Operator.java

/*
* Copyright 2003-2010 Tufts University  Licensed under the
 * Educational Community 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.osedu.org/licenses/ECL-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.
 */

/*
 * Class.java
 *
 * Created on February 13, 2004, 2:36 PM
 */

package tufts.vue.filter;

/**
 * 
 * @author  akumar03
 *
 *An operator is used to compare metadata statements.  It has a displayName, Symbol 
 *and compare function. A symbol is short representation of for the operator. It could be =, <, >, ..
 * or eq, gt,lt, ....
 */


public interface Operator {
    
    /** Creates a new instance of Class */
    public void setDisplayName(String displayName);
    public String getDisplayName();
    public void setSymbol(String symbol);
    public String getSymbol();
    
    /*
     * compares statement1 and statment 2 and returns true iff statement2 is true given statement 1
     */
    
    public boolean compare(Statement s1,Statement s2);
    
    /*
     * returns true if operator can be set by  user.  Some operators like contains, matches  
     * may be used only  for filtering.  The default value shall be false.
     *
     */
    
    public boolean isSettable();
}