/*
* Copyright 2011 Rickard Öberg.
*
* 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.qi4j.index.rdf.query.internal;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Collection;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.TimeZone;
import org.apache.commons.lang.StringEscapeUtils;
import org.qi4j.api.composite.Composite;
import org.qi4j.api.entity.EntityComposite;
import org.qi4j.api.query.grammar.AndSpecification;
import org.qi4j.api.query.grammar.AssociationNotNullSpecification;
import org.qi4j.api.query.grammar.AssociationNullSpecification;
import org.qi4j.api.query.grammar.ComparisonSpecification;
import org.qi4j.api.query.grammar.ContainsAllSpecification;
import org.qi4j.api.query.grammar.ContainsSpecification;
import org.qi4j.api.query.grammar.EqSpecification;
import org.qi4j.api.query.grammar.GeSpecification;
import org.qi4j.api.query.grammar.GtSpecification;
import org.qi4j.api.query.grammar.LeSpecification;
import org.qi4j.api.query.grammar.LtSpecification;
import org.qi4j.api.query.grammar.ManyAssociationContainsSpecification;
import org.qi4j.api.query.grammar.MatchesSpecification;
import org.qi4j.api.query.grammar.NeSpecification;
import org.qi4j.api.query.grammar.NotSpecification;
import org.qi4j.api.query.grammar.OrSpecification;
import org.qi4j.api.query.grammar.OrderBy;
import org.qi4j.api.query.grammar.PropertyFunction;
import org.qi4j.api.query.grammar.PropertyNotNullSpecification;
import org.qi4j.api.query.grammar.PropertyNullSpecification;
import org.qi4j.api.query.grammar.QuerySpecification;
import org.qi4j.api.query.grammar.Variable;
import org.qi4j.api.value.ValueSerializer;
import org.qi4j.api.value.ValueSerializer.Options;
import org.qi4j.functional.Iterables;
import org.qi4j.functional.Specification;
import org.qi4j.index.rdf.query.RdfQueryParser;
import org.qi4j.spi.Qi4jSPI;
import org.slf4j.LoggerFactory;
import static java.lang.String.format;
/**
* JAVADOC Add JavaDoc
*/
public class RdfQueryParserImpl
implements RdfQueryParser
{
private static final ThreadLocal<DateFormat> ISO8601_UTC = new ThreadLocal<DateFormat>()
{
@Override
protected DateFormat initialValue()
{
SimpleDateFormat dateFormat = new SimpleDateFormat( "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'" );
dateFormat.setTimeZone( TimeZone.getTimeZone( "UTC" ) );
return dateFormat;
}
};
private static final Map<Class<? extends ComparisonSpecification>, String> OPERATORS;
private static final Set<Character> RESERVED_CHARS;
private final Namespaces namespaces = new Namespaces();
private final Triples triples = new Triples( namespaces );
private final Qi4jSPI spi;
private final ValueSerializer valueSerializer;
private Map<String, Object> variables;
static
{
OPERATORS = new HashMap<>( 6 );
OPERATORS.put( EqSpecification.class, "=" );
OPERATORS.put( GeSpecification.class, ">=" );
OPERATORS.put( GtSpecification.class, ">" );
OPERATORS.put( LeSpecification.class, "<=" );
OPERATORS.put( LtSpecification.class, "<" );
OPERATORS.put( NeSpecification.class, "!=" );
RESERVED_CHARS = new HashSet<>( Arrays.asList(
'\"', '^', '.', '\\', '?', '*', '+', '{', '}', '(', ')', '|', '$', '[', ']'
) );
}
public RdfQueryParserImpl( Qi4jSPI spi, ValueSerializer valueSerializer )
{
this.spi = spi;
this.valueSerializer = valueSerializer;
}
@Override
public String constructQuery( final Class<?> resultType,
final Specification<Composite> specification,
final OrderBy[] orderBySegments,
final Integer firstResult,
final Integer maxResults,
final Map<String, Object> variables
)
{
this.variables = variables;
if( QuerySpecification.isQueryLanguage( "SPARQL", specification ) )
{
// Custom query
StringBuilder queryBuilder = new StringBuilder();
String query = ( (QuerySpecification) specification ).query();
queryBuilder.append( query );
if( orderBySegments != null )
{
queryBuilder.append( "\nORDER BY " );
