org.springframework.batch.item.database.JdbcParameterUtils.java Source code

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Here is the source code for org.springframework.batch.item.database.JdbcParameterUtils.java

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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
 *
 *      https://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.springframework.batch.item.database;

import java.util.Map;
import java.util.HashMap;
import java.util.List;

/**
 * Helper methods for SQL statement parameter parsing.
 *
 * Only intended for internal use.
 *
 * @author Thomas Risberg
 * @author Juergen Hoeller
 * @since 2.0
 */
public class JdbcParameterUtils {

    /**
     * Count the occurrences of the character placeholder in an SQL string
     * <code>sql</code>. The character placeholder is not counted if it appears
     * within a literal, that is, surrounded by single or double quotes. This method will
     * count traditional placeholders in the form of a question mark ('?') as well as
     * named parameters indicated with a leading ':' or '&amp;'.
     *
     * The code for this method is taken from an early version of the
     * {@link org.springframework.jdbc.core.namedparam.NamedParameterUtils}
     * class. That method was later removed after some refactoring, but the code
     * is useful here for the Spring Batch project. The code has been altered to better
     * suite the batch processing requirements.
     *
     * @param sql String to search in. Returns 0 if the given String is <code>null</code>.
     * @param namedParameterHolder holder for the named parameters
     * @return the number of named parameter placeholders
     */
    public static int countParameterPlaceholders(String sql, List<String> namedParameterHolder) {
        if (sql == null) {
            return 0;
        }

        char[] statement = sql.toCharArray();
        boolean withinQuotes = false;
        Map<String, StringBuilder> namedParameters = new HashMap<>();
        char currentQuote = '-';
        int parameterCount = 0;
        int i = 0;
        while (i < statement.length) {
            if (withinQuotes) {
                if (statement[i] == currentQuote) {
                    withinQuotes = false;
                    currentQuote = '-';
                }
            } else {
                if (statement[i] == '"' || statement[i] == '\'') {
                    withinQuotes = true;
                    currentQuote = statement[i];
                } else {
                    if (statement[i] == ':' || statement[i] == '&') {
                        int j = i + 1;
                        StringBuilder parameter = new StringBuilder();
                        while (j < statement.length && parameterNameContinues(statement, j)) {
                            parameter.append(statement[j]);
                            j++;
                        }
                        if (j - i > 1) {
                            if (!namedParameters.containsKey(parameter.toString())) {
                                parameterCount++;
                                namedParameters.put(parameter.toString(), parameter);
                                i = j - 1;
                            }
                        }
                    } else {
                        if (statement[i] == '?') {
                            parameterCount++;
                        }
                    }
                }
            }
            i++;
        }
        if (namedParameterHolder != null) {
            namedParameterHolder.addAll(namedParameters.keySet());
        }
        return parameterCount;
    }

    /**
     * Determine whether a parameter name continues at the current position,
     * that is, does not end delimited by any whitespace character yet.
     * @param statement the SQL statement
     * @param pos the position within the statement
     */
    private static boolean parameterNameContinues(char[] statement, int pos) {
        return (statement[pos] != ' ' && statement[pos] != ',' && statement[pos] != ')' && statement[pos] != '"'
                && statement[pos] != '\'' && statement[pos] != '|' && statement[pos] != ';'
                && statement[pos] != '\n' && statement[pos] != '\r');
    }

}