src/main/java/freemarker/ext/jython/JythonWrapper.java - freemarker - Git at Google

 /*
  * 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 freemarker.ext.jython;

 import java.math.BigDecimal;
 import java.math.BigInteger;
 import java.util.ArrayList;
 import java.util.List;

 import org.python.core.Py;
 import org.python.core.PyDictionary;
 import org.python.core.PyFloat;
 import org.python.core.PyInteger;
 import org.python.core.PyLong;
 import org.python.core.PyObject;
 import org.python.core.PySequence;
 import org.python.core.PyString;
 import org.python.core.PyStringMap;

 import freemarker.ext.util.ModelCache;
 import freemarker.ext.util.WrapperTemplateModel;
 import freemarker.template.AdapterTemplateModel;
 import freemarker.template.ObjectWrapper;
 import freemarker.template.TemplateBooleanModel;
 import freemarker.template.TemplateHashModel;
 import freemarker.template.TemplateHashModelEx;
 import freemarker.template.TemplateMethodModel;
 import freemarker.template.TemplateMethodModelEx;
 import freemarker.template.TemplateModel;
 import freemarker.template.TemplateModelAdapter;
 import freemarker.template.TemplateModelException;
 import freemarker.template.TemplateNumberModel;
 import freemarker.template.TemplateScalarModel;
 import freemarker.template.TemplateSequenceModel;
 import freemarker.template.utility.OptimizerUtil;

 /**
  * An object wrapper that wraps Jython objects into FreeMarker template models
  * and vice versa.
  */
 public class JythonWrapper implements ObjectWrapper {
     private static final Class PYOBJECT_CLASS = PyObject.class;
     public static final JythonWrapper INSTANCE = new JythonWrapper();

     private final ModelCache modelCache = new JythonModelCache(this);

     private boolean attributesShadowItems = true;

     public JythonWrapper() {
     }

     /**
      * Sets whether this wrapper caches model instances. Default is false.
      * When set to true, calling {@link #wrap(Object)} multiple times for
      * the same object will return the same model.
      */
     public void setUseCache(boolean useCache) {
         modelCache.setUseCache(useCache);
     }

     /**
      * Sets whether attributes shadow items in wrapped objects. When true
      * (this is the default value), <code>${object.name}</code> will first
      * try to locate a python attribute with the specified name on the object
      * using {@link PyObject#__findattr__(java.lang.String)}, and only if it
      * doesn't find the attribute will it call
      * {@link PyObject#__getitem__(org.python.core.PyObject)}.
      * When set to false, the lookup order is reversed and items
      * are looked up before attributes.
      */
     public synchronized void setAttributesShadowItems(boolean attributesShadowItems) {
         this.attributesShadowItems = attributesShadowItems;
     }

     boolean isAttributesShadowItems() {
         return attributesShadowItems;
     }

     /**
      * Wraps the passed Jython object into a FreeMarker template model. If
      * the object is not a Jython object, it's first coerced into one using
      * {@link Py#java2py(java.lang.Object)}. {@link PyDictionary} and {@link
      * PyStringMap} are wrapped into a hash model, {@link PySequence}
      * descendants are wrapped into a sequence model, {@link PyInteger}, {@link
      * PyLong}, and {@link PyFloat} are wrapped into a number model. All objects
      * are wrapped into a scalar model (using {@link Object#toString()} and a
      * boolean model (using {@link PyObject#__nonzero__()}. For internal
      * general-purpose {@link PyObject}s returned from a call to {@link
      * #unwrap(TemplateModel)}, the template model that was passed to
      * <code>unwrap</code> is returned.
      */
     public TemplateModel wrap(Object obj) {
         if (obj == null) {
             return null;
         }
         return modelCache.getInstance(obj);
     }

     /**
      * Coerces a template model into a {@link PyObject}.
      * @param model the model to coerce
      * @return the coerced model.
      * <ul>
      * <li>
      * <li>{@link AdapterTemplateModel}s (i.e. {@link freemarker.ext.beans.BeanModel}) are marshalled
      *   using the standard Python marshaller {@link Py#java2py(Object)} on
      *   the result of <code>getWrappedObject(PyObject.class)</code>s. The
      *   native JythonModel instances will just return the underlying PyObject.
      * <li>All other models that are {@link TemplateScalarModel scalars} are
      *   marshalled as {@link PyString}.
      * <li>All other models that are {@link TemplateNumberModel numbers} are
      *   marshalled using the standard Python marshaller
      *   {@link Py#java2py(Object)} on their underlying <code>Number</code></li>
      * <li>All other models  are marshalled to a generic internal
      *   <code>PyObject</code> subclass that'll correctly pass
      *   <code>__finditem__</code>, <code>__len__</code>,
      *   <code>__nonzero__</code>, and <code>__call__</code> invocations to
      *   appropriate hash, sequence, and method models.</li>
      * </ul>
      */
     public PyObject unwrap(TemplateModel model) throws TemplateModelException {
         if (model instanceof AdapterTemplateModel) {
             return Py.java2py(((AdapterTemplateModel) model).getAdaptedObject(
                     PYOBJECT_CLASS));
         }
         if (model instanceof WrapperTemplateModel) {
             return Py.java2py(((WrapperTemplateModel) model).getWrappedObject());
         }

