Java tutorial
/* * * 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 org.apache.hadoop.hbase.rest; import java.io.IOException; import java.util.ArrayList; import java.util.Iterator; import java.util.List; import javax.ws.rs.DefaultValue; import javax.ws.rs.GET; import javax.ws.rs.HeaderParam; import javax.ws.rs.PathParam; import javax.ws.rs.Produces; import javax.ws.rs.QueryParam; import javax.ws.rs.core.Context; import javax.ws.rs.core.Response; import javax.ws.rs.core.Response.ResponseBuilder; import javax.ws.rs.core.UriInfo; import javax.xml.bind.annotation.XmlAccessType; import javax.xml.bind.annotation.XmlAccessorType; import javax.xml.bind.annotation.XmlElement; import javax.xml.bind.annotation.XmlRootElement; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.classification.InterfaceAudience; import org.apache.hadoop.hbase.Cell; import org.apache.hadoop.hbase.CellUtil; import org.apache.hadoop.hbase.client.Result; import org.apache.hadoop.hbase.client.ResultScanner; import org.apache.hadoop.hbase.rest.model.CellModel; import org.apache.hadoop.hbase.rest.model.RowModel; import org.codehaus.jackson.annotate.JsonIgnore; import org.codehaus.jackson.annotate.JsonProperty; @InterfaceAudience.Private public class TableScanResource extends ResourceBase { private static final Log LOG = LogFactory.getLog(TableScanResource.class); TableResource tableResource; ResultScanner results; int userRequestedLimit; public TableScanResource(ResultScanner scanner, int userRequestedLimit) throws IOException { super(); this.results = scanner; this.userRequestedLimit = userRequestedLimit; } @GET @Produces({ Constants.MIMETYPE_XML, Constants.MIMETYPE_JSON }) public CellSetModelStream get(final @Context UriInfo uriInfo) { servlet.getMetrics().incrementRequests(1); final int rowsToSend = userRequestedLimit; servlet.getMetrics().incrementSucessfulScanRequests(1); final Iterator<Result> itr = results.iterator(); return new CellSetModelStream(new ArrayList<RowModel>() { public Iterator<RowModel> iterator() { return new Iterator<RowModel>() { int count = rowsToSend; @Override public boolean hasNext() { if (count > 0) { return itr.hasNext(); } else { return false; } } @Override public void remove() { throw new UnsupportedOperationException( "Remove method cannot be used in CellSetModelStream"); } @Override public RowModel next() { Result rs = itr.next(); if ((rs == null) || (count <= 0)) { return null; } byte[] rowKey = rs.getRow(); RowModel rModel = new RowModel(rowKey); List<Cell> kvs = rs.listCells(); for (Cell kv : kvs) { rModel.addCell(new CellModel(CellUtil.cloneFamily(kv), CellUtil.cloneQualifier(kv), kv.getTimestamp(), CellUtil.cloneValue(kv))); } count--; return rModel; } }; } }); } @GET @Produces({ Constants.MIMETYPE_PROTOBUF, Constants.MIMETYPE_PROTOBUF_IETF }) public Response getProtobuf(final @Context UriInfo uriInfo, final @PathParam("scanspec") String scanSpec, final @HeaderParam("Accept") String contentType, @DefaultValue(Integer.MAX_VALUE + "") @QueryParam(Constants.SCAN_LIMIT) int userRequestedLimit, @DefaultValue("") @QueryParam(Constants.SCAN_START_ROW) String startRow, @DefaultValue("") @QueryParam(Constants.SCAN_END_ROW) String endRow, @DefaultValue("column") @QueryParam(Constants.SCAN_COLUMN) List<String> column, @DefaultValue("1") @QueryParam(Constants.SCAN_MAX_VERSIONS) int maxVersions, @DefaultValue("-1") @QueryParam(Constants.SCAN_BATCH_SIZE) int batchSize, @DefaultValue("0") @QueryParam(Constants.SCAN_START_TIME) long startTime, @DefaultValue(Long.MAX_VALUE + "") @QueryParam(Constants.SCAN_END_TIME) long endTime, @DefaultValue("true") @QueryParam(Constants.SCAN_BATCH_SIZE) boolean cacheBlocks) { servlet.getMetrics().incrementRequests(1); try { int fetchSize = this.servlet.getConfiguration().getInt(Constants.SCAN_FETCH_SIZE, 10); ProtobufStreamingUtil stream = new ProtobufStreamingUtil(this.results, contentType, userRequestedLimit, fetchSize); servlet.getMetrics().incrementSucessfulScanRequests(1); ResponseBuilder response = Response.ok(stream); response.header("content-type", contentType); return response.build(); } catch (Exception exp) { servlet.getMetrics().incrementFailedScanRequests(1); processException(exp); LOG.warn(exp); return null; } } @XmlRootElement(name = "CellSet") @XmlAccessorType(XmlAccessType.FIELD) public static class CellSetModelStream { // JAXB needs an arraylist for streaming @XmlElement(name = "Row") @JsonIgnore private ArrayList<RowModel> Row; public CellSetModelStream() { } public CellSetModelStream(final ArrayList<RowModel> rowList) { this.Row = rowList; } // jackson needs an iterator for streaming @JsonProperty("Row") public Iterator<RowModel> getIterator() { return Row.iterator(); } } }