/**
* 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.jdbc.results;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import org.apache.jena.atlas.lib.Closeable;
import org.apache.jena.graph.Node ;
import org.apache.jena.jdbc.results.metadata.SelectResultsMetadata;
import org.apache.jena.jdbc.statements.JenaStatement;
import org.apache.jena.query.QueryCancelledException ;
import org.apache.jena.query.QueryExecution ;
import org.apache.jena.query.ResultSetFactory ;
import org.apache.jena.sparql.core.Var ;
import org.apache.jena.sparql.engine.binding.Binding ;
import org.apache.jena.sparql.resultset.ResultSetPeekable ;
/**
* Represents SPARQL SELECT results
*
*/
public class SelectResults extends StreamedResults<Binding> {
private ResultSetPeekable innerResults;
private List<String> columns;
private SelectResultsMetadata metadata;
/**
* Creates new select results
*
* @param statement
* Statement that created the result set
* @param qe
* Query Execution
* @param results
* SPARQL Results
* @param commit
* Whether a commit is necessary when the results are closed
* @throws SQLException
* Thrown if the arguments are invalid
*/
public SelectResults(JenaStatement statement, QueryExecution qe, ResultSetPeekable results, boolean commit)
throws SQLException {
super(statement, qe, commit);
if (results == null)
throw new SQLException("SPARQL Results cannot be null");
this.innerResults = results;
this.columns = new ArrayList<String>(this.innerResults.getResultVars());
this.metadata = statement.getJenaConnection().applyPostProcessors(new SelectResultsMetadata(this, this.innerResults));
}
/**
* Creates new select results
*
* @param statement
* Statement that created the result set
* @param qe
* Query Execution
* @param results
* SPARQL Results
* @param commit
* Whether a commit is necessary when the results are closed
* @throws SQLException
* Thrown if the arguments are invalid
*/
public SelectResults(JenaStatement statement, QueryExecution qe, org.apache.jena.query.ResultSet results, boolean commit)
throws SQLException {
this(statement, qe, ResultSetFactory.makePeekable(results), commit);
}
@Override
public void closeStreamInternal() {
if (this.innerResults != null) {
if (this.innerResults instanceof Closeable) {
((Closeable) this.innerResults).close();
}
this.innerResults = null;
}
}
public int findColumn(String columnLabel) throws SQLException {
if (this.isClosed())
throw new SQLException("Result Set is closed");
for (int i = 0; i < this.columns.size(); i++) {
if (this.columns.get(i).equals(columnLabel)) {
// Remember that JDBC uses a 1 based index
return i + 1;
}
}
throw new SQLException("The given column does not exist in this result set");
}
@Override
protected String findColumnLabel(int columnIndex) throws SQLException {
if (this.isClosed())
throw new SQLException("Result Set is closed");
if (columnIndex >= 1 && columnIndex <= this.columns.size()) {
// Remember that JDBC uses a 1 based index
return this.columns.get(columnIndex - 1);
} else {
throw new SQLException("Column Index is out of bounds");
}
}
@Override
protected Node getNode(String columnLabel) throws SQLException {
if (this.isClosed())
throw new SQLException("Result Set is closed");
if (this.getCurrentRow() == null)
throw new SQLException("Not currently at a row");
if (!this.columns.contains(columnLabel))
throw new SQLException("The given column does not exist in the result set");
return this.getCurrentRow().get(Var.alloc(columnLabel));
}
@Override
public ResultSetMetaData getMetaData() {
return this.metadata;
}
/**
* Gets whether there are further rows in the underlying SELECT results
*/
@Override
protected boolean hasNext() throws SQLException {
// No null check here because superclass will not call us after we are
// closed and set to null
try {
return this.innerResults.hasNext();
} catch (QueryCancelledException e) {
throw new SQLException("Query was cancelled, it is likely that your query exceeded the specified execution timeout",
e);
} catch (Throwable e) {
// Wrap as SQL exception
throw new SQLException("Unexpected error while moving through results", e);
}
}
/**
* Gets the next row from the underlying SELECT results
*/
@Override
protected Binding moveNext() throws SQLException {
// No null check here because superclass will not call us after we are
// closed and set to null
try {
return this.innerResults.nextBinding();
} catch (QueryCancelledException e) {
throw new SQLException("Query was cancelled, it is likely that your query exceeded the specified execution timeout",
e);
} catch (Throwable e) {
// Wrap as SQL exception
throw new SQLException("Unexpected error while moving through results", e);
}
}
}