processOrderBy( orderBySegments, queryBuilder );
}
if( firstResult != null )
{
queryBuilder.append( "\nOFFSET " ).append( firstResult );
}
if( maxResults != null )
{
queryBuilder.append( "\nLIMIT " ).append( maxResults );
}
return queryBuilder.toString();
}
else
{
// Add type+identity triples last. This makes queries faster since the query engine can reduce the number
// of triples to check faster
triples.addDefaultTriples( resultType.getName() );
}
// and collect namespaces
StringBuilder filter = new StringBuilder();
processFilter( specification, true, filter );
StringBuilder orderBy = new StringBuilder();
processOrderBy( orderBySegments, orderBy );
StringBuilder query = new StringBuilder();
for( String namespace : namespaces.namespaces() )
{
query.append( format( "PREFIX %s: <%s> %n", namespaces.namespacePrefix( namespace ), namespace ) );
}
query.append( "SELECT DISTINCT ?identity\n" );
if( triples.hasTriples() )
{
query.append( "WHERE {\n" );
StringBuilder optional = new StringBuilder();
for( Triples.Triple triple : triples )
{
final String subject = triple.subject();
final String predicate = triple.predicate();
final String value = triple.value();
if( triple.isOptional() )
{
optional.append( format( "OPTIONAL {%s %s %s}. ", subject, predicate, value ) );
optional.append( '\n' );
}
else
{
query.append( format( "%s %s %s. ", subject, predicate, value ) );
query.append( '\n' );
}
}
// Add OPTIONAL statements last
if( optional.length() > 0 )
{
query.append( optional.toString() );
}
if( filter.length() > 0 )
{
query.append( "FILTER " ).append( filter );
}
query.append( "\n}" );
}
if( orderBy.length() > 0 )
{
query.append( "\nORDER BY " ).append( orderBy );
}
if( firstResult != null )
{
query.append( "\nOFFSET " ).append( firstResult );
}
if( maxResults != null )
{
query.append( "\nLIMIT " ).append( maxResults );
}
LoggerFactory.getLogger( getClass() ).debug( "Query:\n" + query );
return query.toString();
}
private void processFilter( final Specification<Composite> expression, boolean allowInline, StringBuilder builder )
{
if( expression == null )
{
return;
}
if( expression instanceof AndSpecification )
{
final AndSpecification conjunction = (AndSpecification) expression;
int start = builder.length();
boolean first = true;
for( Specification<Composite> operand : conjunction.operands() )
{
int size = builder.length();
processFilter( operand, allowInline, builder );
if( builder.length() > size )
{
if( first )
{
first = false;
}
else
{
builder.insert( size, " && " );
}
}
}
if( builder.length() > start )
{
builder.insert( start, '(' );
builder.append( ')' );
}
}
else if( expression instanceof OrSpecification )
{
final OrSpecification disjunction = (OrSpecification) expression;
int start = builder.length();
boolean first = true;
for( Specification<Composite> operand : disjunction.operands() )
{
int size = builder.length();
processFilter( operand, false, builder );
if( builder.length() > size )
{
if( first )
{
first = false;
}
else
{
builder.insert( size, "||" );
}
}
}
if( builder.length() > start )
{
builder.insert( start, '(' );
builder.append( ')' );
}
}
else if( expression instanceof NotSpecification )
{
builder.insert( 0, "(!" );
processFilter( ( (NotSpecification) expression ).operand(), false, builder );
builder.append( ")" );
}
else if( expression instanceof ComparisonSpecification )
{
processComparisonPredicate( expression, allowInline, builder );
}
else if( expression instanceof ContainsAllSpecification )
{
processContainsAllPredicate( (ContainsAllSpecification) expression, builder );
}
else if( expression instanceof ContainsSpecification<?> )
{
processContainsPredicate( (ContainsSpecification<?>) expression, builder );
}
else if( expression instanceof MatchesSpecification )
{
processMatchesPredicate( (MatchesSpecification) expression, builder );
}
