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ARQ is a SPARQL 1.1 query engine for Apache Jena
/**
* 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.jena.riot.writer;
import java.io.OutputStream ;
import java.io.Writer ;
import java.util.Collection ;
import java.util.List ;
import java.util.Objects;
import org.apache.jena.atlas.io.IndentedWriter ;
import org.apache.jena.graph.Node ;
import org.apache.jena.graph.Triple ;
import org.apache.jena.riot.other.GLib ;
import org.apache.jena.riot.system.RiotLib ;
import org.apache.jena.sparql.core.Quad ;
/** An output of triples / quads that print batches of same subject / same graph, same subject.
* It writes something that is easier to read than
* N-triples, N-quads but it's not full pretty printing
* which usually requires analysing the data before any output.
*
* If fed only quads, the output is valid TriG.
* If fed only triples, the output is valid Turtle.
*/
public class WriterStreamRDFBlocks extends WriterStreamRDFBatched
{
protected static final boolean NL_GDFT_START = WriterConst.NL_GDFT_START ;
protected static final boolean NL_GNMD_START = WriterConst.NL_GNMD_START ;
protected static final boolean NL_GDFT_END = WriterConst.NL_GDFT_END ;
protected static final boolean NL_GNMD_END = WriterConst.NL_GNMD_END ;
// Subject column - normal width
protected static final int INDENT_PREDICATE = WriterConst.INDENT_PREDICATE ;
protected static final int MIN_PREDICATE = 6 ; //WriterConst.MIN_PREDICATE ;
protected static final int LONG_PREDICATE = WriterConst.LONG_PREDICATE ;
protected static final int LONG_SUBJECT = WriterConst.LONG_SUBJECT ;
protected static final int INDENT_MIN_S = 6 ; // Range of subject indent
protected static final int INDENT_MAX_S = 14 ;
protected static final int GAP_S_P = 2 ;
protected static final int GAP_P_O = 2 ;
protected static final int INDENT_GDFT = 2 ; // Default graph indent
protected static final int INDENT_GNMD = 4 ; // Named graph indent
// Quad output
protected Node lastGraph = null ;
protected Node lastSubject = null ;
protected boolean firstGraph = true ;
protected int currentGraphIndent = 0;
public WriterStreamRDFBlocks(OutputStream output) {
super(output) ;
}
public WriterStreamRDFBlocks(Writer output) {
super(output) ;
}
public WriterStreamRDFBlocks(IndentedWriter output) {
super(output) ;
}
@Override
protected void printBatchQuads(Node g, Node s, List quads) {
if ( g == null )
g = Quad.defaultGraphNodeGenerated ;
if ( Objects.equals(g, lastGraph) ) {
// Same graph, different subject.
out.println(" .") ;
out.println() ;
} else {
// Start graph
endGraph(g) ;
startGraph(g) ;
lastGraph = g ;
}
List triples = GLib.quads2triples(quads.iterator()).toList() ;
printBatch(s, triples) ;
// No trailing "." has been printed.
lastSubject = s ;
}
private void gap(int gap) {
out.print(' ', gap) ;
}
@Override
protected void printBatchTriples(Node s, List triples) {
// Blank line?
// Not if not prefixes and first batch.
if ( out.getRow() > 1 )
out.println() ;
printBatch(s, triples) ;
// End of cluster.
out.print(" .") ;
out.println() ;
}
private void printBatch(Node s, List triples) {
outputNode(s) ;
if ( out.getCol() > LONG_SUBJECT )
out.println() ;
else
gap(GAP_S_P) ;
out.incIndent(INDENT_PREDICATE) ;
out.pad() ;
writePredicateObjectList(triples) ;
out.decIndent(INDENT_PREDICATE) ;
}
private void writePredicateObjectList(Collection triples) {
// Find width
int predicateMaxWidth = RiotLib.calcWidthTriples(pMap, baseURI, triples, MIN_PREDICATE, LONG_PREDICATE) ;
boolean first = true ;
for ( Triple triple : triples ) {
if ( !first )
out.println(" ;") ;
else
first = false ;
Node p = triple.getPredicate() ;
outputNode(p) ;
out.pad(predicateMaxWidth) ;
out.print(' ', GAP_P_O) ;
Node o = triple.getObject() ;
outputNode(o) ;
}
}
@Override
protected void finalizeRun() {
if ( lastGraph != null )
// last was a quad
endGraph(null) ;
}
protected boolean dftGraph() { return lastGraph == Quad.defaultGraphNodeGenerated ; }
protected boolean dftGraph(Node g) { return g == Quad.defaultGraphNodeGenerated ; }
protected void startGraph(Node g) {
// Start graph
if ( lastGraph == null ) {
boolean NL_START = (dftGraph(g) ? NL_GDFT_START : NL_GNMD_START) ;
if ( !firstGraph )
out.println() ;
firstGraph = false ;
lastSubject = null ;
if ( !dftGraph(g) ) {
outputNode(g) ;
out.print(" ") ;
}
if ( NL_START )
out.println("{") ;
else
out.print("{ ") ;
if ( dftGraph() )
setGraphIndent(INDENT_GDFT) ;
else {
int x = NL_START ? INDENT_GNMD : out.getCol() ;
setGraphIndent(x) ;
}
out.incIndent(graphIndent()) ;
}
lastGraph = g ;
}
protected void endGraph(Node g) {
if ( lastGraph == null )
return ;
// End of graph
if ( !Objects.equals(lastGraph, g) ) {
boolean NL_END = (dftGraph(g) ? NL_GDFT_END : NL_GNMD_END) ;
if ( lastSubject != null )
out.print(" .") ;
if ( NL_END ) {
// } on a new line.
out.decIndent(graphIndent()) ;
out.println() ;
out.println("}") ;
} else {
// Possibly on same line as last quad/triple.
out.decIndent(graphIndent()) ;
if ( out.atLineStart() )
out.println("}") ;
else
out.println(" }") ;
}
lastSubject = null ;
lastGraph = null ;
}
}
protected void setGraphIndent(int x) { currentGraphIndent = x ; }
protected int graphIndent() { return currentGraphIndent ; }
}
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