svn commit: r369704 - in /struts/shale/trunk/core-library/src/java/org/apache/shale/util: ConverterHelper.java PropertyHelper.java

[cr...@apache.org]

Author: craigmcc
Date: Mon Jan 16 23:12:46 2006
New Revision: 369704

URL: http://svn.apache.org/viewcvs?rev=369704&view=rev
Log:
Add JSF-friendly helper beans to access property values and converters, so that
Shale code does not need to depend on commons-beanutils directly for these
purposes (although it currently inherits a transitive dependency by virtue
of the fact that it uses Commons Digester to parse configuration files).

Added:
    struts/shale/trunk/core-library/src/java/org/apache/shale/util/ConverterHelper.java   (with props)
    struts/shale/trunk/core-library/src/java/org/apache/shale/util/PropertyHelper.java   (with props)

Added: struts/shale/trunk/core-library/src/java/org/apache/shale/util/ConverterHelper.java
URL: http://svn.apache.org/viewcvs/struts/shale/trunk/core-library/src/java/org/apache/shale/util/ConverterHelper.java?rev=369704&view=auto
==============================================================================
--- struts/shale/trunk/core-library/src/java/org/apache/shale/util/ConverterHelper.java (added)
+++ struts/shale/trunk/core-library/src/java/org/apache/shale/util/ConverterHelper.java Mon Jan 16 23:12:46 2006
@@ -0,0 +1,100 @@
+/*
+ * Copyright 2006 The Apache Software Foundation.
+ *
+ * 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.apache.shale.util;
+
+import javax.faces.FacesException;
+import javax.faces.context.FacesContext;
+import javax.faces.convert.Converter;
+import javax.faces.convert.ConverterException;
+
+/**
+ * <p>Helper class to provide access to by-type JavaServer Faces
+ * <code>Converter</code> capabilities.  This implementation is stateless
+ * and maintains no cached information, so instances may be freely created
+ * and destroyed with no side effects.</p>
+ *
+ * $Id$
+ *
+ * @since 1.0.1
+ */
+public class ConverterHelper {
+    
+
+    // ---------------------------------------------------------- Public Methods
+
+
+    /**
+     * <p>Use the registered by-type <code>Converter</code> to convert the
+     * specified String value to a corresponding Object value.</p>
+     *
+     * @param context <code>FacesContext</code> for the current request
+     * @param type Type to which this value should be converted
+     *  (used to select the appropriate by-type converter)
+     * @param value Value to be converted
+     *
+     * @exception ConverterException if a conversion error occurs
+     */
+    public Object asObject(FacesContext context, Class type, String value) {
+
+        return converter(context, type).getAsObject(context, context.getViewRoot(), value);
+
+    }
+
+
+    /**
+     * <p>Use the registered by-type <code>Converter</code> to convert the
+     * specified Object value to a corresponding String value.</p>
+     *
+     * @param context <code>FacesContext</code> for the current request
+     * @param type Type from which this value should be converted
+     *  (used to select the appropriate by-type converter)
+     * @param value Value to be converted
+     *
+     * @exception ConverterException if a conversion error occurs
+     */
+    public String asString(FacesContext context, Class type, Object value) {
+
+        return converter(context, type).getAsString(context, context.getViewRoot(), value);
+
+    }
+
+
+    // --------------------------------------------------------- Private Methods
+
+
+    /**
+     * <p>Return an appropriate <code>Converter</code> instance for the
+     * specified type.</p>
+     *
+     * @param context <code>FacesContext</code> for the current request
+     * @param type Type for which to retrieve a <code>Converter</code>
+     *
+     * @exception ConverterException if no <code>Converter</code> has been
+     *  registered for the specified type
+     */
+    private Converter converter(FacesContext context, Class type) {
+
+        try {
+            return context.getApplication().createConverter(type);
+        } catch (FacesException e) {
+            throw new ConverterException(e);
+        }
+
+    }
+
+
+}

