FIX: correct behavior of "startsWith, "contains" etc (#1031)

* FIX: correct behavior of "startsWith" if string contains "like"-wildcards

* Removed likeClasues with disabled escaping in database platforms as bind values are properly escaped now.

src/main/java/io/ebean/LikeType.java

@@ -6,22 +6,22 @@ package io.ebean;
 public enum LikeType {
 
   /**
-   * You need to put in your own wildcards.
+   * You need to put in your own wildcards - no escaping is performed.
    */
   RAW,
 
   /**
-   * The % wildcard is added to the end of the search word.
+   * The % wildcard is added to the end of the search word and search word is escaped.
    */
   STARTS_WITH,
 
   /**
-   * The % wildcard is added to the beginning of the search word.
+   * The % wildcard is added to the beginning of the search word and search word is escaped.
    */
   ENDS_WITH,
 
   /**
-   * The % wildcard is added to the beginning and end of the search word.
+   * The % wildcard is added to the beginning and end of the search word and search word is escaped.
    */
   CONTAINS,
 

src/main/java/io/ebean/config/dbplatform/DatabasePlatform.java

@@ -174,6 +174,8 @@ public class DatabasePlatform {
   protected boolean supportsNativeIlike;
 
   protected SqlExceptionTranslator exceptionTranslator = new SqlCodeTranslator();
+  
+  protected char[] specialLikeCharacters = { '%', '_' };
 
   /**
    * Instantiates a new database platform.
@@ -617,4 +619,37 @@ public class DatabasePlatform {
       logger.error("Error closing resultSet", e);
     }
   }
+
+  /**
+   * Escapes the like string for this DB-Platform
+   */
+  public String escapeLikeString(String value) {
+    StringBuilder sb = null;
+    for (int i = 0; i < value.length(); i++) {
+      char ch = value.charAt(i);
+      boolean escaped = false;
+      for (char escapeChar: specialLikeCharacters) {
+        if (ch == escapeChar) {
+          if (sb == null) {
+            sb = new StringBuilder(value.substring(0, i));
+          }
+          escapeLikeCharacter(escapeChar, sb);
+          escaped = true;
+          break;
+        }
+      }
+      if (!escaped && sb != null) {
+        sb.append(ch);
+      }
+    }
+    if (sb == null) {
+      return value;
+    } else {
+      return sb.toString();
+    }
+  }
+  
+  protected void escapeLikeCharacter(char ch, StringBuilder sb) {
+    sb.append('\\').append(ch);
+  }
 }

src/main/java/io/ebean/config/dbplatform/h2/H2Platform.java

@@ -40,10 +40,6 @@ public class H2Platform extends DatabasePlatform {
     this.dbIdentity.setSupportsSequence(true);
     this.dbIdentity.setSupportsIdentity(true);
 
-    // like ? escape'' not working in the latest version H2 so just using no
-    // escape clause for now noting that backslash is an escape char for like in H2
-    this.likeClause = "like ?";
-
     dbTypeMap.put(DbType.UUID, new DbPlatformType("uuid", false));
   }
 

src/main/java/io/ebean/config/dbplatform/mysql/MySqlPlatform.java

@@ -30,7 +30,6 @@ public class MySqlPlatform extends DatabasePlatform {
     super();
     this.platform = Platform.MYSQL;
     this.useExtraTransactionOnIterateSecondaryQueries = true;
-    this.likeClause = "like ? escape''";
     this.selectCountWithAlias = true;
     this.dbEncrypt = new MySqlDbEncrypt();
     this.platformDdl = new MySqlDdl(this);

src/main/java/io/ebean/config/dbplatform/postgres/PostgresPlatform.java

@@ -28,7 +28,6 @@ public class PostgresPlatform extends DatabasePlatform {
     super();
     this.platform = Platform.POSTGRES;
     this.supportsNativeIlike = true;
-    this.likeClause = "like ? escape''";
     this.selectCountWithAlias = true;
     this.blobDbType = Types.LONGVARBINARY;
     this.clobDbType = Types.VARCHAR;