         // Scalars are marshalled to PyString.
         if (model instanceof TemplateScalarModel) {
             return new PyString(((TemplateScalarModel) model).getAsString());
         }

         // Numbers are wrapped to Python built-in numeric types.
         if (model instanceof TemplateNumberModel) {
             Number number = ((TemplateNumberModel) model).getAsNumber();
             if (number instanceof BigDecimal) {
                 number = OptimizerUtil.optimizeNumberRepresentation(number);
             }
             if (number instanceof BigInteger) {
                 // Py.java2py can't automatically coerce a BigInteger into
                 // a PyLong. This will probably get fixed in later Jython
                 // release.
                 return new PyLong((BigInteger) number);
             } else {
                 return Py.java2py(number);
             }
         }
         // Return generic TemplateModel-to-Python adapter
         return new TemplateModelToJythonAdapter(model);
     }

     private class TemplateModelToJythonAdapter extends PyObject
     implements TemplateModelAdapter {
         private final TemplateModel model;

         TemplateModelToJythonAdapter(TemplateModel model) {
             this.model = model;
         }

         public TemplateModel getTemplateModel() {
             return model;
         }

         @Override
         public PyObject __finditem__(PyObject key) {
             if (key instanceof PyInteger) {
                 return __finditem__(((PyInteger) key).getValue());
             }
             return __finditem__(key.toString());
         }

         @Override
         public PyObject __finditem__(String key) {
             if (model instanceof TemplateHashModel) {
                 try {
                     return unwrap(((TemplateHashModel) model).get(key));
                 } catch (TemplateModelException e) {
                     throw Py.JavaError(e);
                 }
             }
             throw Py.TypeError("item lookup on non-hash model (" + getModelClass() + ")");
         }

         @Override
         public PyObject __finditem__(int index) {
             if (model instanceof TemplateSequenceModel) {
                 try {
                     return unwrap(((TemplateSequenceModel) model).get(index));
                 } catch (TemplateModelException e) {
                     throw Py.JavaError(e);
                 }
             }
             throw Py.TypeError("item lookup on non-sequence model (" + getModelClass() + ")");
         }

         @Override
         public PyObject __call__(PyObject args[], String keywords[]) {
             if (model instanceof TemplateMethodModel) {
                 boolean isEx = model instanceof TemplateMethodModelEx;
                 List list = new ArrayList(args.length);
                 try {
                     for (int i = 0; i < args.length; ++i) {
                         list.add(
                             isEx
                             ? (Object) wrap(args[i])
                             : (Object) (
                                 args[i] == null
                                 ? null
                                 : args[i].toString()));
                     }
                     return unwrap((TemplateModel) ((TemplateMethodModelEx) model).exec(list));
                 } catch (TemplateModelException e) {
                     throw Py.JavaError(e);
                 }
             }
             throw Py.TypeError("call of non-method model (" + getModelClass() + ")");
         }

         @Override
         public int __len__() {
             try {
                 if (model instanceof TemplateSequenceModel) {
                     return ((TemplateSequenceModel) model).size();
                 }
                 if (model instanceof TemplateHashModelEx) {
                     return ((TemplateHashModelEx) model).size();
                 }
             } catch (TemplateModelException e) {
                 throw Py.JavaError(e);
             }

             return 0;
         }

         @Override
         public boolean __nonzero__() {
             try {
                 if (model instanceof TemplateBooleanModel) {
                     return ((TemplateBooleanModel) model).getAsBoolean();
                 }
                 if (model instanceof TemplateSequenceModel) {
                     return ((TemplateSequenceModel) model).size() > 0;
                 }
                 if (model instanceof TemplateHashModel) {
                     return !((TemplateHashModelEx) model).isEmpty();
                 }
             } catch (TemplateModelException e) {
                 throw Py.JavaError(e);
             }
             return false;
         }

