/*
 * Copyright 1999-2004 The Apache Software Foundation.
 * 
 * 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.apache.commons.dbcp;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.SQLWarning;
import java.sql.Statement;
import java.util.List;

/**
 * A base delegating implementation of {@link Statement}.
 * <p>
 * All of the methods from the {@link Statement} interface
 * simply check to see that the {@link Statement} is active,
 * and call the corresponding method on the "delegate"
 * provided in my constructor.
 * <p>
 * Extends AbandonedTrace to implement Statement tracking and
 * logging of code which created the Statement. Tracking the
 * Statement ensures that the Connection which created it can
 * close any open Statement's on Connection close.
 *
 * @author Rodney Waldhoff
 * @author Glenn L. Nielsen
 * @author James House
 * @author Dirk Verbeeck
 * @version $Revision: 1.17 $ $Date: 2004/03/06 13:35:31 $
 */
public class DelegatingStatement extends AbandonedTrace implements Statement {
    /** My delegate. */
    protected Statement _stmt = null;
    /** The connection that created me. **/
    protected DelegatingConnection _conn = null;

    /**
     * Create a wrapper for the Statement which traces this
     * Statement to the Connection which created it and the
     * code which created it.
     *
     * @param s the {@link Statement} to delegate all calls to.
     * @param c the {@link DelegatingConnection} that created this statement.
     */
    public DelegatingStatement(DelegatingConnection c, Statement s) {
        super(c);
        _stmt = s;
        _conn = c;
    }

    /**
     * Returns my underlying {@link Statement}.
     * @return my underlying {@link Statement}.
     * @see #getInnermostDelegate
     */
    public Statement getDelegate() {
        return _stmt;
    }

    public boolean equals(Object obj) {
        Statement delegate = getInnermostDelegate();
        if (delegate == null) {
            return false;
        }
        if (obj instanceof DelegatingStatement) {
            DelegatingStatement s = (DelegatingStatement) obj;
            return delegate.equals(s.getInnermostDelegate());
        }
        else {
            return delegate.equals(obj);
        }
    }

    public int hashCode() {
        Object obj = getInnermostDelegate();
        if (obj == null) {
            return 0;
        }
        return obj.hashCode();
    }
    
    /**
     * If my underlying {@link Statement} is not a
     * <tt>DelegatingStatement</tt>, returns it,
     * otherwise recursively invokes this method on
     * my delegate.
     * <p>
     * Hence this method will return the first
     * delegate that is not a <tt>DelegatingStatement</tt>
     * or <tt>null</tt> when no non-<tt>DelegatingStatement</tt>
     * delegate can be found by transversing this chain.
     * <p>
     * This method is useful when you may have nested
     * <tt>DelegatingStatement</tt>s, and you want to make
     * sure to obtain a "genuine" {@link Statement}.
     * @see #getDelegate
     */
    public Statement getInnermostDelegate() {
        Statement s = _stmt;
        while(s != null && s instanceof DelegatingStatement) {
            s = ((DelegatingStatement)s).getDelegate();
            if(this == s) {
                return null;
            }
        }
        return s;
    }

    /** Sets my delegate. */
    public void setDelegate(Statement s) {
        _stmt = s;
    }

    protected boolean _closed = false;

    protected boolean isClosed() {
        return _closed;
    }

    protected void checkOpen() throws SQLException {
        if(isClosed()) {
            throw new SQLException(this.getClass().getName() + " is closed.");
        }
    }

    /**
     * Close this DelegatingStatement, and close
     * any ResultSets that were not explicitly closed.
     */
    public void close() throws SQLException {
        try {
            try {
                if (_conn != null) {
                    _conn.removeTrace(this);
                    _conn = null;
                }
        
