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/*
 * 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 com.hazelcast.org.apache.calcite.util;

import com.hazelcast.org.apache.calcite.avatica.util.ByteString;
import com.hazelcast.org.apache.calcite.runtime.SqlFunctions;
import com.hazelcast.org.apache.calcite.sql.SqlCollation;
import com.hazelcast.org.apache.calcite.sql.SqlDialect;
import com.hazelcast.org.apache.calcite.sql.SqlUtil;
import com.hazelcast.org.apache.calcite.sql.dialect.AnsiSqlDialect;

import com.hazelcast.com.google.common.cache.CacheBuilder;
import com.hazelcast.com.google.common.cache.CacheLoader;
import com.hazelcast.com.google.common.cache.LoadingCache;

import java.nio.ByteBuffer;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.IllegalCharsetNameException;
import java.nio.charset.UnsupportedCharsetException;
import java.util.List;
import java.util.Locale;
import java.util.Objects;
import javax.annotation.Nonnull;

import static com.hazelcast.org.apache.calcite.util.Static.RESOURCE;

/**
 * A string, optionally with {@link Charset character set} and
 * {@link SqlCollation}. It is immutable.
 */
public class NlsString implements Comparable, Cloneable {
  //~ Instance fields --------------------------------------------------------

  private static final LoadingCache, String>
      DECODE_MAP =
      CacheBuilder.newBuilder()
          .softValues()
          .build(
              new CacheLoader, String>() {
                public String load(@Nonnull Pair key) {
                  final Charset charset = key.right;
                  final CharsetDecoder decoder = charset.newDecoder();
                  final byte[] bytes = key.left.getBytes();
                  final ByteBuffer buffer = ByteBuffer.wrap(bytes);
                  try {
                    return decoder.decode(buffer).toString();
                  } catch (CharacterCodingException ex) {
                    throw RESOURCE.charsetEncoding(
                        //CHECKSTYLE: IGNORE 1
                        new String(bytes, Charset.defaultCharset()),
                        charset.name()).ex();
                  }
                }
              });

  private final String stringValue;
  private final ByteString bytesValue;
  private final String charsetName;
  private final Charset charset;
  private final SqlCollation collation;

  //~ Constructors -----------------------------------------------------------

  /**
   * Creates a string in a specified character set.
   *
   * @param bytesValue  Byte array constant, must not be null
   * @param charsetName Name of the character set, must not be null
   * @param collation   Collation, may be null
   *
   * @throws IllegalCharsetNameException If the given charset name is illegal
   * @throws UnsupportedCharsetException If no support for the named charset
   *     is available in this instance of the Java virtual machine
   * @throws RuntimeException If the given value cannot be represented in the
   *     given charset
   */
  public NlsString(ByteString bytesValue, String charsetName,
      SqlCollation collation) {
    this(null, Objects.requireNonNull(bytesValue),
        Objects.requireNonNull(charsetName), collation);
  }

  /**
   * Easy constructor for Java string.
   *
   * @param stringValue String constant, must not be null
   * @param charsetName Name of the character set, may be null
   * @param collation Collation, may be null
   *
   * @throws IllegalCharsetNameException If the given charset name is illegal
   * @throws UnsupportedCharsetException If no support for the named charset
   *     is available in this instance of the Java virtual machine
   * @throws RuntimeException If the given value cannot be represented in the
   *     given charset
   */
  public NlsString(String stringValue, String charsetName,
      SqlCollation collation) {
    this(Objects.requireNonNull(stringValue), null, charsetName, collation);
  }

  /** Internal constructor; other constructors must call it. */
  private NlsString(String stringValue, ByteString bytesValue,
      String charsetName, SqlCollation collation) {
    if (charsetName != null) {
      this.charsetName = charsetName.toUpperCase(Locale.ROOT);
      this.charset = SqlUtil.getCharset(charsetName);
    } else {
      this.charsetName = null;
      this.charset = null;
    }
    if ((stringValue != null) == (bytesValue != null)) {
      throw new IllegalArgumentException("Specify stringValue or bytesValue");
    }
    if (bytesValue != null) {
      if (charsetName == null) {
        throw new IllegalArgumentException("Bytes value requires charset");
      }
      SqlUtil.validateCharset(bytesValue, charset);
    } else {
      // Java string can be malformed if LATIN1 is required.
      if (this.charsetName != null
          && (this.charsetName.equals("LATIN1")
          || this.charsetName.equals("ISO-8859-1"))) {
        if (!charset.newEncoder().canEncode(stringValue)) {
          throw RESOURCE.charsetEncoding(stringValue, charset.name()).ex();
        }
      }
    }
    this.collation = collation;
    this.stringValue = stringValue;
    this.bytesValue = bytesValue;
  }

