Common base class for all of FOP's transcoders.

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@196176 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/fop/svg/AbstractFOPTranscoder.java

@@ -0,0 +1,317 @@
+/*
+ * $Id$
+ * ============================================================================
+ *                    The Apache Software License, Version 1.1
+ * ============================================================================
+ * 
+ * Copyright (C) 1999-2003 The Apache Software Foundation. All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without modifica-
+ * tion, are permitted provided that the following conditions are met:
+ * 
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 
+ * 3. The end-user documentation included with the redistribution, if any, must
+ *    include the following acknowledgment: "This product includes software
+ *    developed by the Apache Software Foundation (http://www.apache.org/)."
+ *    Alternately, this acknowledgment may appear in the software itself, if
+ *    and wherever such third-party acknowledgments normally appear.
+ * 
+ * 4. The names "FOP" and "Apache Software Foundation" must not be used to
+ *    endorse or promote products derived from this software without prior
+ *    written permission. For written permission, please contact
+ *    apache@apache.org.
+ * 
+ * 5. Products derived from this software may not be called "Apache", nor may
+ *    "Apache" appear in their name, without prior written permission of the
+ *    Apache Software Foundation.
+ * 
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * APACHE SOFTWARE FOUNDATION OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLU-
+ * DING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * ============================================================================
+ * 
+ * This software consists of voluntary contributions made by many individuals
+ * on behalf of the Apache Software Foundation and was originally created by
+ * James Tauber <jtauber@jtauber.com>. For more information on the Apache
+ * Software Foundation, please see <http://www.apache.org/>.
+ */ 
+package org.apache.fop.svg;
+
+import java.awt.Dimension;
+import java.awt.geom.AffineTransform;
+import java.awt.geom.Dimension2D;
+
+import org.xml.sax.EntityResolver;
+
+import org.apache.avalon.framework.logger.ConsoleLogger;
+import org.apache.avalon.framework.logger.LogEnabled;
+import org.apache.avalon.framework.logger.Logger;
+import org.apache.batik.bridge.UserAgent;
+import org.apache.batik.bridge.UserAgentAdapter;
+import org.apache.batik.dom.svg.SVGDOMImplementation;
+import org.apache.batik.dom.util.DocumentFactory;
+import org.apache.batik.transcoder.ErrorHandler;
+import org.apache.batik.transcoder.TranscoderException;
+import org.apache.batik.transcoder.XMLAbstractTranscoder;
+import org.apache.batik.transcoder.image.ImageTranscoder;
+import org.apache.batik.util.SVGConstants;
+import org.apache.batik.util.XMLResourceDescriptor;
+import org.w3c.dom.DOMImplementation;
+
+/**
+ * This is the common base class of all of FOP's transcoders.
+ */
+public abstract class AbstractFOPTranscoder extends XMLAbstractTranscoder
+            implements LogEnabled {
+
+    /**
+     * The user agent dedicated to this Transcoder.
+     */
+    protected UserAgent userAgent = createUserAgent();
+
+    private Logger logger;
+    private EntityResolver resolver;
+
+    /**
+     * Constructs a new FOP-style transcoder.
+     */
+    public AbstractFOPTranscoder() {
+        hints.put(KEY_DOCUMENT_ELEMENT_NAMESPACE_URI,
+                  SVGConstants.SVG_NAMESPACE_URI);
+        hints.put(KEY_DOCUMENT_ELEMENT, SVGConstants.SVG_SVG_TAG);
+        hints.put(KEY_DOM_IMPLEMENTATION,
+                  SVGDOMImplementation.getDOMImplementation());
+    }
+    
+    /**
+     * Creates and returns the default user agent for this transcoder. Override
+     * this method if you need non-default behaviour.
+     * @return UserAgent the newly created user agent
+     */
+    protected UserAgent createUserAgent() {
+        return new FOPTranscoderUserAgent();
+    }
+    
+    /**
+     * @see org.apache.avalon.framework.logger.LogEnabled#enableLogging(Logger)
+     */
+    public void enableLogging(Logger logger) {
+        this.logger = logger;
+    }
+
+    /**
+     * Sets the EntityResolver that should be used when building SVG documents.
+     * @param resolver the resolver
+     */
+    public void setEntityResolver(EntityResolver resolver) {
+        this.resolver = resolver;
+    }
+    
+    /**
+     * Returns the logger associated with this transcoder. It returns a 
+     * ConsoleLogger if no logger has been explicitly set.
+     * @return Logger the logger for the transcoder.
+     */
+    protected final Logger getLogger() {
+        if (this.logger == null) {
+            this.logger = new ConsoleLogger(ConsoleLogger.LEVEL_INFO);
+        }
+        return this.logger;
+    }
+    
+    /**
+     * Creates a <tt>DocumentFactory</tt> that is used to create an SVG DOM
+     * tree. The specified DOM Implementation is ignored and the Batik
+     * SVG DOM Implementation is automatically used.
