/**
* 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.lucene.gdata.search.analysis;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.Field.Index;
import org.apache.lucene.document.Field.Store;
import org.apache.lucene.gdata.data.ServerBaseEntry;
import org.apache.lucene.gdata.search.config.IndexSchemaField;
import org.apache.lucene.gdata.search.config.IndexSchemaField.ContentType;
import org.apache.lucene.gdata.search.index.GdataIndexerException;
import org.apache.lucene.gdata.utils.ReflectionUtils;
import org.w3c.dom.Node;
/**
* Creating Indexable document requires processing of incoming entities as
* GData Entries. Entries in the GData protocol might have very different
* structures and content. They all have on thing in common as they are atom xml
* format. To retrieve the configured elements of the atom format and process the
* actual content might differ from element to element.
* <p>
* Each predefined ContentStrategy can be used to retrieve certain content from
* the defined element. Which element to process is defined using a XPath
* expression in the gdata-config.xml file.
* </p>
* <p>
* <tt>ContentStrategy</tt> implementation should not be accessed directly. To
* get a <tt>ContentStrategy</tt> for a specific
* {@link org.apache.lucene.gdata.search.config.IndexSchemaField.ContentType}
* use the {@link ContentStrategy#getFieldStrategy} factory method. This method
* expects a IndexSchemaField instance with a set <tt>ContentType</tt>. The
* return value is a new <tt>ContentStrategy</tt> instance for the defined
* <tt>ContentType</tt>.
* </p>
*
* @see org.apache.lucene.gdata.search.config.IndexSchemaField.ContentType
* @see org.apache.lucene.gdata.search.index.IndexDocumentBuilder
*
* @author Simon Willnauer
*/
public abstract class ContentStrategy {
protected final Store store;
protected final Index index;
protected final IndexSchemaField config;
protected String content;
protected String fieldName;
protected ContentStrategy(IndexSchemaField fieldConfiguration) {
this(null, null, fieldConfiguration);
}
protected ContentStrategy(Index index, Store store,
IndexSchemaField fieldConfig) {
if(fieldConfig == null)
throw new IllegalArgumentException("IndexSchemaField must not be null");
this.config = fieldConfig;
this.fieldName = fieldConfig.getName();
if (index != null) {
this.index = index;
} else {
this.index = fieldConfig.getIndex() == null ? IndexSchemaField.DEFAULT_INDEX_STRATEGY
: fieldConfig.getIndex();
}
if (store != null) {
this.store = store;
} else {
this.store = fieldConfig.getStore() == null ? IndexSchemaField.DEFAULT_STORE_STRATEGY
: fieldConfig.getStore();
}
}
/**
* @param indexable
* @throws NotIndexableException
*/
public abstract void processIndexable(
Indexable<? extends Node, ? extends ServerBaseEntry> indexable)
throws NotIndexableException;
/**
* This method creates a lucene field from the retrieved content of the
* entity. Values for Field.Index, Field.Store, the field name and the boost
* factor are configured in the <tt>IndexSchemaField</tt> passed by the
* constructor e.g the factory method. This method might be overwritten by
* subclasses.
*
* @return the Lucene {@link Field}
*/
public Field[] createLuceneField() {
/*
* should I test the content for being empty?!
* does that make any difference if empty fields are indexed?!
*/
if(this.fieldName==null|| this.content == null)
throw new GdataIndexerException("Required field not set fieldName: "+this.fieldName+" content: "+this.content);
if(this.content.length()==0){
return new Field[0];
}
Field retValue = new Field(this.fieldName, this.content, this.store,
this.index);
float boost = this.config.getBoost();
if (boost != 1.0f)
retValue.setBoost(boost);
return new Field[]{retValue};
}
/**
* This factory method creates the <tt>ContentStrategy</tt> corresponding
* to the set <tt>ContentType</tt> value in the <tt>IndexSchemaField</tt>
* passed to the method as the single parameter.
* <p>
* The ContentType must not be null
* </p>
*
* @param fieldConfig -
* the field config to use to identify the corresponding
* <tt>ContentStrategy</tt>
* @return - a new <tt>ContentStrategy</tt> instance
*/
public static ContentStrategy getFieldStrategy(IndexSchemaField fieldConfig) {
if (fieldConfig == null)
throw new IllegalArgumentException(
"field configuration must not be null");
ContentType type = fieldConfig.getContentType();
if (type == null)
throw new IllegalArgumentException(
"ContentType in IndexSchemaField must not be null");
fieldConfig.getAnalyzerClass();
switch (type) {
case CATEGORY:
return new GdataCategoryStrategy(fieldConfig);
case HTML:
return new HTMLStrategy(fieldConfig);
case XHTML:
return new XHtmlStrategy(fieldConfig);
case GDATADATE:
return new GdataDateStrategy(fieldConfig);
case TEXT:
return new PlainTextStrategy(fieldConfig);
case KEYWORD:
return new KeywordStrategy(fieldConfig);
case CUSTOM:
/*
* check if this class can be created with default constructor is checked
* in IndexSchemaField#setFieldClass and throws RuntimeEx if not. So
* server can not start up.
*/
return ReflectionUtils.getDefaultInstance(fieldConfig
.getFieldClass());
case MIXED:
return new MixedContentStrategy(fieldConfig);
default:
throw new RuntimeException("No content strategy found for " + type);
}
}
}
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