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From sebb <seb...@gmail.com>
Subject Re: [JEXL] svn commit: r799492
Date Sat, 01 Aug 2009 01:56:54 GMT
On 31/07/2009, Rahul Akolkar <rahul.akolkar@gmail.com> wrote:
> On Thu, Jul 30, 2009 at 10:24 PM, <sebb@apache.org> wrote:
>  > Author: sebb
>  > Date: Fri Jul 31 02:24:07 2009
>  > New Revision: 799492
>  >
>  > URL: http://svn.apache.org/viewvc?rev=799492&view=rev
>  > Log:
>  > Initial implementation of Jexl Script engine and simple unit test
>  >
>  > Added:
>  >    commons/proper/jexl/branches/2.0/src/java/org/apache/commons/jexl/scripting/JexlScriptEngine.java
  (with props)
>  >    commons/proper/jexl/branches/2.0/src/test/org/apache/commons/jexl/scripting/JexlScriptEngineTest.java
  (with props)
>  >
>  > Added: commons/proper/jexl/branches/2.0/src/java/org/apache/commons/jexl/scripting/JexlScriptEngine.java
>  > URL: http://svn.apache.org/viewvc/commons/proper/jexl/branches/2.0/src/java/org/apache/commons/jexl/scripting/JexlScriptEngine.java?rev=799492&view=auto
>  > ==============================================================================
>  > --- commons/proper/jexl/branches/2.0/src/java/org/apache/commons/jexl/scripting/JexlScriptEngine.java
(added)
>  > +++ commons/proper/jexl/branches/2.0/src/java/org/apache/commons/jexl/scripting/JexlScriptEngine.java
Fri Jul 31 02:24:07 2009
>  > @@ -0,0 +1,202 @@
>  > +/*
>  > + * 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.apache.commons.jexl.scripting;
>  > +
>  > +import java.io.BufferedReader;
>  > +import java.io.IOException;
>  > +import java.io.Reader;
>  > +import java.util.Collection;
>  > +import java.util.Map;
>  > +import java.util.Set;
>  > +
>  > +import javax.script.AbstractScriptEngine;
>  > +import javax.script.Bindings;
>  > +import javax.script.ScriptContext;
>  > +import javax.script.ScriptEngineFactory;
>  > +import javax.script.ScriptException;
>  > +import javax.script.SimpleBindings;
>  > +
>  > +import org.apache.commons.jexl.JexlContext;
>  > +import org.apache.commons.jexl.JexlEngine;
>  > +import org.apache.commons.jexl.Script;
>  > +
>  > +// Note: this is a generated class, so won't be present until JavaCC has been
run
>  > +import org.apache.commons.jexl.parser.ParseException;
>  > +
>  > +/**
>  > + * Implements the Jexl ScriptEngine for JSF-223.
>  > + * <p>
>  > + * See
>  > + * <a href="http://java.sun.com/javase/6/docs/api/javax/script/package-summary.html">Java
Scripting API</a>
>  > + * Javadoc.
>  > + */
>  > +public class JexlScriptEngine extends AbstractScriptEngine {
>  > +
>  > +    private final ScriptEngineFactory factory;
>  > +
>  > +    private final JexlEngine engine;
>  > +
>  > +    public JexlScriptEngine() {
>  > +        this(null);
>  > +    }
>  > +
>  > +    public JexlScriptEngine(final ScriptEngineFactory _factory) {
>  > +        factory = _factory;
>  > +        engine = new JexlEngine();
>  > +    }
>  > +
>  > +    /** {@inheritDoc} */
>  > +    public Bindings createBindings() {
>  > +        return new SimpleBindings();
>  > +    }
>  > +
>  > +    /** {@inheritDoc} */
>  > +    public Object eval(Reader script, ScriptContext context) throws ScriptException
{
>  > +        BufferedReader reader = new BufferedReader(script);
>  > +        StringBuilder buffer = new StringBuilder();
>  > +        try {
>  > +            String line;
>  > +            try {
>  > +                while ((line = reader.readLine()) != null) {
>  > +                    buffer.append(line).append('\n');
>  > +                }
>  > +            } catch (IOException e) {
>  > +                throw new ScriptException(e);
>  > +            }
>  > +        } finally {
>  > +            try {
>  > +                reader.close();
>  > +            } catch (IOException e) {
>  > +            }
>  > +        }
>  > +        return eval(buffer.toString(), context);
>  > +    }
>  > +
>  > +    /** {@inheritDoc} */
>  > +    @SuppressWarnings("unchecked")
>  > +    public Object eval(String scriptText, final ScriptContext context) throws
ScriptException {
>  > +        if (scriptText == null) {
>  > +            return null;
>  > +        }
>  > +        context.setAttribute("context", context, ScriptContext.ENGINE_SCOPE);
>  <snip/>
>
>  Not sure what the above line is upto ...
>

JSR-223 mandates that:

>>>
In all cases, the ScriptContext used during a script execution must be
a value in the Engine Scope of the ScriptEngine whose key is the
String “context”.
<<<

Will document.

