bitmap images without resolution information.
+ </td>
+ <td>72 dpi</td>
+ </tr>
+ <tr>
+ <td>target-resolution</td>
+ <td>Integer, dpi</td>
+ <td>
+ Resolution in dpi (dots per inch) 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.
+ </td>
+ <td>72 dpi</td>
+ </tr>
+ <tr>
+ <td>strict-configuration</td>
+ <td>Boolean (true, false)</td>
+ <td>
+ Setting this option to 'true' will cause FOP to strictly verify the contents of the
+ FOP configuration file to ensure that defined resources (such as fonts and base
+ URLs/directories) are valid and available to FOP. Any errors found will cause FOP to
+ immediately raise an exception.</td>
+ <td>false</td>
+ </tr>
+ <tr>
+ <td>strict-validation</td>
+ <td>Boolean (true, false)</td>
+ <td>
+ Setting this option to 'false' causes FOP to be more forgiving about XSL-FO validity,
+ for example, you're allowed to specify a border on a region-body which is supported
+ by some FO implementations but is non-standard. Note that such a border would
+ currently have no effect in Apache FOP.</td>
+ <td>true</td>
+ </tr>
+ <tr>
+ <td>break-indent-inheritance</td>
+ <td>Boolean (true, false)</td>
+ <td>
+ Setting this option to 'true' causes FOP to use an alternative rule set to determine
+ text indents specified through margins, start-indent and end-indent. Many commercial
+ FO implementations have chosen to break the XSL specification in this aspect. This
+ option tries to mimic their behaviour. Please note that Apache FOP may still not
+ behave exactly like those implementations either because FOP has not fully matched
+ the desired behaviour and because the behaviour among the commercial implementations
+ varies. The default for this option (i.e. false) is to behave exactly like the
+ specification describes.</td>
+ <td>false</td>
+ </tr>
+ <tr>
+ <td>complex-scripts</td>
+ <td>attribute disabled (optional)</td>
+ <td>
+ If present and if an attribute 'disabled' is specified with the value 'false', then
+ complex script features are disabled. The same result can be obtained on an FOP
+ per-invocation basis by specifying a '-nocs' command line option when invoking FOP.
+ When complex script features are disabled, all bidirectional processing and complex
+ character to glyph mapping processing is disabled; in addition, the loading of
+ GDEF, GSUB, and GPOS advanced typographic tables is disabled for OpenType and
+ TrueType fonts. Unless disabled by this mechanism or by use of the '-nocs' command
+ line option, complex script features will be enabled by default.
+ </td>
+ <td>n/a</td>
+ </tr>
+ <tr>
+ <td>default-page-settings</td>
+ <td>n/a</td>
+ <td>
+ Specifies the default width and height of a page if "auto" is specified
+ for either or both values. Use "height" and "width" attributes on the
+ default-page-settings element to specify the two values.</td>
+ <td>"height" 11 inches, "width" 8.26 inches</td>
+ </tr>
+ <!-- Disabled: no simultaneous Renderer and IF implementations at the moment
+ <tr>
+ <td>prefer-renderer</td>
+ <td>boolean (true, false)</td>
+ <td>
+ By default, FOP prefers the newer output implementations based on the
+ <code>IFDocumentHandler</code> interface. If no such implementation can be found for
+ a given MIME type, it looks for an implementation of the <code>Renderer</code> interface.
+ If necessary, you can invert the lookup order to prefer the Renderer variant over the
+ IFDocumentHandler variant by setting this value to true.
+ </td>
+ <td>false</td>
+ </tr>
+ -->
+ <tr>
+ <td>use-cache</td>
+ <td>boolean (true, false)</td>
+ <td>All fonts information that has been gathered as a result of "directory"
+ or "auto-detect" font configurations will be cached for future rendering runs.
+ This setting should improve performance on systems where
+ fonts have been configured using the "directory" or "auto-detect" tag mechanisms.
+ By default this option is switched on.</td>
+ <td>true</td>
+ </tr>
+ <tr>
+ <td>cache-file</td>
+ <td>String</td>
+ <td>This option specifies the file/directory path of the fop cache file.
+ This file is currently only used to cache font triplet information for future reference.</td>
+ <td>${base}/conf/fop.cache</td>
+ </tr>
+ <tr>
+ <td>renderers</td>
+ <td>(see text below)</td>
+ <td>Contains the configuration for each renderer. See below.</td>
+ <td>N/A</td>
+ </tr>
+ </table>
+ <p>
+ This is an excerpt from the example configuration file coming with FOP:
+ </p>
+ <source><![CDATA[
+<fop version="1.0">
+
+ <!-- Strict user configuration -->
+ <strict-configuration>true</strict-configuration>
+
+ <!-- Strict FO validation -->
+ <strict-validation>true</strict-validation>
+
+ <!-- Base URL for resolving relative URLs -->
+ <base>./</base>
+
+ <!-- Font Base URL for resolving relative font URLs -->
+ <font-base>./</font-base>
+
+ <!-- Source resolution in dpi (dots/pixels per inch) for determining the size of pixels in SVG and bitmap images, default: 72dpi -->
+ <source-resolution>72</source-resolution>
+ <!-- Target resolution in dpi (dots/pixels per inch) for specifying the target resolution for generated bitmaps, default: 72dpi -->
+ <target-resolution>72</target-resolution>
+
+ <!-- default page-height and page-width, in case
+ value is specified as auto -->
+ <default-page-settings height="11in" width="8.26in"/>
+
+ <!-- Use file name nl_Bel instead of the default nl_BE -->
+ <hyphenation-pattern lang="nl" country="BE">nl_Bel</hyphenation-pattern>
+
+ <!-- etc. etc..... -->
+</fop>]]></source>
+ </section>
+ <section id="image-loading">
+ <title>Image Loading Customization</title>
+ <p>
+ Apache FOP uses the image loading framework from
+ <a href="http://xmlgraphics.apache.org/commons/">Apache XML Graphics Commons</a> to load
+ images using various plug-ins. Every image loader plug-in has a hard-coded usage penalty
+ that influences which solution is chosen if there are multiple possibilities to load an image.
