SOLR-248 -- Added CapitalizationFilterFactory

git-svn-id: https://svn.apache.org/repos/asf/lucene/solr/trunk@556196 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -100,6 +100,10 @@ New Features
     backwards compatibility.
     (Will Johnson via hossman)
     
+17. SOLR-248: Added CapitalizationFilterFactory that creates tokens with 
+    normalized capitalization.  This filter is useful for facet display,
+    but will not work with a prefix query.  (ryan)
+    
 Changes in runtime behavior
 
 Optimizations

src/java/org/apache/solr/analysis/CapitalizationFilterFactory.java

@@ -0,0 +1,214 @@
+/**
+ * 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.solr.analysis;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.StringTokenizer;
+
+import org.apache.lucene.analysis.Token;
+import org.apache.lucene.analysis.TokenFilter;
+import org.apache.lucene.analysis.TokenStream;
+import org.apache.solr.analysis.BaseTokenFilterFactory;
+
+/**
+ * A filter to apply normal capitalization rules to Tokens.  It will make the first letter
+ * capital and the rest lower case.  
+ * 
+ * This filter is particularly useful to build nice looking facet parameters.  This filter
+ * is not appropriate if you intend to use a prefix query.
+ * 
+ * The factory takes parameters:
+ * "onlyFirstWord" - should each word be capitalized or all of the words?
+ * "keep" - a keep word list.  Each word that should be kept separated by whitespace.
+ * "okPrefix" - do not change word capitalization if a word begins with something in this list.
+ *   for example if "McK" is on the okPrefix list, the word "McKinley" should not be changed to
+ *   "Mckinley"
+ * "minWordLength" - how long the word needs to be to get capitalization applied.  If the 
+ *   minWordLength is 3, "and" > "And" but "or" stays "or"
+ * "maxWordCount" - if the token contains more then maxWordCount words, the capitalization is
+ *   assumed to be correct.
+ * 
+ * @since solr 1.3
+ * @version $Id$
+ */
+public class CapitalizationFilterFactory extends BaseTokenFilterFactory 
+{
+  public static final String KEEP = "keep";
+  public static final String OK_PREFIX = "okPrefix";
+  public static final String MIN_WORD_LENGTH = "minWordLength";
+  public static final String MAX_WORD_COUNT = "maxWordCount";
+  public static final String MAX_TOKEN_LENGTH = "maxTokenLength";
+  public static final String ONLY_FIRST_WORD = "onlyFirstWord";
+  public static final String FORCE_FIRST_LETTER = "forceFirstLetter";
+  
+  Map<String,String> keep = new HashMap<String, String>(); // not synchronized because it is only initialized once
+  
+  Collection<String> okPrefix = new ArrayList<String>(); // for Example: McK
+  
+  int minWordLength = 0;  // don't modify capitalization for words shorter then this
+  int maxWordCount  = Integer.MAX_VALUE;
+  int maxTokenLength = Integer.MAX_VALUE;
+  boolean onlyFirstWord = true;
+  boolean forceFirstLetter = true; // make sure the first letter is capitol even if it is in the keep list
+  
+  @Override
+  public void init(Map<String,String> args) {
+    super.init( args );
+    
+    String k = args.get( KEEP );
+    if( k != null ) {
+      StringTokenizer st = new StringTokenizer( k );
+      while( st.hasMoreTokens() ) {
+        k = st.nextToken().trim();
+        keep.put( k.toUpperCase(), k );
+      }
+    }
+    
+    k = args.get( OK_PREFIX );
+    if( k != null ) {
+      StringTokenizer st = new StringTokenizer( k );
+      while( st.hasMoreTokens() ) {
+        okPrefix.add( st.nextToken().trim() );
+      }
+    }
+    
+    k = args.get( MIN_WORD_LENGTH );
+    if( k != null ) {
+      minWordLength = Integer.valueOf( k );
+    }
+
+    k = args.get( MAX_WORD_COUNT );
+    if( k != null ) {
+      maxWordCount = Integer.valueOf( k );
+    }
+
+    k = args.get( MAX_TOKEN_LENGTH );
+    if( k != null ) {
+      maxTokenLength = Integer.valueOf( k );
+    }
+
+    k = args.get( ONLY_FIRST_WORD );
+    if( k != null ) {
+      onlyFirstWord = Boolean.valueOf( k );
+    }
+
+    k = args.get( FORCE_FIRST_LETTER );
+    if( k != null ) {
+      forceFirstLetter = Boolean.valueOf( k );
+    }
+  }
+  
+  public String processWord( String w, int wordCount )
+  {
+    if( w.length() < 1 ) {
+      return w;
+    }
+    if( onlyFirstWord && wordCount > 0 ) {
+      return w.toLowerCase();
+    }
+    
+    String k = keep.get( w.toUpperCase() );
+    if( k != null ) {
+      if( wordCount == 0 && forceFirstLetter && Character.isLowerCase( k.charAt(0) ) ) {
+        return Character.toUpperCase( k.charAt(0) ) + k.substring( 1 );
+      }
+      return k;
+    }
+    if( w.length() < minWordLength ) {
+      return w;
+    }
+    for( String prefix : okPrefix ) {
+      if( w.startsWith( prefix ) ) {
+        return w;
+      }
+    }
+    
+    // We know it has at least one character
+    char[] chars = w.toCharArray();
+    StringBuilder word = new StringBuilder( w.length() );
+    word.append( Character.toUpperCase( chars[0] ) );
+    for( int i=1; i<chars.length; i++ ) {
+      word.append( Character.toLowerCase( chars[i] ) );
+    }
+    return word.toString();
+  }
+  
+  public TokenStream create(TokenStream input) {
+    return new CapitalizationFilter(input,this);
+  }
+}
+
+
+
+/**
+ * This relies on the Factory so that the difficult stuff does not need to be
+ * re-initialized each time the filter runs.
+ * 
+ * This is package protected since it is not useful without the Factory
+ */
+class CapitalizationFilter extends TokenFilter 
+{
+  protected final CapitalizationFilterFactory factory;
+  
+  public CapitalizationFilter(TokenStream in, final CapitalizationFilterFactory factory ) {
+    super(in);
+    this.factory = factory;
+  }
+  
+  @Override
+  public final Token next() throws IOException {
+    
+    Token t = input.next();
+    if( t != null ) {
+      String s = t.termText();
+      if( s.length() < factory.maxTokenLength ) {
+        int wordCount = 0;
+
+        StringBuilder word = new StringBuilder( s.length() );
+        StringBuilder text = new StringBuilder( s.length() );
+        for( char c : s.toCharArray() ) {
+          if( c <= ' ' || c == '.' ) { 
+            if( word.length() > 0 ) {
+              text.append( factory.processWord( word.toString(), wordCount++ ) );
+              word.setLength( 0 );
+            }
+            text.append( c );
+          }
+          else { 
+            word.append( c );
+          }
+        }
+        
+        // Add the last word
+        if( word.length() > 0 ) {
+          text.append( factory.processWord( word.toString(), wordCount++ ) );
+        }
+        
+        if( wordCount <= factory.maxWordCount ) {
+          t.setTermText( text.toString() );
+        }
+      }
+    }
+    return t;
+  }
+}
+

