Condition.java

/*
 * Copyright 2004-2014 H2 Group. Multiple-Licensed under the MPL 2.0,
 * and the EPL 1.0 (http://h2database.com/html/license.html).
 * Initial Developer: H2 Group
 */
package org.h2.expression;

import org.h2.value.Value;
import org.h2.value.ValueBoolean;

/**
 * Represents a condition returning a boolean value, or NULL.
 */
abstract class Condition extends Expression {
	//所有Condition的子类都默认使用如下4个方法的返回值，没有子类覆盖
    @Override
    public int getType() {
        return Value.BOOLEAN;
    }

    @Override
    public int getScale() {
        return 0;
    }

    @Override
    public long getPrecision() {
        return ValueBoolean.PRECISION;
    }

    @Override
    public int getDisplaySize() {
        return ValueBoolean.DISPLAY_SIZE;
    }

}