+ Sometimes, though, these penalties need to be tweaked and this can be done in the FOP
+ configuration. An example:
+ </p>
+ <source><![CDATA[<fop version="1.0">
+ [..]
+ <image-loading>
+ <penalty value="10000"
+ class="org.apache.xmlgraphics.image.loader.impl.ImageLoaderRawCCITTFax"/>
+ <penalty value="INFINITE"
+ class="org.apache.xmlgraphics.image.loader.impl.ImageLoaderInternalTIFF"/>
+ </image-loading>
+ <renderers....
+</fop>]]></source>
+ <p>
+ The first penalty element increases the penalty for the raw CCITT loader. This practically
+ forces the decoding of CCITT compressed TIFF images except if there are no TIFF codecs
+ available.
+ </p>
+ <p>
+ The second penalty element sets an "infinite" penalty for the TIFF loader using the internal
+ TIFF codec. This practically disables that plug-in as it will never be chosen as a possible
+ solution.
+ </p>
+ <p>
+ Negative penalties are possible to promote a plug-in but a negative penalty sum will be
+ treated as zero penalty in most cases. For more details on the image loading framework,
+ please consult the documentation there.
+ </p>
+ </section>
+ <section id="renderers">
+ <title>Renderer configuration</title>
+ <p>
+ Each Renderer has its own configuration section which is identified by the
+ MIME type the Renderer is written for, ex. "application/pdf" for the PDF Renderer.
+ </p>
+ <p>
+ The configuration for the PDF Renderer could look like this:
+ </p>
+ <source><![CDATA[
+ <renderers>
+ <renderer mime="application/pdf">
+ <filterList>
+ <!-- provides compression using zlib flate (default is on) -->
+ <value>flate</value>
+ </filterList>
+ <fonts>
+ <font metrics-url="arial.xml" kerning="yes" embed-url="arial.ttf">
+ <font-triplet name="Arial" style="normal" weight="normal"/>
+ <font-triplet name="ArialMT" style="normal" weight="normal"/>
+ </font>
+ <font metrics-url="arialb.xml" kerning="yes" embed-url="arialb.ttf">
+ <font-triplet name="Arial" style="normal" weight="bold"/>
+ <font-triplet name="ArialMT" style="normal" weight="bold"/>
+ </font>
+ </fonts>
+ </renderer>
+
+ <renderer mime="application/postscript">
+ <!-- etc. etc..... -->]]></source>
+ <p>
+ The details on the font configuration can be found on the separate <a href="fonts.html">Fonts</a> page.
+ Note especially the section entitled <a href="fonts.html#register">Register Fonts with FOP</a>.
+ </p>
+ <section id="pdf-renderer">
+ <title>Special Settings for the PDF Renderer</title>
+ <p>
+ The configuration element for the PDF renderer contains two elements. One is for the font configuration
+ (please follow the link above) and one is for the "filter list". The filter list controls how the
+ individual objects in a PDF file are encoded. By default, all objects get "flate" encoded (i.e. simply
+ compressed with the same algorithm that is also used in ZIP files). Most users don't need to change that
+ setting. For debugging purposes, it may be desired not to compress the internal objects at all so the
+ generated PDF commands can be read. In that case, you can simply use the following filter list. The
+ second filter list (type="image") ensures that all images still get compressed but also ASCII-85 encoded
+ so the produced PDF file is still easily readable in a text editor.
+ </p>
+ <source><![CDATA[
+ <renderer mime="application/pdf">
+ <filterList>
+ <value>null</value>
+ </filterList>
+ <filterList type="image">
+ <value>flate</value>
+ <value>ascii-85</value>
+ </filterList>
+
+ <fonts....
+ </renderer>]]></source>
+ <p>
+ Another (optional) setting specific to the PDF Renderer is an output color profile, an ICC
+ color profile which indicates the target color space the PDF file is generated for. This
+ setting is mainly used in conjunction with the <a href="pdfx.html">PDF/X</a> feature.
+ An example:
+ </p>
+ <source><![CDATA[
+ <renderer mime="application/pdf">
+ <filterList...
+
+ <output-profile>C:\FOP\Color\EuropeISOCoatedFOGRA27.icc</output-profile>
+
+ <fonts....
+ </renderer>]]></source>
+ <p>
+ Some people don't have high requirements on color fidelity but instead want the smallest
+ PDF file sizes possible. In this case it's possible to disable the default sRGB color space
+ which XSL-FO requires. This will cause RGB colors to be generated as device-specific RGB.
+ Please note that this option is unavailable (and will cause an error) if you enable
+ PDF/A or PDF/X functionality or if you specify an output profile. This setting will make the
+ PDF about 4KB smaller. To disable the sRGB color space add the following setting:
+ </p>
+ <source><![CDATA[
+ <renderer mime="application/pdf">
+ <filterList...
