solr/contrib/analytics/src/java/org/apache/solr/analytics/function/mapping/DateMathFunction.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.analytics.function.mapping;

import java.util.Date;
import java.util.function.Consumer;
import java.util.function.LongConsumer;

import org.apache.solr.analytics.ExpressionFactory.CreatorFunction;
import org.apache.solr.analytics.value.AnalyticsValueStream;
import org.apache.solr.analytics.value.DateValue;
import org.apache.solr.analytics.value.DateValueStream;
import org.apache.solr.analytics.value.StringValue;
import org.apache.solr.analytics.value.DateValue.AbstractDateValue;
import org.apache.solr.analytics.value.DateValueStream.AbstractDateValueStream;
import org.apache.solr.analytics.value.constant.ConstantStringValue;
import org.apache.solr.analytics.value.constant.ConstantValue;
import org.apache.solr.common.SolrException;
import org.apache.solr.common.SolrException.ErrorCode;
import org.apache.solr.util.DateMathParser;

/**
 * A mapping function that computes date math.
 * <p>
 * The first parameter is the {@link DateValue} or {@link DateValueStream} to compute date math on. (Required)
 * <br>
 * The trailing parameters must be constant date math strings (e.g. "+1DAY"). (At least 1 required)
 */
public class DateMathFunction {
  public static final String name = "date_math";
  public static final CreatorFunction creatorFunction = (params -> {
    if (params.length < 2) {
      throw new SolrException(ErrorCode.BAD_REQUEST,"The "+name+" function requires at least 2 paramaters, " + params.length + " found.");
    }
    StringBuilder mathParam = new StringBuilder();
    for (int i = 1; i < params.length; ++i) {
      if (params[i] instanceof StringValue && params[i] instanceof ConstantValue) {
        mathParam.append(((StringValue) params[i]).getString());
      } else {
        throw new SolrException(ErrorCode.BAD_REQUEST,"The "+name+" function requires all math parameters to be a constant strings.");
      }
    }
    if (params[0] instanceof DateValue) {
      return new DateMathValueFunction((DateValue)params[0], new ConstantStringValue(mathParam.toString()));
    } else if (params[0] instanceof DateValueStream) {
      return new DateMathStreamFunction((DateValueStream)params[0], new ConstantStringValue(mathParam.toString()));
    } else {
      throw new SolrException(ErrorCode.BAD_REQUEST,"The "+name+" function requires a date as the first parameter.");
    }
  });
}
/**
 * DateMath function that supports {@link DateValue}s.
 */
class DateMathValueFunction extends AbstractDateValue {
  private final DateValue dateParam;
  private final String mathParam;
  DateMathParser parser = new DateMathParser();
  public static final String name = DateMathFunction.name;
  private final String exprStr;
  private final ExpressionType funcType;

  public DateMathValueFunction(DateValue dateParam, ConstantStringValue mathParam) throws SolrException {
    this.dateParam = dateParam;
    this.mathParam = "NOW" + mathParam.getString();
    this.exprStr = AnalyticsValueStream.createExpressionString(name,dateParam,mathParam);
    this.funcType = AnalyticsValueStream.determineMappingPhase(exprStr,dateParam);
  }

  private boolean exists = false;

  @Override
  public long getLong() {
    Date date = getDate();
    return (exists) ? date.getTime() : 0;
  }
  @Override
  public Date getDate() {
    Date date = dateParam.getDate();
    if (dateParam.exists()) {
      exists = true;
      return DateMathParser.parseMath(date,mathParam);
    } else {
      exists = false;
      return null;
    }
  }
  @Override
  public boolean exists() {
    return exists;
  }

  @Override
  public String getName() {
    return name;
  }
  @Override
  public String getExpressionStr() {
    return exprStr;
  }
  @Override
  public ExpressionType getExpressionType() {
    return funcType;
  }
}
/**
 * DateMath function that supports {@link DateValueStream}s.
 */
class DateMathStreamFunction extends AbstractDateValueStream {
  private final DateValueStream dateParam;
  private final String mathParam;
  public static final String name = DateMathFunction.name;
  private final String exprStr;
  private final ExpressionType funcType;

  public DateMathStreamFunction(DateValueStream dateParam, ConstantStringValue mathParam) throws SolrException {
    this.dateParam = dateParam;
    this.mathParam = "NOW" + mathParam.getString();
    this.exprStr = AnalyticsValueStream.createExpressionString(name,dateParam,mathParam);
    this.funcType = AnalyticsValueStream.determineMappingPhase(exprStr,dateParam);
  }

  @Override
  public void streamLongs(LongConsumer cons) {
    streamDates(value -> cons.accept(value.getTime()));
  }
  @Override
  public void streamDates(Consumer<Date> cons) {
    dateParam.streamDates(value -> cons.accept(DateMathParser.parseMath(value, mathParam)));
  }

  @Override
  public String getName() {
    return name;
  }
  @Override
  public String getExpressionStr() {
    return exprStr;
  }
  @Override
  public ExpressionType getExpressionType() {
    return funcType;
  }
}