/*
 * 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.lucene.queries.function.valuesource;

import java.io.IOException;

import org.apache.lucene.queries.function.FunctionValues;
import org.apache.lucene.queries.function.ValueSource;

/**
 * <code>MaxFloatFunction</code> returns the max of its components.
 */
public class MaxFloatFunction extends MultiFloatFunction {
  public MaxFloatFunction(ValueSource[] sources) {
    super(sources);
  }
  
  @Override
  protected String name() {
    return "max";
  }

  @Override
  protected float func(int doc, FunctionValues[] valsArr) throws IOException {
    if ( ! exists(doc, valsArr) ) return 0.0f;

    float val = Float.NEGATIVE_INFINITY;
    for (FunctionValues vals : valsArr) {
      if (vals.exists(doc)) {
        val = Math.max(vals.floatVal(doc), val);
      }
    }
    return val;
  }

  /** 
   * True if <em>any</em> of the specified <code>values</code> 
   * {@link FunctionValues#exists} for the specified doc, else false.
   *
   * @see MultiFunction#anyExists
   */
  @Override
  protected boolean exists(int doc, FunctionValues[] valsArr) throws IOException {
    return MultiFunction.anyExists(doc, valsArr);
  }
}