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/*
* Copyright 1999-2006 The Apache Software Foundation.
*
* Licensed 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.
*/
/* $Id$ */
package org.apache.fop.fo;
// Java
import java.util.ListIterator;
import org.xml.sax.Attributes;
import org.xml.sax.Locator;
import org.xml.sax.helpers.LocatorImpl;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.fop.apps.FOPException;
import org.apache.fop.apps.FOUserAgent;
import org.apache.fop.fo.extensions.ExtensionAttachment;
import org.apache.fop.fo.extensions.ExtensionElementMapping;
import org.apache.fop.fo.extensions.svg.SVGElementMapping;
import org.apache.fop.fo.pagination.Root;
import org.apache.fop.util.CharUtilities;
import org.apache.fop.util.ContentHandlerFactory;
/**
* Base class for nodes in the XML tree
*/
public abstract class FONode implements Cloneable {
/** the XSL-FO namespace URI */
protected static final String FO_URI = FOElementMapping.URI;
/** Parent FO node */
protected FONode parent;
/**
* Marks location of this object from the input FO
* Call locator.getSystemId(), getLineNumber(),
* getColumnNumber() for file, line, column
* information
*/
protected Locator locator;
/** Logger for fo-tree related messages **/
protected static Log log = LogFactory.getLog(FONode.class);
//TODO Remove getLogger() method!
/**
* Main constructor.
* @param parent parent of this node
*/
protected FONode(FONode parent) {
this.parent = parent;
}
/**
* Perform a shallow cloning operation,
* set its parent, and optionally clean the list of child nodes
* @param cloneparent the intended parent of the clone
* @param removeChildren if true, clean the list of child nodes
* @return the cloned FO node
* @throws FOPException if there's a problem while cloning the node
*/
public FONode clone(FONode cloneparent, boolean removeChildren)
throws FOPException {
FONode foNode = (FONode) clone();
foNode.parent = cloneparent;
cloneparent.addChildNode(foNode);
return foNode;
}
/**
* Perform a shallow cloning operation
*
* @see java.lang.Object#clone()
* @return the cloned object
*/
protected Object clone() {
try {
return super.clone();
} catch (CloneNotSupportedException e) {
return null;
}
}
/**
* Set the location information for this element
* @param locator the org.xml.sax.Locator object
*/
public void setLocator(Locator locator) {
if (locator != null) {
//Create a copy of the locator so the info is preserved when we need to
//give pointers during layout.
this.locator = new LocatorImpl(locator);
}
}
/** @return the location information for this element or null, if not available */
public Locator getLocator() {
return this.locator;
}
/**
* Recursively goes up the FOTree hierarchy until the fo:root is found,
* which returns the parent FOEventHandler.
* @return the FOEventHandler object that is the parent of the FO Tree
*/
public FOEventHandler getFOEventHandler() {
return parent.getFOEventHandler();
}
/**
* Returns the user agent for the node.
* @return FOUserAgent
*/
public FOUserAgent getUserAgent() {
return getFOEventHandler().getUserAgent();
}
/**
* Returns the logger for the node.
* @return the logger
*/
public Log getLogger() {
return log;
}
/**
* Initialize the node with its name, location information, and attributes
* The attributes must be used immediately as the sax attributes
* will be altered for the next element.
* @param elementName element name (e.g., "fo:block")
* @param locator Locator object (ignored by default)
* @param attlist Collection of attributes passed to us from the parser.
* @param pList the property list of the parent node
* @throws FOPException for errors or inconsistencies in the attributes
*/
public void processNode(String elementName, Locator locator,
Attributes attlist, PropertyList pList) throws FOPException {
if (log.isDebugEnabled()) {
log.debug("Unhandled element: " + elementName
+ (locator != null ? " at " + getLocatorString(locator) : ""));
}
}
/**
* Create a property list for this node. Return null if the node does not
* need a property list.
* @param pList the closest parent propertylist.
* @param foEventHandler The FOEventHandler where the PropertyListMaker
* instance can be found.
* @return A new property list.