                // The JDBC spec requires that a statment close any open
                // ResultSet's when it is closed.
                // FIXME The PreparedStatement we're wrapping should handle this for us.
                // See bug 17301 for what could happen when ResultSets are closed twice.
                List resultSets = getTrace();
                if( resultSets != null) {
                    ResultSet[] set = (ResultSet[]) resultSets.toArray(new ResultSet[resultSets.size()]);
                    for (int i = 0; i < set.length; i++) {
                        set[i].close();
                    }
                    clearTrace();
                }
        
                _stmt.close();
            }
            catch (SQLException e) {
                handleException(e);
            }
        }
        finally {
            _closed = true;
        }
    }

    protected void handleException(SQLException e) throws SQLException {
        if (_conn != null) {
            _conn.handleException(e);
        }
        else {
            throw e;
        }
    }

    protected void activate() throws SQLException {
        if(_stmt instanceof DelegatingStatement) {
            ((DelegatingStatement)_stmt).activate();
        }
    }

    protected void passivate() throws SQLException {
        if(_stmt instanceof DelegatingStatement) {
            ((DelegatingStatement)_stmt).passivate();
        }
    }

    public Connection getConnection() throws SQLException {
        checkOpen();
        return _conn; // return the delegating connection that created this
    }

    public ResultSet executeQuery(String sql) throws SQLException {
        checkOpen();
        try {
            return DelegatingResultSet.wrapResultSet(this,_stmt.executeQuery(sql));
        }
        catch (SQLException e) {
            handleException(e);
            return null;
        }
    }

    public ResultSet getResultSet() throws SQLException {
        checkOpen();
        try {
            return DelegatingResultSet.wrapResultSet(this,_stmt.getResultSet());
        }
        catch (SQLException e) {
            handleException(e);
            return null;
        }
    }

    public int executeUpdate(String sql) throws SQLException
    { checkOpen(); try { return _stmt.executeUpdate(sql); } catch (SQLException e) { handleException(e); return 0; } }

    public int getMaxFieldSize() throws SQLException
    { checkOpen(); try { return _stmt.getMaxFieldSize(); } catch (SQLException e) { handleException(e); return 0; } }

    public void setMaxFieldSize(int max) throws SQLException
    { checkOpen(); try { _stmt.setMaxFieldSize(max); } catch (SQLException e) { handleException(e); } }

    public int getMaxRows() throws SQLException
    { checkOpen(); try { return _stmt.getMaxRows(); } catch (SQLException e) { handleException(e); return 0; } }

    public void setMaxRows(int max) throws SQLException
    { checkOpen(); try { _stmt.setMaxRows(max); } catch (SQLException e) { handleException(e); } }

    public void setEscapeProcessing(boolean enable) throws SQLException
    { checkOpen(); try { _stmt.setEscapeProcessing(enable); } catch (SQLException e) { handleException(e); } }

    public int getQueryTimeout() throws SQLException
    { checkOpen(); try { return _stmt.getQueryTimeout(); } catch (SQLException e) { handleException(e); return 0; } }

    public void setQueryTimeout(int seconds) throws SQLException
    { checkOpen(); try { _stmt.setQueryTimeout(seconds); } catch (SQLException e) { handleException(e); } }

    public void cancel() throws SQLException
    { checkOpen(); try { _stmt.cancel(); } catch (SQLException e) { handleException(e); } }

    public SQLWarning getWarnings() throws SQLException
    { checkOpen(); try { return _stmt.getWarnings(); } catch (SQLException e) { handleException(e); return null; } }

    public void clearWarnings() throws SQLException
    { checkOpen(); try { _stmt.clearWarnings(); } catch (SQLException e) { handleException(e); } }

    public void setCursorName(String name) throws SQLException
    { checkOpen(); try { _stmt.setCursorName(name); } catch (SQLException e) { handleException(e); } }

    public boolean execute(String sql) throws SQLException
    { checkOpen(); try { return _stmt.execute(sql); } catch (SQLException e) { handleException(e); return false; } }

