| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF 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 |
| * |
| * 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.apache.ant.props; |
| |
| import java.text.ParsePosition; |
| |
| import org.apache.tools.ant.Project; |
| import org.apache.tools.ant.property.ParseNextProperty; |
| import org.apache.tools.ant.property.PropertyExpander; |
| |
| /** |
| * By popular demand: Nested property expander. |
| */ |
| public class NestedPropertyExpander implements PropertyExpander { |
| private static final NestedPropertyExpander INSTANCE = new NestedPropertyExpander(); |
| |
| /** |
| * Parse the next property name. |
| * @param value the String to parse. |
| * @param pos the ParsePosition in use. |
| * @param parseNextProperty parse next property |
| * @return parsed String if any, else <code>null</code>. |
| */ |
| public String parsePropertyName(String value, ParsePosition pos, |
| ParseNextProperty parseNextProperty) { |
| int start = pos.getIndex(); |
| if (value.length() - start >= 3 |
| && '$' == value.charAt(start) && '{' == value.charAt(start + 1)) { |
| parseNextProperty.getProject().log("Attempting nested property processing", |
| Project.MSG_DEBUG); |
| pos.setIndex(start + 2); |
| StringBuffer sb = new StringBuffer(); |
| for (int c = pos.getIndex(); c < value.length(); c = pos.getIndex()) { |
| if (value.charAt(c) == '}') { |
| pos.setIndex(c + 1); |
| return sb.toString(); |
| } |
| Object o = parseNextProperty.parseNextProperty(value, pos); |
| if (o != null) { |
| sb.append(o); |
| } else { |
| // be aware that the parse position may now have changed; |
| // update: |
| c = pos.getIndex(); |
| sb.append(value.charAt(c)); |
| pos.setIndex(c + 1); |
| } |
| } |
| } |
| pos.setIndex(start); |
| return null; |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean equals(Object obj) { |
| return obj == this || obj instanceof NestedPropertyExpander && obj.hashCode() == hashCode(); |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public int hashCode() { |
| if (NestedPropertyExpander.class.equals(getClass())) { |
| return System.identityHashCode(INSTANCE); |
| } |
| throw new UnsupportedOperationException("Get your own hashCode implementation!"); |
| } |
| } |