ODataQueryExecution.java

/*
 * JBoss, Home of Professional Open Source.
 * See the COPYRIGHT.txt file distributed with this work for information
 * regarding copyright ownership.  Some portions may be licensed
 * to Red Hat, Inc. under one or more contributor license agreements.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301 USA.
 */
package org.teiid.translator.odata;

import java.io.IOException;
import java.sql.Blob;
import java.sql.SQLException;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;

import javax.ws.rs.core.Response.Status;

import org.odata4j.edm.EdmDataServices;
import org.teiid.core.util.ObjectConverterUtil;
import org.teiid.language.QueryExpression;
import org.teiid.metadata.RuntimeMetadata;
import org.teiid.metadata.Schema;
import org.teiid.translator.DataNotAvailableException;
import org.teiid.translator.ExecutionContext;
import org.teiid.translator.ResultSetExecution;
import org.teiid.translator.TranslatorException;
import org.teiid.translator.WSConnection;
import org.teiid.translator.ws.BinaryWSProcedureExecution;

public class ODataQueryExecution extends BaseQueryExecution implements ResultSetExecution {
    
	private ODataSQLVisitor visitor;
	private int countResponse = -1;
	private Class<?>[] expectedColumnTypes;
	private ODataEntitiesResponse response;
	
	public ODataQueryExecution(ODataExecutionFactory translator,
			QueryExpression command, ExecutionContext executionContext,
			RuntimeMetadata metadata, WSConnection connection) throws TranslatorException {
		super(translator, executionContext, metadata, connection);
		
		this.visitor = new ODataSQLVisitor(this.translator, metadata);
    	this.visitor.visitNode(command);
    	if (!this.visitor.exceptions.isEmpty()) {
    		throw visitor.exceptions.get(0);
    	}
    	
    	this.expectedColumnTypes = command.getColumnTypes();
	}

	@Override
	public void execute() throws TranslatorException {
		String URI = this.visitor.buildURL();

		if (this.visitor.isCount()) {
			Map<String, List<String>> headers = new TreeMap<String, List<String>>();
			headers.put("Accept", Arrays.asList("text/xml", "text/plain"));  //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
			
			BinaryWSProcedureExecution execution = executeDirect("GET", URI, null, headers); //$NON-NLS-1$
			if (execution.getResponseCode() != Status.OK.getStatusCode()) {
				throw buildError(execution);
			}
			
			Blob blob = (Blob)execution.getOutputParameterValues().get(0);
			try {
				this.countResponse = Integer.parseInt(ObjectConverterUtil.convertToString(blob.getBinaryStream()));
			} catch (IOException e) {
				throw new TranslatorException(e);
			} catch (SQLException e) {
				throw new TranslatorException(e);
			}			
		}
		else {
			Schema schema = visitor.getEnityTable().getParent();
			EdmDataServices edm = new TeiidEdmMetadata(schema.getName(), ODataEntitySchemaBuilder.buildMetadata( schema));
			this.response = executeWithReturnEntity("GET", URI, null, visitor.getEnityTable().getName(), edm, null, Status.OK, Status.NO_CONTENT, Status.NOT_FOUND); //$NON-NLS-1$
			if (this.response != null && this.response.hasError()) {
				throw this.response.getError();
			}
		}
	}
	
	@Override
	public List<?> next() throws TranslatorException, DataNotAvailableException {
		if (visitor.isCount() && this.countResponse != -1) {
			int count = this.countResponse;
			this.countResponse = -1;
			return Arrays.asList(count);
		}

		// Feed based response
		if (this.response != null && !this.response.hasError()) {
			return this.response.getNextRow(visitor.getSelect(), this.expectedColumnTypes);
		}
		return null;
	}
	
	@Override
	public void close() {
	}

	@Override
	public void cancel() throws TranslatorException {
	}	
}