+
+ <disable-srgb-colorspace>true</disable-srgb-colorspace>
+
+ <fonts....
+ </renderer>]]></source>
+
+ <p>FOP supports encryption of PDF output, thanks to Patrick C. Lankswert.
+ This feature is commonly used to prevent unauthorized viewing, printing, editing, copying text
+ from the document and doing annotations. It is also possible to ask the user for a password in
+ order to view the contents. Note that there already exist third party applications which can
+ decrypt an encrypted PDF without effort and allow the aforementioned operations, therefore the
+ degree of protection is limited. For further information about features and restrictions
+ regarding PDF encryption, look at the documentation coming with Adobe Acrobat or the technical
+ documentation on the Adobe web site.</p>
+ <source><![CDATA[
+ <renderer mime="application/pdf">
+ <encryption-params>
+ <encryption-length>128</encryption-length>
+ <user-password>testuserpass</user-password>
+ <owner-password>testownerpass</owner-password>
+ <noprint/>
+ <nocopy/>
+ <noedit/>
+ <noannotations/>
+ <nofillinforms/>
+ <noaccesscontent/>
+ <noassembledoc/>
+ <noprinthq/>
+ </encryption-params>
+ </renderer>]]></source>
+ <p>
+ By default FOP produces PDF files of version 1.4, but this can be changed in order to benefit
+ from features that appeared in newer versions of PDF. At the moment, only a few features from
+ PDF 1.5 have been implemented, but the configuration element will accept any value between
+ 1.4 and 1.7. This is the value that will appear in the PDF header, although only features up
+ to 1.5 will actually be used.
+ <source><![CDATA[
+ <renderer mime="application/pdf">
+ <version>1.5</version>
+ <!-- Versions 1.4, 1.5, 1.6 and 1.7 are accepted, all other values are invalid -->
+ </renderer>]]></source>
+ </p>
+
+ </section>
+ <section id="ps-renderer">
+ <title>Special Settings for the PostScript Renderer</title>
+ <p>
+ Besides the normal font configuration (the same "fonts" element as for the PDF renderer) the PostScript
+ renderer has an additional setting to force landscape pages to be rotated to fit on a page inserted into
+ the printer in portrait mode. Set the value to "true" to activate this feature. The default is "false".
+ Example:
+ </p>
+ <source><![CDATA[
+ <renderer mime="application/postscript">
+ <auto-rotate-landscape>true</auto-rotate-landscape>
+
+ <fonts>
+ <font metrics-url="arial.xml" kerning="yes" embed-url="arial.ttf">
+ <font-triplet name="Arial" style="normal" weight="normal"/>
+ <font-triplet name="ArialMT" style="normal" weight="normal"/>
+ </font>
+ <font metrics-url="arialb.xml" kerning="yes" embed-url="arialb.ttf">
+ <font-triplet name="Arial" style="normal" weight="bold"/>
+ <font-triplet name="ArialMT" style="normal" weight="bold"/>
+ </font>
+ </fonts>
+ </renderer>]]></source>
+ </section>
+ <section id="pcl-renderer">
+ <title>Special Settings for the PCL Renderer</title>
+ <p>
+ Non-standard fonts for the PCL renderer are made available through the Java2D subsystem which means that
+ you don't have to do any custom font configuration in this case but you have to use the font names
+ offered by Java.
+ </p>
+ <p>
+ Additionally, there are certain settings that control how the renderer handles various elements.
+ </p>
+<source><![CDATA[<renderer mime="application/x-pcl">
+ <rendering>quality</rendering>
+ <text-rendering>bitmap</text-rendering>
+</renderer>]]></source>
+ <p>
+ The default value for the "rendering" setting is "speed" which causes borders
+ to be painted as plain rectangles. In this mode, no special borders (dotted,
+ dashed etc.) are available. If you want support for all border modes, set the
+ value to "quality" as indicated above. This will cause the borders to be painted
+ as bitmaps.
+ </p>
+ <p>
+ The default value for the "text-rendering" setting is "auto" which paints the
+ base fonts using PCL fonts. Non-base fonts are painted as bitmaps through Java2D.
+ If the mix of painting methods results in unwelcome output, you can set this
+ to "bitmap" which causes all text to be rendered as bitmaps.
+ </p>
+ </section>
+ <section id="afp-renderer">
+ <title>Special Settings for the AFP Renderer</title>
+ <p>
+ </p>
+ <p>
+ Additionally, there are certain settings that control how the renderer handles various elements.
+ </p>
+<source><![CDATA[<renderer mime="application/x-afp">
+ <images mode="b+w" bits-per-pixel="8" native="true"/>
+ <renderer-resolution>240</renderer-resolution>
+ <line-width-correction>2.5</line-width-correction>
+
+ <!-- a default external resource group file -->
+ <resource-group-file>resources.afp</resource-group-file>
+</renderer>]]></source>
+ <p>
+ The default value for the images "mode" setting is "b+w" (black and white). When the images "mode" setting is "b+w" a "bits-per-pixel" setting can be provided to aid the grayscale conversion process. With this setting all images referenced in your source document are converted to an IOCA FS45 grayscale bitmap image form.
+ When the setting is "color" all images are converted to an IOCA FS45 color bitmap image form. When "native" setting is "true", all images encountered (TIFF, GIF, JPEG and Encapsulated Postscript etc.) will be embedded directly in the datastream in their native form using a MO:DCA Object Container.
