pylucene 3.5.0-3

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

diff --git a/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/spans/Spans.java b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/spans/Spans.java
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+package org.apache.lucene.search.spans;
+
+/**
+ * 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.util.Collection;
+
+/** Expert: an enumeration of span matches.  Used to implement span searching.
+ * Each span represents a range of term positions within a document.  Matches
+ * are enumerated in order, by increasing document number, within that by
+ * increasing start position and finally by increasing end position. */
+public abstract class Spans {
+  /** Move to the next match, returning true iff any such exists. */
+  public abstract boolean next() throws IOException;
+
+  /** Skips to the first match beyond the current, whose document number is
+   * greater than or equal to <i>target</i>. <p>Returns true iff there is such
+   * a match.  <p>Behaves as if written: <pre>
+   *   boolean skipTo(int target) {
+   *     do {
+   *       if (!next())
+   *        return false;
+   *     } while (target > doc());
+   *     return true;
+   *   }
+   * </pre>
+   * Most implementations are considerably more efficient than that.
+   */
+  public abstract boolean skipTo(int target) throws IOException;
+
+  /** Returns the document number of the current match.  Initially invalid. */
+  public abstract int doc();
+
+  /** Returns the start position of the current match.  Initially invalid. */
+  public abstract int start();
+
+  /** Returns the end position of the current match.  Initially invalid. */
+  public abstract int end();
+  
+  /**
+   * Returns the payload data for the current span.
+   * This is invalid until {@link #next()} is called for
+   * the first time.
+   * This method must not be called more than once after each call
+   * of {@link #next()}. However, most payloads are loaded lazily,
+   * so if the payload data for the current position is not needed,
+   * this method may not be called at all for performance reasons. An ordered
+   * SpanQuery does not lazy load, so if you have payloads in your index and
+   * you do not want ordered SpanNearQuerys to collect payloads, you can
+   * disable collection with a constructor option.<br>
+   * <br>
+    * Note that the return type is a collection, thus the ordering should not be relied upon.
+    * <br/>
+   * @lucene.experimental
+   *
+   * @return a List of byte arrays containing the data of this payload, otherwise null if isPayloadAvailable is false
+   * @throws java.io.IOException
+    */
+  // TODO: Remove warning after API has been finalized
+  public abstract Collection<byte[]> getPayload() throws IOException;
+
+  /**
+   * Checks if a payload can be loaded at this position.
+   * <p/>
+   * Payloads can only be loaded once per call to
+   * {@link #next()}.
+   *
+   * @return true if there is a payload available at this position that can be loaded
+   */
+  public abstract boolean isPayloadAvailable();
+
+}