org.xmlbeam.util.intern.duplex.DuplexExpression Maven / Gradle / Ivy
/**
* Copyright 2014 Sven Ewald
*
* 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.
*/
package org.xmlbeam.util.intern.duplex;
import java.util.Arrays;
import java.util.Collections;
import java.util.Deque;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import javax.xml.xpath.XPathVariableResolver;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.xmlbeam.util.intern.DOMHelper;
import org.xmlbeam.util.intern.duplex.BuildDocumentVisitor.MODE;
import org.xmlbeam.util.intern.duplex.INodeEvaluationVisitor.VisitorClosure;
import org.xmlbeam.util.intern.duplex.SimpleNode.StepListFilter;
/**
* @author sven
*/
public class DuplexExpression {
private final static StepListFilter ALL_BUT_LAST = new StepListFilter() {
@Override
public List filter(final SimpleNode[] children) {
if (children.length < 2) {
return Collections.emptyList();
}
final List list = Arrays.asList(children).subList(0, children.length - 1);
assert list.size() == (children.length - 1);
return list;
}
};
private final static StepListFilter ONLY_LAST_STEP = new StepListFilter() {
@Override
public List filter(final SimpleNode[] children) {
if (children.length < 1) {
return Collections.emptyList();
}
assert children[children.length - 1] != null;
return Collections.singletonList(children[children.length - 1]);
}
};
private XPathVariableResolver variableResolver = null;
/**
* @param resolver
* @return this for convenience
*/
public DuplexExpression setXPathVariableResolver(final XPathVariableResolver resolver) {
this.variableResolver = resolver;
return this;
}
@Override
public String toString() {
return "DuplexExpression [xpath=" + xpath + "]";
}
private final SimpleNode node;
private final String xpath;
private final Map variableFormatPatterns = new HashMap();
private final String strippedXPath;
private final String expressionFormatPattern;
private final Map userDefinedMapping;
/**
* @param node
*/
DuplexExpression(final SimpleNode node, final CharSequence xpath, final Map userDefinedMapping) {
this.node = node;
this.xpath = xpath.toString();
this.userDefinedMapping = userDefinedMapping;
final Deque removeStartPositions = new LinkedList();
final Deque removeEndPositions = new LinkedList();
node.getFirstChildWithId(XParserTreeConstants.JJTXPATH).eachChild(new VisitorClosure() {
@Override
public void apply(final SimpleNode node, final Node data) {
if (node.getID() != XParserTreeConstants.JJTVARNAME) {
return;
}
SimpleNode qnameNode = node.getFirstChildWithId(XParserTreeConstants.JJTQNAME);
if (qnameNode == null) {
return;
}
SimpleNode formatNode = node.getFirstChildWithId(XParserTreeConstants.JJTVARIABLEFORMAT);
if (formatNode == null) {
variableFormatPatterns.put(qnameNode.getValue(), null);
return;
}
variableFormatPatterns.put(qnameNode.getValue(), stripFormatMarkers(formatNode.getValue()));
removeStartPositions.push(formatNode.getStartColumn());
removeEndPositions.push(formatNode.getEndColumn());
}
}, null);
SimpleNode formatPatternNode = node.getFirstChildWithId(XParserTreeConstants.JJTEXPRESSIONFORMAT);
if (formatPatternNode != null) {
this.expressionFormatPattern = formatPatternNode.getValue();
removeStartPositions.push(formatPatternNode.getStartColumn());
removeEndPositions.push(formatPatternNode.getEndColumn());
} else {
formatPatternNode = node.getFirstChildWithId(XParserTreeConstants.JJTVARIABLEFORMAT);
if (formatPatternNode != null) {
this.expressionFormatPattern = stripFormatMarkers(formatPatternNode.getValue());
removeStartPositions.push(formatPatternNode.getStartColumn());
removeEndPositions.push(formatPatternNode.getEndColumn());
} else {
this.expressionFormatPattern = null;
}
}
StringBuilder stringBuilder = new StringBuilder(xpath);
while (!removeEndPositions.isEmpty()) {
stringBuilder.delete(removeStartPositions.pop(), removeEndPositions.pop() + 1);
}
strippedXPath = stringBuilder.toString();
}
/**
* @return true if expression makes use of XPath variables
*/
public boolean isUsingVariables() {
return !variableFormatPatterns.keySet().isEmpty();
}
/**
* @param value
* @return
*/
private String stripFormatMarkers(String value) {
value = value.substring(2, value.length() - 2);
return value.startsWith("using ") ? value.substring("using ".length()) : value;
}
/**
* Calculates the return type of the expression.
*
* @return ExpressionType
*/
public ExpressionType getExpressionType() {
try { //TODO: cache expression type ?
final ExpressionType expressionType = node.firstChildAccept(new ExpressionTypeEvaluationVisitor(), null);
return expressionType;
} catch (IllegalArgumentException e) {
throw new IllegalArgumentException("Please report this bug: Can not determine type of XPath:" + xpath, e);
}
}
/**
* Creates nodes until selecting such a path would return something.
*
* @param contextNode
* @return the node that this expression would select.