  //~ Methods ----------------------------------------------------------------

  public Object clone() {
    try {
      return super.clone();
    } catch (CloneNotSupportedException e) {
      throw new AssertionError();
    }
  }

  public int hashCode() {
    return Objects.hash(stringValue, bytesValue, charsetName, collation);
  }

  public boolean equals(Object obj) {
    return this == obj
        || obj instanceof NlsString
        && Objects.equals(stringValue, ((NlsString) obj).stringValue)
        && Objects.equals(bytesValue, ((NlsString) obj).bytesValue)
        && Objects.equals(charsetName, ((NlsString) obj).charsetName)
        && Objects.equals(collation, ((NlsString) obj).collation);
  }

  @Override public int compareTo(NlsString other) {
    // TODO jvs 18-Jan-2006:  Actual collation support.  This just uses
    // the default collation.
    return getValue().compareTo(other.getValue());
  }

  public String getCharsetName() {
    return charsetName;
  }

  public Charset getCharset() {
    return charset;
  }

  public SqlCollation getCollation() {
    return collation;
  }

  public String getValue() {
    if (stringValue == null) {
      assert bytesValue != null;
      return DECODE_MAP.getUnchecked(Pair.of(bytesValue, charset));
    }
    return stringValue;
  }

  /**
   * Returns a string the same as this but with spaces trimmed from the
   * right.
   */
  public NlsString rtrim() {
    String trimmed = SqlFunctions.rtrim(getValue());
    if (!trimmed.equals(getValue())) {
      return new NlsString(trimmed, charsetName, collation);
    }
    return this;
  }

  /** As {@link #asSql(boolean, boolean, SqlDialect)} but with SQL standard
   * dialect. */
  public String asSql(boolean prefix, boolean suffix) {
    return asSql(prefix, suffix, AnsiSqlDialect.DEFAULT);
  }

  /**
   * Returns the string quoted for SQL, for example _ISO-8859-1'is it a
   * plane? no it''s superman!'.
   *
   * @param prefix if true, prefix the character set name
   * @param suffix if true, suffix the collation clause
   * @param dialect Dialect
   * @return the quoted string
   */
  public String asSql(
      boolean prefix,
      boolean suffix,
      SqlDialect dialect) {
    StringBuilder ret = new StringBuilder();
    dialect.quoteStringLiteral(ret, prefix ? charsetName : null, getValue());

    // NOTE jvs 3-Feb-2005:  see FRG-78 for why this should go away
    if (false) {
      if (suffix && (null != collation)) {
        ret.append(" ");
        ret.append(collation.toString());
      }
    }
    return ret.toString();
  }

  /**
   * Returns the string quoted for SQL, for example _ISO-8859-1'is it a
   * plane? no it''s superman!'.
   */
  public String toString() {
    return asSql(true, true);
  }

  /**
   * Concatenates some {@link NlsString} objects. The result has the charset
   * and collation of the first element. The other elements must have matching
   * (or null) charset and collation. Concatenates all at once, not pairwise,
   * to avoid string copies.
   *
   * @param args array of {@link NlsString} to be concatenated
   */
  public static NlsString concat(List args) {
    if (args.size() < 2) {
      return args.get(0);
    }
    String charSetName = args.get(0).charsetName;
    SqlCollation collation = args.get(0).collation;
    int length = args.get(0).getValue().length();

    // sum string lengths and validate
    for (int i = 1; i < args.size(); i++) {
      final NlsString arg = args.get(i);
      length += arg.getValue().length();
      if (!((arg.charsetName == null)
          || arg.charsetName.equals(charSetName))) {
        throw new IllegalArgumentException("mismatched charsets");
      }
      if (!((arg.collation == null)
          || arg.collation.equals(collation))) {
        throw new IllegalArgumentException("mismatched collations");
      }
    }

    StringBuilder sb = new StringBuilder(length);
    for (NlsString arg : args) {
      sb.append(arg.getValue());
    }
    return new NlsString(
        sb.toString(),
        charSetName,
        collation);
  }

  /** Creates a copy of this {@code NlsString} with different content but same
   * charset and collation. */
  public NlsString copy(String value) {
    return new NlsString(value, charsetName, collation);
  }

  /** Returns the value as a {@link ByteString}. */
  public ByteString getValueBytes() {
    return bytesValue;
  }
}




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