* @throws FOPException if there's a problem during processing
*/
protected PropertyList createPropertyList(PropertyList pList, FOEventHandler foEventHandler)
throws FOPException {
return null;
}
/**
* Checks to make sure, during SAX processing of input document, that the
* incoming node is valid for the this (parent) node (e.g., checking to
* see that fo:table is not an immediate child of fo:root)
* called within FObj constructor
* @param loc location in the FO source file
* @param namespaceURI namespace of incoming node
* @param localName (e.g. "table" for "fo:table")
* @throws ValidationException if incoming node not valid for parent
*/
protected void validateChildNode(Locator loc, String namespaceURI, String localName)
throws ValidationException {
//nop
}
/**
* Adds characters (does nothing here)
* @param data array of characters containing text to be added
* @param start starting array element to add
* @param end ending array element to add
* @param pList currently applicable PropertyList
* @param locator location in fo source file.
* @throws FOPException if there's a problem during processing
*/
protected void addCharacters(char[] data, int start, int end,
PropertyList pList,
Locator locator) throws FOPException {
// ignore
}
/**
* Called after processNode() is called. Subclasses can do additional processing.
* @throws FOPException if there's a problem during processing
*/
protected void startOfNode() throws FOPException {
// do nothing by default
}
/**
* Primarily used for making final content model validation checks
* and/or informing the FOEventHandler that the end of this FO
* has been reached.
* @throws FOPException if there's a problem during processing
*/
protected void endOfNode() throws FOPException {
// do nothing by default
}
/**
* Adds a node as a child of this node. The default implementation of this method
* just ignores any child node being added.
* @param child child node to be added to the childNodes of this node
* @throws FOPException if there's a problem during processing
*/
protected void addChildNode(FONode child) throws FOPException {
// do nothing by default
}
/**
* Removes a child node. Used by the child nodes to remove themselves, for
* example table-body if it has no children.
* @param child child node to be removed
*/
public void removeChild(FONode child) {
//nop
}
/**
* @return the parent node of this node
*/
public FONode getParent() {
return this.parent;
}
/**
* Return an iterator over all the child nodes of this FObj.
* @return A ListIterator.
*/
public ListIterator getChildNodes() {
return null;
}
/**
* Return an iterator over the object's child nodes starting
* at the pased node.
* @param childNode First node in the iterator
* @return A ListIterator or null if child node isn't a child of
* this FObj.
*/
public ListIterator getChildNodes(FONode childNode) {
return null;
}
/**
* @return an iterator for the characters in this node
*/
public CharIterator charIterator() {
return new OneCharIterator(CharUtilities.CODE_EOT);
}
/**
* Helper function to standardize the names of all namespace URI - local
* name pairs in text messages.
* For readability, using fo:, fox:, svg:, for those namespaces even
* though that prefix may not have been chosen in the document.
* @param namespaceURI URI of node found
* (e.g., "http://www.w3.org/1999/XSL/Format")
* @param localName local name of node, (e.g., "root" for "fo:root")
* @return the prefix:localname, if fo/fox/svg, or a longer representation
* with the unabbreviated URI otherwise.
