+
−/*
+
− * This Source Code Form is subject to the terms of the Mozilla Public
+
− * License, v. 2.0.  If a copy of the MPL was not distributed with this
+
− * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
− *
+
− * Copyright 2016 MonetDB B.V.
+
− */
+
−
+
−package nl.cwi.monetdb.embedded;
+
−
+
−import java.util.Arrays;
+
−import java.util.ListIterator;
+
−
+
−/**
+
− * Embedded MonetDB query result.
+
− * The query result columns are not eagerly copied from the native code to Java.
+
− * Instead, they are kept around at MonetDB native C-level, materialised in Java 
+
− * on demand and freed on {@code super.close()}.
+
− *
+
− * @author <a href="mailto:pedro.ferreira@monetdbsolutions.com">Pedro Ferreira</a>
+
− */
+
−public class QueryResultSet extends AbstractStatementResult implements Iterable {
+
−
+
−    /**
+
−     * Pointer to the native result set.
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−     * We need to keep it around for getting columns.
+
−     * The native result set is kept until the the close method is called.
+
−     */
+
−    protected long resultPointer;
+
−
+
−    /**
+
−     * The number of columns in the query result.
+
−     */
+
−    protected final int numberOfColumns;
+
−
+
−    /**
+
−     * The number of rows in the query result.
+
−     */
+
−    protected final int numberOfRows;
+
−
+
−	/**
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−	 * The query result set columns listing.
+
−	 */
+
−    private final QueryResultSetColumn<?>[] columns;
+
−
+
−	protected QueryResultSet(MonetDBEmbeddedConnection connection, long resultPointer,
+
−                             QueryResultSetColumn<?>[] columns, int numberOfRows) {
+
−        super(connection);
+
−        this.resultPointer = resultPointer;
+
−        this.numberOfColumns = columns.length;
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−        this.numberOfRows = numberOfRows;
+
−        this.columns = columns;
+
−	}
+
−
+
−    /**
+
−     * Tells if the connection of this statement result has been closed or not.
+
−     *
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−     * @return A boolean indicating if the statement result has been cleaned or not
+
−     */
+
−    public boolean isStatementClosed() { return this.resultPointer == 0; }
+
−
+
−    /**
+
−     * Returns the number of columns in the result set.
+
−     *
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−     * @return Number of columns
+
−     */
+
−    public int getNumberOfColumns() {
+
−        return this.numberOfColumns;
+
−    }
+
−
+
−    /**
+
−     * Returns the number of rows in the result set.
+
−     *
+
−     * @return Number of rows
+
−     */
+
−    public int getNumberOfRows() {
+
−        return this.numberOfRows;
+
−    }
+
−
+
−    /**
+
−     * Get the columns names as a string array.
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−     *
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−     * @return The columns names array
+
−     */
+
−    public String[] getColumnNames() {
+
−        int i = 0;
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−        String[] result = new String[this.numberOfColumns];
+
−        for(AbstractColumn col : this.columns) {
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−            result[i] = col.getColumnName();
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−        }
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−        return result;
+
−    }
+
−
+
−    /**
+
−     * Get the columns types as a string array.
+
−     *
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−     * @return The columns types array
+
−     */
+
−    public String[] getColumnTypes() {
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−        int i = 0;
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−        String[] result = new String[this.numberOfColumns];
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−        for(AbstractColumn col : this.columns) {
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−            result[i] = col.getColumnType();
+
−        }
+
−        return result;
+
−    }
+
−
+
−    /**
+
−     * Get the Java mappings as a MonetDBToJavaMapping array.
+
−     *
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−     * @return The columns MonetDBToJavaMapping array
+
−     */
+
−    public MonetDBToJavaMapping[] getMappings() {
+
−        int i = 0;
+
−        MonetDBToJavaMapping[] result = new MonetDBToJavaMapping[this.numberOfColumns];
+
−        for(AbstractColumn col : this.columns) {
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−            result[i] = col.getMapping();
+
−        }
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−        return result;
+
−    }
+
−
+
−    /**
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−     * Get the columns digits as a int array.
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−     *
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−     * @return The columns digits array
+
−     */
+
−    public int[] getColumnDigits() {
+
−        int i = 0;
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−        int[] result = new int[this.numberOfColumns];
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−        for(AbstractColumn col : this.columns) {
+
−            result[i] = col.getColumnDigits();
+
−        }
+
−        return result;
+
−    }
+
−
+
−    /**
+
−     * Get the columns scales as a int array.
+
−     *
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−     * @return The columns scales array
+
−     */
+
−    public int[] getColumnScales() {
+
−        int i = 0;
+
−        int[] result = new int[this.numberOfColumns];
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−        for(AbstractColumn col : this.columns) {
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−            result[i] = col.getColumnScale();
+
−        }
+
−        return result;
+
−    }
+
−
+
−    /**
+
−     * Get a columns' values from the result set by index.
+
−     *
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−     * @param index QueryResultSetColumn index (starting from 0)
+
−     * @return The columns, {@code null} if index not in bounds
+
−     */
+
−    @SuppressWarnings("unchecked")
+
−    public <T> QueryResultSetColumn<T> getColumn(int index) {
+
−        return (QueryResultSetColumn<T>) columns[index];
+
−    }
+
−
+
−    /**
+
−     * Get a columns from the result set by name.
