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/*
* Copyright 2002-2008 the original author or authors.
*
* 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 com.github.quintans.jdbc;
import java.util.Collection;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import com.github.quintans.jdbc.exceptions.PersistenceException;
/**
* Helper methods for named parameter parsing.
* Only intended for internal use within Spring's JDBC framework.
*
* @author Thomas Risberg
* @author Juergen Hoeller
* @since 2.0
*/
public abstract class NamedParameterUtils {
/**
* Set of characters that qualify as parameter separators,
* indicating that a parameter name in a SQL String has ended.
*/
private static final char[] PARAMETER_SEPARATORS =
new char[] { '"', '\'', ':', '&', ',', ';', '(', ')', '|', '=', '+', '-', '*', '%', '/', '\\', '<', '>', '^' };
/**
* Set of characters that qualify as comment or quotes starting characters.
*/
private static final String[] START_SKIP =
new String[] { "'", "\"", "--", "/*" };
/**
* Set of characters that at are the corresponding comment or quotes ending characters.
*/
private static final String[] STOP_SKIP =
new String[] { "'", "\"", "\n", "*/" };
// -------------------------------------------------------------------------
// Core methods used by NamedParameterJdbcTemplate and SqlQuery/SqlUpdate
// -------------------------------------------------------------------------
/**
* Parse the SQL statement and locate any placeholders or named parameters.
* Named parameters are substituted for a JDBC placeholder.
*
* @param sql
* the SQL statement
* @return the parsed statement, represented as ParsedSql instance
*/
@SuppressWarnings({ "unchecked", "rawtypes" })
public static ParsedSql parseSqlStatement(String sql) {
Set namedParameters = new HashSet();
ParsedSql parsedSql = new ParsedSql(sql);
char[] statement = sql.toCharArray();
int namedParameterCount = 0;
int unnamedParameterCount = 0;
int totalParameterCount = 0;
int i = 0;
while (i < statement.length) {
int skipToPosition = skipCommentsAndQuotes(statement, i);
if (i != skipToPosition) {
if (skipToPosition >= statement.length) {
break;
}
i = skipToPosition;
}
char c = statement[i];
if (c == ':' || c == '&') {
int j = i + 1;
if (j < statement.length && statement[j] == ':' && c == ':') {
// Postgres-style "::" casting operator - to be skipped.
i = i + 2;
continue;
}
while (j < statement.length && !isParameterSeparator(statement[j])) {
j++;
}
if (j - i > 1) {
String parameter = sql.substring(i + 1, j);
if (!namedParameters.contains(parameter)) {
namedParameters.add(parameter);
namedParameterCount++;
}
parsedSql.addNamedParameter(parameter, i, j);
totalParameterCount++;
}
i = j - 1;
} else {
if (c == '?') {
unnamedParameterCount++;
totalParameterCount++;
}
}
i++;
}
parsedSql.setNamedParameterCount(namedParameterCount);
parsedSql.setUnnamedParameterCount(unnamedParameterCount);
parsedSql.setTotalParameterCount(totalParameterCount);
return parsedSql;
}
/**
* Skip over comments and quoted names present in an SQL statement
*
* @param statement
* character array containing SQL statement
* @param position
* current position of statement
* @return next position to process after any comments or quotes are skipped
*/
private static int skipCommentsAndQuotes(char[] statement, int position) {
for (int i = 0; i < START_SKIP.length; i++) {
if (statement[position] == START_SKIP[i].charAt(0)) {
boolean match = true;
for (int j = 1; j < START_SKIP[i].length(); j++) {
if (!(statement[position + j] == START_SKIP[i].charAt(j))) {
match = false;
break;
}
}
if (match) {
int offset = START_SKIP[i].length();
for (int m = position + offset; m < statement.length; m++) {
if (statement[m] == STOP_SKIP[i].charAt(0)) {
boolean endMatch = true;
int endPos = m;
for (int n = 1; n < STOP_SKIP[i].length(); n++) {
if (m + n >= statement.length) {
// last comment not closed properly
return statement.length;
}
if (!(statement[m + n] == STOP_SKIP[i].charAt(n))) {
endMatch = false;
break;
}
endPos = m + n;
}
if (endMatch) {
// found character sequence ending comment or quote
return endPos + 1;
}
}
}
// character sequence ending comment or quote not found
return statement.length;
}
}
}
return position;
}
/**
* Parse the SQL statement and locate any placeholders or named parameters.
* Named parameters are substituted for a JDBC placeholder and any select list
* is expanded to the required number of placeholders. Select lists may contain
* an array of objects and in that case the placeholders will be grouped and
* enclosed with parantheses. This allows for the use of "expression lists" in
* the SQL statement like:
* select id, name, state from table where (name, age) in (('John', 35), ('Ann', 50))
*
* The parameter values passed in are used to determine the number of placeholder to be used for a select list. Select lists should be limited to 100 or fewer elements. A
* larger number of elements is not guaramteed to be supported by the database and is strictly vendor-dependent.