+ </p>
+ <p>
+ The default value for the "renderer-resolution" is 240 dpi.
+ </p>
+ <p>
+ The default line width is device dependent and may need to be fine tuned so that the output matches the expected result. The default correction value is 2.5.
+ </p>
+ <!--
+ <p>
+ The default value for the MO:DCA "interchange-set" is "MO:DCA-L". Other compliance settings include presentation interchange sets "MO:DCA-P IS/1" and "MO:DCA-P IS/2" (Resource Groups).
+ </p>
+ -->
+ <p>
+ By default if there is no configuration definition for "resource-group-file", external resources will be placed in a file called resources.afp.
+ </p>
+ </section>
+ </section>
+
+ <section>
+ <title>When it does not work</title>
+
+ <p>FOP searches the configuration file for the information it
+expects, at the position it expects. When that information is not
+present, FOP will not complain, it will just continue. When there is
+other information in the file, FOP will not complain, it will just
+ignore it. That means that when your configuration information is in
+the file but in a different XML element, or in a different XML path,
+than FOP expects, it will be silently ignored.</p>
+
+ <p>Check the following possibilities:</p>
+
+ <ul>
+ <li>The format of the configuration file has changed
+considerably between FOP 0.20.5 and FOP 1.0 and its beta versions. Did
+you convert your file to the new format?</li>
+
+ <li>The FOP distribution contains a schema for configuration
+files, at src/foschema/fop-configuration.xsd. Did you validate your
+configuration file against it? Add the following schema location to
+the <code>schema</code> element:
+
+<source><![CDATA[<fop
+xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+xsi:noNamespaceSchemaLocation=
+"http://svn.apache.org/viewvc/xmlgraphics/fop/trunk/src/foschema/fop-configuration.xsd?view=co">]]>
+</source>
+
+and run the configuration file through a validating schema
+parser. Note that the schema cannot detect all errors, and that it is
+stricter about the order of some elements than FOP itself is.</li>
+
+ <li>Run FOP in debug mode (command line option
+<code>-d</code>). This makes FOP report which configuration
+information it finds. Check if FOP finds what you expect.</li>
+
+ </ul>
+
+ </section>
+ </body>
+</document>
Added: xmlgraphics/fop/branches/fop-1_1/src/documentation/content/xdocs/1.1rc1/embedding.xml
URL: http://svn.apache.org/viewvc/xmlgraphics/fop/branches/fop-1_1/src/documentation/content/xdocs/1.1rc1/embedding.xml?rev=1357814&view=auto
==============================================================================
--- xmlgraphics/fop/branches/fop-1_1/src/documentation/content/xdocs/1.1rc1/embedding.xml (added)
+++ xmlgraphics/fop/branches/fop-1_1/src/documentation/content/xdocs/1.1rc1/embedding.xml Thu Jul 5 19:15:13 2012
@@ -0,0 +1,752 @@
+<?xml version="1.0" encoding="UTF-8" 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 Apache⢠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. MIME type) to use and, if the selected output format 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 document handler
+ instance (details below). Finally, you retrieve a SAX DefaultHandler instance from
+ the Fop object and use that as the SAXResult of your transformation.
+ </p>
+ </section>
+ <section id="API">
+ <title>The API</title>
+ <p>
+ FOP has many classes which express the "public" access modifier, however, this is not
+ indicative of their inclusion into the public API. Every attempt will be made to keep the
+ public API static, to minimize regressions for existing users, however, since the API is not
+ clearly defined, the list of classes below are the generally agreed public API:
+ <source><![CDATA[
+org.apache.fop.apps.*
+org.apache.fop.fo.FOEventHandler
+org.apache.fop.fo.ElementMappingRegistry
+org.apache.fop.fonts.FontManager
+org.apache.fop.events.EventListener
+org.apache.fop.events.Event
+org.apache.fop.events.model.EventSeverity
+org.apache.fop.render.ImageHandlerRegistry
+org.apache.fop.render.RendererFactory
+org.apache.fop.render.intermediate.IFContext
+org.apache.fop.render.intermediate.IFDocumentHandler
+org.apache.fop.render.intermediate.IFException
+org.apache.fop.render.intermediate.IFParser
+org.apache.fop.render.intermediate.IFSerializer
+org.apache.fop.render.intermediate.IFUtil
+org.apache.fop.render.intermediate.util.IFConcatenator]]></source>
+ </p>
+ </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: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>
+ <p>
+ By default, <a href="ext: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:commons-logging">documentation for Jakarta Commons Logging</a> on
+ how to configure alternative backends.
+ </p>
+ <p>
+ As a result of the above we differentiate between two kinds of "logging":
+ </p>
+ <ul>
+ <li>(FOP-)Developer-oriented logging</li>
+ <li><a href="events.html">User/Integrator-oriented feedback</a> (NEW!)</li>
+ </ul>
+ <p>
+ The use of "feedback" instead of "logging" is intentional. Most people were using
+ log output as a means to get feedback from events within FOP. Therefore, FOP now
+ includes an <code>event</code> package which can be used to receive feedback from
+ the layout engine and other components within FOP <strong>per rendering run</strong>.
+ This feedback is not just some
+ text but event objects with parameters so these events can be interpreted by code.
+ Of course, there is a facility to turn these events into normal human-readable
+ messages. For details, please read on on the <a href="events.html">Events page</a>.
