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Partial Java port of the OpenFST library; forked from the CMU Sphinx project

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/*
 * FrozenWriteableSymbolTableAdapter.java
 *
 * Copyright (c) 2017 Amazon.com, Inc. or its affiliates. All rights reserved.
 *
 * PROPRIETARY/CONFIDENTIAL
 *
 * Use is subject to license terms.
 */
package com.github.steveash.jopenfst;

import com.carrotsearch.hppc.cursors.IntCursor;
import com.carrotsearch.hppc.cursors.ObjectIntCursor;

import java.util.Iterator;

/**
 * Adapter/decorator for a symbol table (any kind) that presents a writeable symbol table interface but throws
 * exceptions if you actually try to write to it
 */
public class FrozenSymbolTable implements WriteableSymbolTable {

  /**
   * Freeze the given symbol table by decorating it (or just returning if its already frozen)
   * @param symbolTable
   * @return
   */
  public static FrozenSymbolTable freeze(SymbolTable symbolTable) {
    if (symbolTable instanceof FrozenSymbolTable) {
      return (FrozenSymbolTable) symbolTable;
    }
    return new FrozenSymbolTable(symbolTable);
  }

  private final SymbolTable backing;

  public FrozenSymbolTable(SymbolTable backing) {
    this.backing = backing;
  }

  @Override
  public int size() {
    return backing.size();
  }

  @Override
  public Iterator> iterator() {
    return backing.iterator();
  }

  @Override
  public Iterable indexes() {
    return backing.indexes();
  }

  @Override
  public Iterable symbols() {
    return backing.symbols();
  }

  @Override
  public int get(String symbol) {
    return backing.get(symbol);
  }

  @Override
  public boolean contains(String symbol) {
    return backing.contains(symbol);
  }

  @Override
  public InvertedSymbolTable invert() {
    return backing.invert();
  }

  @Override
  public int getOrAdd(String symbol) {
    try {
      return backing.get(symbol);
    } catch (IllegalArgumentException e) {
      throw new IllegalArgumentException("You cannot add a new symbol to a frozen symbol table", e);
    }
  }

  @Override
  public void put(String symbol, int id) {
    throw new IllegalArgumentException("You cannot put a mapping in a frozen symbol table; trying to add " +
        symbol + " -> " + id);
  }
}