*
* @param parsedSql
* the parsed represenation of the SQL statement
* @param paramSource
* the source for named parameters
* @return the SQL statement with substituted parameters
* @see #parseSqlStatement
*/
@SuppressWarnings("rawtypes")
public static String substituteNamedParameters(ParsedSql parsedSql, Map paramSource) {
String originalSql = parsedSql.getOriginalSql();
StringBuffer actualSql = new StringBuffer();
List paramNames = parsedSql.getParameterNames();
int lastIndex = 0;
for (int i = 0; i < paramNames.size(); i++) {
String paramName = (String) paramNames.get(i);
int[] indexes = parsedSql.getParameterIndexes(i);
int startIndex = indexes[0];
int endIndex = indexes[1];
actualSql.append(originalSql.substring(lastIndex, startIndex));
if (paramSource != null && paramSource.containsKey(paramName)) {
Object value = paramSource.get(paramName);
if (value instanceof Collection) {
Iterator entryIter = ((Collection) value).iterator();
int k = 0;
while (entryIter.hasNext()) {
if (k > 0) {
actualSql.append(", ");
}
k++;
Object entryItem = entryIter.next();
if (entryItem instanceof Object[]) {
Object[] expressionList = (Object[]) entryItem;
actualSql.append("(");
for (int m = 0; m < expressionList.length; m++) {
if (m > 0) {
actualSql.append(", ");
}
actualSql.append("?");
}
actualSql.append(")");
} else {
actualSql.append("?");
}
}
} else {
actualSql.append("?");
}
} else {
actualSql.append("?");
}
lastIndex = endIndex;
}
actualSql.append(originalSql.substring(lastIndex, originalSql.length()));
return actualSql.toString();
}
/**
* Convert a Map of named parameter values to a corresponding array.
*
* @param parsedSql
* the parsed SQL statement
* @param paramMap
* the source for named parameters
* @return the array of values
*/
@SuppressWarnings("rawtypes")
public static Object[] buildValueArray(ParsedSql parsedSql, Map paramMap) {
Object[] paramArray = new Object[parsedSql.getTotalParameterCount()];
if (parsedSql.getNamedParameterCount() > 0 && parsedSql.getUnnamedParameterCount() > 0) {
throw new PersistenceException(
"You can't mix named and traditional ? placeholders. You have " +
parsedSql.getNamedParameterCount() + " named parameter(s) and " +
parsedSql.getUnnamedParameterCount() + " traditonal placeholder(s) in [" +
parsedSql.getOriginalSql() + "]");
}
List paramNames = parsedSql.getParameterNames();
for (int i = 0; i < paramNames.size(); i++) {
String paramName = (String) paramNames.get(i);
try {
paramArray[i] = paramMap.get(paramName);
} catch (IllegalArgumentException ex) {
throw new PersistenceException("No value supplied for the SQL parameter '" + paramName + "': " + ex.getMessage());
}
}
return paramArray;
}
/**
* Determine whether a parameter name ends at the current position,
* that is, whether the given character qualifies as a separator.
*
* @param c
* @return
*/
private static boolean isParameterSeparator(char c) {
if (Character.isWhitespace(c)) {
return true;
}
for (int i = 0; i < PARAMETER_SEPARATORS.length; i++) {
if (c == PARAMETER_SEPARATORS[i]) {
return true;
}
}
return false;
}
// -------------------------------------------------------------------------
// Convenience methods operating on a plain SQL String
// -------------------------------------------------------------------------
/**
* Parse the SQL statement and locate any placeholders or named parameters.
* Named parameters are substituted for a JDBC placeholder.
*
* This is a shortcut version of {@link #parseSqlStatement(String)} in combination with {@link #substituteNamedParameters(ParsedSql, Map)}.
*
* @param sql
* the SQL statement
* @return the actual (parsed) SQL statement
*/
public static String parseSqlStatementIntoString(String sql) {
ParsedSql parsedSql = parseSqlStatement(sql);
return substituteNamedParameters(parsedSql, null);
}
/**
* Convert a Map of named parameter values to a corresponding array.
*
* This is a shortcut version of {@link #buildValueArray(ParsedSql, Map)}.
*
* @param sql
* the SQL statement
* @param paramMap
* the Map of parameters
* @return the array of values
*/
@SuppressWarnings("rawtypes")
public static Object[] buildValueArray(String sql, Map paramMap) {
ParsedSql parsedSql = parseSqlStatement(sql);
return buildValueArray(parsedSql, paramMap);
}
}