7 Replies Latest reply on Aug 16, 2007 1:35 PM by mgrouch

    EL functions library

    mgrouch Expert

      Here are few additional EL functions I couldn't live without.
      (Might be they could be included into Seam code base)

      package org.el.func;
      
      import java.lang.reflect.InvocationTargetException;
      import java.text.SimpleDateFormat;
      import java.util.Collection;
      import java.util.Date;
      
      import org.apache.commons.beanutils.PropertyUtils;
      import org.jboss.seam.Entity;
      import org.jboss.seam.core.Expressions;
      
      public class SeamFunc {
      
       public static Object getId(Object bean) {
       Class<?> clazz = bean.getClass();
       if (!clazz.isAnnotationPresent(javax.persistence.Entity.class)) {
       // this better be instrumented proxy class
       clazz = clazz.getSuperclass();
       }
       return Entity.forClass(clazz).getIdentifier(bean);
       }
      
       public static String toString(Object obj) {
       return "" + obj;
       }
      
       public static Object[] toArray(Collection<Object> collect) {
       if (collect == null) {
       return null;
       } else {
       return collect.toArray();
       }
       }
      
       public static int size(Collection<Object> collect) {
       if (collect == null) {
       return 0;
       } else {
       return collect.size();
       }
       }
      
       public static boolean isBlank(String str) {
       if (str == null) {
       return true;
       } else {
       return "".equals(str.trim());
       }
       }
      
       public static String trunc(String str, int len) {
       if (str == null) {
       return null;
       } else {
       return str.substring(0, len);
       }
       }
      
       public static String concat(String... strings) {
       StringBuilder buff = new StringBuilder();
       if (strings != null) {
       for (String str : strings) {
       buff.append(str);
       }
       }
       return buff.toString();
       }
      
       public static boolean matches(String str, String regex) {
       if (str == null) {
       return false;
       } else {
       return str.matches(regex);
       }
       }
      
       public static String formatDate(Date date, String pattern) {
       if (date == null) {
       return null;
       }
       else {
       return new SimpleDateFormat(pattern).format(date);
       }
       }
      
       public static String getProperty(String propName) {
       return System.getProperty(propName);
       }
      
       public static String getEnv(String varName) {
       return System.getenv(varName);
       }
      
       public static Object getBeanProperty(Object bean, String propName) {
       Object obj = null;
       try {
       obj = PropertyUtils.getProperty(bean, propName);
       } catch (IllegalAccessException ex) {
       throw new RuntimeException(ex);
       } catch (InvocationTargetException ex) {
       throw new RuntimeException(ex);
       } catch (NoSuchMethodException ex) {
       throw new RuntimeException(ex);
       }
       return obj;
       }
      
       public static Object evalEl(String expression) {
       String framedExpr = "#{" + expression + "}";
       Object value = Expressions.instance().createValueBinding(framedExpr).getValue();
       return value;
       }
      }
      



      /**
       * Licensed under the Common Development and Distribution License,
       * you may not use this file except in compliance with the License.
       * You may obtain a copy of the License at
       *
       * http://www.sun.com/cddl/
       *
       * 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.el.func;
      
      import java.lang.reflect.Method;
      import java.lang.reflect.Modifier;
      import java.util.HashMap;
      import java.util.Map;
      
      import javax.faces.FacesException;
      
      import com.sun.facelets.tag.TagConfig;
      import com.sun.facelets.tag.TagHandler;
      import com.sun.facelets.tag.TagLibrary;
      
      public class FnLibrary implements TagLibrary {
      
       public final static String Namespace = "http://org.el.func/func";
      
       private final Map<String, Method> fns = new HashMap<String, Method>();
      
       public FnLibrary() {
       super();
       try {
       Method[] methods = SeamFunc.class.getMethods();
       putMethods(methods);
       } catch (Exception e) {
       throw new RuntimeException(e);
       }
       }
      
       private void putMethods(Method[] methods) {
       for (int i = 0; i < methods.length; i++) {
       if (Modifier.isStatic(methods.getModifiers())) {
       fns.put(methods.getName(), methods);
       }
       }
       }
      
       public boolean containsNamespace(String ns) {
       return Namespace.equals(ns);
       }
      
       public boolean containsTagHandler(String ns, String localName) {
       return false;
       }
      
       public TagHandler createTagHandler(String ns, String localName,
       TagConfig tag) throws FacesException {
       return null;
       }
      
       public boolean containsFunction(String ns, String name) {
       if (Namespace.equals(ns)) {
       return this.fns.containsKey(name);
       }
       return false;
       }
      
       public Method createFunction(String ns, String name) {
       if (Namespace.equals(ns)) {
       return (Method) this.fns.get(name);
       }
       return null;
       }
      
       public static void main(String[] argv) {
       FnLibrary lib = new FnLibrary();
       System.out.println(lib.containsFunction(FnLibrary.Namespace, "isBlank"));
       }
       }
      


      META-INF/elfunc.taglib.xml
      <facelet-taglib>
       <library-class>org.el.func.FnLibrary</library-class>
      </facelet-taglib>