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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to you 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.hazelcast.org.apache.calcite.sql.util;

import com.hazelcast.org.apache.calcite.sql.SqlCall;
import com.hazelcast.org.apache.calcite.sql.SqlDataTypeSpec;
import com.hazelcast.org.apache.calcite.sql.SqlDynamicParam;
import com.hazelcast.org.apache.calcite.sql.SqlIdentifier;
import com.hazelcast.org.apache.calcite.sql.SqlIntervalQualifier;
import com.hazelcast.org.apache.calcite.sql.SqlLiteral;
import com.hazelcast.org.apache.calcite.sql.SqlNode;
import com.hazelcast.org.apache.calcite.sql.SqlNodeList;

import com.hazelcast.org.checkerframework.checker.nullness.qual.Nullable;

import java.util.ArrayList;
import java.util.List;

/**
 * Basic implementation of {@link SqlVisitor} which returns each leaf node
 * unchanged.
 *
 * 

This class is useful as a base class for classes which implement the * {@link SqlVisitor} interface and have {@link SqlNode} as the return type. The * derived class can override whichever methods it chooses. */ public class SqlShuttle extends SqlBasicVisitor<@Nullable SqlNode> { //~ Methods ---------------------------------------------------------------- @Override public @Nullable SqlNode visit(SqlLiteral literal) { return literal; } @Override public @Nullable SqlNode visit(SqlIdentifier id) { return id; } @Override public @Nullable SqlNode visit(SqlDataTypeSpec type) { return type; } @Override public @Nullable SqlNode visit(SqlDynamicParam param) { return param; } @Override public @Nullable SqlNode visit(SqlIntervalQualifier intervalQualifier) { return intervalQualifier; } @Override public @Nullable SqlNode visit(final SqlCall call) { // Handler creates a new copy of 'call' only if one or more operands // change. CallCopyingArgHandler argHandler = new CallCopyingArgHandler(call, false); call.getOperator().acceptCall(this, call, false, argHandler); return argHandler.result(); } @Override public @Nullable SqlNode visit(SqlNodeList nodeList) { boolean update = false; final List<@Nullable SqlNode> newList = new ArrayList<>(nodeList.size()); for (SqlNode operand : nodeList) { SqlNode clonedOperand; if (operand == null) { clonedOperand = null; } else { clonedOperand = operand.accept(this); if (clonedOperand != operand) { update = true; } } newList.add(clonedOperand); } if (update) { return SqlNodeList.of(nodeList.getParserPosition(), newList); } else { return nodeList; } } //~ Inner Classes ---------------------------------------------------------- /** * Implementation of * {@link com.hazelcast.org.apache.calcite.sql.util.SqlBasicVisitor.ArgHandler} * that deep-copies {@link SqlCall}s and their operands. */ protected class CallCopyingArgHandler implements ArgHandler<@Nullable SqlNode> { boolean update; @Nullable SqlNode[] clonedOperands; private final SqlCall call; private final boolean alwaysCopy; public CallCopyingArgHandler(SqlCall call, boolean alwaysCopy) { this.call = call; this.update = false; final List<@Nullable SqlNode> operands = (List<@Nullable SqlNode>) call.getOperandList(); this.clonedOperands = operands.toArray(new SqlNode[0]); this.alwaysCopy = alwaysCopy; } @Override public SqlNode result() { if (update || alwaysCopy) { return call.getOperator().createCall( call.getFunctionQuantifier(), call.getParserPosition(), clonedOperands); } else { return call; } } @Override public @Nullable SqlNode visitChild( SqlVisitor<@Nullable SqlNode> visitor, SqlNode expr, int i, @Nullable SqlNode operand) { if (operand == null) { return null; } SqlNode newOperand = operand.accept(SqlShuttle.this); if (newOperand != operand) { update = true; } clonedOperands[i] = newOperand; return newOperand; } } }





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