+ This leaves normal logging to be mostly a thing used by the FOP developers
+ although anyone can surely activate certain logging categories but the feedback
+ from the loggers won't be separated by processing runs. If this is required,
+ the <a href="events.html">Events subsystem</a> is the right approach.
+ </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.getFontManager().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 Document Handler</strong>. This feature can be used for several purposes, the most likey usage of which would probably be
+ binding a MIME type when the output is Intermediate Format (see <a href="#documenthandlers">Document Handlers</a>). This also allows advanced
+ users to create their own implementation of the document handler.
+ </p>
+ <source>userAgent.setDocumentHandlerOverride(documentHandler) // documentHandler is an instance of org.apache.fop.render.intermediate.IFDocumentHandler</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="documenthandlers">
+ <title>Document Handlers</title>
+ <p>
+ The document handlers are classes that inherit from <code>org.apache.fop.render.intermediate.IFDocumentHandler</code>. This
+ is an interface for which a MIME type specific implementation can be created. This same handler is used either when XSL-FO
+ is used as the input or when Intermediate Format is used. Since IF is output format agnostic, if custom fonts or other
+ configuration information that affect layout (specific to a particular MIME type) are given then FOP needs that contextual
+ information. The document handler provides that context so that when the IF is rendered, it is more visually consistent with
+ FO rendering. The code below shows an example of how a document handler can be used to provide PDF configuration data to the
+ IFSerializer.
+ <source><![CDATA[
+IFDocumentHandler targetHandler = userAgent.getRendererFactory().createDocumentHandler(userAgent, MimeConstants.MIME_PDF);
+
+IFSerializer ifSerializer = new IFSerializer(); //Create the IFSerializer to write the intermediate format
+ifSerializer.setContext(new IFContext(userAgent));
+ifSerializer.mimicDocumentHandler(targetHandler); //Tell the IFSerializer to mimic the target format
+
+userAgent.setDocumentHandlerOverride(ifSerializer); //Make sure the prepared document handler is used
+ ]]></source>
+ The rest of the code is the same as in <a href="#basics">Basic Usage Patterns</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>
+ <li>
+ You may also wish to consider trying to reduce <a href="http://xmlgraphics.apache.org/fop/trunk/running.html#memory">memory usage</a>.
+ </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="ExampleConcat">
+ <title>ExampleConcat.java (IF Concatenation example)</title>
+ <p>
+This can be found in the <code>embedding.intermediate</code> package within the
+examples and describes how IF can be concatenated to produce a document. Because
+IF has been through FOPs layout engine, it should be visually consistent with FO
+rendered documents while allowing the user to merge numerous documents together.
+ </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>
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--- xmlgraphics/fop/branches/fop-1_1/src/documentation/content/xdocs/1.1rc1/events.xml (added)
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@@ -0,0 +1,449 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+ 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">
+<document>
+ <header>
+ <title>Apache⢠FOP: Events/Processing Feedback</title>
+ <version>$Revision$</version>
+ </header>
+ <body>
+ <section id="introduction">
+ <title>Introduction</title>
+ <p>
+ In versions until 0.20.5, Apache⢠FOP used
+ <a href="http://excalibur.apache.org/framework/index.html">Avalon-style Logging</a> where
+ it was possible to supply a logger per processing run. During the redesign
+ the logging infrastructure was switched over to
+ <a href="http://commons.apache.org/logging/">Commons Logging</a> which is (like Log4J or
+ java.util.logging) a "static" logging framework (the logger is accessed through static
+ variables). This made it very difficult in a multi-threaded system to retrieve information
+ for a single processing run.
+ </p>
+ <p>
+ With FOP's event subsystem, we'd like to close this gap again and even go further. The
+ first point is to realize that we have two kinds of "logging". Firstly, we have the logging
+ infrastructure for the (FOP) developer who needs to be able to enable finer log messages
+ for certain parts of FOP to track down a certain problem. Secondly, we have the user who
+ would like to be informed about missing images, overflowing lines or substituted fonts.
+ These messages (or events) are targeted at less technical people and may ideally be
+ localized (translated). Furthermore, tool and solution builders would like to integrate
+ FOP into their own solutions. For example, an FO editor should be able to point the user
+ to the right place where a particular problem occurred while developing a document template.
+ Finally, some integrators would like to abort processing if a resource (an image or a font)
+ has not been found, while others would simply continue. The event system allows to
+ react on these events.
+ </p>
+ <p>
+ On this page, we won't discuss logging as such. We will show how the event subsystem can
+ be used for various tasks. We'll first look at the event subsystem from the consumer side.
+ Finally, the production of events inside FOP will be discussed (this is mostly interesting
+ for FOP developers only).
+ </p>
+ </section>
+ <section id="consumer">
+ <title>The consumer side</title>
+ <p>
+ The event subsystem is located in the <code>org.apache.fop.events</code> package and its
+ base is the <code>Event</code> class. An instance is created for each event and is sent
+ to a set of <code>EventListener</code> instances by the <code>EventBroadcaster</code>.
+ An <code>Event</code> contains:
+ </p>
+ <ul>
+ <li>an event ID,</li>
+ <li>a source object (which generated the event),</li>
+ <li>a severity level (Info, Warning, Error and Fatal Error) and</li>
+ <li>a map of named parameters.</li>
+ </ul>
+ <p>
+ The <code>EventFormatter</code> class can be used to translate the events into
+ human-readable, localized messages.
