001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018 package org.apache.commons.betwixt.expression; 019 020 import org.apache.commons.beanutils.DynaBean; 021 022 /** 023 * An Expression that gets a property value from a DynaBean. 024 * 025 * @see org.apache.commons.beanutils.DynaBean 026 * 027 * @author Michael Becke 028 * @since 0.5 029 */ 030 public class DynaBeanExpression implements Expression { 031 032 /** The name of the DynaBean property to get */ 033 private String propertyName; 034 035 /** 036 * Crates a new DynaBeanExpression. 037 */ 038 public DynaBeanExpression() { 039 super(); 040 } 041 042 /** 043 * Crates a new DynaBeanExpression. 044 * 045 * @param propertyName the name of the DynaBean property to use 046 */ 047 public DynaBeanExpression(String propertyName) { 048 super(); 049 setPropertyName(propertyName); 050 } 051 052 /** 053 * Returns the value of a DynaBean property from the bean stored in 054 * the Context. Returns <code>null</code> if no DynaBean is stored 055 * in the Context or if the propertyName has not been set. 056 * 057 * @param context the content containing the DynaBean 058 * 059 * @return the DynaBean property value or <code>null</code> 060 */ 061 public Object evaluate(Context context) { 062 063 if (context.getBean() instanceof DynaBean && propertyName != null) { 064 return ((DynaBean)context.getBean()).get(propertyName); 065 } else { 066 return null; 067 } 068 } 069 070 /** 071 * Do nothing. 072 * @see Expression#update 073 */ 074 public void update(Context context, String newValue) { 075 // do nothing 076 } 077 078 /** 079 * Gets the name of the property to get from the DynaBean. 080 * @return the name of the property that this expression reads 081 */ 082 public String getPropertyName() { 083 return propertyName; 084 } 085 086 /** 087 * Sets the name of the property to get from the DynaBean. 088 * @param propertyName the property that this expression reads, not null 089 */ 090 public void setPropertyName(String propertyName) { 091 if (propertyName == null) { 092 throw new IllegalArgumentException("propertyName is null"); 093 } 094 this.propertyName = propertyName; 095 } 096 097 }