pylucene 3.5.0-3

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

diff --git a/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/Explanation.java b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/Explanation.java
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+++ b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/Explanation.java
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+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.Serializable;
+import java.util.ArrayList;
+
+/** Expert: Describes the score computation for document and query. */
+public class Explanation implements java.io.Serializable {
+  private float value;                            // the value of this node
+  private String description;                     // what it represents
+  private ArrayList<Explanation> details;                      // sub-explanations
+
+  public Explanation() {}
+
+  public Explanation(float value, String description) {
+    this.value = value;
+    this.description = description;
+  }
+
+  /**
+   * Indicates whether or not this Explanation models a good match.
+   *
+   * <p>
+   * By default, an Explanation represents a "match" if the value is positive.
+   * </p>
+   * @see #getValue
+   */
+  public boolean isMatch() {
+    return (0.0f < getValue());
+  }
+
+
+  
+  /** The value assigned to this explanation node. */
+  public float getValue() { return value; }
+  /** Sets the value assigned to this explanation node. */
+  public void setValue(float value) { this.value = value; }
+
+  /** A description of this explanation node. */
+  public String getDescription() { return description; }
+  /** Sets the description of this explanation node. */
+  public void setDescription(String description) {
+    this.description = description;
+  }
+
+  /**
+   * A short one line summary which should contain all high level
+   * information about this Explanation, without the "Details"
+   */
+  protected String getSummary() {
+    return getValue() + " = " + getDescription();
+  }
+  
+  /** The sub-nodes of this explanation node. */
+  public Explanation[] getDetails() {
+    if (details == null)
+      return null;
+    return details.toArray(new Explanation[0]);
+  }
+
+  /** Adds a sub-node to this explanation node. */
+  public void addDetail(Explanation detail) {
+    if (details == null)
+      details = new ArrayList<Explanation>();
+    details.add(detail);
+  }
+
+  /** Render an explanation as text. */
+  @Override
+  public String toString() {
+    return toString(0);
+  }
+  protected String toString(int depth) {
+    StringBuilder buffer = new StringBuilder();
+    for (int i = 0; i < depth; i++) {
+      buffer.append("  ");
+    }
+    buffer.append(getSummary());
+    buffer.append("\n");
+
+    Explanation[] details = getDetails();
+    if (details != null) {
+      for (int i = 0 ; i < details.length; i++) {
+        buffer.append(details[i].toString(depth+1));
+      }
+    }
+
+    return buffer.toString();
+  }
+
+
+  /** Render an explanation as HTML. */
+  public String toHtml() {
+    StringBuilder buffer = new StringBuilder();
+    buffer.append("<ul>\n");
+
+    buffer.append("<li>");
+    buffer.append(getSummary());
+    buffer.append("<br />\n");
+
+    Explanation[] details = getDetails();
+    if (details != null) {
+      for (int i = 0 ; i < details.length; i++) {
+        buffer.append(details[i].toHtml());
+      }
+    }
+
+    buffer.append("</li>\n");
+    buffer.append("</ul>\n");
+
+    return buffer.toString();
+  }
+  
+  /**
+   * Small Util class used to pass both an idf factor as well as an
+   * explanation for that factor.
+   * 
+   * This class will likely be held on a {@link Weight}, so be aware 
+   * before storing any large or un-serializable fields.
+   *
+   */
+  public static abstract class IDFExplanation implements Serializable {
+    /**
+     * @return the idf factor
+     */
+    public abstract float getIdf();
+    /**
+     * This should be calculated lazily if possible.
+     * 
+     * @return the explanation for the idf factor.
+     */
+    public abstract String explain();
+  }
+}