- /* $Id: VariableSubstitutor.java,v 1.8 2004/05/10 06:46:31 skitching Exp $
- *
- * Copyright 2003-2004 The Apache Software Foundation.
- *
- * Licensed 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.commons.digester.substitution;
-
- import org.apache.commons.digester.Substitutor;
-
- import org.xml.sax.Attributes;
-
- /**
- * Substitutor implementation that support variable replacement
- * for both attributes and body text.
- * The actual expansion of variables into text is delegated to {@link VariableExpander}
- * implementations.
- * Supports setting an expander just for body text or just for attributes.
- * Also supported is setting no expanders for body text and for attributes.
- *
- * @since 1.6
- */
- public class VariableSubstitutor extends Substitutor {
-
- /**
- * The expander to be used to expand variables in the attributes.
- * Null when no expansion should be performed.
- */
- private VariableExpander attributesExpander;
-
- /**
- * Attributes implementation that (lazily) performs variable substitution.
- * Will be lazily created when needed then reused.
- */
- private VariableAttributes variableAttributes;
-
- /**
- * The expander to be used to expand variables in the body text.
- * Null when no expansion should be performed.
- */
- private VariableExpander bodyTextExpander;
-
- /**
- * Constructs a Substitutor which uses the same VariableExpander for both
- * body text and attibutes.
- * @param expander VariableExpander implementation,
- * null if no substitutions are to be performed
- */
- public VariableSubstitutor(VariableExpander expander) {
- this(expander, expander);
- }
-
- /**
- * Constructs a Substitutor.
- * @param attributesExpander VariableExpander implementation to be used for attributes,
- * null if no attribute substitutions are to be performed
- * @param bodyTextExpander VariableExpander implementation to be used for bodyTextExpander,
- * null if no attribute substitutions are to be performed
- */
- public VariableSubstitutor(VariableExpander attributesExpander, VariableExpander bodyTextExpander) {
- this.attributesExpander = attributesExpander;
- this.bodyTextExpander = bodyTextExpander;
- variableAttributes = new VariableAttributes();
- }
-
- /**
- * Substitutes the attributes (before they are passed to the
- * <code>Rule</code> implementations's)
- */
- public Attributes substitute(Attributes attributes) {
- Attributes results = attributes;
- if (attributesExpander != null) {
- variableAttributes.init(attributes, attributesExpander);
- results = variableAttributes;
- }
- return results;
- }
-
- /**
- * Substitutes for the body text.
- * This method may substitute values into the body text of the
- * elements that Digester parses.
- *
- * @param bodyText the body text (as passed to <code>Digester</code>)
- * @return the body text to be passed to the <code>Rule</code> implementations
- */
- public String substitute(String bodyText) {
- String result = bodyText;
- if (bodyTextExpander != null) {
- result = bodyTextExpander.expand(bodyText);
- }
- return result;
- }
- }