+
−     *
+
−     * @param name QueryResultSetColumn name
+
−     * @return The columns
+
−     */
+
−    public <T> QueryResultSetColumn<T> getColumn(String name) {
+
−        int index = 0;
+
−        for (AbstractColumn col : this.columns) {
+
−            if (col.getColumnName().equals(name)) {
+
−                return this.getColumn(index);
+
−            }
+
−            index++;
+
−        }
+
−        throw new ArrayIndexOutOfBoundsException("The columns is not present in the result set!");
+
−    }
+
−
+
−    /**
+
−     * Fetches rows from the result set.
+
−     *
+
−     * @param startIndex The first row index to retrieve
+
−     * @param endIndex The last row index to retrieve
+
−     * @return The rows as {@code QueryResultSetRows}
+
−     * @throws MonetDBEmbeddedException If an error in the database occurred
+
−     */
+
−	public QueryResultSetRows fetchResultSetRows(int startIndex, int endIndex) throws MonetDBEmbeddedException {
+
−        if(endIndex < startIndex) {
+
−            int aux = startIndex;
+
−            startIndex = endIndex;
+
−            endIndex = aux;
+
−        }
+
−        if (startIndex < 0) {
+
−            throw new ArrayIndexOutOfBoundsException("The start index must be larger than 0!");
+
−        } else if (endIndex > this.numberOfRows) {
+
−            throw new ArrayIndexOutOfBoundsException("The index must be smaller than the number of elements in the columns!");
+
−        } else if(startIndex == endIndex) {
+
−            throw new ArrayIndexOutOfBoundsException("Retrieving 0 rows?");
+
−        }
+
−        int numberOfRowsToRetrieve = endIndex - startIndex;
+
−        Object[][] temp = new Object[numberOfRowsToRetrieve][this.numberOfColumns];
+
−		for (int i = 0 ; i < this.numberOfColumns; i++) {
+
−            Object[] nextColumn = this.columns[i].fetchColumnValues(startIndex, endIndex);
+
−            for(int j = 0; j < numberOfRowsToRetrieve ; j++) {
+
−                temp[j][i] = nextColumn[j];
+
−			}
+
−		}
+
−        return new QueryResultSetRows(this, this.getMappings(), temp);
+
−	}
+
−
+
−    /**
+
−     * Fetches rows from the result set asynchronously.
+
−     *
+
−     * @param startIndex The first row index to retrieve
+
−     * @param endIndex The last row index to retrieve
+
−     * @return The rows as {@code QueryResultSetRows}
+
−     * @throws MonetDBEmbeddedException If an error in the database occurred
+
−     */
+
−    public QueryResultSetRows fetchResultSetRowsAsync(int startIndex, int endIndex) throws MonetDBEmbeddedException {
+
−        /* CompletableFuture.supplyAsync(() -> this.fetchResultSetRows(startIndex, endIndex)); */
+
−        throw new UnsupportedOperationException("Must wait for Java 8 :(");
+
−    }
+
−
+
−    /**
+
−     * Fetches the first N rows from the result set.
+
−     *
+
−     * @param n The last row index to retrieve
+
−     * @return The rows as {@code QueryResultSetRows}
+
−     * @throws MonetDBEmbeddedException If an error in the database occurred
+
−     */
+
−    public QueryResultSetRows fetchFirstNRowValues(int n) throws MonetDBEmbeddedException {
+
−        return this.fetchResultSetRows(0, n);
+
−    }
+
−
+
−    /**
+
−     * Fetches the first N rows from the result set asynchronously.
+
−     *
+
−     * @param n The last row index to retrieve
+
−     * @return The rows as {@code QueryResultSetRows}
+
−     * @throws MonetDBEmbeddedException If an error in the database occurred
+
−     */
+
−    public QueryResultSetRows fetchFirstNRowValuesAsync(int n) throws MonetDBEmbeddedException {
+
−        return this.fetchResultSetRowsAsync(0, n);
+
−    }
+
−
+
−    /**
+
−     * Fetches all rows from the result set.
+
−     *
+
−     * @return The rows as {@code QueryResultSetRows}
+
−     * @throws MonetDBEmbeddedException If an error in the database occurred
+
−     */
+
−    public QueryResultSetRows fetchAllRowValues() throws MonetDBEmbeddedException {
+
−        return this.fetchResultSetRows(0, this.numberOfRows);
+
−    }
+
−
+
−    /**
+
−     * Fetches all rows from the result set asynchronously.
+
−     *
+
−     * @return The rows as {@code QueryResultSetRows}
+
−     * @throws MonetDBEmbeddedException If an error in the database occurred
+
−     */
+
−    public QueryResultSetRows fetchAllRowValuesAsync() throws MonetDBEmbeddedException {
+
−        return this.fetchResultSetRowsAsync(0, this.numberOfRows);
+
−    }
+
−
+
−    @Override
+
−    public ListIterator<QueryResultSetRows.QueryResulSetRow> iterator() {
+
−        try {
+
−            return Arrays.asList(this.fetchAllRowValues().getAllRows()).listIterator();
+
−        } catch (MonetDBEmbeddedException ex) {
+
−            return null;
+
−        }
+
−    }
+
−
+
−    /**
+
−     * Close the query data so no more new results can be retrieved.
+
−     */
+
−    @Override
+
−    public void closeImplementation() {
+
−        this.cleanupResultInternal(this.resultPointer);
+
−        this.resultPointer = 0;
+
−    }
+
−
+
−    private native void cleanupResultInternal(long resultPointer);
+
−}