*/
public static String getNodeString(String namespaceURI, String localName) {
if (namespaceURI.equals(FOElementMapping.URI)) {
return "fo:" + localName;
} else if (namespaceURI.equals(ExtensionElementMapping.URI)) {
return "fox:" + localName;
} else if (namespaceURI.equals(SVGElementMapping.URI)) {
return "svg:" + localName;
} else {
return "(Namespace URI: \"" + namespaceURI + "\", "
+ "Local Name: \"" + localName + "\")";
}
}
/**
* Helper function to standardize property error exceptions
* (e.g., not specifying either an internal- or an external-destination
* property for an FO:link)
* @param problem text to display that indicates the problem
* @throws ValidationException the validation error provoked by the method call
*/
protected void attributeError(String problem)
throws ValidationException {
throw new ValidationException(errorText(locator) + getName()
+ ", " + problem, locator);
}
/**
* Helper function to standardize attribute warnings
* (e.g., currently unsupported properties)
* @param problem text to display that indicates the problem
*/
protected void attributeWarning(String problem) {
log.warn(warningText(locator) + getName() + ", " + problem);
}
/**
* Helper function to standardize "too many" error exceptions
* (e.g., two fo:declarations within fo:root)
* @param loc org.xml.sax.Locator object of the error (*not* parent node)
* @param nsURI namespace URI of incoming invalid node
* @param lName local name (i.e., no prefix) of incoming node
* @throws ValidationException the validation error provoked by the method call
*/
protected void tooManyNodesError(Locator loc, String nsURI, String lName)
throws ValidationException {
throw new ValidationException(errorText(loc) + "For " + getName()
+ ", only one " + getNodeString(nsURI, lName) + " may be declared.",
loc);
}
/**
* Helper function to standardize "too many" error exceptions
* (e.g., two fo:declarations within fo:root)
* This overrloaded method helps make the caller code better self-documenting
* @param loc org.xml.sax.Locator object of the error (*not* parent node)
* @param offendingNode incoming node that would cause a duplication.
* @throws ValidationException the validation error provoked by the method call
*/
protected void tooManyNodesError(Locator loc, String offendingNode)
throws ValidationException {
throw new ValidationException(errorText(loc) + "For " + getName()
+ ", only one " + offendingNode + " may be declared.", loc);
}
/**
* Helper function to standardize "out of order" exceptions
* (e.g., fo:layout-master-set appearing after fo:page-sequence)
* @param loc org.xml.sax.Locator object of the error (*not* parent node)
* @param tooLateNode string name of node that should be earlier in document
* @param tooEarlyNode string name of node that should be later in document
* @throws ValidationException the validation error provoked by the method call
*/
protected void nodesOutOfOrderError(Locator loc, String tooLateNode,
String tooEarlyNode) throws ValidationException {
throw new ValidationException(errorText(loc) + "For " + getName() + ", " + tooLateNode
+ " must be declared before " + tooEarlyNode + ".", loc);
}
/**
* Helper function to return "invalid child" exceptions
* (e.g., fo:block appearing immediately under fo:root)
* @param loc org.xml.sax.Locator object of the error (*not* parent node)
* @param nsURI namespace URI of incoming invalid node
* @param lName local name (i.e., no prefix) of incoming node
* @throws ValidationException the validation error provoked by the method call
*/
protected void invalidChildError(Locator loc, String nsURI, String lName)
throws ValidationException {
invalidChildError(loc, nsURI, lName, null);
}
/**
* Helper function to return "invalid child" exceptions with more
* complex validation rules (i.e., needing more explanation of the problem)
* @param loc org.xml.sax.Locator object of the error (*not* parent node)
* @param nsURI namespace URI of incoming invalid node
* @param lName local name (i.e., no prefix) of incoming node
* @param ruleViolated text explanation of problem
* @throws ValidationException the validation error provoked by the method call
*/
protected void invalidChildError(Locator loc, String nsURI, String lName,
String ruleViolated)
throws ValidationException {
throw new ValidationException(errorText(loc) + getNodeString(nsURI, lName)
+ " is not a valid child element of " + getName()
+ ((ruleViolated != null) ? ": " + ruleViolated : "."), loc);
}
/**
* Helper function to throw an error caused by missing mandatory child elements.
* E.g., fo:layout-master-set not having any page-master child element.
* @param contentModel The XSL Content Model for the fo: object or a similar description
* indicating the necessary child elements.
* @throws ValidationException the validation error provoked by the method call
*/
protected void missingChildElementError(String contentModel)
throws ValidationException {
throw new ValidationException(errorText(locator) + getName()
+ " is missing child elements. \nRequired Content Model: "
+ contentModel, locator);
}
/**
* Helper function to throw an error caused by missing mandatory properties
* @param propertyName the name of the missing property.
