content: /*
   * 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 org.apache.asterix.lang.common.rewrites;
  
  import java.util.HashMap;
  import java.util.Map;
  
  import org.apache.asterix.lang.common.base.Expression;
  import org.apache.asterix.lang.common.expression.VariableExpr;
  
  public class VariableSubstitutionEnvironment {
  
      private Map<String, Expression> oldVarToNewExpressionMap = new HashMap<String, Expression>();
  
      public VariableSubstitutionEnvironment() {
          // Default constructor.
      }
  
      public VariableSubstitutionEnvironment(Map<VariableExpr, Expression> varExprMap) {
          varExprMap.forEach((key, value) -> oldVarToNewExpressionMap.put(key.getVar().getValue(), value));
      }
  
      public VariableSubstitutionEnvironment(VariableSubstitutionEnvironment env) {
          oldVarToNewExpressionMap.putAll(env.oldVarToNewExpressionMap);
      }
  
      public void addMappings(Map<String, Expression> varExprMap) {
          oldVarToNewExpressionMap.putAll(varExprMap);
      }
  
      public Expression findSubstitution(VariableExpr oldVar) {
          return oldVarToNewExpressionMap.get(oldVar.getVar().getValue());
      }
  
      public boolean constainsOldVar(VariableExpr oldVar) {
          return oldVarToNewExpressionMap.containsKey(oldVar.getVar().getValue());
      }
  
      public void addSubstituion(VariableExpr oldVar, Expression newExpr) {
          oldVarToNewExpressionMap.put(oldVar.getVar().getValue(), newExpr);
      }
  
      public void removeSubstitution(VariableExpr oldVar) {
          if (oldVar == null) {
              return;
          }
          oldVarToNewExpressionMap.remove(oldVar.getVar().getValue());
      }
  
      @Override
      public String toString() {
          return oldVarToNewExpressionMap.toString();
      }
  }
  