path: root/policy-management/src/main/java/org/onap/policy/drools/protocol/coders/JsonProtocolFilter.java

/*
 * ============LICENSE_START=======================================================
 * ONAP
 * ================================================================================
 * Copyright (C) 2017-2018 AT&T Intellectual Property. 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.
 * ============LICENSE_END=========================================================
 */

package org.onap.policy.drools.protocol.coders;

import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
import org.onap.policy.drools.utils.Pair;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * JSON Protocol Filter.
 */
public class JsonProtocolFilter {

    private static final String MISSING_RULE_NAME = "no rule name provided";
    /**
     * Logger.
     */
    private static final Logger logger = LoggerFactory.getLogger(JsonProtocolFilter.class);

    /**
     * Helper class to collect Filter information.
     */
    public static class FilterRule {
        /**
         * Field name.
         */
        private String name;

        /**
         * Field Value regex.
         */
        private String regex;

        /**
         * Filter Constructor.
         * 
         * @param name field name
         * @param regex field regex value
         */
        public FilterRule(String name, String regex) {
            this.setName(name);
            this.setRegex(regex);
        }

        /**
         * Default constructor (for serialization only).
         */
        public FilterRule() {
            super();
        }

        /**
         * gets name.
         * 
         * @return name
         */
        public String getName() {
            return name;
        }

        /**
         * gets regex.
         * 
         * @return regular expression string
         */
        public String getRegex() {
            return regex;
        }

        /**
         * Sets field name.
         * 
         * @param name field name
         */
        public void setName(String name) {
            if (name == null || name.isEmpty()) {
                throw new IllegalArgumentException("filter field name must be provided");
            }

            this.name = name;
        }

        /**
         * sets regex name.
         * 
         * @param regex expression
         */
        public void setRegex(String regex) {
            if (regex == null || regex.isEmpty()) {
                this.regex = ".*";
            }

            this.regex = regex;
        }

        @Override
        public String toString() {
            StringBuilder builder = new StringBuilder();
            builder.append("Filter [name=").append(name).append(", regex=").append(regex).append("]");
            return builder.toString();
        }
    }

    /**
     * all the filters to be applied.
     */
    protected List<FilterRule> rules = new CopyOnWriteArrayList<>();

    /**
     * Create a Protocol Filter.
     * 
     * @throws IllegalArgumentException an invalid input has been provided
     */
    public JsonProtocolFilter() {
        super();
    }

    /**
     * Constructor.
     * 
     * @param filters filter list
     * 
     * @throws IllegalArgumentException an invalid input has been provided
     */
    public JsonProtocolFilter(List<FilterRule> filters) {
        List<FilterRule> temp = new ArrayList<>();
        for (FilterRule rule : filters) {
            if (rule.getName() == null || rule.getName().isEmpty()) {
                continue;
            }

            if (rule.getRegex() == null || rule.getRegex().isEmpty()) {
                rule.setRegex(".*");
            }

            temp.add(rule);
        }

        this.rules.addAll(temp);
    }

    /**
     * From raw filters.
     * 
     * @param rawFilters raw filter initialization
     * 
     * @throws IllegalArgumentException an invalid input has been provided
     */
    public static JsonProtocolFilter fromRawFilters(List<Pair<String, String>> rawFilters) {

        if (rawFilters == null) {
            throw new IllegalArgumentException("No raw filters provided");
        }

        List<FilterRule> filters = new ArrayList<>();
        for (Pair<String, String> filterPair: rawFilters) {
            if  (filterPair.first() == null || filterPair.first().isEmpty()) {
                continue;
            }

            filters.add(new FilterRule(filterPair.first(), filterPair.second()));
        }
        return new JsonProtocolFilter(filters);
    }

    /**
     * are there any filters.
     * 
     * @return true if there are filters, false otherwise
     */
    public boolean isRules() {
        return !this.rules.isEmpty();
    }

    /**
     * accept a JSON string as conformant it if passes all filters.
     * 
     * @param json json is a JSON object
     * @return true if json string is conformant
     * 
     * @throws IllegalArgumentException an invalid input has been provided
     */
    public boolean accept(JsonElement json) {
        if (json == null) {
            throw new IllegalArgumentException("no JSON provided");
        }

        if (!json.isJsonObject()) {
            return false;
        }

        if (rules.isEmpty()) {
            return true;
        }

        try {
            JsonObject event = json.getAsJsonObject();
            for (FilterRule filter: rules) {
                if (filter.getRegex() == null
                        || filter.getRegex().isEmpty()
                        || ".*".equals(filter.getRegex())) {

