001 package org.apache.commons.digester3;
002
003 /*
004 * Licensed to the Apache Software Foundation (ASF) under one
005 * or more contributor license agreements. See the NOTICE file
006 * distributed with this work for additional information
007 * regarding copyright ownership. The ASF licenses this file
008 * to you under the Apache License, Version 2.0 (the
009 * "License"); you may not use this file except in compliance
010 * with the License. You may obtain a copy of the License at
011 *
012 * http://www.apache.org/licenses/LICENSE-2.0
013 *
014 * Unless required by applicable law or agreed to in writing,
015 * software distributed under the License is distributed on an
016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017 * KIND, either express or implied. See the License for the
018 * specific language governing permissions and limitations
019 * under the License.
020 */
021
022 import static java.lang.String.format;
023
024 import org.xml.sax.Attributes;
025
026 /**
027 * <p>
028 * Rule implementation that saves a parameter for use by a surrounding <code>CallMethodRule<code>.
029 * </p>
030 * <p>
031 * This parameter may be:
032 * <ul>
033 * <li>an arbitrary Object defined programatically, assigned when the element pattern associated with the Rule is
034 * matched. See {@link #ObjectParamRule(int paramIndex, Object param)}.
035 * <li>an arbitrary Object defined programatically, assigned if the element pattern AND specified attribute name are
036 * matched. See {@link #ObjectParamRule(int paramIndex, String attributeName, Object param)}.
037 * </ul>
038 * </p>
039 *
040 * @since 1.4
041 */
042 public class ObjectParamRule
043 extends Rule
044 {
045 // ----------------------------------------------------------- Constructors
046 /**
047 * Construct a "call parameter" rule that will save the given Object as the parameter value.
048 *
049 * @param paramIndex The zero-relative parameter number
050 * @param param the parameter to pass along
051 */
052 public ObjectParamRule( int paramIndex, Object param )
053 {
054 this( paramIndex, null, param );
055 }
056
057 /**
058 * Construct a "call parameter" rule that will save the given Object as the parameter value, provided that the
059 * specified attribute exists.
060 *
061 * @param paramIndex The zero-relative parameter number
062 * @param attributeName The name of the attribute to match
063 * @param param the parameter to pass along
064 */
065 public ObjectParamRule( int paramIndex, String attributeName, Object param )
066 {
067 this.paramIndex = paramIndex;
068 this.attributeName = attributeName;
069 this.param = param;
070 }
071
072 // ----------------------------------------------------- Instance Variables
073
074 /**
075 * The attribute which we are attempting to match
076 */
077 protected String attributeName = null;
078
079 /**
080 * The zero-relative index of the parameter we are saving.
081 */
082 protected int paramIndex = 0;
083
084 /**
085 * The parameter we wish to pass to the method call
086 */
087 protected Object param = null;
088
089 // --------------------------------------------------------- Public Methods
090
091 /**
092 * {@inheritDoc}
093 */
094 @Override
095 public void begin( String namespace, String name, Attributes attributes )
096 throws Exception
097 {
098 Object anAttribute = null;
099 Object parameters[] = getDigester().peekParams();
100
101 if ( attributeName != null )
102 {
103 anAttribute = attributes.getValue( attributeName );
104 if ( anAttribute != null )
105 {
106 parameters[paramIndex] = param;
107 }
108 // note -- if attributeName != null and anAttribute == null, this rule
109 // will pass null as its parameter!
110 }
111 else
112 {
113 parameters[paramIndex] = param;
114 }
115 }
116
117 /**
118 * {@inheritDoc}
119 */
120 @Override
121 public String toString()
122 {
123 return format( "ObjectParamRule[paramIndex=%s, attributeName=%s, param=%s]", paramIndex, attributeName, param );
124 }
125
126 }