src/test/org/apache/solr/analysis/BaseTokenTestCase.java

@@ -171,6 +171,15 @@ public abstract class BaseTokenTestCase extends TestCase
     public IterTokenStream(Iterator<Token> toks) {
       this.toks = toks;
     }
+    public IterTokenStream(String ... text) {
+      int off = 0;
+      ArrayList<Token> t = new ArrayList<Token>( text.length );
+      for( String txt : text ) {
+        t.add( new Token( txt, off, off+txt.length() ) );
+        off += txt.length() + 2;
+      }
+      this.toks = t.iterator();
+    }
     @Override
     public Token next() {
       if (toks.hasNext()) {

src/test/org/apache/solr/analysis/TestCapitalizationFilter.java

@@ -0,0 +1,80 @@
+/**
+ * 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.solr.analysis;
+
+import java.util.HashMap;
+import java.util.Map;
+
+
+/**
+ * @version $Id:$
+ */
+public class TestCapitalizationFilter extends BaseTokenTestCase {
+  
+  public void testCapitalization() throws Exception 
+  {
+    Map<String,String> args = new HashMap<String, String>();
+    args.put( CapitalizationFilterFactory.KEEP, "and the it BIG" );
+    args.put( CapitalizationFilterFactory.ONLY_FIRST_WORD, "true" );  
+    
+    CapitalizationFilterFactory factory = new CapitalizationFilterFactory();
+    factory.init( args );
+
+    assertEquals( "Kitten", factory.processWord( "kiTTEN", 0 ) );
+    factory.forceFirstLetter = true;
+    assertEquals( "And", factory.processWord( "AnD", 0 ) ); // first is forced
+    factory.forceFirstLetter = false;
+    assertEquals( "and", factory.processWord( "AnD", 0 ) ); // first is forced
+    factory.forceFirstLetter = true;
+    assertEquals( "BIG", factory.processWord( "big", 0 ) );
+    
+    String out = tsToString( factory.create( new IterTokenStream( "Hello thEre my Name is Ryan" ) ) );
+    assertEquals( "Hello there my name is ryan", out );
+    
+    // now each token
+    factory.onlyFirstWord = false;
+    out = tsToString( factory.create( new IterTokenStream( "Hello thEre my Name is Ryan" ) ) );
+    assertEquals( "Hello There My Name Is Ryan", out );
+    
+    // now only the long words
+    factory.minWordLength = 3;
+    out = tsToString( factory.create( new IterTokenStream( "Hello thEre my Name is Ryan" ) ) );
+    assertEquals( "Hello There my Name is Ryan", out );
+    
+    // without prefix
+    out = tsToString( factory.create( new IterTokenStream( "McKinley" ) ) );
+    assertEquals( "Mckinley", out );
+    
+    // Now try some prefixes
+    factory = new CapitalizationFilterFactory();
+    args.put( "okPrefix", "McK" );  // all words
+    factory.init( args );
+    out = tsToString( factory.create( new IterTokenStream( "McKinley" ) ) );
+    assertEquals( "McKinley", out );
+    
+    // now try some stuff with numbers
+    factory.forceFirstLetter = false;
+    factory.onlyFirstWord = false;
+    out = tsToString( factory.create( new IterTokenStream( "1st 2nd third" ) ) );
+    assertEquals( "1st 2nd Third", out );
+    
+    factory.forceFirstLetter = true;
+    out = tsToString( factory.create( new IterTokenStream( "the The" ) ) );
+    assertEquals( "The the", out );
+  }
+}