sqlgeneratedentityaliases.java

介绍了hibernate的入门有一些基本常用的事例

/*
 * Created on 15-Mar-2005
 *
 */
package org.hibernate.loader;

import java.util.Map;

import org.hibernate.persister.entity.Loadable;
import org.hibernate.persister.entity.SQLLoadable;

/**
 * Describes the SQL result set column aliases for a 
 * select clause generated by an entity persister or overridden by propertyresults in a
 * named query.
 * 
 * @author Max Rydahl Andersen,
 */
public class SQLGeneratedEntityAliases implements EntityAliases {
		
		private /*final*/ String[] suffixedKeyColumns;
		private final String[] suffixedVersionColumn;
		private final String[][] suffixedPropertyColumns;
		private final String suffixedDiscriminatorColumn;
		private final String suffix;
		private final String rowIdAlias;
		private Map propertyResults;

		/**
		 * Calculate and cache select-clause suffixes.
		 * @param map 
		 */
		public SQLGeneratedEntityAliases(Map propertyResults, SQLLoadable persister, String suffix) {
			this.suffix = suffix;
			this.propertyResults = propertyResults;
			
			suffixedKeyColumns = get(persister.getIdentifierPropertyName(), (String[])null);
			if(suffixedKeyColumns==null) {
				suffixedKeyColumns = get("id", persister.getIdentifierAliases(suffix));
			}
			
			intern(suffixedKeyColumns);
			suffixedPropertyColumns = getSuffixedPropertyAliases(persister);
			suffixedDiscriminatorColumn = get("class", persister.getDiscriminatorAlias(suffix));
			if ( persister.isVersioned() ) {
				suffixedVersionColumn = suffixedPropertyColumns[ persister.getVersionProperty() ];
			}
			else {
				suffixedVersionColumn = null;
			}
			rowIdAlias = Loadable.ROWID_ALIAS + suffix; // TODO: not visible to the user!
		}

		private String[] get(String propertyPath, String[] aliases) {
			String[] columns = (String[]) propertyResults.get(propertyPath);
			if(columns==null) {
				return aliases;
			} else {
				return columns;
			}
		}

		private String get(String propertyPath, String alias) {
			String[] columns = (String[]) propertyResults.get(propertyPath);
			if(columns==null) {
				return alias;
			} else {
				return columns[0];
			}
		}
		
		public String[][] getSuffixedPropertyAliases(Loadable persister) {
			int size = persister.getPropertyNames().length;
			String[][] suffixedPropertyAliases = new String[size][];
			for ( int j = 0; j < size; j++ ) {
				suffixedPropertyAliases[j] = get(persister.getPropertyNames()[j],persister.getPropertyAliases(suffix, j));
				intern( suffixedPropertyAliases[j] );
			}			
			return suffixedPropertyAliases;
		}

		public String[] getSuffixedVersionAliases() {
			return suffixedVersionColumn;
		}

		public String[][] getSuffixedPropertyAliases() {
			return suffixedPropertyColumns;
		}

		public String getSuffixedDiscriminatorAlias() {
			return suffixedDiscriminatorColumn;
		}

		public String[] getSuffixedKeyAliases() {
			return suffixedKeyColumns;
		}

		public String getRowIdAlias() {
			return rowIdAlias;
		}
		
		private static void intern(String[] strings) {
			for (int i=0; i<strings.length; i++ ) {
				strings[i] = strings[i].intern();
			}
		}
		
	}