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.strategy;
019    
020    import org.apache.commons.betwixt.ElementDescriptor;
021    import org.apache.commons.betwixt.XMLUtils;
022    
023    /**
024     * <p>Basic implementation for {@link MixedContentEncodingStrategy} 
025     * supports variations of most common use case.
026     * </p>
027     * <p>This supports subclasses that choose to encode body content
028     * either as a <code>CDATA</code> section or by escaping the characters.
029     * Implementations should override {@link #encodeAsCDATA}
030     * with an appropriate decision algorithm.
031     * </p>
032     * @author <a href='http://commons.apache.org/'>Apache Commons Team</a>
033     * @since 0.5
034     */
035    public abstract class BaseMixedContentEncodingStrategy
036        extends MixedContentEncodingStrategy {
037    
038        /**
039         * Escapes a sequence of body content.
040         * @param bodyContent the content whose character data should be escaped, 
041         * not null
042         * @return the escaped character data, not null
043         */
044        protected String escapeCharacters(String bodyContent) {
045            return XMLUtils.escapeBodyValue(bodyContent);
046        }
047        
048        /**
049         * Wraps the given content into a CDATA section.
050         * @param bodyContent the content to be encoded into a CDATA
051         * section
052         * @return the content wrapped inside a CDATA section, not null
053         */
054        protected String encodeInCDATA(String bodyContent) {
055            StringBuffer buffer = new StringBuffer(bodyContent);
056            buffer.ensureCapacity(12);
057            XMLUtils.escapeCDATAContent(buffer);
058            return buffer.insert(0, "<![CDATA[").append("]]>").toString();
059        }
060        
061        /**
062         * Encodes the given body content by either escaping the character data
063         * or by encoding within a <code>CDATA</code> section.
064         * The algorithm used to decide whether a particular element's mixed 
065         * should be escaped is delegated to the concrete subclass through
066         * {@link #encodeAsCDATA}
067         * @see org.apache.commons.betwixt.strategy.MixedContentEncodingStrategy#encode(java.lang.String, org.apache.commons.betwixt.ElementDescriptor)
068         */
069        public String encode(String bodyContent, ElementDescriptor element) {
070            if (encodeAsCDATA(element)) {
071                return encodeInCDATA(bodyContent);
072            }
073             
074            return escapeCharacters(bodyContent);
075        }
076    
077        /**
078         * <p>Should the element described by the given 
079         * <code>ElementDescriptor</code> be encoded as a <code>CDATA</code>
080         * section?
081         * </p>
082         * <p><strong>Usage:</strong> subclasses should provide a strategy
083         * to determine whether an element should be encoded using a 
084         * <code>CDATA</code> section.
085         * </p>
086         * 
087         * @param element <code>ElementDescriptor</code>, not null
088         * @return true if the element should be encoded 
089         * as a <code>CDATA</code> section
090         */
091        protected abstract boolean encodeAsCDATA(ElementDescriptor element);
092        
093    }