+     *
+     * @param domImpl the DOM Implementation (not used)
+     * @param parserClassname the XML parser classname
+     * @return the document factory
+     */
+    protected DocumentFactory createDocumentFactory(DOMImplementation domImpl,
+            String parserClassname) {
+        final FOPSAXSVGDocumentFactory factory = 
+                new FOPSAXSVGDocumentFactory(parserClassname);
+        if (this.resolver != null) {
+            factory.setAdditionalEntityResolver(this.resolver);
+        }
+        return factory;
+    }
+
+    // --------------------------------------------------------------------
+    // FOP's default error handler (for transcoders)
+    // --------------------------------------------------------------------
+
+    /**
+     * This is the default transcoder error handler for FOP. It logs error
+     * to an Avalon Logger instead of to System.out. The remaining behaviour 
+     * is the same as Batik's DefaultErrorHandler.
+     */    
+    protected class FOPErrorHandler implements ErrorHandler {
+        
+        /**
+         * @see org.apache.batik.transcoder.ErrorHandler#error(TranscoderException)
+         */
+        public void error(TranscoderException te)
+                throws TranscoderException {
+            getLogger().error(te.getMessage());
+        }
+
+        /**
+         * @see org.apache.batik.transcoder.ErrorHandler#fatalError(TranscoderException)
+         */
+        public void fatalError(TranscoderException te)
+                throws TranscoderException {
+            throw te;
+        }
+
+        /**
+         * @see org.apache.batik.transcoder.ErrorHandler#warning(TranscoderException)
+         */
+        public void warning(TranscoderException te)
+                throws TranscoderException {
+            getLogger().warn(te.getMessage());
+        }
+
+    }
+
+    // --------------------------------------------------------------------
+    // UserAgent implementation
+    // --------------------------------------------------------------------
+
+    /**
+     * A user agent implementation for FOP's Transcoders.
+     */
+    protected class FOPTranscoderUserAgent extends UserAgentAdapter {
+
+        /**
+         * Returns the default size of this user agent (400x400).
+         * @return the default viewport size
+         */
+        public Dimension2D getViewportSize() {
+            return new Dimension(400, 400);
+        }
+
+        /**
+         * Displays the specified error message using the <tt>ErrorHandler</tt>.
+         * @param message the message to display
+         */
+        public void displayError(String message) {
+            try {
+                getErrorHandler().error(new TranscoderException(message));
+            } catch (TranscoderException ex) {
+                throw new RuntimeException();
+            }
+        }
+
+        /**
+         * Displays the specified error using the <tt>ErrorHandler</tt>.
+         * @param e the exception to display
+         */
+        public void displayError(Exception e) {
+            try {
+                getErrorHandler().error(new TranscoderException(e));
+            } catch (TranscoderException ex) {
+                throw new RuntimeException();
+            }
+        }
+
+        /**
+         * Displays the specified message using the <tt>ErrorHandler</tt>.
+         * @param message the message to display
+         */
+        public void displayMessage(String message) {
+            getLogger().info(message);
+        }
+
+        /**
+         * Returns the pixel to millimeter conversion factor specified in the
+         * <tt>TranscodingHints</tt> or 0.3528 if any.
+         * @return the pixel unit to millimeter factor
+         */
+        public float getPixelUnitToMillimeter() {
+            Object key = ImageTranscoder.KEY_PIXEL_UNIT_TO_MILLIMETER;
+            if (getTranscodingHints().containsKey(key)) {
+                return ((Float)getTranscodingHints().get(key)).floatValue();
+            } else {
+                // return 0.3528f; // 72 dpi
+                return 0.26458333333333333333333333333333f;    // 96dpi
+            }
+        }
+
+        /**
+         * Returns the user language specified in the
+         * <tt>TranscodingHints</tt> or "en" (english) if any.
+         * @return the languages for the transcoder
+         */
+        public String getLanguages() {
+            Object key = ImageTranscoder.KEY_LANGUAGE;
+            if (getTranscodingHints().containsKey(key)) {
+                return (String)getTranscodingHints().get(key);
+            } else {
+                return "en";
+            }
+        }
+
+        /**
+         * Get the media for this transcoder. Which is always print.
+         * @return PDF media is "print"
+         */
+        public String getMedia() {
+            return "print";
+        }
+
+        /**
+         * Returns the user stylesheet specified in the
+         * <tt>TranscodingHints</tt> or null if any.
+         * @return the user style sheet URI specified in the hints
+         */
+        public String getUserStyleSheetURI() {
+            return (String)getTranscodingHints()
+                        .get(ImageTranscoder.KEY_USER_STYLESHEET_URI);
+        }
+
+        /**
+         * Returns the XML parser to use from the TranscodingHints.
+         * @return the XML parser class name
+         */
+        public String getXMLParserClassName() {
+            Object key = KEY_XML_PARSER_CLASSNAME;
+            if (getTranscodingHints().containsKey(key)) {
+                return (String)getTranscodingHints().get(key);
+            } else {
+                return XMLResourceDescriptor.getXMLParserClassName();
+            }
+        }
+
+        /**
+         * Check if the XML parser is validating.
+         * @return true if the XML parser is validating
+         */
+        public boolean isXMLParserValidating() {
+            return false;
+        }
+
+        /**
+         * Unsupported operation.
+         * @return null since this is unsupported
+         */
+        public AffineTransform getTransform() {
+            return null;
+        }
+    }
+    
+}