Lucene example source code file (PathQueryNode.java)

This example Lucene source code file (PathQueryNode.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

arraylist, charsequence, charsequence, clonenotsupportedexception, list, override, pathquerynode, pathquerynode, querynodeimpl, querytext, querytext, string, stringbuilder, stringbuilder, util

The Lucene PathQueryNode.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.ArrayList;
import java.util.List;
import java.util.Locale;

import org.apache.lucene.queryParser.core.parser.EscapeQuerySyntax;
import org.apache.lucene.queryParser.core.parser.EscapeQuerySyntax.Type;

/**
 * A {@link PathQueryNode} is used to store queries like
 * /company/USA/California /product/shoes/brown. QueryText are objects that
 * contain the text, begin position and end position in the query.
 * <p>
 * Example how the text parser creates these objects:
 * </p>
 * <pre>
 * List values = ArrayList(); 
 * values.add(new PathQueryNode.QueryText("company", 1, 7)); 
 * values.add(new PathQueryNode.QueryText("USA", 9, 12)); 
 * values.add(new PathQueryNode.QueryText("California", 14, 23)); 
 * QueryNode q = new PathQueryNode(values);
 * </pre>
 */
public class PathQueryNode extends QueryNodeImpl {

  private static final long serialVersionUID = -8325921322405804789L;

  public static class QueryText implements Cloneable {
    CharSequence value = null;
    /**
     * != null The term's begin position.
     */
    int begin;

    /**
     * The term's end position.
     */
    int end;

    /**
     * @param value
     *          - text value
     * @param begin
     *          - position in the query string
     * @param end
     *          - position in the query string
     */
    public QueryText(CharSequence value, int begin, int end) {
      super();
      this.value = value;
      this.begin = begin;
      this.end = end;
    }

    @Override
    public QueryText clone() throws CloneNotSupportedException {
      QueryText clone = (QueryText) super.clone();
      clone.value = this.value;
      clone.begin = this.begin;
      clone.end = this.end;
      return clone;
    }

    /**
     * @return the value
     */
    public CharSequence getValue() {
      return value;
    }

    /**
     * @return the begin
     */
    public int getBegin() {
      return begin;
    }

    /**
     * @return the end
     */
    public int getEnd() {
      return end;
    }

    @Override
    public String toString() {
      return value + ", " + begin + ", " + end;
    }
  }

  private List<QueryText> values = null;

  /**
   * @param pathElements
   *          - List of QueryText objects
   */
  public PathQueryNode(List<QueryText> pathElements) {
    this.values = pathElements;
    if (pathElements.size() <= 1) {
      // this should not happen
      throw new RuntimeException(
          "PathQuerynode requires more 2 or more path elements.");
    }
  }

  /**
   * Returns the a List with all QueryText elements
   * 
   * @return QueryText List size
   */
  public List<QueryText> getPathElements() {
    return values;
  }

  /**
   * Returns the a List with all QueryText elements
   */
  public void setPathElements(List<QueryText> elements) {
    this.values = elements;
  }

  /**
   * Returns the a specific QueryText element
   * 
   * @return QueryText List size
   */
  public QueryText getPathElement(int index) {
    return values.get(index);
  }

  /**
   * Returns the CharSequence value of a specific QueryText element
   * 
   * @return the CharSequence for a specific QueryText element
   */
  public CharSequence getFirstPathElement() {
    return values.get(0).value;
  }

  /**
   * Returns a List QueryText element from position startIndex
   * 
   * @return a List QueryText element from position startIndex
   */
  public List<QueryText> getPathElements(int startIndex) {
    List<PathQueryNode.QueryText> rValues = new ArrayList();
    for (int i = startIndex; i < this.values.size(); i++) {
      try {
        rValues.add(this.values.get(i).clone());
      } catch (CloneNotSupportedException e) {
        // this will not happen
      }
    }
    return rValues;
  }

  private CharSequence getPathString() {
    StringBuilder path = new StringBuilder();

    for (QueryText pathelement : values) {
      path.append("/").append(pathelement.value);
    }
    return path.toString();
  }

  public CharSequence toQueryString(EscapeQuerySyntax escaper) {
    StringBuilder path = new StringBuilder();
    path.append("/").append(getFirstPathElement());

    for (QueryText pathelement : getPathElements(1)) {
      CharSequence value = escaper.escape(pathelement.value, Locale
          .getDefault(), Type.STRING);
      path.append("/\"").append(value).append("\"");
    }
    return path.toString();
  }

  @Override
  public String toString() {
    QueryText text = this.values.get(0);

    return "<path start='" + text.begin + "' end='" + text.end + "' path='"
        + getPathString() + "'/>";
  }

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

    // copy children
    if (this.values != null) {
      List<QueryText> localValues = new ArrayList();
      for (QueryText value : this.values) {
        localValues.add(value.clone());
      }
      clone.values = localValues;
    }

    return clone;
  }

}