+ </p>
+ <p>
+ A full example of what is shown here can be found in the
+ <code>examples/embedding/java/embedding/events</code> directory in the FOP distribution.
+ The example can also be accessed
+ <a href="http://svn.apache.org/viewvc/xmlgraphics/fop/trunk/examples/embedding/java/embedding/events/">via the web</a>.
+ </p>
+ <section id="write-listener">
+ <title>Writing an EventListener</title>
+ <p>
+ The following code sample shows a very simple EventListener. It basically just sends
+ all events to System.out (stdout) or System.err (stderr) depending on the event severity.
+ </p>
+ <source><![CDATA[import org.apache.fop.events.Event;
+import org.apache.fop.events.EventFormatter;
+import org.apache.fop.events.EventListener;
+import org.apache.fop.events.model.EventSeverity;
+
+/** A simple event listener that writes the events to stdout and stderr. */
+public class SysOutEventListener implements EventListener {
+
+ /** {@inheritDoc} */
+ public void processEvent(Event event) {
+ String msg = EventFormatter.format(event);
+ EventSeverity severity = event.getSeverity();
+ if (severity == EventSeverity.INFO) {
+ System.out.println("[INFO ] " + msg);
+ } else if (severity == EventSeverity.WARN) {
+ System.out.println("[WARN ] " + msg);
+ } else if (severity == EventSeverity.ERROR) {
+ System.err.println("[ERROR] " + msg);
+ } else if (severity == EventSeverity.FATAL) {
+ System.err.println("[FATAL] " + msg);
+ } else {
+ assert false;
+ }
+ }
+}]]></source>
+ <p>
+ You can see that for every event the method <code>processEvent</code> of the
+ <code>EventListener</code> will be called. Inside this method you can do whatever
+ processing you would like including throwing a <code>RuntimeException</code>, if you want
+ to abort the current processing run.
+ </p>
+ <p>
+ The code above also shows how you can turn an event into a human-readable, localized
+ message that can be presented to a user. The <code>EventFormatter</code> class does
+ this for you. It provides additional methods if you'd like to explicitly specify
+ the locale.
+ </p>
+ <p>
+ It is possible to gather all events for a whole processing run so they can be
+ evaluated afterwards. However, care should be taken about memory consumption since
+ the events provide references to objects inside FOP which may themselves have
+ references to other objects. So holding on to these objects may mean that whole
+ object trees cannot be released!
+ </p>
+ </section>
+ <section id="add-listener">
+ <title>Adding an EventListener</title>
+ <p>
+ To register the event listener with FOP, get the <code>EventBroadcaster</code> which
+ is associated with the user agent (<code>FOUserAgent</code>) and add it there:
+ </p>
+ <source><![CDATA[FOUserAgent foUserAgent = fopFactory.newFOUserAgent();
+foUserAgent.getEventBroadcaster().addEventListener(new SysOutEventListener());]]></source>
+ <p>
+ Please note that this is done separately for each processing run, i.e. for each
+ new user agent.
+ </p>
+ </section>
+ <section id="listener-example1">
+ <title>An additional listener example</title>
+ <p>
+ Here's an additional example of an event listener:
+ </p>
+ <p>
+ By default, FOP continues processing even if an image wasn't found. If you have
+ more strict requirements and want FOP to stop if an image is not available, you can
+ do something like the following in the simplest case:
+ </p>
+ <source><![CDATA[public class MyEventListener implements EventListener {
+
+ public void processEvent(Event event) {
+ if ("org.apache.fop.ResourceEventProducer".equals(
+ event.getEventGroupID())) {
+ event.setSeverity(EventSeverity.FATAL);
+ } else {
+ //ignore all other events (or do something of your choice)
+ }
+ }
+
+}]]></source>
+ <p>
+ Increasing the event severity to FATAL will signal the event broadcaster to throw
+ an exception and stop further processing. In the above case, all resource-related
+ events will cause FOP to stop processing.
+ </p>
+ <p>
+ You can also customize the exception to throw (you can may throw a RuntimeException
+ or subclass yourself) and/or which event to respond to:
+ </p>
+ <source><![CDATA[public class MyEventListener implements EventListener {
+
+ public void processEvent(Event event) {
+ if ("org.apache.fop.ResourceEventProducer.imageNotFound"
+ .equals(event.getEventID())) {
+
+ //Get the FileNotFoundException that's part of the event's parameters
+ FileNotFoundException fnfe = (FileNotFoundException)event.getParam("fnfe");
+
+ throw new RuntimeException(EventFormatter.format(event), fnfe);
+ } else {
+ //ignore all other events (or do something of your choice)
+ }
+ }
+
+}]]></source>
+ <p>
+ This throws a <code>RuntimeException</code> with the <code>FileNotFoundException</code>
+ as the cause. Further processing effectively stops in FOP. You can catch the exception
+ in your code and react as you see necessary.
+ </p>
+ </section>
+ </section>
+ <section id="producer">
+ <title>The producer side (for FOP developers)</title>
+ <p>
+ This section is primarily for FOP and FOP plug-in developers. It describes how to use
+ the event subsystem for producing events.
+ </p>
+ <note>
+ The event package has been designed in order to be theoretically useful for use cases
+ outside FOP. If you think this is interesting independently from FOP, please talk to
+ <a href="mailto:fop-dev@xmlgraphics.apache.org">us</a>.