         private String getModelClass() {
             return model == null ? "null" : model.getClass().getName();
         }
     }
 }
	/*
	* 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 freemarker.ext.jython;

	import java.math.BigDecimal;
	import java.math.BigInteger;
	import java.util.ArrayList;
	import java.util.List;

	import org.python.core.Py;
	import org.python.core.PyDictionary;
	import org.python.core.PyFloat;
	import org.python.core.PyInteger;
	import org.python.core.PyLong;
	import org.python.core.PyObject;
	import org.python.core.PySequence;
	import org.python.core.PyString;
	import org.python.core.PyStringMap;

	import freemarker.ext.util.ModelCache;
	import freemarker.ext.util.WrapperTemplateModel;
	import freemarker.template.AdapterTemplateModel;
	import freemarker.template.ObjectWrapper;
	import freemarker.template.TemplateBooleanModel;
	import freemarker.template.TemplateHashModel;
	import freemarker.template.TemplateHashModelEx;
	import freemarker.template.TemplateMethodModel;
	import freemarker.template.TemplateMethodModelEx;
	import freemarker.template.TemplateModel;
	import freemarker.template.TemplateModelAdapter;
	import freemarker.template.TemplateModelException;
	import freemarker.template.TemplateNumberModel;
	import freemarker.template.TemplateScalarModel;
	import freemarker.template.TemplateSequenceModel;
	import freemarker.template.utility.OptimizerUtil;

	/**
	* An object wrapper that wraps Jython objects into FreeMarker template models
	* and vice versa.
	*/
	public class JythonWrapper implements ObjectWrapper {
	private static final Class PYOBJECT_CLASS = PyObject.class;
	public static final JythonWrapper INSTANCE = new JythonWrapper();

	private final ModelCache modelCache = new JythonModelCache(this);

	private boolean attributesShadowItems = true;

	public JythonWrapper() {
	}

	/**
	* Sets whether this wrapper caches model instances. Default is false.
	* When set to true, calling {@link #wrap(Object)} multiple times for
	* the same object will return the same model.
	*/
	public void setUseCache(boolean useCache) {
	modelCache.setUseCache(useCache);
	}

	/**
	* Sets whether attributes shadow items in wrapped objects. When true
	* (this is the default value), <code>${object.name}</code> will first
	* try to locate a python attribute with the specified name on the object
	* using {@link PyObject#__findattr__(java.lang.String)}, and only if it
	* doesn't find the attribute will it call
	* {@link PyObject#__getitem__(org.python.core.PyObject)}.
	* When set to false, the lookup order is reversed and items
	* are looked up before attributes.
	*/
	public synchronized void setAttributesShadowItems(boolean attributesShadowItems) {
	this.attributesShadowItems = attributesShadowItems;
	}

	boolean isAttributesShadowItems() {
	return attributesShadowItems;
	}

	/**
	* Wraps the passed Jython object into a FreeMarker template model. If
	* the object is not a Jython object, it's first coerced into one using
	* {@link Py#java2py(java.lang.Object)}. {@link PyDictionary} and {@link
	* PyStringMap} are wrapped into a hash model, {@link PySequence}
	* descendants are wrapped into a sequence model, {@link PyInteger}, {@link
	* PyLong}, and {@link PyFloat} are wrapped into a number model. All objects
	* are wrapped into a scalar model (using {@link Object#toString()} and a
	* boolean model (using {@link PyObject#__nonzero__()}. For internal
	* general-purpose {@link PyObject}s returned from a call to {@link
	* #unwrap(TemplateModel)}, the template model that was passed to
	* <code>unwrap</code> is returned.
	*/
	public TemplateModel wrap(Object obj) {
	if (obj == null) {
	return null;
	}
	return modelCache.getInstance(obj);
	}

	/**
	* Coerces a template model into a {@link PyObject}.
	* @param model the model to coerce
	* @return the coerced model.
	* <ul>
	* <li>
	* <li>{@link AdapterTemplateModel}s (i.e. {@link freemarker.ext.beans.BeanModel}) are marshalled
	* using the standard Python marshaller {@link Py#java2py(Object)} on
	* the result of <code>getWrappedObject(PyObject.class)</code>s. The
	* native JythonModel instances will just return the underlying PyObject.
	* <li>All other models that are {@link TemplateScalarModel scalars} are
	* marshalled as {@link PyString}.
	* <li>All other models that are {@link TemplateNumberModel numbers} are
	* marshalled using the standard Python marshaller
	* {@link Py#java2py(Object)} on their underlying <code>Number</code></li>
	* <li>All other models are marshalled to a generic internal
	* <code>PyObject</code> subclass that'll correctly pass
	* <code>__finditem__</code>, <code>__len__</code>,
	* <code>__nonzero__</code>, and <code>__call__</code> invocations to
	* appropriate hash, sequence, and method models.</li>
	* </ul>
	*/
	public PyObject unwrap(TemplateModel model) throws TemplateModelException {
	if (model instanceof AdapterTemplateModel) {
	return Py.java2py(((AdapterTemplateModel) model).getAdaptedObject(
	PYOBJECT_CLASS));
	}
	if (model instanceof WrapperTemplateModel) {
	return Py.java2py(((WrapperTemplateModel) model).getWrappedObject());
	}

