core/api/src/main/java/org/qi4j/api/query/grammar/ComparisonSpecification.java

/*
 * 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.qi4j.api.query.grammar;

import org.qi4j.api.composite.Composite;
import org.qi4j.api.property.Property;

/**
 * Base comparison Specification.
 */
public abstract class ComparisonSpecification<T>
    extends ExpressionSpecification
{
    protected final PropertyFunction<T> property;
    protected final T value;

    public ComparisonSpecification( PropertyFunction<T> property, T value )
    {
        this.property = property;
        this.value = value;
    }

    public PropertyFunction<T> property()
    {
        return property;
    }

    @Override
    public final boolean satisfiedBy( Composite item )
    {
        try
        {
            Property<T> prop = property.map( item );

            if( prop == null )
            {
                return false;
            }

            T propValue = prop.get();
            if( propValue == null )
            {
                return false;
            }

            return compare( propValue );
        }
        catch( IllegalArgumentException e )
        {
            return false;
        }
    }

    protected abstract boolean compare( T value );

    public T value()
    {
        return value;
    }
}