// Copyright 2004, 2005 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.
package org.apache.hivemind.impl;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.hivemind.ApplicationRuntimeException;
import org.apache.hivemind.Attribute;
import org.apache.hivemind.Element;
import org.apache.hivemind.Location;
import org.apache.hivemind.schema.AttributeModel;
import org.apache.hivemind.schema.ElementModel;
import org.apache.hivemind.schema.Rule;
import org.apache.hivemind.schema.SchemaProcessor;
import org.apache.hivemind.schema.Translator;
import org.apache.hivemind.schema.rules.NullTranslator;
/**
* A wrapper around {@link org.apache.hivemind.schema.ElementModel} used by
* {@link org.apache.hivemind.impl.SchemaProcessorImpl}.
*
* @author Howard Lewis Ship
*/
final class SchemaElement
{
private SchemaProcessor _processor;
private ElementModel _model;
private List _requiredAttributes = new ArrayList();
private Set _knownAttributes = new HashSet();
private String _keyAttribute;
private Map _nestedElements;
/**
* Keyed on attribute name, value is string (possibly null) used to access a translator.
*/
private Map _attributeTranslators = new HashMap();
/**
* Map of Maps. The outer key is an attribute name string, this indicates that the attribute
* values should be unique. Inner map is keyed on attribute value (as a string), the value is
* the {@link org.apache.hivemind.Location} defining that value.
*/
private Map _attributeValues = new HashMap();
SchemaElement(SchemaProcessor processor, ElementModel model)
{
_processor = processor;
_model = model;
_keyAttribute = model.getKeyAttribute();
List attributeModels = model.getAttributeModels();
int count = attributeModels.size();
for (int i = 0; i < count; i++)
{
AttributeModel am = (AttributeModel) attributeModels.get(i);
String name = am.getName();
_knownAttributes.add(name);
if (am.isRequired())
_requiredAttributes.add(name);
// If the attribute should be unique, add a map for that attribute
// to track unique values for that attribute.
if (am.isUnique())
_attributeValues.put(name, new HashMap());
if (name.equals(_keyAttribute))
{
_requiredAttributes.add(name);
_attributeValues.put(name, new HashMap());
}
_attributeTranslators.put(name, am.getTranslator());
}
}
/**
* Returns a {@link SchemaElement} for a nested element, or null if no such element exists.
*/
SchemaElement getNestedElement(String elementName)
{
if (_nestedElements == null)
buildNestedElements();
return (SchemaElement) _nestedElements.get(elementName);
}
private void buildNestedElements()
{
_nestedElements = new HashMap();
List l = _model.getElementModel();
int count = l.size();
for (int i = 0; i < count; i++)
{
ElementModel nested = (ElementModel) l.get(i);
SchemaElement nestedElement = new SchemaElement(_processor, nested);
// TODO: Check for duplicates here, or at parse!
_nestedElements.put(nested.getElementName(), nestedElement);
}
}
/**
* Validates the attributes of the element; checks that all required attributes are present and
* that all attributes are defined. Validation errors result in logged error messages.
*/
void validateAttributes(Element element)
{
List l = element.getAttributes();
int count = l.size();
Set required = new HashSet(_requiredAttributes);
List errors = new ArrayList();
for (int i = 0; i < count; i++)
{
Attribute a = (Attribute) l.get(i);
String name = a.getName();
if (!_knownAttributes.contains(name))
errors.add(ImplMessages.unknownAttribute(name));
checkUniquness(name, a.getValue(), element.getLocation(), errors);
required.remove(name);
}
Iterator it = required.iterator();
while (it.hasNext())
{
String name = (String) it.next();
errors.add(ImplMessages.missingAttribute(name));
}
count = errors.size();
if (count == 0)
return;
StringBuffer buffer = new StringBuffer();
buffer.append(ImplMessages.elementErrors(_processor, element));
for (int i = 0; i < count; i++)
{
buffer.append(' ');
buffer.append(errors.get(i).toString());
}
// TODO: refactor to use the ErrorHandler rather than throw an exception
// (these errors are somewhat recoverable).
throw new ApplicationRuntimeException(buffer.toString(), element.getLocation(), null);
}
private void checkUniquness(String name, String value, Location location, List errors)
{
Map valuesMap = (Map) _attributeValues.get(name);
// If null, then not checking on uniqueness.
if (valuesMap == null)
return;
Object translatedValue = getAttributeTranslator(name).translate(
_processor.getContributingModule(),
Object.class,
value,
location);
Location prior = (Location) valuesMap.get(translatedValue);
if (prior == null)
{
valuesMap.put(translatedValue, location);
return;
}
// A conflict.
errors.add(ImplMessages.uniqueAttributeConstraintBroken(
name,
translatedValue.toString(),
prior));
}
void fireBegin(Element element)
{
List rules = _model.getRules();
int count = rules.size();
for (int i = 0; i < count; i++)
{
Rule r = (Rule) rules.get(i);
r.begin(_processor, element);
}
}
void fireEnd(Element element)
{
List rules = _model.getRules();
int count = rules.size();
for (int i = count - 1; i >= 0; i--)
{
Rule r = (Rule) rules.get(i);
r.end(_processor, element);
}
}
private Translator _nullTranslator = new NullTranslator();
private Translator _contentTranslator;
public Translator getContentTranslator()
{
if (_contentTranslator == null)
_contentTranslator = getTranslator(_model.getContentTranslator());
return _contentTranslator;
}
private Translator getTranslator(String translator)
{
if (translator == null)
return _nullTranslator;
return _processor.getTranslator(translator);
}
public Translator getAttributeTranslator(String attributeName)
{
String translator = (String) _attributeTranslators.get(attributeName);
return getTranslator(translator);
}
public String getKeyAttribute()
{
return _keyAttribute;
}
}