001/*
002 * Copyright (c) 2007-2015 Concurrent, Inc. All Rights Reserved.
003 *
004 * Project and contact information: http://www.cascading.org/
005 *
006 * This file is part of the Cascading project.
007 *
008 * Licensed under the Apache License, Version 2.0 (the "License");
009 * you may not use this file except in compliance with the License.
010 * You may obtain a copy of the License at
011 *
012 *     http://www.apache.org/licenses/LICENSE-2.0
013 *
014 * Unless required by applicable law or agreed to in writing, software
015 * distributed under the License is distributed on an "AS IS" BASIS,
016 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
017 * See the License for the specific language governing permissions and
018 * limitations under the License.
019 */
020
021package cascading.operation.expression;
022
023import java.beans.ConstructorProperties;
024import java.io.IOException;
025import java.io.StringReader;
026
027import cascading.operation.OperationException;
028import cascading.tuple.Fields;
029import org.codehaus.commons.compiler.CompileException;
030import org.codehaus.janino.ExpressionEvaluator;
031import org.codehaus.janino.Scanner;
032import org.codehaus.janino.ScriptEvaluator;
033
034import static cascading.tuple.coerce.Coercions.asClass;
035
036/**
037 * Class ExpressionOperation is the base class for {@link ExpressionFunction}, {@link ExpressionFilter},
038 * {@link cascading.operation.assertion.AssertExpression}.
039 */
040public class ExpressionOperation extends ScriptOperation
041  {
042  @ConstructorProperties({"expression"})
043  protected ExpressionOperation( String expression )
044    {
045    super( ANY, expression, Boolean.class );
046    }
047
048  @ConstructorProperties({"fieldDeclaration", "expression"})
049  protected ExpressionOperation( Fields fieldDeclaration, String expression )
050    {
051    super( ANY, fieldDeclaration, expression, asClass( fieldDeclaration.getType( 0 ) ) );
052    }
053
054  @ConstructorProperties({"fieldDeclaration", "expression", "parameterType"})
055  protected ExpressionOperation( Fields fieldDeclaration, String expression, Class parameterType )
056    {
057    super( 1, fieldDeclaration, expression, asClass( fieldDeclaration.getType( 0 ) ), null,
058      new Class[]{parameterType} );
059    }
060
061  @ConstructorProperties({"fieldDeclaration", "expression", "parameterNames", "parameterTypes"})
062  protected ExpressionOperation( Fields fieldDeclaration, String expression, String[] parameterNames, Class[] parameterTypes )
063    {
064    super( parameterTypes.length, fieldDeclaration, expression, asClass( fieldDeclaration.getType( 0 ) ), parameterNames, parameterTypes );
065    }
066
067  @ConstructorProperties({"expression", "parameterType"})
068  protected ExpressionOperation( String expression, Class parameterType )
069    {
070    super( 1, expression, Object.class, null, new Class[]{parameterType} );
071    }
072
073  @ConstructorProperties({"expression", "parameterNames", "parameterTypes"})
074  protected ExpressionOperation( String expression, String[] parameterNames, Class[] parameterTypes )
075    {
076    super( parameterTypes.length, expression, Object.class, parameterNames, parameterTypes );
077    }
078
079  public String getExpression()
080    {
081    return getBlock();
082    }
083
084  protected String[] guessParameterNames() throws CompileException, IOException
085    {
086    return ExpressionEvaluator.guessParameterNames( new Scanner( "expressionEval", new StringReader( block ) ) );
087    }
088
089  @Override
090  protected ScriptEvaluator getEvaluator( Class returnType, String[] parameterNames, Class[] parameterTypes )
091    {
092    try
093      {
094      return new ExpressionEvaluator( block, getReturnType(), parameterNames, parameterTypes );
095      }
096    catch( CompileException exception )
097      {
098      throw new OperationException( "could not compile expression: " + block, exception );
099      }
100    }
101  }