                    // Only check for presence
                    if (!event.has(filter.getName())) {
                        return false;
                    }
                } else {
                    JsonElement field = event.get(filter.getName());
                    if (field == null) {
                        return false;
                    }

                    String fieldValue = field.getAsString();
                    if (!fieldValue.matches(filter.getRegex())) {
                        return false;
                    }
                }
            }
            return true;
        } catch (Exception e) {
            throw new IllegalArgumentException(e);
        }
    }

    /**
     * Accept a JSON string as conformant it if passes all filters.
     * 
     * @param json json string
     * @return true if json string is conformant
     * 
     * @throws IllegalArgumentException an invalid input has been provided
     */
    public boolean accept(String json) {
        if (json == null || json.isEmpty()) {
            throw new IllegalArgumentException("no JSON provided");
        }

        if (rules.isEmpty()) {
            return true;
        }

        try {
            JsonElement element = new JsonParser().parse(json);
            if (element == null || !element.isJsonObject()) {
                return false;
            }

            return this.accept(element.getAsJsonObject());
        } catch (IllegalArgumentException ile) {
            throw ile;
        } catch (Exception e) {
            logger.info("{}: cannot accept {} because of {}", 
                    this, json, e.getMessage(), e);
            throw new IllegalArgumentException(e);
        }
    }

    public List<FilterRule> getRules() {
        return new ArrayList<>(this.rules);
    }

    /**
     * Get rules.
     * 
     * @param name name
     * @return list of filter rules
     */
    public List<FilterRule> getRules(String name) {
        if (name == null || name.isEmpty()) {
            throw new IllegalArgumentException(MISSING_RULE_NAME);
        }

        ArrayList<FilterRule> temp = new ArrayList<>();
        for (FilterRule rule : this.rules) {
            if (rule.getName().equals(name)) {
                temp.add(rule);
            }
        }
        return temp;
    }

    /**
     * Set Rules.
     * 
     * @param rulesFilters filters
     */
    public void setRules(List<FilterRule> rulesFilters) {
        if (rulesFilters == null) {
            throw new IllegalArgumentException("no rules provided");
        }

        this.rules.clear();
        this.rules.addAll(rulesFilters);
    }

    /**
     * Delete rules.
     * 
     * @param name name
     */
    public void deleteRules(String name) {
        if (name == null || name.isEmpty()) {
            throw new IllegalArgumentException(MISSING_RULE_NAME);
        }

        List<FilterRule> temp = new ArrayList<>();
        for (FilterRule rule : this.rules) {
            if (rule.name.equals(name)) {
                temp.add(rule);
            }
        }
        this.rules.removeAll(temp);
    }

    /**
     * Delete rule.
     * 
     * @param name name
     * @param regex regex
     */
    public void deleteRule(String name, String regex) {
        if (name == null || name.isEmpty()) {
            throw new IllegalArgumentException(MISSING_RULE_NAME);
        }

        String nonNullRegex = regex;
        if (regex == null || regex.isEmpty()) {
            nonNullRegex = ".*";
        }

        List<FilterRule> temp = new ArrayList<>();
        for (FilterRule rule : this.rules) {
            if (rule.name.equals(name) && rule.getRegex().equals(nonNullRegex)) {
                temp.add(rule);
            }
        }

        this.rules.removeAll(temp);
    }

    /**
     * Add rule.
     * 
     * @param name name
     * @param regex regex
     */
    public void addRule(String name, String regex) {
        if (name == null || name.isEmpty()) {
            throw new IllegalArgumentException(MISSING_RULE_NAME);
        }

        String nonNullRegex = regex;
        if (regex == null || regex.isEmpty()) {
            nonNullRegex = ".*";
        }

        for (FilterRule rule : this.rules) {
            if (rule.getName().equals(name) && rule.getRegex().equals(regex)) {
                return;
            }
        }

        this.rules.add(new FilterRule(name, nonNullRegex));
    }

    @Override
    public String toString() {
        StringBuilder builder = new StringBuilder();
        builder.append("JsonProtocolFilter [rules=").append(rules).append("]");
        return builder.toString();
    }

}