/*
* The contents of this file are subject to the Mozilla Public License
* Version 1.1 (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.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS"
* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
* the License for the specific language governing rights and limitations
* under the License.
*
* The Original Code is the Kowari Metadata Store.
*
* The Initial Developer of the Original Code is Plugged In Software Pty
* Ltd (http://www.pisoftware.com, mailto:info@pisoftware.com). Portions
* created by Plugged In Software Pty Ltd are Copyright (C) 2001,2002
* Plugged In Software Pty Ltd. All Rights Reserved.
*
* Contributor(s): N/A.
*
* [NOTE: The text of this Exhibit A may differ slightly from the text
* of the notices in the Source Code files of the Original Code. You
* should use the text of this Exhibit A rather than the text found in the
* Original Code Source Code for Your Modifications.]
*
*/
package org.mulgara.resolver;
// Java 2 standard packages
import java.util.Arrays;
// Third party packages
import org.apache.log4j.Logger;
// Locally written packages
import org.mulgara.query.AbstractAnswer;
import org.mulgara.query.Answer;
import org.mulgara.query.AnswerOperations;
import org.mulgara.query.TuplesException;
import org.mulgara.query.Variable;
import org.mulgara.resolver.spi.GlobalizeException;
import org.mulgara.resolver.spi.ResolverSession;
import org.mulgara.store.tuples.Tuples;
/**
* Wrapper around database-local {@link Tuples} instances, converting them
* into globally valid {@link Answer}s.
*
* @created 2003-10-28
*
* @author <a href="http://staff.pisoftware.com/raboczi">Simon Raboczi</a>
*
* @version $Revision: 1.8 $
*
* @modified $Date: 2005/01/05 04:58:23 $
*
* @maintenanceAuthor $Author: newmana $
*
* @company <a href="mailto:info@PIsoftware.com">Plugged In Software</a>
*
* @copyright ©2003-2004 <a href="http://www.PIsoftware.com/">Plugged In
* Software Pty Ltd</a>
*
* @licence <a href="{@docRoot}/../../LICENCE">Mozilla Public License v1.1</a>
*/
class GlobalizedAnswer extends AbstractAnswer implements Answer, Cloneable {
/** Logger. */
private final static Logger logger =
Logger.getLogger(GlobalizedAnswer.class.getName());
/** The session against which globalization occurs. */
protected ResolverSession resolverSession;
/** The wrapped {@link Tuples} instance. */
protected Tuples tuples;
/** Have we reached the last tuple from the {@link #tuples}? */
protected boolean beforeEnd;
/**
* Construct an {@link Answer} by wrapping {@link Tuples}.
*
* @param tuples the local result to wrap
* @param resolverSession the session used to globalize the <var>tuples</var>
* @throws IllegalArgumentException if the <var>tuples</var> or
* <var>resolverSession</var> are <code>null</code>
*/
GlobalizedAnswer(Tuples tuples, ResolverSession resolverSession) {
// Validate "tuples" parameter
if (tuples == null) {
throw new IllegalArgumentException("Null \"tuples\" parameter");
}
// Validate "resolverSession" parameter
if (resolverSession == null) {
throw new IllegalArgumentException("Null \"resolverSession\" parameter");
}
// Initialize fields
if (logger.isDebugEnabled()) {
try {
logger.debug("Globalizing " + tuples.getRowCount() + " rows");
} catch (TuplesException e) {
logger.debug("Globalizing indeterminate number of rows");
}
}
// Initialize fields
this.beforeEnd = true;
this.resolverSession = resolverSession;
this.tuples = (Tuples) tuples.clone();
// Tuples require that beforeFirst is called before use, but Answers don't
// so make sure our tuples are initialized
try {
this.tuples.beforeFirst();
} catch (TuplesException e) {
logger.warn("Unable to reset tuples", e);
}
}
//
// Methods implementing Cursor superinterface of Answer
//
public void beforeFirst() throws TuplesException {
if (logger.isDebugEnabled()) {
logger.debug("Resetting " + getRowCount() + " rows of " +
tuples.getClass() + " with columns " +
Arrays.asList(tuples.getVariables()));
}
tuples.beforeFirst();
beforeEnd = true;
}
public void close() throws TuplesException {
tuples.close();
}
public int getColumnIndex(Variable variable) throws TuplesException {
return tuples.getColumnIndex(variable);
}
public int getNumberOfVariables() {
return tuples.getNumberOfVariables();
}
public long getRowCount() throws TuplesException {
return tuples.getRowCount();
}
public long getRowUpperBound() throws TuplesException {
return tuples.getRowUpperBound();
}
public long getRowExpectedCount() throws TuplesException {
return tuples.getRowExpectedCount();
}
public int getRowCardinality() throws TuplesException {
return tuples.getRowCardinality();
}
public boolean isEmpty() throws TuplesException {
return tuples.isEmpty();
}
public Variable[] getVariables() {
return tuples.getVariables();
}
public boolean isUnconstrained() throws TuplesException {
return tuples.isUnconstrained();
}
public boolean next() throws TuplesException {
if (beforeEnd) {
beforeEnd = tuples.next();
}
return beforeEnd;
}
//
// Methods implementing Answer
//
public Object getObject(int column) throws TuplesException {
try {
long l = tuples.getColumnValue(column);
return (l == Tuples.UNBOUND) ? null : resolverSession.globalize(l);
} catch (GlobalizeException e) {
throw new TuplesException("Couldn't globalize column " + column, e);
}
}
public Object getObject(String columnName) throws TuplesException {
return getObject(getColumnIndex(new Variable(columnName)));
}
public Object clone() {
// Copy immutable fields by reference
GlobalizedAnswer cloned = (GlobalizedAnswer)super.clone();
assert cloned != null;
// Copy mutable fields by value
cloned.tuples = (Tuples) tuples.clone();
return cloned;
}
public boolean equals(Object object) {
if ((object != null) && (object instanceof Answer)) {
try {
return AnswerOperations.equal(this, (Answer) object);
} catch (TuplesException e) {
logger.fatal("Couldn't test equality of answers", e);
}
}
return false;
}
/**
* Added to match {@link #equals(Object)}.
*/
public int hashCode() {
return super.hashCode();
}
}