package org.apache.commons.digester3.substitution;

/*
 * 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.
 */

import org.apache.commons.digester3.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 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/**
 * 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.
/**
     * The expander to be used to expand variables in the attributes. Null when no expansion should be performed.
     */
    private final VariableExpander attributesExpander;

    
Attributes implementation that (lazily) performs variable substitution. Will be lazily created when needed then
reused.
/**
     * Attributes implementation that (lazily) performs variable substitution. Will be lazily created when needed then
     * reused.
     */
    private final VariableAttributes variableAttributes;

    
The expander to be used to expand variables in the body text. Null when no expansion should be performed.
/**
     * The expander to be used to expand variables in the body text. Null when no expansion should be performed.
     */
    private final VariableExpander bodyTextExpander;

    
Constructs a Substitutor which uses the same VariableExpander for both body text and attibutes.
Params:
expander – VariableExpander implementation, null if no substitutions are to be performed/**
     * 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.
Params:
attributesExpander – VariableExpander implementation to be used for attributes, null if no attribute
           substitutions are to be performed
bodyTextExpander – VariableExpander implementation to be used for bodyTextExpander, null if no attribute
           substitutions are to be performed/**
     * 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();
    }

    
{@inheritDoc}
/**
     * {@inheritDoc}
     */
    @Override
    public Attributes substitute( Attributes attributes )
    {
        Attributes results = attributes;
        if ( attributesExpander != null )
        {
            variableAttributes.init( attributes, attributesExpander );
            results = variableAttributes;
        }
        return results;
    }

    
{@inheritDoc}
/**
     * {@inheritDoc}
     */
    @Override
    public String substitute( String bodyText )
    {
        String result = bodyText;
        if ( bodyTextExpander != null )
        {
            result = bodyTextExpander.expand( bodyText );
        }
        return result;
    }

}