Bug 180842 Config memory buffer size in data engine execution.
To tuning the performance, it is necessary for DtE to expose API for clients to config the size of memory it used to store the final result set. A new AppContext string, "org.eclipse.birt.data.cache.memory.size" is proposed. The new appcontext entry only accept positive integer as input, the unit of which would be MB.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/i18n/ResourceConstants.java
public final static String INVALID_TOTAL_NAME = "data.engine.InvalidTotalFuncName";
	public final static String INVALID_TOTAL_EXPRESSION = "data.engine.InvalidTotalFunc";
	public final static String INVALID_CALL_AGGR = "data.engine.NoAggrFunc";
	public final static String INVALID_EXPR_HANDLE = "data.engine.InvalidExprHandle";	
	
	public final static String INVALID_KEY_COLUMN = "data.engine.InvalidSortKeyColumn";
	public final static String INVALID_GROUP_LEVEL = "data.engine.InvalidGroupLevel";
	public final static String INVALID_GROUP_KEY_COLUMN = "data.engine.InvalidGroupKeyName";
	public final static String INVALID_CLOSESCRIPT = "data.engine.BadCloseScript";
	public final static String INVALID_CUSTOM_FIELD_INDEX = "data.engine.InvalidCustomFieldIdx";
	public final static String INVALID_GROUP_NAME = "data.engine.InvalidGroupName";
	public final static String DUPLICATE_GROUP_NAME = "data.engine.DuplicateGroupName";
	public final static String INVALID_OPENSCRIPT = "data.engine.BadOpenScript";
	public final static String DS_HAS_OPENED = "data.engine.DataSourceIsOpen";
	public final static String DS_NOT_OPEN = "data.engine.DataSourceNotOpen";
	public final static String CUSTOM_FIELD_EMPTY = "data.engine.EmptyCustomFieldName";
	public final static String DUP_CUSTOM_FIELD_NAME = "data.engine.DupCustomFieldName";
	public final static String NO_RESULT_SET = "data.engine.NoResultSet";
	public final static String METADATA_NOT_AVAILABLE = "data.engine.NoResultMetadata";
	public final static String QUERY_HAS_PREPARED = "data.engine.QueryAlreadyPrepared";
	public final static String QUERY_HAS_NOT_PREPARED = "data.engine.QueryNotPrepared";
	public final static String INAVLID_FIELD_NAME = "data.engine.InvalidFieldName";
	public final static String DUPLICATE_COLUMN_NAME = "data.engine.DupColumnName";
	public final static String DUPLICATE_ALIAS_NAME = "data.engine.DupAlias";
	public final static String INVALID_FIELD_INDEX = "data.engine.InvalidFieldIndex";
	
	public final static String MATCH_ERROR = "data.engine.MatchError";
	public final static String UNSUPPORTED_DATA_TYPE = "data.engine.BadOperandType";
	
	public final static String BAD_PARAM_COUNT = "data.engine.BadParameterCount";