org.apache.activemq.artemis.selector.filter.ConstantExpression Maven / Gradle / Ivy

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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

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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 org.apache.activemq.artemis.selector.filter;

import java.math.BigDecimal;


/**
 * Represents a constant expression
 *
 * @version $Revision: 1.2 $
 */
public class ConstantExpression implements Expression
{

   static class BooleanConstantExpression extends ConstantExpression implements BooleanExpression
   {
      public BooleanConstantExpression(Object value)
      {
         super(value);
      }

      public boolean matches(Filterable message) throws FilterException
      {
         Object object = evaluate(message);
         return object != null && object == Boolean.TRUE;
      }
   }

   public static final BooleanConstantExpression NULL = new BooleanConstantExpression(null);
   public static final BooleanConstantExpression TRUE = new BooleanConstantExpression(Boolean.TRUE);
   public static final BooleanConstantExpression FALSE = new BooleanConstantExpression(Boolean.FALSE);

   private Object value;

   public ConstantExpression(Object value)
   {
      this.value = value;
   }

   public static ConstantExpression createFromDecimal(String text)
   {

      // Strip off the 'l' or 'L' if needed.
      if (text.endsWith("l") || text.endsWith("L"))
      {
         text = text.substring(0, text.length() - 1);
      }

      Number value;
      try
      {
         value = new Long(text);
      }
      catch (NumberFormatException e)
      {
         // The number may be too big to fit in a long.
         value = new BigDecimal(text);
      }

      long l = value.longValue();
      if (Integer.MIN_VALUE <= l && l <= Integer.MAX_VALUE)
      {
         value = Integer.valueOf(value.intValue());
      }
      return new ConstantExpression(value);
   }

   public static ConstantExpression createFromHex(String text)
   {
      Number value = Long.valueOf(Long.parseLong(text.substring(2), 16));
      long l = value.longValue();
      if (Integer.MIN_VALUE <= l && l <= Integer.MAX_VALUE)
      {
         value = Integer.valueOf(value.intValue());
      }
      return new ConstantExpression(value);
   }

   public static ConstantExpression createFromOctal(String text)
   {
      Number value = Long.valueOf(Long.parseLong(text, 8));
      long l = value.longValue();
      if (Integer.MIN_VALUE <= l && l <= Integer.MAX_VALUE)
      {
         value = Integer.valueOf(value.intValue());
      }
      return new ConstantExpression(value);
   }

   public static ConstantExpression createFloat(String text)
   {
      Number value = new Double(text);
      return new ConstantExpression(value);
   }

   public Object evaluate(Filterable message) throws FilterException
   {
      return value;
   }

   public Object getValue()
   {
      return value;
   }

   /**
    * @see java.lang.Object#toString()
    */
   public String toString()
   {
      if (value == null)
      {
         return "NULL";
      }
      if (value instanceof Boolean)
      {
         return ((Boolean) value).booleanValue() ? "TRUE" : "FALSE";
      }
      if (value instanceof String)
      {
         return encodeString((String) value);
      }
      return value.toString();
   }

   /**
    * @see java.lang.Object#hashCode()
    */
   public int hashCode()
   {
      return value != null ? value.hashCode() : 0;
   }

   /**
    * @see java.lang.Object#equals(Object)
    */
   public boolean equals(final Object o)
   {
      if (this == o)
      {
         return true;
      }
      if (o == null || getClass() != o.getClass())
      {
         return false;
      }
      final ConstantExpression that = (ConstantExpression)o;
      if (value != null && !value.equals(that.value))
      {
         return false;
      }
      return true;
   }

   /**
    * Encodes the value of string so that it looks like it would look like when
    * it was provided in a selector.
    *
    * @param s
    * @return
    */
   public static String encodeString(String s)
   {
      StringBuffer b = new StringBuffer();
      b.append('\'');
      for (int i = 0; i < s.length(); i++)
      {
         char c = s.charAt(i);
         if (c == '\'')
         {
            b.append(c);
         }
         b.append(c);
      }
      b.append('\'');
      return b.toString();
   }

}