*/
@SuppressWarnings("unchecked")
public org.w3c.dom.Node ensureExistence(final org.w3c.dom.Node contextNode) {
final Document document = DOMHelper.getOwnerDocumentFor(contextNode);
final Map namespaceMapping = new HashMap(userDefinedMapping);
namespaceMapping.putAll(DOMHelper.getNamespaceMapping(document));
//node.dump("");
return ((List) node.firstChildAccept(new BuildDocumentVisitor(variableResolver, namespaceMapping), contextNode)).get(0);
}
/**
* @param contextNode
* @return the parent element
*/
@SuppressWarnings("unchecked")
// due to JCC-API
public Element ensureParentExistence(final Node contextNode) {
final Document document = DOMHelper.getOwnerDocumentFor(contextNode);
final Map namespaceMapping = new HashMap(userDefinedMapping);
namespaceMapping.putAll(DOMHelper.getNamespaceMapping(document));
//node.dump("");
return (Element) ((List) node.firstChildAccept(new BuildDocumentVisitor(variableResolver, namespaceMapping, ALL_BUT_LAST, MODE.CREATE_IF_NOT_EXISTS), contextNode)).get(0);
}
/**
* @param parentNode
*/
public void deleteAllMatchingChildren(final Node parentNode) {
final Document document = DOMHelper.getOwnerDocumentFor(parentNode);
final Map namespaceMapping = DOMHelper.getNamespaceMapping(document);
BuildDocumentVisitor visitor = new BuildDocumentVisitor(variableResolver, namespaceMapping, ONLY_LAST_STEP, MODE.DELETE);
List result;
int lastLength = -1;
do {
result = (List) node.firstChildAccept(visitor, parentNode);
if (result.size() == lastLength) {
throw new IllegalStateException("Infinite loop detected. Please report issue with example.");
}
lastLength = result.size();
} while ((!result.isEmpty()) && (null != result.get(0)));
}
/**
* @param parentNode
* @return fresh new node
*/
@SuppressWarnings("unchecked")
public Node createChildWithPredicate(final Node parentNode) {
final Document document = DOMHelper.getOwnerDocumentFor(parentNode);
//final Map namespaceMapping = DOMHelper.getNamespaceMapping(document);
final Map namespaceMapping = new HashMap(userDefinedMapping);
namespaceMapping.putAll(DOMHelper.getNamespaceMapping(document));
BuildDocumentVisitor visitor = new BuildDocumentVisitor(variableResolver, namespaceMapping, ONLY_LAST_STEP, MODE.JUST_CREATE);
List nodes = (List) node.firstChildAccept(visitor, parentNode);
assert nodes.size() == 1;
return nodes.get(0);
}
/**
* Dumps the tree behind the expression for debugging purpose.
*/
public void dump() {
this.node.dump("");
}
/**
* @return String representation of expressions pattern
*/
public String getExpressionFormatPattern() {
return expressionFormatPattern;
// SimpleNode formatPatternNode = node.getFirstChildWithId(XParserTreeConstants.JJTEXPRESSIONFORMAT);
// if (formatPatternNode != null) {
// return formatPatternNode.getValue();
// }
// formatPatternNode = node.getFirstChildWithId(XParserTreeConstants.JJTVARIABLEFORMAT);
// if (formatPatternNode == null) {
// return null;
// }
// String value = formatPatternNode.getValue();
// value = value.substring(2, value.length() - 2);
// return value.startsWith("using ") ? value.substring("using ".length()) : value;
// //return (String) node.secondChildAccept(new GetExpressionFormatPatternVisitor(),null);
// //node.getFirstChildWithId(XParserTreeConstants.JJTEXPRESSIONFORMAT);
}
/**
* @return xpath compileable with regular xpath engine.
*/
public String getExpressionAsStringWithoutFormatPatterns() {
return strippedXPath;
// SimpleNode formatPatternNode = node.getFirstChildWithId(XParserTreeConstants.JJTEXPRESSIONFORMAT);
// if (formatPatternNode != null) {
// return removeStringPart(xpath, formatPatternNode.getStartColumn(), formatPatternNode.getEndColumn() + 1);
// };
//
// formatPatternNode = node.getFirstChildWithId(XParserTreeConstants.JJTVARIABLEFORMAT);
// if (formatPatternNode != null) {
// return removeStringPart(xpath, formatPatternNode.getStartColumn(), formatPatternNode.getEndColumn() + 1);
// };
//
// return this.xpath;
}
// /**
// * @param xpath2
// * @param begin
// * @param end
// * @return
// */
// private final static String removeStringPart(final String string, final int begin, final int end) {
// return string.substring(0, begin) + (end > string.length() ? "" : string.substring(end, string.length()));
// }
/**
* @param name
* @return pattern for variable or null if no format is defined.
*/
public String getVariableFormatPattern(final String name) {
return variableFormatPatterns.get(name);
}
// Method may be obsolete
// /**
// * @return true if getExpressionFormat is not null.
// */
// public boolean hasExpressionFormatPattern() {
// return expressionFormatPattern != null;
// }
}
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