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/*
* JPPF.
* Copyright (C) 2005-2015 JPPF Team.
* http://www.jppf.org
*
* 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.jppf.node.protocol;
import java.io.*;
import java.util.*;
import org.jppf.scripting.*;
import org.jppf.utils.FileUtils;
/**
* A task implementation which executes a script in a specified JSR 223 ({@code javax.script} APIs) script language.
* In addition to the user-specified bindings, this task always provides to the script engine a reference to itself
* with the name 'jppfTask'.
*
A reusableId can be specified via the constructors, indicating that, if the script engine has that capability,
* compiled scripts will be stored and reused, to avoid compiling the same scripts repeatedly.
* @param the type of result returned by this task.
* @author Laurent Cohen
*/
public class ScriptedTask extends AbstractTask {
/**
* The JSR 223 script language to use.
*/
protected String language;
/**
* The script to execute from this task.
*/
protected String script;
/**
* Unique identifier for the script, which allows reusing a compiled version if one has already been produced.
*/
protected String reusableId;
/**
* The bindings provide variables available to the script engine during execution of the script.
*/
protected Map bindings = new HashMap<>();
/**
* Default constructor provided as a convenience for subclassing.
*/
protected ScriptedTask() {
}
/**
* Initialize this task with the specified script language, script provided as a string,
* and a set of variable bindings to be used in the scripts.
* @param language the JSR 223 script language to use.
* @param script the script to execute from this task.
* @param reusableId a unique identifier for the script, which allows reusing a compiled version if one has already been produced.
* @param bindings a set of variables that will be available to the script.
* @throws IllegalArgumentException if {@code language} or {@code script} is {@code null}.
*/
public ScriptedTask(final String language, final String script, final String reusableId, final Map bindings) throws IllegalArgumentException {
if (language == null) throw new IllegalArgumentException("the script language cannot be null");
if (script == null) throw new IllegalArgumentException("the script source cannot be null");
this.language = language;
this.script = script;
this.reusableId = reusableId;
if (bindings != null) this.bindings.putAll(bindings);
}
/**
* Initialize this task with the specified script language, script provided from a {@link Reader},
* and a set of variable bindings to be used in the scripts.
* @param language the JSR 223 script language to use.
* @param scriptReader a reader form which to read the script source.
* @param reusableId a unique identifier for the script, which allows reusing a compiled version if one has already been produced.
* @param bindings a set of variables that will be available to the script.
* @throws IllegalArgumentException if {@code language} or {@code script} is {@code null}.
* @throws IOException if an I/O error occurs while reading the script source.
*/
public ScriptedTask(final String language, final Reader scriptReader, final String reusableId, final Map bindings)
throws IllegalArgumentException, IOException {
this(language, FileUtils.readTextFile(scriptReader), reusableId, bindings);
}
/**
* Initialize this task with the specified script language, script provided as a file,
* and a set of variable bindings to be used in the scripts.
* @param language the JSR 223 script language to use.
* @param scriptFile a file from which to read the script source.
* @param reusableId a unique identifier for the script, which allows reusing a compiled version if one has already been produced.
* @param bindings a set of variables that will be available to the script.
* @throws IllegalArgumentException if {@code language} or {@code script} is {@code null}.
* @throws IOException if an I/O error occurs while reading the script source.
*/
public ScriptedTask(final String language, final File scriptFile, final String reusableId, final Map bindings)
throws IllegalArgumentException, IOException {
this(language, FileUtils.readTextFile(scriptFile), reusableId, bindings);
}
@Override
public void run() {
ScriptRunner runner = null;
try {
runner = ScriptRunnerFactory.getScriptRunner(language);
if (runner != null) {
Map bnd = new HashMap<>(bindings);
bnd.put("jppfTask", this);
T result = (T) runner.evaluate(reusableId, script, bnd);
if (result != null) {
System.out.println("language=" + language + ", result=" + result + ", class=" + result.getClass().getName());
}
// may have been set from the script
if ((getResult() == null) && (result != null)) setResult(result);
}
} catch(Exception e) {
setThrowable(e);
} finally {
ScriptRunnerFactory.releaseScriptRunner(runner);
}
}
/**
* Get the JSR 223 script language to use.
* @return the script language a s a script.
*/
public String getLanguage() {
return language;
}
/**
* Get the script to execute from this task.
* @return the script source as a string.
*/
public String getScript() {
return script;
}
/**
* Get the unique identifier for the script.
* @return the identifier as a string.
*/
public String getReusableId() {
return reusableId;
}
/**
* Get the user-defined variable bindings.
* @return a map of variable names to their value.
*/
public Map getBindings() {
return bindings;
}
/**
* Add the specified variable to the user-defined bindings.
* @param name the name of the variable binding to add.
* @param value the value of the variable.
*/
public void addBinding(final String name, final Object value) {
bindings.put(name, value);
}
/**
* Remove the specified variable from the user-defined bindings.
* @param name the name of the variable binding to remove.
* @return the value of the variable, or {@code null} if the variable was not bound.
*/
public Object removeBinding(final String name) {
return bindings.remove(name);
}
}