| /* |
| * Copyright (c) 2003, 2014, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package javax.sql.rowset; |
| |
| import javax.sql.*; |
| import java.sql.*; |
| |
| /** |
| * The standard interface that provides the framework for all |
| * <code>FilteredRowSet</code> objects to describe their filters. |
| * |
| * <h3>1.0 Background</h3> |
| * The <code>Predicate</code> interface is a standard interface that |
| * applications can implement to define the filter they wish to apply to a |
| * a <code>FilteredRowSet</code> object. A <code>FilteredRowSet</code> |
| * object consumes implementations of this interface and enforces the |
| * constraints defined in the implementation of the method <code>evaluate</code>. |
| * A <code>FilteredRowSet</code> object enforces the filter constraints in a |
| * bi-directional manner: It outputs only rows that are within |
| * the constraints of the filter; and conversely, it inserts, modifies, or updates |
| * only rows that are within the constraints of the filter. |
| * |
| * <h3>2.0 Implementation Guidelines</h3> |
| * In order to supply a predicate for the <code>FilteredRowSet</code>. |
| * this interface must be implemented. At this time, the JDBC RowSet |
| * Implementations (JSR-114) does not specify any standard filters definitions. |
| * By specifying a standard means and mechanism for a range of filters to be |
| * defined and deployed with both the reference and vendor implementations |
| * of the <code>FilteredRowSet</code> interface, this allows for a flexible |
| * and application motivated implementations of <code>Predicate</code> to emerge. |
| * <p> |
| * A sample implementation would look something like this: |
| * <pre>{@code |
| * public class Range implements Predicate { |
| * |
| * private int[] lo; |
| * private int[] hi; |
| * private int[] idx; |
| * |
| * public Range(int[] lo, int[] hi, int[] idx) { |
| * this.lo = lo; |
| * this.hi = hi; |
| * this.idx = idx; |
| * } |
| * |
| * public boolean evaluate(RowSet rs) { |
| * |
| * // Check the present row determine if it lies |
| * // within the filtering criteria. |
| * |
| * for (int i = 0; i < idx.length; i++) { |
| * int value; |
| * try { |
| * value = (Integer) rs.getObject(idx[i]); |
| * } catch (SQLException ex) { |
| * Logger.getLogger(Range.class.getName()).log(Level.SEVERE, null, ex); |
| * return false; |
| * } |
| * |
| * if (value < lo[i] && value > hi[i]) { |
| * // outside of filter constraints |
| * return false; |
| * } |
| * } |
| * // Within filter constraints |
| * return true; |
| * } |
| * } |
| * }</pre> |
| * <P> |
| * The example above implements a simple range predicate. Note, that |
| * implementations should but are not required to provide <code>String</code> |
| * and integer index based constructors to provide for JDBC RowSet Implementation |
| * applications that use both column identification conventions. |
| * |
| * @author Jonathan Bruce, Amit Handa |
| * @since 1.5 |
| * |
| */ |
| |
| // <h3>3.0 FilteredRowSet Internals</h3> |
| // internalNext, First, Last. Discuss guidelines on how to approach this |
| // and cite examples in reference implementations. |
| public interface Predicate { |
| /** |
| * This method is typically called a <code>FilteredRowSet</code> object |
| * internal methods (not public) that control the <code>RowSet</code> object's |
| * cursor moving from row to the next. In addition, if this internal method |
| * moves the cursor onto a row that has been deleted, the internal method will |
| * continue to ove the cursor until a valid row is found. |
| * @param rs The {@code RowSet} to be evaluated |
| * @return <code>true</code> if there are more rows in the filter; |
| * <code>false</code> otherwise |
| */ |
| public boolean evaluate(RowSet rs); |
| |
| |
| /** |
| * This method is called by a <code>FilteredRowSet</code> object |
| * to check whether the value lies between the filtering criterion (or criteria |
| * if multiple constraints exist) set using the <code>setFilter()</code> method. |
| * <P> |
| * The <code>FilteredRowSet</code> object will use this method internally |
| * while inserting new rows to a <code>FilteredRowSet</code> instance. |
| * |
| * @param value An <code>Object</code> value which needs to be checked, |
| * whether it can be part of this <code>FilterRowSet</code> object. |
| * @param column a <code>int</code> object that must match the |
| * SQL index of a column in this <code>RowSet</code> object. This must |
| * have been passed to <code>Predicate</code> as one of the columns |
| * for filtering while initializing a <code>Predicate</code> |
| * @return <code>true</code> if row value lies within the filter; |
| * <code>false</code> otherwise |
| * @throws SQLException if the column is not part of filtering criteria |
| */ |
| public boolean evaluate(Object value, int column) throws SQLException; |
| |
| /** |
| * This method is called by the <code>FilteredRowSet</code> object |
| * to check whether the value lies between the filtering criteria set |
| * using the setFilter method. |
| * <P> |
| * The <code>FilteredRowSet</code> object will use this method internally |
| * while inserting new rows to a <code>FilteredRowSet</code> instance. |
| * |
| * @param value An <code>Object</code> value which needs to be checked, |
| * whether it can be part of this <code>FilterRowSet</code>. |
| * |
| * @param columnName a <code>String</code> object that must match the |
| * SQL name of a column in this <code>RowSet</code>, ignoring case. This must |
| * have been passed to <code>Predicate</code> as one of the columns for filtering |
| * while initializing a <code>Predicate</code> |
| * |
| * @return <code>true</code> if value lies within the filter; <code>false</code> otherwise |
| * |
| * @throws SQLException if the column is not part of filtering criteria |
| */ |
| public boolean evaluate(Object value, String columnName) throws SQLException; |
| |
| } |