	// Scalars are marshalled to PyString.
	if (model instanceof TemplateScalarModel) {
	return new PyString(((TemplateScalarModel) model).getAsString());
	}

	// Numbers are wrapped to Python built-in numeric types.
	if (model instanceof TemplateNumberModel) {
	Number number = ((TemplateNumberModel) model).getAsNumber();
	if (number instanceof BigDecimal) {
	number = OptimizerUtil.optimizeNumberRepresentation(number);
	}
	if (number instanceof BigInteger) {
	// Py.java2py can't automatically coerce a BigInteger into
	// a PyLong. This will probably get fixed in later Jython
	// release.
	return new PyLong((BigInteger) number);
	} else {
	return Py.java2py(number);
	}
	}
	// Return generic TemplateModel-to-Python adapter
	return new TemplateModelToJythonAdapter(model);
	}

	private class TemplateModelToJythonAdapter extends PyObject
	implements TemplateModelAdapter {
	private final TemplateModel model;

	TemplateModelToJythonAdapter(TemplateModel model) {
	this.model = model;
	}

	public TemplateModel getTemplateModel() {
	return model;
	}

	@Override
	public PyObject __finditem__(PyObject key) {
	if (key instanceof PyInteger) {
	return __finditem__(((PyInteger) key).getValue());
	}
	return __finditem__(key.toString());
	}

	@Override
	public PyObject __finditem__(String key) {
	if (model instanceof TemplateHashModel) {
	try {
	return unwrap(((TemplateHashModel) model).get(key));
	} catch (TemplateModelException e) {
	throw Py.JavaError(e);
	}
	}
	throw Py.TypeError("item lookup on non-hash model (" + getModelClass() + ")");
	}

	@Override
	public PyObject __finditem__(int index) {
	if (model instanceof TemplateSequenceModel) {
	try {
	return unwrap(((TemplateSequenceModel) model).get(index));
	} catch (TemplateModelException e) {
	throw Py.JavaError(e);
	}
	}
	throw Py.TypeError("item lookup on non-sequence model (" + getModelClass() + ")");
	}

	@Override
	public PyObject __call__(PyObject args[], String keywords[]) {
	if (model instanceof TemplateMethodModel) {
	boolean isEx = model instanceof TemplateMethodModelEx;
	List list = new ArrayList(args.length);
	try {
	for (int i = 0; i < args.length; ++i) {
	list.add(
	isEx
	? (Object) wrap(args[i])
	: (Object) (
	args[i] == null
	? null
	: args[i].toString()));
	}
	return unwrap((TemplateModel) ((TemplateMethodModelEx) model).exec(list));
	} catch (TemplateModelException e) {
	throw Py.JavaError(e);
	}
	}
	throw Py.TypeError("call of non-method model (" + getModelClass() + ")");
	}

	@Override
	public int __len__() {
	try {
	if (model instanceof TemplateSequenceModel) {
	return ((TemplateSequenceModel) model).size();
	}
	if (model instanceof TemplateHashModelEx) {
	return ((TemplateHashModelEx) model).size();
	}
	} catch (TemplateModelException e) {
	throw Py.JavaError(e);
	}

	return 0;
	}

	@Override
	public boolean __nonzero__() {
	try {
	if (model instanceof TemplateBooleanModel) {
	return ((TemplateBooleanModel) model).getAsBoolean();
	}
	if (model instanceof TemplateSequenceModel) {
	return ((TemplateSequenceModel) model).size() > 0;
	}
	if (model instanceof TemplateHashModel) {
	return !((TemplateHashModelEx) model).isEmpty();
	}
	} catch (TemplateModelException e) {
	throw Py.JavaError(e);
	}
	return false;
	}

	private String getModelClass() {
	return model == null ? "null" : model.getClass().getName();
	}
	}
	}