/*
 * Copyright Red Hat, Inc. and/or its affiliates
 * and other contributors as indicated by the @author tags and
 * the COPYRIGHT.txt file distributed with this work.
 *
 * 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 org.teiid.core.types.basic;

import java.io.BufferedReader;
import java.io.IOException;
import java.sql.SQLException;

import org.teiid.core.CorePlugin;
import org.teiid.core.types.ClobType;
import org.teiid.core.types.DataTypeManager;
import org.teiid.core.types.TransformationException;
import org.teiid.core.types.DataTypeManager.DefaultDataClasses;


public class ClobToStringTransform extends AnyToStringTransform {

	public ClobToStringTransform() {
		super(DefaultDataClasses.CLOB);
	}
	
    /**
     * This method transforms a value of the source type into a value
     * of the target type.
     * @param value Incoming value of source type
     * @return Outgoing value of target type
     * @throws TransformationException if value is an incorrect input type or
     * the transformation fails
     */
    public Object transformDirect(Object value) throws TransformationException {
        ClobType source = (ClobType)value;
        BufferedReader reader = null;
        try {
            reader = new BufferedReader (source.getCharacterStream());
            StringBuffer contents = new StringBuffer();
            
            int chr = reader.read();
            while (chr != -1 && contents.length() < DataTypeManager.MAX_STRING_LENGTH) {
                contents.append((char)chr);
                chr = reader.read();
            }
            return contents.toString();         
        } catch (SQLException e) {
              throw new TransformationException(CorePlugin.Event.TEIID10080, e, CorePlugin.Util.gs(CorePlugin.Event.TEIID10080, new Object[] {getSourceType().getName(), getTargetType().getName()}));
        } catch(IOException e) {
              throw new TransformationException(CorePlugin.Event.TEIID10080, e, CorePlugin.Util.gs(CorePlugin.Event.TEIID10080, new Object[] {getSourceType().getName(), getTargetType().getName()}));
        } finally {
        	if (reader != null) {
        		try {
					reader.close();
				} catch (IOException e) {
				}
        	}
        }
    }

    /** 
     * @see org.teiid.core.types.Transform#isExplicit()
     */
    public boolean isExplicit() {
        return true;
    }
}
