text: /*
   * 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.jackrabbit.spi.commons.query;
  
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.Set;
  
  import javax.jcr.RepositoryException;
  
  /**
   * <code>PropertyFunctionQueryNode</code> allows to place function calls on properties
   * in a query. Supported function names are:
   * <ul>
   * <li><code>upper-case</code> as specified in <a href="http://www.w3.org/TR/xquery-operators/#func-upper-case">fn:upper-case()</a></li>
   * <li><code>lower-case</code> as specified in <a href="http://www.w3.org/TR/xquery-operators/#func-lower-case">fn:lower-case()</a></li>
   * </ul>
   */
  public class PropertyFunctionQueryNode extends QueryNode {
  
      /**
       * Requests that property values in a {@link RelationQueryNode} are
       * converted to upper case before they are matched with the literal.
       */
      public static final String UPPER_CASE = "upper-case";
  
      /**
       * Requests that property values in a {@link RelationQueryNode} are
       * converted to lower case before they are matched with the literal.
       */
      public static final String LOWER_CASE = "lower-case";
  
      /**
       * The set of supported function names.
       */
      private static final Set SUPPORTED_FUNCTION_NAMES;
  
      static {
          Set tmp = new HashSet();
          tmp.add(UPPER_CASE);
          tmp.add(LOWER_CASE);
          SUPPORTED_FUNCTION_NAMES = Collections.unmodifiableSet(tmp);
      }
  
      /**
       * The function name.
       */
      private final String functionName;
  
      /**
       * Creates a property function query node. This query node describes a
       * function which is applied to a property parameter of the
       * <code>parent</code> query node.
       *
       * @param parent       the query node where this function is applied to.
       * @param functionName the name of the function which is applied to
       *                     <code>parent</code>.
       * @throws IllegalArgumentException if <code>functionName</code> is not a
       *                                  supported function.
       */
      protected PropertyFunctionQueryNode(QueryNode parent, String functionName)
              throws IllegalArgumentException {
          super(parent);
          if (!SUPPORTED_FUNCTION_NAMES.contains(functionName)) {
              throw new IllegalArgumentException("unknown function name");
          }
          this.functionName = functionName;
      }
  
      /**
       * {@inheritDoc}
       * @throws RepositoryException
       */
      public Object accept(QueryNodeVisitor visitor, Object data) throws RepositoryException {
          return visitor.visit(this, data);
      }
  
      /**
       * Returns the type of this node.
       *
       * @return the type of this node.
       */
      public int getType() {
          return QueryNode.TYPE_PROP_FUNCTION;
      }
  
      /**
       * {@inheritDoc}
       */
      public boolean equals(Object obj) {
          if (obj instanceof PropertyFunctionQueryNode) {
              PropertyFunctionQueryNode other = (PropertyFunctionQueryNode) obj;
              return functionName.equals(other.functionName);
          }
          return false;
      }
  
      /**
       * @return the name of this function.
       */
      public String getFunctionName() {
          return functionName;
      }
  
      /**
       * {@inheritDoc}
       */
      public boolean needsSystemTree() {
          return false;
      }
  
  }
  