>  > +        try {
>  > +            Script script = engine.createScript(scriptText);
>  > +            JexlContext ctxt = new JexlContext(){
>  > +                public void setVars(Map vars) {
>  > +                    context.setBindings(new SimpleBindings(vars), ScriptContext.ENGINE_SCOPE);
>  > +                }
>  > +
>  > +                public Map getVars() {
>  > +                    return new JexlContextWrapper(context);
>  > +                }
>  > +            };
>  > +
>  > +            ctxt.getVars().put("context", "value");
>  <snap/>
>
>  ... but it seems related to this other line above. Please elaborate.
>

Oops, the last line is a bug. Will fix.

>  > +
>  > +            return script.execute(ctxt);
>  > +        } catch (ParseException e) {
>  > +            e.printStackTrace();
>  > +            throw new ScriptException(e);
>  > +        } catch (Exception e) {
>  > +            e.printStackTrace();
>  > +            throw new ScriptException(e.toString());
>  > +        }
>  > +    }
>  > +
>  > +    /** {@inheritDoc} */
>  > +    public ScriptEngineFactory getFactory() {
>  > +        return factory == null ? new JexlScriptEngineFactory() : factory;
>  > +    }
>  > +
>  > +    /**
>  > +     * Wrapper to convert a JSR-223 ScriptContext into a JexlContext.
>  > +     *
>  <snip/>
>
>  The above statement (and perhaps the class name itself) is a bit
>  misleading. Its not that the ScriptContext is converted to a
>  JexlContext by this wrapper, but rather that it makes it easier to
>  complete the said conversion. However, given this is private, not the
>  most important.

OK, will clarify.

