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Free Java Reporting Library
/*
* JasperReports - Free Java Reporting Library.
* Copyright (C) 2001 - 2019 TIBCO Software Inc. All rights reserved.
* http://www.jaspersoft.com
*
* Unless you have purchased a commercial license agreement from Jaspersoft,
* the following license terms apply:
*
* This program is part of JasperReports.
*
* JasperReports is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* JasperReports is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with JasperReports. If not, see
* The data source is constructed around a node set (record set) selected
* by an XPath expression from the xml document.
*
*
* Each field can provide an additional XPath expression that will be used to
* select its value. This expression must be specified using the {@link #PROPERTY_FIELD_EXPRESSION}
* custom property at field level. The use of the {@link net.sf.jasperreports.engine.JRField#getDescription() field description} to specify the XPath expression
* is still supported, but is now discouraged, the above mentioned custom property taking precedence
* over the field description. In case no XPath expression is specified, the name of the field will be used for the selection of the value.
* The expression is evaluated in the context of the current
* node thus the expression should be relative to the current node.
*
*
* To support subreports, sub data sources can be created. There are two different methods
* for creating sub data sources. The first one allows to create a sub data source rooted
* at the current node. The current node can be seen as a new document around which the
* sub data source is created. The second method allows to create a sub data source that
* is rooted at the same document that is used by the data source but uses a different
* XPath select expression.
*
*
* Example:
*
* <A>
* <B id="0">
* <C>
* <C>
* </B>
* <B id="1">
* <C>
* <C>
* </B>
* <D id="3">
* <E>
* <E>
* </D>
* </A>
*
*
* Data source creation
*
* - new JRXmlDataSource(document, "/A/B") - creates a data source with two nodes of type /A/B
*
- new JRXmlDataSource(document, "/A/D") - creates a data source with two nodes of type /A/D
*
* Field selection
*
* - @id - will select the "id" attribute from the current node
*
- C - will select the value of the first node of type C under the current node.
*
* Sub data source creation
*
* - "((net.sf.jasperreports.engine.data.JRXmlDataSource)$P{REPORT_DATA_SOURCE}).subDataSource("/B/C")
* - in the context of the node B, creates a data source with elements of type /B/C
*
- "((net.sf.jasperreports.engine.data.JRXmlDataSource)$P{REPORT_DATA_SOURCE}).dataSource("/A/D")
* - creates a data source with elements of type /A/D
*
*
*
* Generally the full power of XPath expression is available. As an example, "/A/B[@id > 0"] will select all the
* nodes of type /A/B having the id greater than 0.
* You'll find a short XPath tutorial here.
*
*
*
* Note on performance. Due to the fact that all the XPath expression are interpreted the
* data source performance is not great. For the cases where more speed is required,
* consider implementing a custom data source that directly accesses the Document through the DOM API.
*
* @author Narcis Marcu ([email protected])
*/
public abstract class AbstractXmlDataSource> extends JRAbstractTextDataSource implements RandomAccessDataSource, HierarchicalDataSource
{
/**
* Property specifying the XPath expression for the dataset field.
*/
@Property (
category = PropertyConstants.CATEGORY_DATA_SOURCE,
scopes = {PropertyScope.FIELD},
scopeQualifications = {JRXPathQueryExecuterFactory.QUERY_EXECUTER_NAME},
sinceVersion = PropertyConstants.VERSION_6_3_1
)
public static final String PROPERTY_FIELD_EXPRESSION = JRPropertiesUtil.PROPERTY_PREFIX + "xpath.field.expression";
private Map fieldExpressions = new HashMap();
public abstract Node getCurrentNode();
public abstract Object getSelectObject(Node currentNode, String expression) throws JRException;
/*
* (non-Javadoc)
*
* @see net.sf.jasperreports.engine.JRDataSource#getFieldValue(net.sf.jasperreports.engine.JRField)
*/
@Override
public Object getFieldValue(JRField jrField) throws JRException
{
if(getCurrentNode() == null)
{
return null;
}
String expression = null;
if (fieldExpressions.containsKey(jrField.getName()))
{
expression = fieldExpressions.get(jrField.getName());
}
else
{
expression = getFieldExpression(jrField);
fieldExpressions.put(jrField.getName(), expression);
}
if (expression == null || expression.length() == 0)
{
return null;
}
Object value = null;
Class valueClass = jrField.getValueClass();
Object selectedObject = getSelectObject(getCurrentNode(), expression);
if(Object.class != valueClass)
{
if (selectedObject != null)
{
if (selectedObject instanceof Node)
{
String text = getText((Node) selectedObject);
if (text != null)
{
value = convertStringValue(text, valueClass);
}
}
else if (selectedObject instanceof Boolean && valueClass.equals(Boolean.class))
{
value = selectedObject;
}
else if (selectedObject instanceof Number && Number.class.isAssignableFrom(valueClass))
{
value = convertNumber((Number) selectedObject, valueClass);
}
else
{
String text = selectedObject.toString();
value = convertStringValue(text, valueClass);
}
}
}
else
{
value = selectedObject;
}
return value;
}
/**
* Creates a sub data source using the current node (record) as the root
* of the document. An additional XPath expression specifies the select criteria applied to
* this new document and that produces the nodes (records) for the data source.
