HHH-19956: Add InterSystemsIRISLimitHandler.java

Author: isc-service

hibernate-community-dialects/src/main/java/org/hibernate/community/dialect/pagination/InterSystemsIRISLimitHandler.java

@@ -0,0 +1,87 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.community.dialect.pagination;
+
+import org.hibernate.dialect.pagination.AbstractLimitHandler;
+import org.hibernate.query.spi.Limit;
+import java.util.Locale;
+
+public class InterSystemsIRISLimitHandler extends AbstractLimitHandler {
+public static final InterSystemsIRISLimitHandler INSTANCE = new InterSystemsIRISLimitHandler(true);
+
+private final boolean variableLimit;
+
+public InterSystemsIRISLimitHandler(boolean variableLimit) {
+this.variableLimit = variableLimit;
+}
+
+@Override
+public String processSql(String sql, Limit limit) {
+
+boolean hasFirstRow = hasFirstRow(limit);
+boolean hasMaxRows = hasMaxRows(limit);
+
+if (!hasFirstRow && !hasMaxRows) {
+return sql;
+}
+
+String lowersql = sql.toLowerCase(Locale.ROOT);
+int selectIndex = lowersql.indexOf("select");
+if (hasFirstRow && hasMaxRows) {
+return new StringBuilder(sql.length() + 27)
+.append(sql)
+.insert(selectIndex + 6, " %ROWOFFSET ? %ROWLIMIT ? ")
+.toString();
+
+}
+else if (hasFirstRow) {
+return new StringBuilder(sql.length() + 15)
+.append(sql)
+.insert(selectIndex + 6, " %ROWOFFSET ? ")
+.toString();
+}
+else {
+final int selectDistinctIndex = lowersql.indexOf("select distinct");
+final int insertionPoint = selectIndex + (selectDistinctIndex == selectIndex ? 15 : 6);
+
+return new StringBuilder(sql.length() + 8)
+.append(sql)
+.insert(insertionPoint, " TOP ? ")
+.toString();
+}
+}
+
+
+@Override
+public final boolean supportsLimit() {
+return true;
+}
+
+@Override
+public final boolean supportsOffset() {
+return true;
+}
+
+@Override
+public boolean supportsLimitOffset() {
+return true;
+}
+
+@Override
+public final boolean supportsVariableLimit() {
+return true;
+}
+
+@Override
+public boolean useMaxForLimit() {
+return false;
+}
+
+@Override
+public boolean bindLimitParametersFirst() {
+return true;
+}
+
+}