+ </note>
+ <section id="basic-event-production">
+ <title>Producing and sending an event</title>
+ <p>
+ The basics are very simple. Just instantiate an <code>Event</code> object and fill
+ it with the necessary parameters. Then pass it to the <code>EventBroadcaster</code>
+ which distributes the events to the interested listeneners. Here's a code example:
+ </p>
+ <source><![CDATA[Event ev = new Event(this, "complain", EventSeverity.WARN,
+ Event.paramsBuilder()
+ .param("reason", "I'm tired")
+ .param("blah", new Integer(23))
+ .build());
+EventBroadcaster broadcaster = [get it from somewhere];
+broadcaster.broadcastEvent(ev);
+]]></source>
+ <p>
+ The <code>Event.paramsBuilder()</code> is a
+ <a href="http://en.wikipedia.org/wiki/Fluent_interface">fluent interface</a>
+ to help with the build-up of the parameters. You could just as well instantiate a
+ <code>Map</code> (<code>Map<String, Object></code>) and fill it with values.
+ </p>
+ </section>
+ <section id="event-producer">
+ <title>The EventProducer interface</title>
+ <p>
+ To simplify event production, the event subsystem provides the <code>EventProducer</code>
+ interface. You can create interfaces which extend <code>EventProducer</code>. These
+ interfaces will contain one method per event to be generated. By contract, each event
+ method must have as its first parameter a parameter named "source" (Type Object) which
+ indicates the object that generated the event. After that come an arbitrary number of
+ parameters of any type as needed by the event.
+ </p>
+ <p>
+ The event producer interface does not need to have any implementation. The implementation
+ is produced at runtime by a dynamic proxy created by <code>DefaultEventBroadcaster</code>.
+ The dynamic proxy creates <code>Event</code> instances for each method call against
+ the event producer interface. Each parameter (except "source") is added to the event's
+ parameter map.
+ </p>
+ <p>
+ To simplify the code needed to get an instance of the event producer interface it is
+ suggested to create a public inner provider class inside the interface.
+ </p>
+ <p>
+ Here's an example of such an event producer interface:
+ </p>
+ <source><![CDATA[public interface MyEventProducer extends EventProducer {
+
+ public class Provider {
+
+ public static MyEventProducer get(EventBroadcaster broadcaster) {
+ return (MyEventProducer)broadcaster.getEventProducerFor(MyEventProducer.class);
+ }
+ }
+
+ /**
+ * Complain about something.
+ * @param source the event source
+ * @param reason the reason for the complaint
+ * @param blah the complaint
+ * @event.severity WARN
+ */
+ void complain(Object source, String reason, int blah);
+
+}]]></source>
+ <p>
+ To produce the same event as in the first example above, you'd use the following code:
+ </p>
+ <source><![CDATA[EventBroadcaster broadcaster = [get it from somewhere];
+TestEventProducer producer = TestEventProducer.Provider.get(broadcaster);
+producer.complain(this, "I'm tired", 23);]]></source>
+ </section>
+ <section id="event-model">
+ <title>The event model</title>
+ <p>
+ Inside an invocation handler for a dynamic proxy, there's no information about
+ the names of each parameter. The JVM doesn't provide it. The only thing you know is
+ the interface and method name. In order to properly fill the <code>Event</code>'s
+ parameter map we need to know the parameter names. These are retrieved from an
+ event object model. This is found in the <code>org.apache.fop.events.model</code>
+ package. The data for the object model is retrieved from an XML representation of the
+ event model that is loaded as a resource. The XML representation is generated using an
+ Ant task at build time (<code>ant resourcegen</code>). The Ant task (found in
+ <code>src/codegen/java/org/apache/fop/tools/EventProducerCollectorTask.java</code>)
+ scans FOP's sources for descendants of the <code>EventProducer</code> interface and
+ uses <a href="http://qdox.codehaus.org/">QDox</a> to parse these interfaces.
+ </p>
+ <p>
+ The event model XML files are generated during build by the Ant task mentioned above when
+ running the "resourcegen" task. So just run <code>"ant resourcegen"</code> if you receive
+ a <code>MissingResourceException</code> at runtime indicating that
+ <code>"event-model.xml"</code> is missing.
+ </p>
+ <p>
+ Primarily, the QDox-based collector task records the parameters' names and types.
+ Furthermore, it extracts additional attributes embedded as Javadoc comments from
+ the methods. At the moment, the only such attribute is "@event.severity" which indicates
+ the default event severity (which can be changed by event listeners). The example event
+ producer above shows the Javadocs for an event method.
+ </p>
+ <p>
+ There's one more information that is extracted from the event producer information for
+ the event model: an optional primary exception. The first exception in the "throws"
+ declaration of an event method is noted. It is used to throw an exception from
+ the invocation handler if the event has an event severity of "FATAL" when all
+ listeners have been called (listeners can update the event severity). Please note
+ that an implementation of
+ <code>org.apache.fop.events.EventExceptionManager$ExceptionFactory</code> has to be
+ registered for the <code>EventExceptionManager</code> to be able to construct the
+ exception from an event.
+ </p>
+ <p>
+ For a given application, there can be multiple event models active at the same time.
+ In FOP, each renderer is considered to be a plug-in and provides its own specific
+ event model. The individual event models are provided through an
+ <code>EventModelFactory</code>. This interface is implemented for each event model
+ and registered through the service provider mechanism
+ (see the <a href="#plug-ins">plug-ins section</a> for details).
