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SQLG is a preprocessor and a library that uses code generation to simplify writing JDBC code
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package sqlg3.runtime.queries;
import java.sql.DatabaseMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.function.Function;
public final class QueryParser {
public static final String SPECIAL = "S$$";
private QueryParser() {
}
private abstract static class TokenMatch {
abstract boolean matchToken(TokenKind id, String currValue, String lastValue,
StringBuilder synthQuery);
abstract void matchEnd(StringBuilder synthQuery);
}
private static String parseQueryAny(String statement, List usedParameters, TokenMatch match) {
StringBuilder synthQuery = new StringBuilder();
SelectTokenizer st = new SelectTokenizer(statement);
String lastValue = null;
while (true) {
TokenKind id = st.getToken();
if (id == TokenKind.R_THEEND)
break;
String currValue = st.getValue(id);
if (!match.matchToken(id, currValue, lastValue, synthQuery)) {
lastValue = null;
continue;
}
if (lastValue != null) {
synthQuery.append(lastValue);
}
if (id == TokenKind.R_PARAM) {
if (usedParameters != null) {
usedParameters.add(st.getParam());
}
lastValue = "?";
} else {
lastValue = currValue;
}
}
if (lastValue != null) {
synthQuery.append(lastValue);
}
match.matchEnd(synthQuery);
return synthQuery.toString();
}
public static final class Range {
private static final char SEPARATOR = '$';
public final String name;
public final int from;
public final int to;
private Range(String name, int from, int to) {
this.name = name;
this.from = from;
this.to = to;
}
public String toString() {
return name + ": " + from + "-" + to;
}
public static Range parseRange(String column) {
try {
int p1 = column.lastIndexOf(SEPARATOR);
if (p1 >= 0) {
int p2 = column.lastIndexOf(SEPARATOR, p1 - 1);
if (p2 < p1) {
String name = column.substring(0, p2);
int from = Integer.parseInt(column.substring(p2 + 1, p1));
int to = Integer.parseInt(column.substring(p1 + 1));
return new Range(name, from, to);
}
}
} catch (NumberFormatException nfex) {
// ignore
}
return null;
}
}
public static String parseQuery(String statement) {
TokenMatch tokenMatch = new TokenMatch() {
private int brackets = 0;
private int columnCount = 1;
private Boolean isSelect = null;
private boolean wasFrom = false;
private final List specials = new ArrayList<>();
private void finishSelectColumns(String lastValue, StringBuilder synthQuery) {
for (Range range : specials) {
if (range.to > 0) {
synthQuery.append(", '' \"" + SPECIAL + range.name + "$" + range.from + "$" + range.to + "\"");
}
}
if (lastValue != null) {
synthQuery.append(lastValue);
}
columnCount = 0;
}
boolean matchToken(TokenKind id, String currValue, String lastValue, StringBuilder synthQuery) {
if (isSelect == null) {
if (id == TokenKind.R_ID && "SELECT".equalsIgnoreCase(currValue)) {
isSelect = true;
} else if (id != TokenKind.R_WS) {
isSelect = false;
}
}
if (id == TokenKind.R_CHAR) {
if ("{".equals(currValue)) {
if (brackets == 0 && columnCount > 0) {
specials.add(new Range(lastValue, columnCount, 0));
}
return false;
} else if ("}".equals(currValue)) {
if (brackets == 0 && specials.size() > 0) {
int lastIndex = specials.size() - 1;
Range range = specials.get(lastIndex);
if (range.to <= 0) {
specials.set(lastIndex, new Range(range.name, range.from, columnCount));
}
}
if (lastValue != null) {
synthQuery.append(lastValue);
}
return false;
} else if ("(".equals(currValue)) {
brackets++;
} else if (")".equals(currValue)) {
brackets--;
} else if (",".equals(currValue)) {
if (brackets == 0 && columnCount > 0) {
columnCount++;
}
}
} else if (id == TokenKind.R_ID) {
if (brackets == 0 && "FROM".equalsIgnoreCase(currValue)) {
finishSelectColumns(lastValue, synthQuery);
synthQuery.append(currValue);
wasFrom = true;
return false;
}
}
return true;
}
void matchEnd(StringBuilder synthQuery) {
if (brackets == 0 && isSelect != null && isSelect.booleanValue() && !wasFrom) {
finishSelectColumns(null, synthQuery);
}
}
};
return parseQueryAny(statement, null, tokenMatch);
}
public static String getParameters(String statement, List usedParameters) {
TokenMatch tokenMatch = new TokenMatch() {
boolean matchToken(TokenKind id, String currValue, String lastValue, StringBuilder synthQuery) {
return true;
}
void matchEnd(StringBuilder synthQuery) {
}
};
return parseQueryAny(statement, usedParameters, tokenMatch);
}
public static String unparseQuery(String statement) {
StringBuilder query = new StringBuilder();
SelectTokenizer st = new SelectTokenizer(statement);
int paramCount = 1;
while (true) {
TokenKind id = st.getToken();
if (id == TokenKind.R_THEEND)
break;
if (id == TokenKind.R_PARAM) {
query.append(':').append(st.getParam());
} else if (id == TokenKind.R_CHAR && "?".equals(st.getValue())) {
query.append(':').append(paramCount++);
} else {
query.append(st.getValue(id));
}
}
return query.toString();
}
public static String[] parseIdent(String name, DatabaseMetaData meta) throws SQLException {
SelectTokenizer st = new SelectTokenizer(name);
while (true) {
TokenKind t1 = st.getToken();
if (t1 == TokenKind.R_WS)
continue;
if (t1 == TokenKind.R_ID)
break;
return null;
}
Function canonicalizer = getCanonicalizer(meta);
String name1 = st.getCanonicIdent(canonicalizer);
while (true) {
TokenKind t2 = st.getToken();
if (t2 == TokenKind.R_THEEND)
return new String[] {name1};
if (t2 == TokenKind.R_WS)
continue;
if (t2 == TokenKind.R_CHAR && ".".equals(st.getValue()))
break;
return null;
}
while (true) {
TokenKind t3 = st.getToken();
if (t3 == TokenKind.R_WS)
continue;
if (t3 == TokenKind.R_ID)
break;
return null;
}
String name2 = st.getCanonicIdent(canonicalizer);
while (true) {
TokenKind t4 = st.getToken();
if (t4 == TokenKind.R_THEEND)
return new String[] {name1, name2};
if (t4 == TokenKind.R_WS)
continue;
if (t4 == TokenKind.R_CHAR && ".".equals(st.getValue()))
break;
return null;
}
while (true) {
TokenKind t5 = st.getToken();
if (t5 == TokenKind.R_WS)
continue;
if (t5 == TokenKind.R_ID)
break;
return null;
}
String name3 = st.getCanonicIdent(canonicalizer);
while (true) {
TokenKind t6 = st.getToken();
if (t6 == TokenKind.R_THEEND)
return new String[] {name1, name2, name3};
if (t6 == TokenKind.R_WS)
continue;
return null;
}
}
public static Function getCanonicalizer(DatabaseMetaData meta) throws SQLException {
if (meta.storesUpperCaseIdentifiers()) {
return String::toUpperCase;
} else if (meta.storesLowerCaseIdentifiers()) {
return String::toLowerCase;
} else {
return Function.identity();
}
}
}