Propchange: struts/shale/trunk/core-library/src/java/org/apache/shale/util/ConverterHelper.java
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Propchange: struts/shale/trunk/core-library/src/java/org/apache/shale/util/ConverterHelper.java
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Added: struts/shale/trunk/core-library/src/java/org/apache/shale/util/PropertyHelper.java
URL: http://svn.apache.org/viewcvs/struts/shale/trunk/core-library/src/java/org/apache/shale/util/PropertyHelper.java?rev=369704&view=auto
==============================================================================
--- struts/shale/trunk/core-library/src/java/org/apache/shale/util/PropertyHelper.java (added)
+++ struts/shale/trunk/core-library/src/java/org/apache/shale/util/PropertyHelper.java Mon Jan 16 23:12:46 2006
@@ -0,0 +1,189 @@
+/*
+ * Copyright 2006 The Apache Software Foundation.
+ *
+ * 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.apache.shale.util;
+
+import java.beans.BeanInfo;
+import java.beans.IntrospectionException;
+import java.beans.Introspector;
+import java.beans.PropertyDescriptor;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import javax.faces.el.EvaluationException;
+import javax.faces.el.PropertyNotFoundException;
+
+/**
+ * <p>Helper class to provide access to the properties of JavaBeans.  This
+ * implementation is stateless and maintains no cached information, so
+ * instances may be freely created and destroyed, with no side effects
+ * (unless there are side effects from caching inside the JDK itself).</p>
+ *
+ * $Id$
+ *
+ * @since 1.0.1
+ */
+public class PropertyHelper {
+
+
+    // ---------------------------------------------------------- Public Methods
+
+
+    /**
+     * <p>Return the value of the specified property from the specified bean.</p>
+     *
+     * @param bean Bean whose property is to be retrieved
+     * @param name Name of the property to get
+     *
+     * @exception PropertyNotFoundException if the bean class does not have
+     *  a property with the specified name, or if the property is write only
+     * @exception EvaluationException if an exception occurs while
+     *  retrieving the property value
+     */
+    public Object getValue(Object bean, String name) {
+
+        PropertyDescriptor descriptor = descriptor(bean, name);
+        Method method = descriptor.getReadMethod();
+        if (method == null) {
+            throw new PropertyNotFoundException(name);
+        }
+
+        try {
+            return method.invoke(bean, new Object[0]);
+        } catch (InvocationTargetException e) {
+            throw new EvaluationException(e.getCause());
+        } catch (Exception e) {
+            throw new EvaluationException(e);
+        }
+
+    }
+
+
+    /**
+     * <p>Return <code>true</code> if the specified property is read only on
+     * the underlying bean class.</p>
+     *
+     * @param bean Bean whose property is to be checked
+     * @param name Name of the property to check
+     *
+     * @exception PropertyNotFoundException if the bean class does not have
+     *  a property with the specified name, or if the property is write only
+     * @exception EvaluationException if an exception occurs while
+     *  checking the read only status
+     */
+    public boolean isReadOnly(Object bean, String name) {
+
+        PropertyDescriptor descriptor = descriptor(bean, name);
+        if (descriptor.getReadMethod() != null) {
+            return descriptor.getWriteMethod() == null;
+        }
+        throw new PropertyNotFoundException(name);
+
+    }
+
+
+    /**
+     * <p>Return the type of the specified property on the underlying bean
+     * class.</p>
+     *
+     * @param bean Bean whose property is to be analyzed
+     * @param name Name of the property to return the type of
+     *
+     * @exception PropertyNotFoundException if the bean class does not have
+     *  a property with the specified name
+     * @exception EvaluationException if an exception occurs while
+     *  retrieving the property type
+     */
+    public Class getType(Object bean, String name) {
+
+        PropertyDescriptor descriptor = descriptor(bean, name);
+        return descriptor.getPropertyType();
+
+    }
+
+
+    /**
+     * <p>Set the specified value on the specified property of the specified
+     * bean.</p>
+     *
+     * @param bean Bean whose property is to be set
+     * @param name Name of the property to be set
+     * @param value New value for this property
+     *
+     * @exception PropertyNotFoundException if the bean class does not have
+     *  a property with the specified name, or if the property is read only
+     * @exception EvaluationException if an exception occurs while
+     *  setting the property value
+     */
+    public void setValue(Object bean, String name, Object value) {
+
+        PropertyDescriptor descriptor = descriptor(bean, name);
+        Method method = descriptor.getWriteMethod();
+        if (method == null) {
+            throw new PropertyNotFoundException(name);
+        }
+
+        try {
+            method.invoke(bean, new Object[] { value });
+        } catch (InvocationTargetException e) {
+            throw new EvaluationException(e.getCause());
+        } catch (Exception e) {
+            throw new EvaluationException(e);
+        }
+
+    }
+
+
+    // ------------------------------------------------------- Private Methods
+
+
+    /**
+     * <p>Return the <code>PropertyDescriptor</code> for the specified
+     * property of the specified class.</p>
+     *
+     * @param bean Bean whose property descriptor is to be returned
+     * @param name Name of the property to retrieve a descrpitor for
+     *
+     * @exception PropertyNotFoundException if the bean class does not have
+     *  a property with the specified name
+     * @exception EvaluationException if an exception occurs introspecting
+     *  the underlying bean class
+     */
+    private PropertyDescriptor descriptor(Object bean, String name) {
+
+        BeanInfo beanInfo = null;
+        try {
+            Introspector.getBeanInfo(bean.getClass());
+        } catch (IntrospectionException e) {
+            throw new EvaluationException(e);
+        }
+
+        PropertyDescriptor descriptors[] = beanInfo.getPropertyDescriptors();
+        if (descriptors == null) {
+            descriptors = new PropertyDescriptor[0];
+        }
+        for (int i = 0; i < descriptors.length; i++) {
+            if (name.equals(descriptors[i].getName())) {
+                return descriptors[i];
+            }
+            return descriptors[i];
+        }
+
+        throw new PropertyNotFoundException(name);
+
+    }
+    
+    
+}

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