src/main/java/io/ebean/config/dbplatform/sqlserver/SqlServerPlatform.java

@@ -41,6 +41,8 @@ public class SqlServerPlatform extends DatabasePlatform {
 
     this.openQuote = "[";
     this.closeQuote = "]";
+    this.specialLikeCharacters =  new char[] { '%', '_', '[' };
+    this.likeClause = "like ? COLLATE Latin1_General_BIN";
 
     booleanDbType = Types.INTEGER;
     dbTypeMap.put(DbType.BOOLEAN, new DbPlatformType("bit default 0"));
@@ -63,4 +65,9 @@ public class SqlServerPlatform extends DatabasePlatform {
 
   }
 
+  @Override
+  protected void escapeLikeCharacter(char ch, StringBuilder sb) {
+    sb.append('[').append(ch).append(']');
+  }
+
 }

src/main/java/io/ebeaninternal/api/SpiExpressionRequest.java

@@ -65,4 +65,9 @@ public interface SpiExpressionRequest {
    * Append a DB Like clause.
    */
   void appendLike();
+
+  /**
+   * Escapes a string to use it as exact match in Like clause.
+   */
+  String escapeLikeString(String value);
 }

src/main/java/io/ebeaninternal/server/core/OrmQueryRequest.java

@@ -96,6 +96,14 @@ public final class OrmQueryRequest<T> extends BeanRequest implements BeanQueryRe
   public String getDBLikeClause() {
     return ebeanServer.getDatabasePlatform().getLikeClause();
   }
+  
+  /**
+   * Return the database platform escaped like string.
+   */
+  @Override
+  public String escapeLikeString(String value) {
+    return ebeanServer.getDatabasePlatform().escapeLikeString(value);
+  }
 
   @Override
   public void executeSecondaryQueries(boolean forEach) {

src/main/java/io/ebeaninternal/server/core/SpiOrmQueryRequest.java

@@ -123,6 +123,11 @@ public interface SpiOrmQueryRequest<T> extends DocQueryRequest<T> {
    * Return the Database platform like clause.
    */
   String getDBLikeClause();
+  
+  /**
+   * Escapes a string to use it as exact match in Like clause.
+   */
+  String escapeLikeString(String value);
 
   /**
    * Mark the underlying transaction as not being query only.

src/main/java/io/ebeaninternal/server/expression/DefaultExpressionRequest.java

@@ -93,6 +93,11 @@ public class DefaultExpressionRequest implements SpiExpressionRequest {
     sql.append(" ");
   }
 
+  @Override
+  public String escapeLikeString(String value) {
+    return queryRequest.escapeLikeString(value);
+  }
+
   /**
    * Increments the parameter index and returns that value.
    */

src/main/java/io/ebeaninternal/server/expression/LikeExpression.java

@@ -34,8 +34,7 @@ class LikeExpression extends AbstractValueExpression {
       String encryptKey = prop.getBeanProperty().getEncryptKey().getStringValue();
       request.addBindEncryptKey(encryptKey);
     }
-
-    String bindValue = getValue(strValue(), caseInsensitive, type);
+    String bindValue = getValue(strValue(), caseInsensitive, type, request);
     request.addBindValue(bindValue);
   }
 
@@ -92,13 +91,15 @@ class LikeExpression extends AbstractValueExpression {
     return strValue().equals(that.strValue());
   }
 
-  private static String getValue(String value, boolean caseInsensitive, LikeType type) {
+  private static String getValue(String value, boolean caseInsensitive, LikeType type, SpiExpressionRequest request) {
     if (caseInsensitive) {
       value = value.toLowerCase();
     }
+    if (type == LikeType.RAW) {
+      return value;
+    }
+    value = request.escapeLikeString(value);
     switch (type) {
-      case RAW:
-        return value;
       case STARTS_WITH:
         return value + "%";
       case ENDS_WITH: