ConstantNode.java

/*
 * Copyright 2015 S. Webber
 *
 * Licensed 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.oakgp.node;

import java.util.Objects;

import org.oakgp.Assignments;
import org.oakgp.Type;

/**
 * Represents a constant value.
 * <p>
 * Return the same value each time is it evaluated.
 */
public final class ConstantNode extends TerminalNode {
   private final Object value;
   private final Type type;

   /**
    * Constructs a new {@code ConstantNode} that represents the specified value.
    *
    * @param value
    *           the value to be represented by the {@code ConstantNode}
    * @param type
    *           the {@code Type} that the value represented by this node is of
    */
   public ConstantNode(Object value, Type type) {
      this.value = value;
      this.type = type;
   }

   /**
    * Returns the value specified when this {@code ConstantNode} was constructed.
    */
   @Override
   public Object evaluate(Assignments assignments) {
      return value;
   }

   @Override
   public Type getType() {
      return type;
   }

   @Override
   public NodeType getNodeType() {
      return NodeType.CONSTANT;
   }

   @Override
   public int hashCode() {
      return value.hashCode();
   }

   @Override
   public boolean equals(Object o) {
      if (this == o) {
         return true;
      } else if (o instanceof ConstantNode) {
         ConstantNode c = (ConstantNode) o;
         return this.type == c.type && Objects.equals(this.value, c.value);
      } else {
         return false;
      }
   }

   @Override
   public String toString() {
      return Objects.toString(value);
   }
}