else if( expression instanceof PropertyNotNullSpecification<?> )
{
processNotNullPredicate( (PropertyNotNullSpecification) expression, builder );
}
else if( expression instanceof PropertyNullSpecification<?> )
{
processNullPredicate( (PropertyNullSpecification) expression, builder );
}
else if( expression instanceof AssociationNotNullSpecification<?> )
{
processNotNullPredicate( (AssociationNotNullSpecification) expression, builder );
}
else if( expression instanceof AssociationNullSpecification<?> )
{
processNullPredicate( (AssociationNullSpecification) expression, builder );
}
else if( expression instanceof ManyAssociationContainsSpecification<?> )
{
processManyAssociationContainsPredicate( (ManyAssociationContainsSpecification) expression, allowInline, builder );
}
else
{
throw new UnsupportedOperationException( "Expression " + expression + " is not supported" );
}
}
private static void join( String[] strings, String delimiter, StringBuilder builder )
{
for( Integer x = 0; x < strings.length; ++x )
{
builder.append( strings[ x] );
if( x + 1 < strings.length )
{
builder.append( delimiter );
}
}
}
private String createAndEscapeJSONString( Object value )
{
return escapeJSONString( valueSerializer.serialize( new Options().withoutTypeInfo(), value ) );
}
private String createRegexStringForContaining( String valueVariable, String containedString )
{
// The matching value must start with [, then contain something (possibly nothing),
// then our value, then again something (possibly nothing), and end with ]
return format( "regex(str(%s), \"^\\\\u005B.*%s.*\\\\u005D$\", \"s\")", valueVariable, containedString );
}
private String escapeJSONString( String jsonStr )
{
StringBuilder builder = new StringBuilder();
char[] chars = jsonStr.toCharArray();
for( int i = 0; i < chars.length; i++ )
{
char c = chars[ i];
/*
if ( reservedJsonChars.contains( c ))
{
builder.append( "\\\\u" ).append( format( "%04X", (int) '\\' ) );
}
*/
if( RESERVED_CHARS.contains( c ) )
{
builder.append( "\\\\u" ).append( format( "%04X", (int) c ) );
}
else
{
builder.append( c );
}
}
return builder.toString();
}
private void processContainsAllPredicate( final ContainsAllSpecification<?> predicate, StringBuilder builder )
{
Iterable<?> values = predicate.containedValues();
String valueVariable = triples.addTriple( predicate.collectionProperty(), false ).value();
String[] strings;
if( values instanceof Collection )
{
strings = new String[ ( (Collection<?>) values ).size() ];
}
else
{
strings = new String[ ( (int) Iterables.count( values ) ) ];
}
Integer x = 0;
for( Object item : (Collection<?>) values )
{
String jsonStr = "";
if( item != null )
{
String serialized = valueSerializer.serialize( item, false );
if( item instanceof String )
{
serialized = "\"" + StringEscapeUtils.escapeJava( serialized ) + "\"";
}
jsonStr = escapeJSONString( serialized );
}
strings[ x] = this.createRegexStringForContaining( valueVariable, jsonStr );
x++;
}
if( strings.length > 0 )
{
// For some reason, just "FILTER ()" causes error in SPARQL query
builder.append( "(" );
join( strings, " && ", builder );
builder.append( ")" );
}
else
{
builder.append( this.createRegexStringForContaining( valueVariable, "" ) );
}
}
private void processContainsPredicate( final ContainsSpecification<?> predicate, StringBuilder builder )
{
Object value = predicate.value();
String valueVariable = triples.addTriple( predicate.collectionProperty(), false ).value();
builder.append( this.createRegexStringForContaining(
valueVariable,
this.createAndEscapeJSONString( value )
) );
}
private void processMatchesPredicate( final MatchesSpecification predicate, StringBuilder builder )
{
String valueVariable = triples.addTriple( predicate.property(), false ).value();
builder.append( format( "regex(%s,\"%s\")", valueVariable, predicate.regexp() ) );
}
private void processComparisonPredicate( final Specification<Composite> predicate,