    public int getUpdateCount() throws SQLException
    { checkOpen(); try { return _stmt.getUpdateCount(); } catch (SQLException e) { handleException(e); return 0; } }

    public boolean getMoreResults() throws SQLException
    { checkOpen(); try { return _stmt.getMoreResults(); } catch (SQLException e) { handleException(e); return false; } }

    public void setFetchDirection(int direction) throws SQLException
    { checkOpen(); try { _stmt.setFetchDirection(direction); } catch (SQLException e) { handleException(e); } }

    public int getFetchDirection() throws SQLException
    { checkOpen(); try { return _stmt.getFetchDirection(); } catch (SQLException e) { handleException(e); return 0; } }

    public void setFetchSize(int rows) throws SQLException
    { checkOpen(); try { _stmt.setFetchSize(rows); } catch (SQLException e) { handleException(e); } }

    public int getFetchSize() throws SQLException
    { checkOpen(); try { return _stmt.getFetchSize(); } catch (SQLException e) { handleException(e); return 0; } }

    public int getResultSetConcurrency() throws SQLException
    { checkOpen(); try { return _stmt.getResultSetConcurrency(); } catch (SQLException e) { handleException(e); return 0; } }

    public int getResultSetType() throws SQLException
    { checkOpen(); try { return _stmt.getResultSetType(); } catch (SQLException e) { handleException(e); return 0; } }

    public void addBatch(String sql) throws SQLException
    { checkOpen(); try { _stmt.addBatch(sql); } catch (SQLException e) { handleException(e); } }

    public void clearBatch() throws SQLException
    { checkOpen(); try { _stmt.clearBatch(); } catch (SQLException e) { handleException(e); } }

    public int[] executeBatch() throws SQLException
    { checkOpen(); try { return _stmt.executeBatch(); } catch (SQLException e) { handleException(e); return null; } }

    // ------------------- JDBC 3.0 -----------------------------------------
    // Will be commented by the build process on a JDBC 2.0 system

/* JDBC_3_ANT_KEY_BEGIN */

    public boolean getMoreResults(int current) throws SQLException
    { checkOpen(); try { return _stmt.getMoreResults(current); } catch (SQLException e) { handleException(e); return false; } }

    public ResultSet getGeneratedKeys() throws SQLException
    { checkOpen(); try { return _stmt.getGeneratedKeys(); } catch (SQLException e) { handleException(e); return null; } }

    public int executeUpdate(String sql, int autoGeneratedKeys) throws SQLException
    { checkOpen(); try { return _stmt.executeUpdate(sql, autoGeneratedKeys); } catch (SQLException e) { handleException(e); return 0; } }

    public int executeUpdate(String sql, int columnIndexes[]) throws SQLException
    { checkOpen(); try { return _stmt.executeUpdate(sql, columnIndexes); } catch (SQLException e) { handleException(e); return 0; } }

    public int executeUpdate(String sql, String columnNames[]) throws SQLException
    { checkOpen(); try { return _stmt.executeUpdate(sql, columnNames); } catch (SQLException e) { handleException(e); return 0; } }

    public boolean execute(String sql, int autoGeneratedKeys) throws SQLException
    { checkOpen(); try { return _stmt.execute(sql, autoGeneratedKeys); } catch (SQLException e) { handleException(e); return false; } }

    public boolean execute(String sql, int columnIndexes[]) throws SQLException
    { checkOpen(); try { return _stmt.execute(sql, columnIndexes); } catch (SQLException e) { handleException(e); return false; } }

    public boolean execute(String sql, String columnNames[]) throws SQLException
    { checkOpen(); try { return _stmt.execute(sql, columnNames); } catch (SQLException e) { handleException(e); return false; } }

    public int getResultSetHoldability() throws SQLException
    { checkOpen(); try { return _stmt.getResultSetHoldability(); } catch (SQLException e) { handleException(e); return 0; } }

/* JDBC_3_ANT_KEY_END */
}