com.pros.jsontransform.plugin.PluginManager.java Source code

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Here is the source code for com.pros.jsontransform.plugin.PluginManager.java

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/*
 * Copyright (c) 2016 PROS, Inc.
 *
 * 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 com.pros.jsontransform.plugin;

import java.io.File;
import java.lang.reflect.Method;
import java.net.URL;
import java.net.URLClassLoader;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.pros.jsontransform.ObjectTransformer;
import com.pros.jsontransform.ObjectTransformerException;

/**
 * Manage json-transform plugins
 */
public class PluginManager {
    /** The class loader */
    private URLClassLoader urlClassLoader;

    /** Where plugins are located */
    private String pluginFolder;

    public PluginManager(final String pluginFolder) {
        this.pluginFolder = pluginFolder;
    }

    @SuppressWarnings({ "unchecked", "rawtypes" })
    public void constraintPluginValidate(final String pluginClassName, final JsonNode constraintNode,
            final JsonNode resultNode, final ObjectTransformer transformer) throws ObjectTransformerException {
        try {
            Class pluginClass = loadPlugin(pluginClassName);
            Method validate = pluginClass.getMethod("validate", JsonNode.class, JsonNode.class,
                    ObjectTransformer.class);
            validate.invoke(null, constraintNode, resultNode, transformer);
        } catch (Exception ex) {
            throw new ObjectTransformerException("Error from constraint plugin " + pluginClassName, ex);
        }
    }

    @SuppressWarnings({ "unchecked", "rawtypes" })
    public JsonNode functionPluginEvaluate(final String pluginClassName, final JsonNode argsNode,
            final JsonNode resultNode, final ObjectTransformer transformer) throws ObjectTransformerException {
        try {
            Class pluginClass = loadPlugin(pluginClassName);
            Method evaluate = pluginClass.getMethod("evaluate", JsonNode.class, JsonNode.class,
                    ObjectTransformer.class);
            return (JsonNode) evaluate.invoke(null, argsNode, resultNode, transformer);
        } catch (Exception ex) {
            throw new ObjectTransformerException("Error from function plugin " + pluginClassName, ex);
        }
    }

    @SuppressWarnings({ "unchecked", "rawtypes" })
    public boolean filterPluginEvaluate(final String pluginClassName, final JsonNode filterNode,
            final JsonNode elementNode, final ObjectTransformer transformer) throws ObjectTransformerException {
        try {
            Class pluginClass = loadPlugin(pluginClassName);
            Method evaluate = pluginClass.getMethod("evaluate", JsonNode.class, JsonNode.class,
                    ObjectTransformer.class);
            return (boolean) evaluate.invoke(null, filterNode, elementNode, transformer);
        } catch (Exception ex) {
            throw new ObjectTransformerException("Error from filter plugin " + pluginClassName, ex);
        }
    }

    @SuppressWarnings({ "unchecked", "rawtypes" })
    public void sortPluginSort(final String pluginClassName, final ArrayNode targetArray, final JsonNode sortNode,
            final ObjectTransformer transformer) throws ObjectTransformerException {
        try {
            Class pluginClass = loadPlugin(pluginClassName);
            Method sort = pluginClass.getMethod("sort", ArrayNode.class, JsonNode.class, ObjectTransformer.class);
            sort.invoke(null, targetArray, sortNode, transformer);
        } catch (Exception ex) {
            throw new ObjectTransformerException("Error from sort plugin " + pluginClassName, ex);
        }
    }

    @SuppressWarnings("rawtypes")
    private Class loadPlugin(final String pluginClassName) throws ObjectTransformerException {
        Class pluginClass = null;

        try {
            if (urlClassLoader == null) {
                File folder = new File(pluginFolder);
                File[] listOfFiles = folder.listFiles();
                int jarCount = 0;
                URL[] jarUrls = new URL[listOfFiles.length];
                for (int i = 0; i < listOfFiles.length; i++) {
                    File jarFile = listOfFiles[i];
                    if (jarFile.isFile() && jarFile.getName().endsWith(".jar")) {
                        jarUrls[jarCount++] = jarFile.toURI().toURL();
                    }
                }
                if (jarCount == 0) {
                    throw new ObjectTransformerException("Cannot load plugin " + pluginClassName
                            + " No jars found in plugin folder " + pluginFolder);
                }
                urlClassLoader = new URLClassLoader(jarUrls);
            }
            pluginClass = urlClassLoader.loadClass(pluginClassName);
        } catch (Exception ex) {
            throw new ObjectTransformerException("Cannot load plugin " + pluginClassName, ex);
        }

        return pluginClass;
    }
}