pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / src / java / org / apache / lucene / document / NumberTools.java

diff --git a/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/document/NumberTools.java b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/document/NumberTools.java
new file mode 100644 (file)
index 0000000..4f29ae9
--- /dev/null
+++ b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/document/NumberTools.java
@@ -0,0 +1,140 @@
+package org.apache.lucene.document;
+
+/**
+ * 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.lucene.document.NumericField; // for javadocs
+import org.apache.lucene.search.NumericRangeQuery; // for javadocs
+import org.apache.lucene.util.NumericUtils; // for javadocs
+
+// do not remove this class in 3.0, it may be needed to decode old indexes!
+
+/**
+ * Provides support for converting longs to Strings, and back again. The strings
+ * are structured so that lexicographic sorting order is preserved.
+ * 
+ * <p>
+ * That is, if l1 is less than l2 for any two longs l1 and l2, then
+ * NumberTools.longToString(l1) is lexicographically less than
+ * NumberTools.longToString(l2). (Similarly for "greater than" and "equals".)
+ * 
+ * <p>
+ * This class handles <b>all</b> long values (unlike
+ * {@link org.apache.lucene.document.DateField}).
+ * 
+ * @deprecated For new indexes use {@link NumericUtils} instead, which
+ * provides a sortable binary representation (prefix encoded) of numeric
+ * values.
+ * To index and efficiently query numeric values use {@link NumericField}
+ * and {@link NumericRangeQuery}.
+ * This class is included for use with existing
+ * indices and will be removed in a future release (possibly Lucene 4.0).
+ */
+@Deprecated
+public class NumberTools {
+
+    private static final int RADIX = 36;
+
+    private static final char NEGATIVE_PREFIX = '-';
+
+    // NB: NEGATIVE_PREFIX must be < POSITIVE_PREFIX
+    private static final char POSITIVE_PREFIX = '0';
+
+    //NB: this must be less than
+    /**
+     * Equivalent to longToString(Long.MIN_VALUE)
+     */
+    public static final String MIN_STRING_VALUE = NEGATIVE_PREFIX
+            + "0000000000000";
+
+    /**
+     * Equivalent to longToString(Long.MAX_VALUE)
+     */
+    public static final String MAX_STRING_VALUE = POSITIVE_PREFIX
+            + "1y2p0ij32e8e7";
+
+    /**
+     * The length of (all) strings returned by {@link #longToString}
+     */
+    public static final int STR_SIZE = MIN_STRING_VALUE.length();
+
+    /**
+     * Converts a long to a String suitable for indexing.
+     */
+    public static String longToString(long l) {
+
+        if (l == Long.MIN_VALUE) {
+            // special case, because long is not symmetric around zero
+            return MIN_STRING_VALUE;
+        }
+
+        StringBuilder buf = new StringBuilder(STR_SIZE);
+
+        if (l < 0) {
+            buf.append(NEGATIVE_PREFIX);
+            l = Long.MAX_VALUE + l + 1;
+        } else {
+            buf.append(POSITIVE_PREFIX);
+        }
+        String num = Long.toString(l, RADIX);
+
+        int padLen = STR_SIZE - num.length() - buf.length();
+        while (padLen-- > 0) {
+            buf.append('0');
+        }
+        buf.append(num);
+
+        return buf.toString();
+    }
+
+    /**
+     * Converts a String that was returned by {@link #longToString} back to a
+     * long.
+     * 
+     * @throws IllegalArgumentException
+     *             if the input is null
+     * @throws NumberFormatException
+     *             if the input does not parse (it was not a String returned by
+     *             longToString()).
+     */
+    public static long stringToLong(String str) {
+        if (str == null) {
+            throw new NullPointerException("string cannot be null");
+        }
+        if (str.length() != STR_SIZE) {
+            throw new NumberFormatException("string is the wrong size");
+        }
+
+        if (str.equals(MIN_STRING_VALUE)) {
+            return Long.MIN_VALUE;
+        }
+
+        char prefix = str.charAt(0);
+        long l = Long.parseLong(str.substring(1), RADIX);
+
+        if (prefix == POSITIVE_PREFIX) {
+            // nop
+        } else if (prefix == NEGATIVE_PREFIX) {
+            l = l - Long.MAX_VALUE - 1;
+        } else {
+            throw new NumberFormatException(
+                    "string does not begin with the correct prefix");
+        }
+
+        return l;
+    }
+}
\ No newline at end of file