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.cassandra.cql3.functions;
  
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.Set;
  
  import com.google.common.base.Objects;
  
  import org.apache.cassandra.cql3.CqlBuilder;
  import org.apache.cassandra.schema.SchemaConstants;
  
  public final class FunctionName
  {
      private static final Set<Character> DISALLOWED_CHARACTERS = Collections.unmodifiableSet(
          new HashSet<>(Arrays.asList('/', '[', ']')));
  
      // We special case the token function because that's the only function which name is a reserved keyword
      private static final FunctionName TOKEN_FUNCTION_NAME = FunctionName.nativeFunction("token");
  
      public final String keyspace;
      public final String name;
  
      public static FunctionName nativeFunction(String name)
      {
          return new FunctionName(SchemaConstants.SYSTEM_KEYSPACE_NAME, name);
      }
  
      /**
       * Validate the function name, e.g. contains no disallowed characters
       * @param name
       * @return true if name is valid; otherwise, false
       */
      public static boolean isNameValid(String name)
      {
          for (int i = 0; i < name.length(); i++)
          {
              char c = name.charAt(i);
              if (DISALLOWED_CHARACTERS.contains(c))
              {
                  return false;
              }
          }
          return true;
      }
  
      public FunctionName(String keyspace, String name)
      {
          assert name != null : "Name parameter must not be null";
          this.keyspace = keyspace;
          this.name = name;
      }
  
      public FunctionName asNativeFunction()
      {
          return FunctionName.nativeFunction(name);
      }
  
      public boolean hasKeyspace()
      {
          return keyspace != null;
      }
  
      @Override
      public final int hashCode()
      {
          return Objects.hashCode(keyspace, name);
      }
  
      @Override
      public final boolean equals(Object o)
      {
          if (!(o instanceof FunctionName))
              return false;
  
          FunctionName that = (FunctionName)o;
          return Objects.equal(this.keyspace, that.keyspace)
              && Objects.equal(this.name, that.name);
      }
  
      public final boolean equalsNativeFunction(FunctionName nativeFunction)
      {
          assert nativeFunction.keyspace.equals(SchemaConstants.SYSTEM_KEYSPACE_NAME);
          if (this.hasKeyspace() && !this.keyspace.equals(SchemaConstants.SYSTEM_KEYSPACE_NAME))
              return false;
  
          return Objects.equal(this.name, nativeFunction.name);
      }
  
      @Override
      public String toString()
      {
          return keyspace == null ? name : keyspace + "." + name;
      }
  
      public void appendCqlTo(CqlBuilder builder)
      {
          if (equalsNativeFunction(TOKEN_FUNCTION_NAME))
          {
              builder.append(name);
          }
          else
          {
              if (keyspace != null)
              {
                  builder.appendQuotingIfNeeded(keyspace)
                         .append('.');
              }
              builder.appendQuotingIfNeeded(name);
          }
      }
  }
  