Common static utility methods that help in implementing JSF tags
/**********************************************************************************
* $URL: https://source.sakaiproject.org/svn/jsf/branches/sakai_2-5-4/widgets/src/java/org/sakaiproject/jsf/util/TagUtil.java $
* $Id: TagUtil.java 9278 2006-05-10 23:29:21Z ray@media.berkeley.edu $
**********************************************************************************
*
* Copyright (c) 2003, 2004 The Sakai Foundation.
*
* Licensed under the Educational Community License, Version 1.0 (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.opensource.org/licenses/ecl1.php
*
* 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.
*
**********************************************************************************/
import java.io.Serializable;
import java.util.HashMap;
import javax.faces.application.Application;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.el.MethodBinding;
import javax.faces.el.ValueBinding;
import javax.faces.event.ActionEvent;
import javax.faces.event.ValueChangeEvent;
import javax.faces.webapp.UIComponentTag;
/**
* Common static utility methods that help in implementing JSF tags.
*/
public class TagUtil
{
/** This class is meant for static use only */
private TagUtil()
{
}
/**
* Set a string value on a component - used by tags setProperties() method.
* Handles value bindings.
*/
public static void setString(UIComponent component, String name, String value)
{
if (value == null)
{
return;
}
if (UIComponentTag.isValueReference(value))
{
setValueBinding(component, name, value);
} else
{
component.getAttributes().put(name, value);
}
}
/**
* Set a string value on a component - used by tags setProperties() method.
* Handles value bindings.
*/
public static void setObject(UIComponent component, String name, String value)
{
if (value == null)
{
return;
}
if (UIComponentTag.isValueReference(value))
{
setValueBinding(component, name, value);
} else
{
component.getAttributes().put(name, value);
}
}
/**
* Set an integer value on a component - used by tags setProperties()
* method. Handles value bindings.
*/
public static void setInteger(UIComponent component, String name, String value)
{
if (value == null)
{
return;
}
if (UIComponentTag.isValueReference(value))
{
setValueBinding(component, name, value);
} else
{
component.getAttributes().put(name, Integer.valueOf(value));
}
}
/**
* Set a Map value on a component - used by tags setProperties() method.
* Handles value bindings.
*/
public static void setMap(UIComponent component, String name, String value)
{
if (value == null)
{
return;
}
if (UIComponentTag.isValueReference(value))
{
setValueBinding(component, name, value);
} else
{
component.getAttributes().put(name, new HashMap());
}
}
/**
* Set a double value on a component - used by tags setProperties() method.
* Handles value bindings.
*/
public static void setDouble(UIComponent component, String name, String value)
{
if (value == null)
{
return;
}
if (UIComponentTag.isValueReference(value))
{
setValueBinding(component, name, value);
} else
{
component.getAttributes().put(name, Double.valueOf(value));
}
}
/**
* Set a boolean value on a component - used by tags setProperties() method.
* Handles value bindings.
*/
public static void setBoolean(UIComponent component, String name, String value)
{
if (value == null)
{
return;
}
if (UIComponentTag.isValueReference(value))
{
setValueBinding(component, name, value);
} else
{
component.getAttributes().put(name, Boolean.valueOf(value));
}
}
/**
* Set a ValueBinding on a component - used by tags setProperties() method.
*/
public static void setValueBinding(UIComponent component, String name, String value)
{
FacesContext context = FacesContext.getCurrentInstance();
Application app = context.getApplication();
ValueBinding vb = app.createValueBinding(value);
component.setValueBinding(name, vb);
}
/**
* Set an ActionListener on a component - used by tags setProperties()
* method. Handles method bindings.
*/
public static void setActionListener(UIComponent component, String value)
{
setMethodBinding(component, "actionListener", value, new Class[] { ActionEvent.class });
}
/**
* Set a ValueChangeListener on a component - used by tags setProperties()
* method. Handles method bindings.
*/
public static void setValueChangeListener(UIComponent component, String value)
{
setMethodBinding(component, "valueChangeListener", value,
new Class[] { ValueChangeEvent.class });
}
/**
* Set a Validator on a component - used by tags setProperties() method.
* Handles method bindings.
*/
public static void setValidator(UIComponent component, String value)
{
setMethodBinding(component, "validator", value, new Class[] { FacesContext.class,
UIComponent.class, Object.class });
}
/**
* Set an action on a component - used by tags setProperties() method.
* Handles method bindings.
*/
public static void setAction(UIComponent component, String value)
{
if (value == null)
{
return;
}
if (UIComponentTag.isValueReference(value))
{
setMethodBinding(component, "action", value, new Class[] {});
} else
{
FacesContext context = FacesContext.getCurrentInstance();
Application app = context.getApplication();
MethodBinding mb = new ActionMethodBinding(value);
component.getAttributes().put("action", mb);
}
}
/**
* Set a MethodBinding on a component - used by tags setProperties() method.
*/
public static void setMethodBinding(UIComponent component, String name, String value,
Class[] paramTypes)
{
if (value == null)
{
return;
}
if (UIComponentTag.isValueReference(value))
{
FacesContext context = FacesContext.getCurrentInstance();
Application app = context.getApplication();
MethodBinding mb = app.createMethodBinding(value, paramTypes);
component.getAttributes().put(name, mb);
}
}
public static String eval(String expression)
{
if (expression == null)
{
return null;
}
if (UIComponentTag.isValueReference(expression))
{
FacesContext context = FacesContext.getCurrentInstance();
Application app = context.getApplication();
return "" + app.createValueBinding(expression).getValue(context);
} else
{
return expression;
}
}
public static Integer evalInteger(String expression)
{
if (expression == null)
{
return null;
}
if (UIComponentTag.isValueReference(expression))
{
FacesContext context = FacesContext.getCurrentInstance();
Application app = context.getApplication();
Object r = app.createValueBinding(expression).getValue(context);
if (r == null)
{
return null;
} else if (r instanceof Integer)
{
return (Integer) r;
} else
{
return Integer.valueOf(r.toString());
}
} else
{
return Integer.valueOf(expression);
}
}
public static Double evalDouble(String expression)
{
if (expression == null)
{
return null;
}
if (UIComponentTag.isValueReference(expression))
{
FacesContext context = FacesContext.getCurrentInstance();
Application app = context.getApplication();
Object r = app.createValueBinding(expression).getValue(context);
if (r == null)
{
return null;
} else if (r instanceof Double)
{
return (Double) r;
} else
{
return Double.valueOf(r.toString());
}
} else
{
return Double.valueOf(expression);
}
}
public static Boolean evalBoolean(String expression)
{
if (expression == null)
{
return null;
}
if (UIComponentTag.isValueReference(expression))
{
FacesContext context = FacesContext.getCurrentInstance();
Application app = context.getApplication();
Object r = app.createValueBinding(expression).getValue(context);
if (r == null)
{
return null;
} else if (r instanceof Boolean)
{
return (Boolean) r;
} else
{
return Boolean.valueOf(r.toString());
}
} else
{
return Boolean.valueOf(expression);
}
}
/**
* A shortcut MethodBinding which just returns a single string result -
* useful when an action should just return a certain result, not call a
* method.
*/
private static class ActionMethodBinding extends MethodBinding implements Serializable
{
private String result;
public ActionMethodBinding(String result)
{
this.result = result;
}
public Object invoke(FacesContext context, Object params[])
{
return result;
}
public String getExpressionString()
{
return result;
}
public Class getType(FacesContext context)
{
return String.class;
}
}
}
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