ValueHolder.java

/**
 * Copyright 2014 Sunny Gleason and original author or authors
 *
 * Licensed 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 io.kazuki.v0.store.index.query;

import java.math.BigDecimal;
import java.math.BigInteger;

/**
 * A class that encapsulates a value and allows translations between types.
 */
public class ValueHolder {
  private final ValueType valueType;
  private final String literal;
  private final Object value;

  public ValueHolder(ValueType valueType, String literal) {
    this.valueType = valueType;
    this.literal = literal;
    switch (valueType) {
      case DECIMAL:
        this.value = new BigDecimal(literal);
        break;
      case INTEGER:
        this.value = new BigInteger(literal);
        break;
      case STRING:
        this.value = parseStringLiteral(literal);
        break;
      case BOOLEAN:
        this.value = Boolean.valueOf(literal);
        break;
      case REFERENCE:
        this.value = parseStringLiteral(literal);
        break;
      case NULL:
        this.value = "";
        break;
      default:
        throw new IllegalArgumentException("unknown type: " + valueType);
    }
  }

  public ValueType getValueType() {
    return valueType;
  }

  public String getLiteral() {
    return literal;
  }

  public Object getValue() {
    return value;
  }

  @Override
  public String toString() {
    switch (valueType) {
      case DECIMAL:
      case INTEGER:
        return this.value.toString();
      case STRING:
        return literal;
      case REFERENCE:
        return literal;
      case BOOLEAN:
        return Boolean.valueOf(literal).toString();
      case NULL:
        return null;
      default:
        throw new IllegalArgumentException("unknown type: " + valueType);
    }
  }

  private static String parseStringLiteral(String literal) {
    if (literal.startsWith("\"") && literal.endsWith("\"")) {
      return literal.substring(1, literal.length() - 1);
    }

    return literal;
  }

  // TODO : equals, hashCode
}