Lucene example source code file (ProximityQueryNode.java)

This example Lucene source code file (ProximityQueryNode.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Lucene tags/keywords

charsequence, charsequence, fieldquerynode, override, override, proximityquerynode, proximitytype, querynode, string, string, stringbuilder, type, type, util, within

The Lucene ProximityQueryNode.java source code

package org.apache.lucene.queryParser.core.nodes;

/**
 * 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.util.List;

import org.apache.lucene.messages.MessageImpl;
import org.apache.lucene.queryParser.core.QueryNodeError;
import org.apache.lucene.queryParser.core.messages.QueryParserMessages;
import org.apache.lucene.queryParser.core.parser.EscapeQuerySyntax;

/**
 * A {@link ProximityQueryNode} represents a query where the terms should meet
 * specific distance conditions. (a b c) WITHIN [SENTENCE|PARAGRAPH|NUMBER]
 * [INORDER] ("a" "b" "c") WITHIN [SENTENCE|PARAGRAPH|NUMBER] [INORDER]
 * 
 * TODO: Add this to the future standard Lucene parser/processor/builder
 */
public class ProximityQueryNode extends BooleanQueryNode {

  private static final long serialVersionUID = 9018220596680832916L;

  public enum Type {
    PARAGRAPH {
      @Override
      CharSequence toQueryString() { return "WITHIN PARAGRAPH"; } 
    },
    SENTENCE  { 
      @Override
      CharSequence toQueryString() { return "WITHIN SENTENCE";  }
    },
    NUMBER    {
      @Override
      CharSequence toQueryString() { return "WITHIN";           }
    };

    abstract CharSequence toQueryString();
  }

  // utility class
  static public class ProximityType {
    int pDistance = 0;

    Type pType = null;

    public ProximityType(Type type) {
      this(type, 0);
    }

    public ProximityType(Type type, int distance) {
      this.pType = type;
      this.pDistance = distance;
    }
  }

  private Type proximityType = Type.SENTENCE;
  private int distance = -1;
  private boolean inorder = false;
  private CharSequence field = null;

  /**
   * @param clauses
   *          - QueryNode children
   * @param field
   *          - field name
   * @param type
   *          - type of proximity query
   * @param distance
   *          - positive integer that specifies the distance
   * @param inorder
   *          - true, if the tokens should be matched in the order of the
   *          clauses
   */
  public ProximityQueryNode(List<QueryNode> clauses, CharSequence field,
      Type type, int distance, boolean inorder) {
    super(clauses);
    setLeaf(false);
    this.proximityType = type;
    this.inorder = inorder;
    this.field = field;
    if (type == Type.NUMBER) {
      if (distance <= 0) {
        throw new QueryNodeError(new MessageImpl(
            QueryParserMessages.PARAMETER_VALUE_NOT_SUPPORTED, "distance",
            distance));

      } else {
        this.distance = distance;
      }

    }
    clearFields(clauses, field);
  }

  /**
   * @param clauses
   *          - QueryNode children
   * @param field
   *          - field name
   * @param type
   *          - type of proximity query
   * @param inorder
   *          - true, if the tokens should be matched in the order of the
   *          clauses
   */
  public ProximityQueryNode(List<QueryNode> clauses, CharSequence field,
      Type type, boolean inorder) {
    this(clauses, field, type, -1, inorder);
  }

  static private void clearFields(List<QueryNode> nodes, CharSequence field) {
    if (nodes == null || nodes.size() == 0)
      return;

    for (QueryNode clause : nodes) {

      if (clause instanceof FieldQueryNode) {
        ((FieldQueryNode) clause).toQueryStringIgnoreFields = true;
        ((FieldQueryNode) clause).setField(field);
      }
    }
  }

  public Type getProximityType() {
    return this.proximityType;
  }

  @Override
  public String toString() {
    String distanceSTR = ((this.distance == -1) ? ("")
        : (" distance='" + this.distance) + "'");

    if (getChildren() == null || getChildren().size() == 0)
      return "<proximity field='" + this.field + "' inorder='" + this.inorder
          + "' type='" + this.proximityType.toString() + "'" + distanceSTR
          + "/>";
    StringBuilder sb = new StringBuilder();
    sb.append("<proximity field='" + this.field + "' inorder='" + this.inorder
        + "' type='" + this.proximityType.toString() + "'" + distanceSTR + ">");
    for (QueryNode child : getChildren()) {
      sb.append("\n");
      sb.append(child.toString());
    }
    sb.append("\n</proximity>");
    return sb.toString();
  }

  @Override
  public CharSequence toQueryString(EscapeQuerySyntax escapeSyntaxParser) {
    String withinSTR = this.proximityType.toQueryString()
        + ((this.distance == -1) ? ("") : (" " + this.distance))
        + ((this.inorder) ? (" INORDER") : (""));

    StringBuilder sb = new StringBuilder();
    if (getChildren() == null || getChildren().size() == 0) {
      // no children case
    } else {
      String filler = "";
      for (QueryNode child : getChildren()) {
        sb.append(filler).append(child.toQueryString(escapeSyntaxParser));
        filler = " ";
      }
    }

    if (isDefaultField(this.field)) {
      return "( " + sb.toString() + " ) " + withinSTR;
    } else {
      return this.field + ":(( " + sb.toString() + " ) " + withinSTR + ")";
    }
  }

  @Override
  public QueryNode cloneTree() throws CloneNotSupportedException {
    ProximityQueryNode clone = (ProximityQueryNode) super.cloneTree();

    clone.proximityType = this.proximityType;
    clone.distance = this.distance;
    clone.field = this.field;

    return clone;
  }

  /**
   * @return the distance
   */
  public int getDistance() {
    return this.distance;
  }

  /**
   * returns null if the field was not specified in the query string
   * 
   * @return the field
   */
  public CharSequence getField() {
    return this.field;
  }

  /**
   * returns null if the field was not specified in the query string
   * 
   * @return the field
   */
  public String getFieldAsString() {
    if (this.field == null)
      return null;
    else
      return this.field.toString();
  }

  /**
   * @param field
   *          the field to set
   */
  public void setField(CharSequence field) {
    this.field = field;
  }

  /**
   * @return terms must be matched in the specified order
   */
  public boolean isInOrder() {
    return this.inorder;
  }

}