/*
* 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.taglibs.standard.tag.common.sql;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspTagException;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.jstl.core.Config;
import javax.servlet.jsp.jstl.sql.Result;
import javax.servlet.jsp.jstl.sql.SQLExecutionTag;
import javax.servlet.jsp.tagext.BodyTagSupport;
import javax.servlet.jsp.tagext.TryCatchFinally;
import javax.sql.DataSource;
import org.apache.taglibs.standard.resources.Resources;
import org.apache.taglibs.standard.tag.common.core.Util;
/**
* <p>Tag handler for <Query> in JSTL.
*
* @author Hans Bergsten
* @author Justyna Horwat
*/
public abstract class QueryTagSupport extends BodyTagSupport
implements TryCatchFinally, SQLExecutionTag {
private String var;
private int scope;
/*
* The following properties take expression values, so the
* setter methods are implemented by the expression type
* specific subclasses.
*/
protected Object rawDataSource;
protected boolean dataSourceSpecified;
protected String sql;
protected int maxRows;
protected boolean maxRowsSpecified;
protected int startRow;
/*
* Instance variables that are not for attributes
*/
private Connection conn;
private List parameters;
private boolean isPartOfTransaction;
//*********************************************************************
// Constructor and initialization
public QueryTagSupport() {
super();
init();
}
private void init() {
startRow = 0;
maxRows = -1;
maxRowsSpecified = dataSourceSpecified = false;
isPartOfTransaction = false;
conn = null;
rawDataSource = null;
parameters = null;
sql = null;
var = null;
scope = PageContext.PAGE_SCOPE;
}
//*********************************************************************
// Accessor methods
/**
* Setter method for the name of the variable to hold the
* result.
*/
public void setVar(String var) {
this.var = var;
}
/**
* Setter method for the scope of the variable to hold the
* result.
*/
public void setScope(String scopeName) {
scope = Util.getScope(scopeName);
}
//*********************************************************************
// Public utility methods
/**
* Called by nested parameter elements to add PreparedStatement
* parameter values.
*/
public void addSQLParameter(Object o) {
if (parameters == null) {
parameters = new ArrayList();
}
parameters.add(o);
}
//*********************************************************************
// Tag logic
/**
* Prepares for execution by setting the initial state, such as
* getting the <code>Connection</code>
*/
public int doStartTag() throws JspException {
if (!maxRowsSpecified) {
Object obj = Config.find(pageContext, Config.SQL_MAX_ROWS);
if (obj != null) {
if (obj instanceof Integer) {
maxRows = ((Integer) obj).intValue();
} else if (obj instanceof String) {
try {
maxRows = Integer.parseInt((String) obj);
} catch (NumberFormatException nfe) {
throw new JspException(
Resources.getMessage("SQL_MAXROWS_PARSE_ERROR",
(String) obj),
nfe);
}
} else {
throw new JspException(
Resources.getMessage("SQL_MAXROWS_INVALID"));
}
}
}
try {
conn = getConnection();
} catch (SQLException e) {
throw new JspException(sql + ": " + e.getMessage(), e);
}
return EVAL_BODY_BUFFERED;
}
/**
* <p>Execute the SQL statement, set either through the <code>sql</code>
* attribute or as the body, and save the result as a variable
* named by the <code>var</code> attribute in the scope specified
* by the <code>scope</code> attribute, as an object that implements
* the Result interface.
*
* <p>The connection used to execute the statement comes either
* from the <code>DataSource</code> specified by the
* <code>dataSource</code> attribute, provided by a parent action
* element, or is retrieved from a JSP scope attribute
* named <code>javax.servlet.jstl.sql.dataSource</code>.
*/
public int doEndTag() throws JspException {
/*
* Use the SQL statement specified by the sql attribute, if any,
* otherwise use the body as the statement.
*/
String sqlStatement = null;
if (sql != null) {
sqlStatement = sql;
}
else if (bodyContent != null) {
sqlStatement = bodyContent.getString();
}
if (sqlStatement == null || sqlStatement.trim().length() == 0) {
throw new JspTagException(
Resources.getMessage("SQL_NO_STATEMENT"));
}
/*
* We shouldn't have a negative startRow or illegal maxrows
*/
if ((startRow < 0) || (maxRows < -1)) {
throw new JspException(
Resources.getMessage("PARAM_BAD_VALUE"));
}
Result result = null;
/*
* Note! We must not use the setMaxRows() method on the
* the statement to limit the number of rows, since the
* Result factory must be able to figure out the correct
* value for isLimitedByMaxRows(); there's no way to check
* if it was from the ResultSet.
*/
try {
PreparedStatement ps = conn.prepareStatement(sqlStatement);
setParameters(ps, parameters);
ResultSet rs = ps.executeQuery();
result = new ResultImpl(rs, startRow, maxRows);
ps.close();
}
catch (Throwable e) {
throw new JspException(sqlStatement + ": " + e.getMessage(), e);
}
pageContext.setAttribute(var, result, scope);
return EVAL_PAGE;
}
/**
* Just rethrows the Throwable.
*/
public void doCatch(Throwable t) throws Throwable {
throw t;
}
/**
* Close the <code>Connection</code>, unless this action is used
* as part of a transaction.
*/
public void doFinally() {
if (conn != null && !isPartOfTransaction) {
try {
conn.close();
} catch (SQLException e) {} // Not much we can do
}
conn = null;
parameters = null;
}
//*********************************************************************
// Private utility methods
private Connection getConnection() throws JspException, SQLException {
// Fix: Add all other mechanisms
Connection conn = null;
isPartOfTransaction = false;
TransactionTagSupport parent = (TransactionTagSupport)
findAncestorWithClass(this, TransactionTagSupport.class);
if (parent != null) {
if (dataSourceSpecified) {
throw new JspTagException(
Resources.getMessage("ERROR_NESTED_DATASOURCE"));
}
conn = parent.getSharedConnection();
isPartOfTransaction = true;
} else {
if ((rawDataSource == null) && dataSourceSpecified) {
throw new JspException(
Resources.getMessage("SQL_DATASOURCE_NULL"));
}
DataSource dataSource = DataSourceUtil.getDataSource(rawDataSource,
pageContext);
try {
conn = dataSource.getConnection();
} catch (Exception ex) {
throw new JspException(
Resources.getMessage("DATASOURCE_INVALID",
ex.getMessage()));
}
}
return conn;
}
private void setParameters(PreparedStatement ps, List parameters)
throws SQLException
{
if (parameters != null) {
for (int i = 0; i < parameters.size(); i++) {
/* The first parameter has index 1. If a null
* is passed to setObject the parameter will be
* set to JDBC null so an explicit call to
* ps.setNull is not required.
*/
ps.setObject(i + 1, parameters.get(i));
}
}
}
}