org.wicketstuff.nashorn.resource.NashornScriptCallable.java Source code

Introduction

Here is the source code for org.wicketstuff.nashorn.resource.NashornScriptCallable.java

Source

/*
 * 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.wicketstuff.nashorn.resource;

import java.io.StringReader;
import java.io.Writer;
import java.util.concurrent.Callable;

import javax.script.Bindings;
import javax.script.ScriptContext;
import javax.script.ScriptEngine;
import javax.script.SimpleScriptContext;

import org.apache.wicket.request.resource.IResource.Attributes;

import jdk.nashorn.api.scripting.ClassFilter;
import jdk.nashorn.api.scripting.NashornScriptEngineFactory;

/**
 * The script callable setup the script environment and evaluates the given script. If the script is
 * running the thread id is going to be determined. This id is used to check the memory usage of the
 * process.
 * 
 * @author Tobias Soloschenko
 *
 */
@SuppressWarnings({ "restriction" })
public class NashornScriptCallable implements Callable<Object> {

    private String script;

    private Attributes attributes;

    private ClassFilter classFilter;

    private Writer writer;

    private Writer errorWriter;

    private volatile long threadId = -1;

    /**
     * Creates a script result
     * 
     * @param script
     *            the script to be executed
     * @param attributes
     *            the attributes to
     * @param classFilter
     *            the class filter to be applied
     * @param writer
     *            the writer to output script prints
     * @param errorWriter
     *            the writer to output errors
     */
    public NashornScriptCallable(String script, Attributes attributes, ClassFilter classFilter, Writer writer,
            Writer errorWriter) {
        this.script = script;
        this.attributes = attributes;
        this.classFilter = classFilter;
        this.writer = writer;
        this.errorWriter = errorWriter;
    }

    @Override
    public Object call() throws Exception {
        enableSecurity();
        ScriptEngine scriptEngine = new NashornScriptEngineFactory().getScriptEngine(getClassFilter());
        Bindings bindings = scriptEngine.createBindings();
        SimpleScriptContext scriptContext = new SimpleScriptContext();
        scriptContext.setWriter(getWriter());
        scriptContext.setErrorWriter(getErrorWriter());
        setup(getAttributes(), bindings);
        Thread thread = Thread.currentThread();
        threadId = thread.getId();
        bindings.put("nashornResourceReferenceScriptExecutionThread", thread);
        scriptContext.setBindings(bindings, ScriptContext.ENGINE_SCOPE);
        return scriptEngine.eval(new StringReader(getScript()), scriptContext);
    }

    /**
     * Enables the security for the current thread
     */
    private void enableSecurity() {
        SecurityManager securityManager = System.getSecurityManager();
        if (securityManager != null && securityManager instanceof NashornSecurityManager) {
            ((NashornSecurityManager) securityManager).enable();
        }
    }

    /**
     * Setup the bindings and make information available to the scripting context
     * 
     * @param attributes
     *            the attributes of the request
     * @param bindings
     *            the bindings to add java objects to
     */
    protected void setup(Attributes attributes, Bindings bindings) {
        // NOOP
    }

    /**
     * Gets the script
     * 
     * @return the script
     */
    public String getScript() {
        return script;
    }

    /**
     * Gets the attributes
     * 
     * @return the attributes
     */
    public Attributes getAttributes() {
        return attributes;
    }

    /**
     * Gets the class filter
     * 
     * @return the class filter
     */
    public ClassFilter getClassFilter() {
        return classFilter;
    }

    /**
     * Gets the writer
     * 
     * @return the writer
     */
    public Writer getWriter() {
        return writer;
    }

    /**
     * Gets the error writer
     * 
     * @return the error writer
     */
    public Writer getErrorWriter() {
        return errorWriter;
    }

    /**
     * Gets the script callable thread id
     * 
     * @return the script callable script id
     */
    public long getThreadId() {
        return threadId;
    }
}