org.usergrid.persistence.query.tree.EqualityOperand Maven / Gradle / Ivy

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Core services for Usergrid system.

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/*******************************************************************************
 * Copyright 2012 Apigee Corporation
 * 
 * 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.usergrid.persistence.query.tree;

import org.antlr.runtime.Token;

/**
 * A base class for any equality expression. Expressions must have a property
 * and a value. Examples are >=, >, =, <, <=,
 * 
 * @author tnine
 * 
 */
public abstract class EqualityOperand extends Operand {

    /**
     * @param property
     * @param literal
     */
    public EqualityOperand(Token t) {
        super(t);
    }

    public EqualityOperand(String propName, Literal value){
        super(null);
    }
    
    
    /**
     * Set the property on this operand
     * @param name
     */
    public void setProperty(String name){
       setAtIndex(0, new Property(name));
    }
    
    /**
     * Set the literal on this operand from the given value
     * @param literal
     */
    public void setLiteral(Object value){
        setAtIndex(1, LiteralFactory.getLiteral(value));
    }
    
    /**
     * Set the child at the specified index.  If it doesn't exist, it's added until it does
     * @param index
     * @param value
     */
    private void setAtIndex(int index, Literal value){
        
        if(children == null){
            children = createChildrenList();
        }
        
        while(children.size() -1 < index){
            children.add(null);
        }
        
        setChild(index, value);
    }
    
    /**
           * @return the property
           */
    public Property getProperty() {
        return (Property) this.children.get(0);
    }

    /**
     * @return the literal
     */
    public Literal getLiteral() {
        return (Literal) this.children.get(1);
    }

}