>  -Rahul
>
>
>
>  > +     * Current implementation only gives access to ENGINE_SCOPE binding.
>  > +     */
>  > +    @SuppressWarnings("unchecked")
>  > +    private static class JexlContextWrapper implements Map {
>  > +
>  > +        private final ScriptContext context;
>  > +
>  > +        private JexlContextWrapper (final ScriptContext _context){
>  > +            context = _context;
>  > +        }
>  > +
>  > +        public void clear() {
>  > +            Bindings bnd = context.getBindings(ScriptContext.ENGINE_SCOPE);
>  > +            bnd.clear();
>  > +        }
>  > +
>  > +        public boolean containsKey(final Object key) {
>  > +            Bindings bnd = context.getBindings(ScriptContext.ENGINE_SCOPE);
>  > +            return bnd.containsKey(key);
>  > +        }
>  > +
>  > +        public boolean containsValue(final Object value) {
>  > +            Bindings bnd = context.getBindings(ScriptContext.ENGINE_SCOPE);
>  > +            return bnd.containsValue(value);
>  > +        }
>  > +
>  > +        public Set entrySet() {
>  > +            Bindings bnd = context.getBindings(ScriptContext.ENGINE_SCOPE);
>  > +            return bnd.entrySet();
>  > +        }
>  > +
>  > +        public Object get(final Object key) {
>  > +            Bindings bnd = context.getBindings(ScriptContext.ENGINE_SCOPE);
>  > +            return bnd.get(key);
>  > +        }
>  > +
>  > +        public boolean isEmpty() {
>  > +            Bindings bnd = context.getBindings(ScriptContext.ENGINE_SCOPE);
>  > +            return bnd.isEmpty();
>  > +        }
>  > +
>  > +        public Set keySet() {
>  > +            Bindings bnd = context.getBindings(ScriptContext.ENGINE_SCOPE);
>  > +            return bnd.keySet();
>  > +        }
>  > +
>  > +        public Object put(final Object key, final Object value) {
>  > +            Bindings bnd = context.getBindings(ScriptContext.ENGINE_SCOPE);
>  > +            return bnd.put(key, value);
>  > +        }
>  > +
>  > +        public void putAll(Map t) {
>  > +            Bindings bnd = context.getBindings(ScriptContext.ENGINE_SCOPE);
>  > +            bnd.putAll(t); // N.B. SimpleBindings checks for valid keys
>  > +        }
>  > +
>  > +        public Object remove(Object key) {
>  > +            Bindings bnd = context.getBindings(ScriptContext.ENGINE_SCOPE);
>  > +            return bnd.remove(key);
>  > +        }
>  > +
>  > +        public int size() {
>  > +            Bindings bnd = context.getBindings(ScriptContext.ENGINE_SCOPE);
>  > +            return bnd.size();
>  > +        }
>  > +
>  > +        public Collection values() {
>  > +            Bindings bnd = context.getBindings(ScriptContext.ENGINE_SCOPE);
>  > +            return bnd.values();
>  > +        }
>  > +
>  > +    }
>  > +}
>  >
>  > Propchange: commons/proper/jexl/branches/2.0/src/java/org/apache/commons/jexl/scripting/JexlScriptEngine.java
>  > ------------------------------------------------------------------------------
>  >    svn:eol-style = native
>  >
>  > Propchange: commons/proper/jexl/branches/2.0/src/java/org/apache/commons/jexl/scripting/JexlScriptEngine.java
>  > ------------------------------------------------------------------------------
>  >    svn:keywords = Author Date Id Revision
>  >
>  > Added: commons/proper/jexl/branches/2.0/src/test/org/apache/commons/jexl/scripting/JexlScriptEngineTest.java
>  > URL: http://svn.apache.org/viewvc/commons/proper/jexl/branches/2.0/src/test/org/apache/commons/jexl/scripting/JexlScriptEngineTest.java?rev=799492&view=auto
>  > ==============================================================================
>  > --- commons/proper/jexl/branches/2.0/src/test/org/apache/commons/jexl/scripting/JexlScriptEngineTest.java
(added)
>  > +++ commons/proper/jexl/branches/2.0/src/test/org/apache/commons/jexl/scripting/JexlScriptEngineTest.java
Fri Jul 31 02:24:07 2009
>  > @@ -0,0 +1,52 @@
>  > +/*
>  > + * 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.apache.commons.jexl.scripting;
>  > +
>  > +import javax.script.ScriptEngine;
>  > +import javax.script.ScriptEngineManager;
>  > +
>  > +import junit.framework.TestCase;
>  > +
>  > +public class JexlScriptEngineTest extends TestCase {
>  > +
>  > +    public void testScripting() throws Exception {
>  > +        ScriptEngineManager manager = new ScriptEngineManager();
>  > +        assertNotNull("Manager should not be null", manager);
>  > +        ScriptEngine engine = manager.getEngineByName("jexl");
>  > +        assertNotNull("Engine should not be null (name)", engine);
>  > +        engine = manager.getEngineByExtension("jexl");
>  > +        assertNotNull("Engine should not be null (ext)", engine);
>  > +        final Integer initialValue = Integer.valueOf(123);
>  > +        assertEquals(initialValue,engine.eval("123"));
>  > +        assertEquals(initialValue,engine.eval("0;123"));// multiple statements
>  > +        long time1 = System.currentTimeMillis();
>  > +        Long time2 = (Long) engine.eval("" +
>  > +                       "sys=context.class.forName(\"java.lang.System\");"
>  > +                       +"now=sys.currentTimeMillis();"
>  > +                       );
>  > +        assertTrue("Must take some time to process this",time1 <= time2.longValue());
>  > +        engine.put("value", initialValue);
>  > +        assertEquals(initialValue,engine.get("value"));
>  > +        final Long newValue = Long.valueOf(124);
>  > +        assertEquals(newValue,engine.eval("old=value;value=value+1"));
>  > +        assertEquals(initialValue,engine.get("old"));
>  > +        assertEquals(newValue,engine.get("value"));
>  > +    }
>  > +
>  > +}
>  >
>  > Propchange: commons/proper/jexl/branches/2.0/src/test/org/apache/commons/jexl/scripting/JexlScriptEngineTest.java
>  > ------------------------------------------------------------------------------
>  >    svn:eol-style = native
>  >
>  > Propchange: commons/proper/jexl/branches/2.0/src/test/org/apache/commons/jexl/scripting/JexlScriptEngineTest.java
>  > ------------------------------------------------------------------------------
>  >    svn:keywords = Author Date Id Revision
>  >
>  >
>  >
>
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