# 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;
        }
    }