+ </p>
+ </section>
+ <section id="event-severity">
+ <title>Event severity</title>
+ <p>
+ Four different levels of severity for events has been defined:
+ </p>
+ <ol>
+ <li>INFO: informational only</li>
+ <li>WARN: a Warning</li>
+ <li>ERROR: an error condition from which FOP can recover. FOP will continue processing.</li>
+ <li>FATAL: a fatal error which causes an exception in the end and FOP will stop processing.</li>
+ </ol>
+ <p>
+ Event listeners can choose to ignore certain events based on their event severity.
+ Please note that you may recieve an event "twice" in a specific case: if there is
+ a fatal error an event is generated and sent to the listeners. After that an exception
+ is thrown with the same information and processing stops. If the fatal event is
+ shown to the user and the following exception is equally presented to the user it
+ may appear that the event is duplicated. Of course, the same information is just
+ published through two different channels.
+ </p>
+ </section>
+ <section id="plug-ins">
+ <title>Plug-ins to the event subsystem</title>
+ <p>
+ The event subsystem is extensible. There are a number of extension points:
+ </p>
+ <ul>
+ <li>
+ <strong><code>org.apache.fop.events.model.EventModelFactory</code>:</strong> Provides
+ an event model to the event subsystem.
+ </li>
+ <li>
+ <strong><code>org.apache.fop.events.EventExceptionManager$ExceptionFactory</code>:</strong>
+ Creates exceptions for events, i.e. turns an event into a specific exception.
+ </li>
+ </ul>
+ <p>
+ The names in bold above are used as filenames for the service provider files that
+ are placed in the <code>META-INF/services</code> directory. That way, they are
+ automatically detected. This is a mechanism defined by the
+ <a href="http://java.sun.com/j2se/1.4.2/docs/guide/jar/jar.html#Service%20Provider">JAR file specification</a>.
+ </p>
+ </section>
+ <section id="l10n">
+ <title>Localization (L10n)</title>
+ <p>
+ One goal of the event subsystem was to have localized (translated) event messages.
+ The <code>EventFormatter</code> class can be used to convert an event to a
+ human-readable message. Each <code>EventProducer</code> can provide its own XML-based
+ translation file. If there is none, a central translation file is used, called
+ "EventFormatter.xml" (found in the same directory as the <code>EventFormatter</code>
+ class).
+ </p>
+ <p>
+ The XML format used by the <code>EventFormatter</code> is the same as
+ <a href="ext:cocoon">Apache Cocoon's</a> catalog format. Here's an example:
+ </p>
+ <source><![CDATA[<?xml version="1.0" encoding="UTF-8"?>
+<catalogue xml:lang="en">
+ <message key="locator">
+ [ (See position {loc})| (See {#gatherContextInfo})| (No context info available)]
+ </message>
+ <message key="org.apache.fop.render.rtf.RTFEventProducer.explicitTableColumnsRequired">
+ RTF output requires that all table-columns for a table are defined. Output will be incorrect.{{locator}}
+ </message>
+ <message key="org.apache.fop.render.rtf.RTFEventProducer.ignoredDeferredEvent">
+ Ignored deferred event for {node} ({start,if,start,end}).{{locator}}
+ </message>
+</catalogue>
+]]></source>
+ <p>
+ The example (extracted from the RTF handler's event producer) has message templates for
+ two event methods. The class used to do variable replacement in the templates is
+ <code>org.apache.fop.util.text.AdvancedMessageFormat</code> which is more powerful
+ than the <code>MessageFormat</code> classes provided by the Java class library
+ (<code>java.util.text</code> package).
+ </p>
+ <p>
+ "locator" is a template that is reused by the other message templates
+ by referencing it through "{{locator}}". This is some kind of include command.
+ </p>
+ <p>
+ Normal event parameters are accessed by name inside single curly braces, for example:
+ "{node}". For objects, this format just uses the <code>toString()</code> method to turn
+ the object into a string, unless there is an <code>ObjectFormatter</code> registered
+ for that type (there's an example for <code>org.xml.sax.Locator</code>).
+ </p>
+ <p>
+ The single curly braces pattern supports additional features. For example, it is possible
+ to do this: "{start,if,start,end}". "if" here is a special field modifier that evaluates
+ "start" as a boolean and if that is true returns the text right after the second comma
+ ("start"). Otherwise it returns the text after the third comma ("end"). The "equals"
+ modifier is similar to "if" but it takes as an additional (comma-separated) parameter
+ right after the "equals" modifier, a string that is compared to the value of the variable.
+ An example: {severity,equals,EventSeverity:FATAL,,some text} (this adds "some text" if
+ the severity is not FATAL).
+ </p>
+ <p>
+ Additional such modifiers can be added by implementing the
+ <code>AdvancedMessageFormat$Part</code> and <code>AdvancedMessageFormat$PartFactory</code>
+ interfaces.
+ </p>
+ <p>
+ Square braces can be used to specify optional template sections. The whole section will
+ be omitted if any of the variables used within are unavailable. Pipe (|) characters can
+ be used to specify alternative sub-templates (see "locator" above for an example).
+ </p>
+ <p>
+ Developers can also register a function (in the above example:
+ <code>{#gatherContextInfo})</code>
+ to do more complex information rendering. These functions are implementations of the
+ <code>AdvancedMessageFormat$Function</code> interface. Please take care that this is
+ done in a locale-independent way as there is no locale information available, yet.
+ </p>
+ </section>
+ </section>
+ </body>
+</document>
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