Java tutorial
/** * Licensed to Apereo under one or more contributor license * agreements. See the NOTICE file distributed with this work * for additional information regarding copyright ownership. * Apereo 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 the following location: * * 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.jasig.portlet.spring; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.expression.AccessException; import org.springframework.expression.EvaluationContext; import org.springframework.expression.PropertyAccessor; import org.springframework.expression.TypedValue; /** * @author Josh Helmer, jhelmer@unicon.net * * Property accessor that tries to log an error and provide a default value * if a property can not be found. * * Limitation: the accessor only gets access to the leaf property name. If * you have a property like: user.login.id, this will only be able to print * "${id}" In the future need to revisit to try and find a more flexible * mechanism for handling without just throwing an exception. */ public class DefaultPropertyAccessor implements PropertyAccessor { protected Logger logger = LoggerFactory.getLogger(getClass()); private String leading; private String trailing; public DefaultPropertyAccessor(final String leading, final String trailing) { this.leading = leading; this.trailing = trailing; } @Override public Class[] getSpecificTargetClasses() { return new Class[] { Object.class }; } @Override public boolean canRead(EvaluationContext evaluationContext, Object o, String s) throws AccessException { return true; } @Override public TypedValue read(EvaluationContext evaluationContext, Object o, String s) throws AccessException { logger.error("Property '" + s + "' not found!"); return new TypedValue(leading + s + trailing); } @Override public boolean canWrite(EvaluationContext evaluationContext, Object o, String s) throws AccessException { return false; } @Override public void write(EvaluationContext evaluationContext, Object o, String s, Object o2) throws AccessException { } }