* @throws ValidationException the validation error provoked by the method call
*/
protected void missingPropertyError(String propertyName)
throws ValidationException {
throw new ValidationException(errorText(locator) + getName()
+ " is missing required \"" + propertyName + "\" property.", locator);
}
/**
* Helper function to return "Error(line#/column#)" string for
* above exception messages
* @param loc org.xml.sax.Locator object
* @return String opening error text
*/
protected static String errorText(Locator loc) {
return "Error(" + getLocatorString(loc) + "): ";
}
/**
* Helper function to return "Warning(line#/column#)" string for
* warning messages
* @param loc org.xml.sax.Locator object
* @return String opening warning text
*/
protected static String warningText(Locator loc) {
return "Warning(" + getLocatorString(loc) + "): ";
}
/**
* Helper function to format a Locator instance.
* @param loc org.xml.sax.Locator object
* @return String the formatted text
*/
public static String getLocatorString(Locator loc) {
if (loc == null) {
return "Unknown location";
} else {
return loc.getLineNumber() + "/" + loc.getColumnNumber();
}
}
/**
* Decorates a log or warning message with context information on the given node.
* @param text the original message
* @param node the context node
* @return the decorated text
*/
public static String decorateWithContextInfo(String text, FONode node) {
if (node != null) {
StringBuffer sb = new StringBuffer(text);
sb.append(" (").append(node.getContextInfo()).append(")");
return sb.toString();
} else {
return text;
}
}
/**
* Returns a String containing as much context information as possible about a node. Call
* this methods only in exceptional conditions because this method may perform quite extensive
* information gathering inside the FO tree.
* @return a String containing
*/
public String getContextInfo() {
StringBuffer sb = new StringBuffer();
if (getLocalName() != null) {
sb.append(getName());
sb.append(", ");
}
if (this.locator != null) {
sb.append("location: ");
sb.append(getLocatorString(this.locator));
} else {
String s = gatherContextInfo();
if (s != null) {
sb.append("\"");
sb.append(s);
sb.append("\"");
} else {
sb.append("no context info available");
}
}
if (sb.length() > 80) {
sb.setLength(80);
}
return sb.toString();
}
/**
* Gathers context information for the getContextInfo() method.
* @return the collected context information or null, if none is available
*/
protected String gatherContextInfo() {
return null;
}
/**
* Returns the root node of this tree
* @return the root node
*/
public Root getRoot() {
return parent.getRoot();
}
/**
* Returns the fully qualified name of the node
* @return the fully qualified name of this node
*/
public String getName() {
return getName(getNormalNamespacePrefix());
}
/**
* Returns the fully qualified name of the node
* @param prefix the namespace prefix to build the name with (may be null)
* @return the fully qualified name of this node
*/
public String getName(String prefix) {
if (prefix != null) {
StringBuffer sb = new StringBuffer();
sb.append(prefix).append(':').append(getLocalName());
return sb.toString();
} else {
return getLocalName();
}
}
/**
* Returns the local name (i.e. without namespace prefix) of the node
* @return the local name of this node
*/
public abstract String getLocalName();
/** @return the normally ussed namespace prefix for this kind of node (ex. "fo" for XSL-FO) */
public abstract String getNormalNamespacePrefix();
/** @return the namespace URI for this node */
public String getNamespaceURI() {
return null;
}
/**
* Returns the Constants class integer value of this node
* @return the integer enumeration of this FO (e.g., FO_ROOT)
* if a formatting object, FO_UNKNOWN_NODE otherwise
*/
public int getNameId() {
return Constants.FO_UNKNOWN_NODE;
}
/**
* This method is overridden by extension elements and allows the extension element
* to return a pass-through attachment which the parent formatting objects should simply
* carry with them but otherwise ignore. This mechanism is used to pass non-standard
* information from the FO tree through to the layout engine and the renderers.
* @return the extension attachment if one is created by the extension element, null otherwise.
*/
public ExtensionAttachment getExtensionAttachment() {
return null;
}
/**
* This method is overridden by extension elements and allows the extension element to return
* a ContentHandlerFactory. This factory can create ContentHandler implementations that handle
* foreign XML content by either building up a specific DOM, a Java object or something else.
* @return the ContentHandlerFactory or null if not applicable
*/
public ContentHandlerFactory getContentHandlerFactory() {
return null;
}
}
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