*
* @param selectExpr the XPath select expression
* @return the xml sub data source
* @throws JRException if the sub data source couldn't be created
* @see JRXmlDataSource#JRXmlDataSource(Document, String)
*/
@Override
public abstract T subDataSource(String selectExpr) throws JRException;
/**
* Creates a sub data source using the current node (record) as the root
* of the document. The data source will contain exactly one record consisting
* of the document node itself.
*
* @return the xml sub data source
* @throws JRException if the data source cannot be created
* @see JRXmlDataSource#subDataSource(String)
* @see JRXmlDataSource#JRXmlDataSource(Document)
*/
@Override
public T subDataSource() throws JRException {
return subDataSource(".");
}
/**
* Creates a document using the current node as root.
*
* @return a document having the current node as root
* @throws JRException
*/
public abstract Document subDocument() throws JRException;
/**
* Creates a sub data source using as root document the document used by "this" data source.
* An additional XPath expression specifies the select criteria applied to
* this document and that produces the nodes (records) for the data source.
*
* @param selectExpr the XPath select expression
* @return the xml sub data source
* @throws JRException if the sub data source couldn't be created
* @see JRXmlDataSource#JRXmlDataSource(Document, String)
*/
public abstract T dataSource(String selectExpr) throws JRException;
/**
* Creates a sub data source using as root document the document used by "this" data source.
* The data source will contain exactly one record consisting of the document node itself.
*
* @return the xml sub data source
* @throws JRException if the data source cannot be created
* @see JRXmlDataSource#dataSource(String)
* @see JRXmlDataSource#JRXmlDataSource(Document)
*/
public T dataSource() throws JRException {
return dataSource(".");
}
/**
* Return the text that a node contains. This routine:
*
* - Ignores comments and processing instructions.
*
- Concatenates TEXT nodes, CDATA nodes, and the results of recursively
* processing EntityRef nodes.
*
- Ignores any element nodes in the sublist. (Other possible options
* are to recurse into element sublists or throw an exception.)
*
*
* @param node a DOM node
* @return a String representing node contents or null
*/
public String getText(Node node) {
if (!node.hasChildNodes())
{
return node.getNodeValue();
}
StringBuilder result = new StringBuilder();
NodeList list = node.getChildNodes();
for (int i = 0; i < list.getLength(); i++) {
Node subnode = list.item(i);
if (subnode.getNodeType() == Node.TEXT_NODE)
{
String value = subnode.getNodeValue();
if(value != null)
{
result.append(value);
}
}
else if (subnode.getNodeType() == Node.CDATA_SECTION_NODE)
{
String value = subnode.getNodeValue();
if(value != null)
{
result.append(value);
}
} else if (subnode.getNodeType() == Node.ENTITY_REFERENCE_NODE) {
// Recurse into the subtree for text
// (and ignore comments)
String value = getText(subnode);
if(value != null)
{
result.append(value);
}
}
}
return result.toString();
}
protected String getFieldExpression(JRField field)
{
String fieldExpression = null;
if (field.hasProperties())
{
fieldExpression = field.getPropertiesMap().getProperty(PROPERTY_FIELD_EXPRESSION);
}
if (fieldExpression == null || fieldExpression.length() == 0)
{
fieldExpression = field.getDescription();
if (fieldExpression == null || fieldExpression.length() == 0)
{
fieldExpression = field.getName();
}
}
return fieldExpression;
}
}