/*
* $Header$
* $Revision: 982 $
* $Date: 2006-12-08 18:42:51 +1000 (Fri, 08 Dec 2006) $
*
* ====================================================================
*
* The Apache Software License, Version 1.1
*
* Copyright (c) 2003-2009 The JRDF Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by the
* the JRDF Project (http://jrdf.sf.net/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The JRDF Project" and "JRDF" must not be used to endorse
* or promote products derived from this software without prior written
* permission. For written permission, please contact
* newmana@users.sourceforge.net.
*
* 5. Products derived from this software may not be called "JRDF"
* nor may "JRDF" appear in their names without prior written
* permission of the JRDF Project.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the JRDF Project. For more
* information on JRDF, please see <http://jrdf.sourceforge.net/>.
*
*/
package org.jrdf.sparql.analysis;
import org.jrdf.graph.Node;
import org.jrdf.query.relation.Attribute;
import org.jrdf.query.relation.attributename.AttributeName;
import org.jrdf.query.relation.attributename.VariableName;
import org.jrdf.query.relation.constants.NullaryAttribute;
import org.jrdf.query.relation.type.NodeType;
import org.jrdf.query.relation.type.PositionalNodeType;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
/**
* A variable collector takes the attribute value pairs from constraints and add them to a map. Used to construct
* queries.
*
* As node types are gathered they are upgraded to compount types if they have stood in different positions in a
* constraint. For example ?uri <> <> . <> ?uri <> would create a attribute ?uri which of of type
* SubjectPredicateNodeType.
*
* @author Andrew Newman
* @version $Revision: 1078 $
*/
public class AttributeCollectorImpl implements VariableCollector {
private static final long serialVersionUID = 5588873511780742278L;
private transient Map<AttributeName, PositionalNodeType> variables
= new HashMap<AttributeName, PositionalNodeType>();
public void addConstraints(final Map<Attribute, Node> avps) {
for (final Attribute attribute : avps.keySet()) {
checkAndAddEntry(attribute);
}
}
public Map<AttributeName, PositionalNodeType> getAttributes() {
return variables;
}
@Override
public String toString() {
return variables.toString();
}
private void checkAndAddEntry(final Attribute attribute) {
if (attribute.getAttributeName() instanceof VariableName) {
if (variables.containsKey(attribute.getAttributeName())) {
updateEntry(attribute);
} else {
addNewEntry(attribute);
}
} else if (!NullaryAttribute.isNullaryAttribute(attribute)) {
addNewEntry(attribute);
}
}
private void updateEntry(final Attribute newAttribute) {
final AttributeName key = newAttribute.getAttributeName();
final PositionalNodeType currentEntry = variables.get(key);
final NodeType type = newAttribute.getType();
if (type instanceof PositionalNodeType) {
if (!currentEntry.getClass().equals(type.getClass())) {
variables.put(key, currentEntry.upgrade((PositionalNodeType) type));
}
}
}
private void addNewEntry(final Attribute attribute) {
final NodeType nodeType = attribute.getType();
if (nodeType instanceof PositionalNodeType) {
variables.put(attribute.getAttributeName(), (PositionalNodeType) nodeType);
}
}
private void writeObject(ObjectOutputStream output) throws IOException {
Set<Map.Entry<AttributeName, PositionalNodeType>> entries = variables.entrySet();
output.writeInt(variables.size());
for (Map.Entry<AttributeName, PositionalNodeType> entry : entries) {
output.writeObject(entry.getKey());
output.writeObject(entry.getValue());
}
}
private void readObject(ObjectInputStream input) throws IOException, ClassNotFoundException {
variables = new HashMap<AttributeName, PositionalNodeType>();
int elements = input.readInt();
for (int i = 0; i < elements; i++) {
AttributeName attribute = (AttributeName) input.readObject();
PositionalNodeType node = (PositionalNodeType) input.readObject();
variables.put(attribute, node);
}
}
}