algebricks/algebricks-core/src/main/java/edu/uci/ics/hyracks/algebricks/core/algebra/base/LogicalVariable.java

/*
 * Copyright 2009-2010 by The Regents of the University of California
 * 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 from
 * 
 *     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 edu.uci.ics.hyracks.algebricks.core.algebra.base;

/**
 * Represents a logical variable in an asterix logical plan.
 * 
 * @author Vinayak R. Borkar [vborkar@ics.uci.edu]
 */
public final class LogicalVariable {
    private final int id;

    public LogicalVariable(int id) {
        this.id = id;
    }

    public int getId() {
        return id;
    }

    @Override
    public String toString() {
        return "$$" + id;
    }

    @Override
    public boolean equals(Object obj) {
        if (!(obj instanceof LogicalVariable)) {
            return false;
        } else {
            return id == ((LogicalVariable) obj).getId();
        }
    }

    @Override
    public int hashCode() {
        return id;
    }
}