pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / src / java / org / apache / lucene / search / TermRangeTermEnum.java

diff --git a/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/TermRangeTermEnum.java b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/TermRangeTermEnum.java
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+++ b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/TermRangeTermEnum.java
@@ -0,0 +1,154 @@
+package org.apache.lucene.search;
+
+/**
+ * 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 java.io.IOException;
+import java.text.Collator;
+
+import org.apache.lucene.index.IndexReader;
+import org.apache.lucene.index.Term;
+import org.apache.lucene.util.StringHelper;
+
+/**
+ * Subclass of FilteredTermEnum for enumerating all terms that match the
+ * specified range parameters.
+ * <p>
+ * Term enumerations are always ordered by Term.compareTo().  Each term in
+ * the enumeration is greater than all that precede it.
+ * @since 2.9
+ */
+public class TermRangeTermEnum extends FilteredTermEnum {
+
+  private Collator collator = null;
+  private boolean endEnum = false;
+  private String field;
+  private String upperTermText;
+  private String lowerTermText;
+  private boolean includeLower;
+  private boolean includeUpper;
+
+  /**
+   * Enumerates all terms greater/equal than <code>lowerTerm</code>
+   * but less/equal than <code>upperTerm</code>. 
+   * 
+   * If an endpoint is null, it is said to be "open". Either or both 
+   * endpoints may be open.  Open endpoints may not be exclusive 
+   * (you can't select all but the first or last term without 
+   * explicitly specifying the term to exclude.)
+   * 
+   * @param reader
+   * @param field
+   *          An interned field that holds both lower and upper terms.
+   * @param lowerTermText
+   *          The term text at the lower end of the range
+   * @param upperTermText
+   *          The term text at the upper end of the range
+   * @param includeLower
+   *          If true, the <code>lowerTerm</code> is included in the range.
+   * @param includeUpper
+   *          If true, the <code>upperTerm</code> is included in the range.
+   * @param collator
+   *          The collator to use to collate index Terms, to determine their
+   *          membership in the range bounded by <code>lowerTerm</code> and
+   *          <code>upperTerm</code>.
+   * 
+   * @throws IOException
+   */
+  public TermRangeTermEnum(IndexReader reader, String field, String lowerTermText, String upperTermText, 
+    boolean includeLower, boolean includeUpper, Collator collator) throws IOException {
+    this.collator = collator;
+    this.upperTermText = upperTermText;
+    this.lowerTermText = lowerTermText;
+    this.includeLower = includeLower;
+    this.includeUpper = includeUpper;
+    this.field = StringHelper.intern(field);
+    
+    // do a little bit of normalization...
+    // open ended range queries should always be inclusive.
+    if (this.lowerTermText == null) {
+      this.lowerTermText = "";
+      this.includeLower = true;
+    }
+    
+    if (this.upperTermText == null) {
+      this.includeUpper = true;
+    }
+
+    String startTermText = collator == null ? this.lowerTermText : "";
+    setEnum(reader.terms(new Term(this.field, startTermText)));
+  }
+
+  @Override
+  public float difference() {
+    return 1.0f;
+  }
+
+  @Override
+  protected boolean endEnum() {
+    return endEnum;
+  }
+
+  @Override
+  protected boolean termCompare(Term term) {
+    if (collator == null) {
+      // Use Unicode code point ordering
+      boolean checkLower = false;
+      if (!includeLower) // make adjustments to set to exclusive
+        checkLower = true;
+      if (term != null && term.field() == field) { // interned comparison
+        if (!checkLower || null==lowerTermText || term.text().compareTo(lowerTermText) > 0) {
+          checkLower = false;
+          if (upperTermText != null) {
+            int compare = upperTermText.compareTo(term.text());
+            /*
+             * if beyond the upper term, or is exclusive and this is equal to
+             * the upper term, break out
+             */
+            if ((compare < 0) ||
+                (!includeUpper && compare==0)) {
+              endEnum = true;
+              return false;
+            }
+          }
+          return true;
+        }
+      } else {
+        // break
+        endEnum = true;
+        return false;
+      }
+      return false;
+    } else {
+      if (term != null && term.field() == field) { // interned comparison
+        if ((lowerTermText == null
+            || (includeLower
+                ? collator.compare(term.text(), lowerTermText) >= 0
+                : collator.compare(term.text(), lowerTermText) > 0))
+           && (upperTermText == null
+               || (includeUpper
+                   ? collator.compare(term.text(), upperTermText) <= 0
+                   : collator.compare(term.text(), upperTermText) < 0))) {
+          return true;
+        }
+        return false;
+      }
+      endEnum = true;
+      return false;
+    }
+  }
+}