| /* |
| * 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.phoenix.expression; |
| |
| import java.io.DataInput; |
| import java.io.DataOutput; |
| import java.io.IOException; |
| |
| import org.apache.hadoop.hbase.io.ImmutableBytesWritable; |
| import org.apache.phoenix.expression.visitor.ExpressionVisitor; |
| import org.apache.phoenix.schema.PDatum; |
| import org.apache.phoenix.schema.RowKeyValueAccessor; |
| import org.apache.phoenix.schema.tuple.Tuple; |
| import org.apache.phoenix.schema.types.PDataType; |
| import org.apache.phoenix.util.ByteUtil; |
| |
| |
| /** |
| * |
| * Class to access a value stored in the row key |
| * |
| * |
| * @since 0.1 |
| */ |
| public class RowKeyColumnExpression extends ColumnExpression { |
| private PDataType fromType; |
| private RowKeyValueAccessor accessor; |
| protected final String name; |
| private int offset; |
| |
| public RowKeyColumnExpression() { |
| name = null; // Only on client |
| } |
| |
| private RowKeyColumnExpression(PDatum datum, RowKeyValueAccessor accessor, PDataType fromType, String name) { |
| super(datum); |
| this.accessor = accessor; |
| this.fromType = fromType; |
| this.name = name; |
| } |
| |
| public RowKeyColumnExpression(PDatum datum, RowKeyValueAccessor accessor) { |
| this(datum, accessor, datum.getDataType(), datum.toString()); |
| } |
| |
| public RowKeyColumnExpression(PDatum datum, RowKeyValueAccessor accessor, String name) { |
| this(datum, accessor, datum.getDataType(), name); |
| } |
| |
| public RowKeyColumnExpression(PDatum datum, RowKeyValueAccessor accessor, PDataType fromType) { |
| this(datum, accessor, fromType, datum.toString()); |
| } |
| |
| /** |
| * Used to set an offset to be skipped from the start of a the row key. Used by |
| * local indexing to skip the region start key bytes. |
| * @param offset the number of bytes to offset accesses to row key columns |
| */ |
| public void setOffset(int offset) { |
| this.offset = offset; |
| } |
| |
| public int getPosition() { |
| return accessor.getIndex(); |
| } |
| |
| public String getName() { |
| return name; |
| } |
| |
| @Override |
| public int hashCode() { |
| final int prime = 31; |
| int result = super.hashCode(); |
| result = prime * result + ((accessor == null) ? 0 : accessor.hashCode()); |
| return result; |
| } |
| |
| @Override |
| public String toString() { |
| return name == null ? "PK[" + accessor.getIndex() + "]" : name; |
| } |
| |
| @Override |
| public boolean equals(Object obj) { |
| if (this == obj) return true; |
| if (!super.equals(obj)) return false; |
| if (getClass() != obj.getClass()) return false; |
| RowKeyColumnExpression other = (RowKeyColumnExpression)obj; |
| return accessor.equals(other.accessor); |
| } |
| |
| @Override |
| public boolean evaluate(Tuple tuple, ImmutableBytesWritable ptr) { |
| tuple.getKey(ptr); |
| int offset = accessor.getOffset(ptr.get(), ptr.getOffset() + this.offset); |
| // Null is represented in the last expression of a multi-part key |
| // by the bytes not being present. |
| int maxOffset = ptr.getOffset() + ptr.getLength(); |
| if (offset < maxOffset) { |
| byte[] buffer = ptr.get(); |
| int byteSize = -1; |
| // FIXME: fixedByteSize <= maxByteSize ? fixedByteSize : 0 required because HBase passes bogus keys to filter to position scan (HBASE-6562) |
| if (fromType.isFixedWidth()) { |
| Integer maxLength = getMaxLength(); |
| byteSize = fromType.getByteSize() == null ? maxLength : fromType.getByteSize(); |
| byteSize = byteSize <= maxOffset ? byteSize : 0; |
| } |
| int length = byteSize >= 0 ? byteSize : accessor.getLength(buffer, offset, maxOffset); |
| // In the middle of the key, an empty variable length byte array represents null |
| if (length > 0) { |
| ptr.set(buffer,offset,length); |
| type.coerceBytes(ptr, fromType, getSortOrder(), getSortOrder()); |
| } else { |
| ptr.set(ByteUtil.EMPTY_BYTE_ARRAY); |
| } |
| } else { |
| ptr.set(ByteUtil.EMPTY_BYTE_ARRAY); |
| } |
| // Always return true because we're always able to evaluate a row key column |
| return true; |
| } |
| |
| @Override |
| public void readFields(DataInput input) throws IOException { |
| super.readFields(input); |
| accessor = new RowKeyValueAccessor(); |
| accessor.readFields(input); |
| fromType = type; // fromType only needed on client side |
| } |
| |
| @Override |
| public void write(DataOutput output) throws IOException { |
| super.write(output); |
| accessor.write(output); |
| } |
| |
| @Override |
| public final <T> T accept(ExpressionVisitor<T> visitor) { |
| return visitor.visit(this); |
| } |
| |
| /** |
| * Since we may never have encountered a key value column of interest, but the |
| * expression may evaluate to true just based on the row key columns, we need |
| * to do a final evaluation. An example of when this would be required is: |
| * SELECT a FROM t WHERE a = 5 OR b = 2 |
| * in the case where a is a PK column, b is a KV column and no b KV is found. |
| */ |
| @Override |
| public boolean requiresFinalEvaluation() { |
| return true; |
| } |
| } |