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* to you under the Apache License, Version 2.0 (the
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package org.apache.cayenne.velocity;
import java.io.IOException;
import java.io.Writer;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.sql.Date;
import java.sql.Time;
import java.sql.Timestamp;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import org.apache.cayenne.access.jdbc.ColumnDescriptor;
import org.apache.cayenne.util.Util;
import org.apache.velocity.context.InternalContextAdapter;
import org.apache.velocity.exception.MethodInvocationException;
import org.apache.velocity.exception.ParseErrorException;
import org.apache.velocity.exception.ResourceNotFoundException;
import org.apache.velocity.runtime.directive.Directive;
import org.apache.velocity.runtime.parser.node.Node;
/**
* A custom Velocity directive to describe a ResultSet column. There are the
* following possible invocation formats inside the template:
*
* <pre>
* #result(column_name) - e.g. #result('ARTIST_ID')
* #result(column_name java_type) - e.g. #result('ARTIST_ID' 'String')
* #result(column_name java_type column_alias) - e.g. #result('ARTIST_ID' 'String' 'ID')
* #result(column_name java_type column_alias data_row_key) - e.g. #result('ARTIST_ID' 'String' 'ID' 'toArtist.ID')
* </pre>
*
* <p>
* 'data_row_key' is needed if SQL 'column_alias' is not appropriate as a
* DataRow key on the Cayenne side. One common case when this happens is when a
* DataRow retrieved from a query is mapped using joint prefetch keys. In this
* case DataRow must use DB_PATH expressions for joint column keys, and their
* format is incompatible with most databases alias format.
* </p>
* <p>
* Most common Java types used in JDBC can be specified without a package. This
* includes all numeric types, primitives, String, SQL dates, BigDecimal and
* BigInteger.
* </p>
*
* @since 1.1
*/
public class ResultDirective extends Directive {
private static final Map<String, String> typesGuess;
static {
// init default types
typesGuess = new HashMap<>();
// primitives
typesGuess.put("long", Long.class.getName());
typesGuess.put("double", Double.class.getName());
typesGuess.put("byte", Byte.class.getName());
typesGuess.put("boolean", Boolean.class.getName());
typesGuess.put("float", Float.class.getName());
typesGuess.put("short", Short.class.getName());
typesGuess.put("int", Integer.class.getName());
// numeric
typesGuess.put("Long", Long.class.getName());
typesGuess.put("Double", Double.class.getName());
typesGuess.put("Byte", Byte.class.getName());
typesGuess.put("Boolean", Boolean.class.getName());
typesGuess.put("Float", Float.class.getName());
typesGuess.put("Short", Short.class.getName());
typesGuess.put("Integer", Integer.class.getName());
// other
typesGuess.put("String", String.class.getName());
typesGuess.put("Date", Date.class.getName());
typesGuess.put("Time", Time.class.getName());
typesGuess.put("Timestamp", Timestamp.class.getName());
typesGuess.put("BigDecimal", BigDecimal.class.getName());
typesGuess.put("BigInteger", BigInteger.class.getName());
}
@Override
public String getName() {
return "result";
}
@Override
public int getType() {
return LINE;
}
@Override
public boolean render(InternalContextAdapter context, Writer writer, Node node) throws IOException,
ResourceNotFoundException, ParseErrorException, MethodInvocationException {
String column = getChildAsString(context, node, 0);
if (column == null) {
throw new ParseErrorException("Column name expected at line " + node.getLine() + ", column "
+ node.getColumn());
}
String alias = getChildAsString(context, node, 2);
String dataRowKey = getChildAsString(context, node, 3);
// determine what we want to name this column in a resulting DataRow...
String label = (!Util.isEmptyString(dataRowKey)) ? dataRowKey : (!Util.isEmptyString(alias)) ? alias : null;
ColumnDescriptor columnDescriptor = new ColumnDescriptor();
columnDescriptor.setName(column);
columnDescriptor.setDataRowKey(label);
String type = getChildAsString(context, node, 1);
if (type != null) {
columnDescriptor.setJavaClass(guessType(type));
}
// TODO: andrus 6/27/2007 - this is an unofficial jdbcType parameter
// that is added
// temporarily pending CAY-813 implementation for the sake of EJBQL
// query...
Object jdbcType = getChild(context, node, 4);
if (jdbcType instanceof Number) {
columnDescriptor.setJdbcType(((Number) jdbcType).intValue());
}
writer.write(column);
// append column alias if needed.
// Note that if table aliases are used, this logic will result in SQL
// like
// "t0.ARTIST_NAME AS ARTIST_NAME". Doing extra regex matching to handle
// this
// won't probably buy us much.
if (!Util.isEmptyString(alias) && !alias.equals(column)) {
writer.write(" AS ");
writer.write(alias);
}
bindResult(context, columnDescriptor);
return true;
}
protected Object getChild(InternalContextAdapter context, Node node, int i) throws MethodInvocationException {
return (i >= 0 && i < node.jjtGetNumChildren()) ? node.jjtGetChild(i).value(context) : null;
}
/**
* Returns a directive argument at a given index converted to String.
*
* @since 1.2
*/
protected String getChildAsString(InternalContextAdapter context, Node node, int i)
throws MethodInvocationException {
Object value = getChild(context, node, i);
return (value != null) ? value.toString() : null;
}
/**
* Converts "short" type notation to the fully qualified class name. Right
* now supports all major standard SQL types, including primitives. All
* other types are expected to be fully qualified, and are not converted.
*/
protected String guessType(String type) {
String guessed = typesGuess.get(type);
return guessed != null ? guessed : type;
}
/**
* Adds value to the list of result columns in the context.
*/
protected void bindResult(InternalContextAdapter context, ColumnDescriptor columnDescriptor) {
Collection<Object> resultColumns = (Collection<Object>) context.getInternalUserContext().get(
VelocitySQLTemplateProcessor.RESULT_COLUMNS_LIST_KEY);
if (resultColumns != null) {
resultColumns.add(columnDescriptor);
}
}
}