# FilePropertyResolver.java

    /*
     * Copyright (c) 2019, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
     *
     * 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.apache.synapse.commons.resolvers;

    import org.apache.commons.logging.Log;
    import org.apache.commons.logging.LogFactory;
    import org.apache.synapse.commons.util.FilePropertyLoader;

    /**
     * File Property resolver can be used to resolve file property variables in the synapse config.
     */
    public class FilePropertyResolver implements Resolver {

        private static final Log LOG = LogFactory.getLog(FilePropertyResolver.class);

        /**
         * input is the file property key value which needs to resolve
         */
        private String input;

        /**
         * set file property variable which needs to resolved
         *
         * @param input
         */
        @Override
        public void setVariable(String input) {
            this.input = input;
        }

        /**
         * file property variable is resolved in this function
         *
         * @return resolved value for the file property variable
         */
        @Override
        public String resolve() {
            FilePropertyLoader propertyLoader = FilePropertyLoader.getInstance();
            String PropertyValue = propertyLoader.getValue(input);

            if (LOG.isDebugEnabled()) {
                LOG.debug("Resolving File parameter key: "+ input + " value: " + PropertyValue);
            }

            if (PropertyValue == null) {
                throw new ResolverException("File parameter key: " + input + " could not be found");
            }
            return PropertyValue;
        }
    }