org.apache.tomcat.util.digester.RulesBase Maven / Gradle / Ivy
/*
* 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.
*/
package org.apache.tomcat.util.digester;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
/**
* Default implementation of the Rules interface that supports
* the standard rule matching behavior. This class can also be used as a
* base class for specialized Rules implementations.
*
* The matching policies implemented by this class support two different
* types of pattern matching rules:
*
* - Exact Match - A pattern "a/b/c" exactly matches a
*
<c> element, nested inside a <b>
* element, which is nested inside an <a> element.
* - Tail Match - A pattern "*/a/b" matches a
*
<b> element, nested inside an <a>
* element, no matter how deeply the pair is nested.
*
*/
public class RulesBase implements Rules {
// ----------------------------------------------------- Instance Variables
/**
* The set of registered Rule instances, keyed by the matching pattern.
* Each value is a List containing the Rules for that pattern, in the
* order that they were originally registered.
*/
protected HashMap> cache = new HashMap<>();
/**
* The Digester instance with which this Rules instance is associated.
*/
protected Digester digester = null;
/**
* The namespace URI for which subsequently added Rule
* objects are relevant, or null for matching independent
* of namespaces.
*/
protected String namespaceURI = null;
/**
* The set of registered Rule instances, in the order that they were
* originally registered.
*/
protected ArrayList rules = new ArrayList<>();
// ------------------------------------------------------------- Properties
/**
* Return the Digester instance with which this Rules instance is
* associated.
*/
@Override
public Digester getDigester() {
return (this.digester);
}
/**
* Set the Digester instance with which this Rules instance is associated.
*
* @param digester The newly associated Digester instance
*/
@Override
public void setDigester(Digester digester) {
this.digester = digester;
Iterator items = rules.iterator();
while (items.hasNext()) {
Rule item = items.next();
item.setDigester(digester);
}
}
/**
* Return the namespace URI that will be applied to all subsequently
* added Rule objects.
*/
@Override
public String getNamespaceURI() {
return (this.namespaceURI);
}
/**
* Set the namespace URI that will be applied to all subsequently
* added Rule objects.
*
* @param namespaceURI Namespace URI that must match on all
* subsequently added rules, or null for matching
* regardless of the current namespace URI
*/
@Override
public void setNamespaceURI(String namespaceURI) {
this.namespaceURI = namespaceURI;
}
// --------------------------------------------------------- Public Methods
/**
* Register a new Rule instance matching the specified pattern.
*
* @param pattern Nesting pattern to be matched for this Rule
* @param rule Rule instance to be registered
*/
@Override
public void add(String pattern, Rule rule) {
// to help users who accidently add '/' to the end of their patterns
int patternLength = pattern.length();
if (patternLength>1 && pattern.endsWith("/")) {
pattern = pattern.substring(0, patternLength-1);
}
List list = cache.get(pattern);
if (list == null) {
list = new ArrayList<>();
cache.put(pattern, list);
}
list.add(rule);
rules.add(rule);
if (this.digester != null) {
rule.setDigester(this.digester);
}
if (this.namespaceURI != null) {
rule.setNamespaceURI(this.namespaceURI);
}
}
/**
* Clear all existing Rule instance registrations.
*/
@Override
public void clear() {
cache.clear();
rules.clear();
}
/**
* Return a List of all registered Rule instances that match the specified
* nesting pattern, or a zero-length List if there are no matches. If more
* than one Rule instance matches, they must be returned
* in the order originally registered through the add()
* method.
*
* @param namespaceURI Namespace URI for which to select matching rules,
* or null to match regardless of namespace URI
* @param pattern Nesting pattern to be matched
*/
@Override
public List match(String namespaceURI, String pattern) {
// List rulesList = (List) this.cache.get(pattern);
List rulesList = lookup(namespaceURI, pattern);
if ((rulesList == null) || (rulesList.size() < 1)) {
// Find the longest key, ie more discriminant
String longKey = "";
Iterator keys = this.cache.keySet().iterator();
while (keys.hasNext()) {
String key = keys.next();
if (key.startsWith("*/")) {
if (pattern.equals(key.substring(2)) ||
pattern.endsWith(key.substring(1))) {
if (key.length() > longKey.length()) {
// rulesList = (List) this.cache.get(key);
rulesList = lookup(namespaceURI, key);
longKey = key;
}
}
}
}
}
if (rulesList == null) {
rulesList = new ArrayList<>();
}
return (rulesList);
}
/**
* Return a List of all registered Rule instances, or a zero-length List
* if there are no registered Rule instances. If more than one Rule
* instance has been registered, they must be returned
* in the order originally registered through the add()
* method.
*/
@Override
public List rules() {
return (this.rules);
}
// ------------------------------------------------------ Protected Methods
/**
* Return a List of Rule instances for the specified pattern that also
* match the specified namespace URI (if any). If there are no such
* rules, return null.
*
* @param namespaceURI Namespace URI to match, or null to
* select matching rules regardless of namespace URI
* @param pattern Pattern to be matched
* @return a rules list
*/
protected List lookup(String namespaceURI, String pattern) {
// Optimize when no namespace URI is specified
List list = this.cache.get(pattern);
if (list == null) {
return (null);
}
if ((namespaceURI == null) || (namespaceURI.length() == 0)) {
return (list);
}
// Select only Rules that match on the specified namespace URI
ArrayList results = new ArrayList<>();
Iterator items = list.iterator();
while (items.hasNext()) {
Rule item = items.next();
if ((namespaceURI.equals(item.getNamespaceURI())) ||
(item.getNamespaceURI() == null)) {
results.add(item);
}
}
return (results);
}
}