solr/solrj/src/java/org/apache/solr/client/solrj/io/eq/MultipleFieldEqualitor.java

/*
 * 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.
 */
package org.apache.solr.client.solrj.io.eq;

import java.io.IOException;
import java.util.UUID;

import org.apache.solr.client.solrj.io.Tuple;
import org.apache.solr.client.solrj.io.comp.MultipleFieldComparator;
import org.apache.solr.client.solrj.io.comp.StreamComparator;
import org.apache.solr.client.solrj.io.stream.expr.Explanation;
import org.apache.solr.client.solrj.io.stream.expr.Expressible;
import org.apache.solr.client.solrj.io.stream.expr.StreamExpressionParameter;
import org.apache.solr.client.solrj.io.stream.expr.StreamExpressionValue;
import org.apache.solr.client.solrj.io.stream.expr.StreamFactory;
import org.apache.solr.client.solrj.io.stream.expr.Explanation.ExpressionType;


/**
 *  Wraps multiple Equalitors.
 **/

public class MultipleFieldEqualitor implements StreamEqualitor {

  private static final long serialVersionUID = 1;
  private UUID equalitorNodeId = UUID.randomUUID();

  private StreamEqualitor[] eqs;

  public MultipleFieldEqualitor(StreamEqualitor... eqs) {
    this.eqs = eqs;
  }
  
  public StreamEqualitor[] getEqs(){
    return eqs;
  }

  @Override
  public StreamExpressionParameter toExpression(StreamFactory factory) throws IOException {
    StringBuilder sb = new StringBuilder();
    for(Equalitor<Tuple> eq : eqs){
      if(eq instanceof Expressible){
        if(sb.length() > 0){ sb.append(","); }
        sb.append(((Expressible)eq).toExpression(factory));
      }
      else{
        throw new IOException("This MultiEqualitor contains a non-expressible equalitor - it cannot be converted to an expression");
      }
    }
    
    return new StreamExpressionValue(sb.toString());
  }

  @Override
  public Explanation toExplanation(StreamFactory factory) throws IOException {
    return new Explanation(equalitorNodeId.toString())
      .withExpressionType(ExpressionType.EQUALITOR)
      .withImplementingClass(getClass().getName())
      .withExpression(toExpression(factory).toString());
  }
  
  @Override
  public boolean isDerivedFrom(StreamEqualitor base){
    if(null == base){ return false; }
    if(base instanceof MultipleFieldEqualitor){
      MultipleFieldEqualitor baseEq = (MultipleFieldEqualitor)base;
      
      if(baseEq.eqs.length >= eqs.length){
        for(int idx = 0; idx < eqs.length; ++idx){
          if(!eqs[idx].isDerivedFrom(baseEq.eqs[idx])){
            return false;
          }
        }        
        return true;
      }
    }
    
    return false;
  }
  
  @Override
  public boolean isDerivedFrom(StreamComparator base){
    if(null == base){ return false; }
    if(base instanceof StreamComparator){
      MultipleFieldComparator baseComps = (MultipleFieldComparator)base;
      
      if(baseComps.getComps().length >= eqs.length){
        for(int idx = 0; idx < eqs.length; ++idx){
          if(!eqs[idx].isDerivedFrom(baseComps.getComps()[idx])){
            return false;
          }
        }        
        return true;
      }
    }
    
    return false;

  }
  
  public boolean test(Tuple t1, Tuple t2) {
    for(Equalitor<Tuple> eq : eqs) {
      if(!eq.test(t1, t2)){
        return false;
      }
    }

    return true;
  }
}