boolean allowInline,
StringBuilder builder
)
{
if( predicate instanceof ComparisonSpecification )
{
ComparisonSpecification<?> comparisonSpecification = (ComparisonSpecification<?>) predicate;
Triples.Triple triple = triples.addTriple( (PropertyFunction) comparisonSpecification.property(), false );
// Don't use FILTER for equals-comparison. Do direct match instead
if( predicate instanceof EqSpecification && allowInline )
{
triple.setValue( "\"" + toString( comparisonSpecification.value() ) + "\"" );
}
else
{
String valueVariable = triple.value();
builder.append( String.format(
"(%s %s \"%s\")",
valueVariable,
getOperator( comparisonSpecification.getClass() ),
toString( comparisonSpecification.value() ) ) );
}
}
else
{
throw new UnsupportedOperationException( "Operator " + predicate.getClass()
.getName() + " is not supported" );
}
}
private void processNullPredicate( final PropertyNullSpecification<?> predicate, StringBuilder builder )
{
final String value = triples.addTriple( predicate.property(), true ).value();
builder.append( format( "(! bound(%s))", value ) );
}
private void processNotNullPredicate( final PropertyNotNullSpecification<?> predicate, StringBuilder builder )
{
final String value = triples.addTriple( predicate.property(), true ).value();
builder.append( format( "(bound(%s))", value ) );
}
private void processNullPredicate( final AssociationNullSpecification<?> predicate, StringBuilder builder )
{
final String value = triples.addTripleAssociation( predicate.association(), true ).value();
builder.append( format( "(! bound(%s))", value ) );
}
private void processNotNullPredicate( final AssociationNotNullSpecification<?> predicate, StringBuilder builder )
{
final String value = triples.addTripleAssociation( predicate.association(), true ).value();
builder.append( format( "(bound(%s))", value ) );
}
private void processManyAssociationContainsPredicate( ManyAssociationContainsSpecification<?> predicate,
boolean allowInline, StringBuilder builder
)
{
Triples.Triple triple = triples.addTripleManyAssociation( predicate.manyAssociation(), false );
if( allowInline )
{
triple.setValue( "<" + toString( predicate.value() ) + ">" );
}
else
{
String valueVariable = triple.value();
builder.append( String.format( "(%s %s <%s>)", valueVariable, "=", toString( predicate.value() ) ) );
}
}
private void processOrderBy( OrderBy[] orderBySegments, StringBuilder builder )
{
if( orderBySegments != null && orderBySegments.length > 0 )
{
for( OrderBy orderBySegment : orderBySegments )
{
processOrderBy( builder, orderBySegment );
}
}
}
private void processOrderBy( StringBuilder builder, OrderBy orderBySegment )
{
if( orderBySegment != null )
{
final String valueVariable = triples.addTriple( orderBySegment.property(), false ).value();
if( orderBySegment.order() == OrderBy.Order.ASCENDING )
{
builder.append( format( "ASC(%s)", valueVariable ) );
}
else
{
builder.append( format( "DESC(%s)", valueVariable ) );
}
}
}
private String getOperator( final Class<? extends ComparisonSpecification> predicateClass )
{
String operator = OPERATORS.get( predicateClass );
if( operator == null )
{
throw new UnsupportedOperationException( "Predicate [" + predicateClass.getName() + "] is not supported" );
}
return operator;
}
private String toString( Object value )
{
if( value == null )
{
return null;
}
if( value instanceof Date )
{
return ISO8601_UTC.get().format( (Date) value );
}
else if( value instanceof EntityComposite )
{
return "urn:qi4j:entity:" + value.toString();
}
else if( value instanceof Variable )
{
Object realValue = variables.get( ( (Variable) value ).variableName() );
if( realValue == null )
{
throw new IllegalArgumentException( "Variable " + ( (Variable) value ).variableName() + " not bound" );
}
return toString( realValue );
}
else
{
return value.toString();
}
}
}