| /* |
| * Copyright 2005 The Apache Software Foundation. |
| * |
| * Licensed 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. |
| */ |
| |
| /* |
| * Query.java |
| * |
| */ |
| |
| package javax.jdo; |
| import java.io.Serializable; |
| import java.util.Collection; |
| import java.util.Map; |
| |
| /** The <code>Query</code> interface allows applications to obtain persistent |
| * instances, values, and aggregate data |
| * from the data store. |
| * |
| * The {@link PersistenceManager} is the factory for <code>Query</code> instances. There |
| * may be many <code>Query</code> instances associated with a <code>PersistenceManager</code>. |
| * Multiple queries might be executed simultaneously by different threads, but the |
| * implementation might choose to execute them serially. In either case, the |
| * implementation must be thread safe. |
| * |
| * <P>There are three required elements in a <code>Query</code>: the class of the results, |
| * the candidate collection of instances, and the filter. |
| * |
| * <P>There are optional elements: parameter declarations, variable |
| * declarations, import statements, ordering and grouping specifications, |
| * result and result class, the range of results, |
| * and flags indicating whether the query result |
| * is unique and whether the query can be modified. |
| * <P>The query namespace is modeled after methods in Java: |
| * <ul> |
| * <li><code>setClass</code> corresponds to the class definition |
| * <li><code>declareParameters</code> corresponds to formal parameters of a method |
| * <li><code>declareVariables</code> corresponds to local variables of a method |
| * <li><code>setFilter</code> and <code>setOrdering</code> correspond to the method body |
| * </ul> |
| * <P>There are two namespaces in queries. Type names have their own |
| * namespace that is separate from the namespace for fields, variables |
| * and parameters. |
| * <P>The method <code>setClass</code> introduces the name of the candidate class in |
| * the type namespace. The method <code>declareImports</code> introduces the names of |
| * the imported class or interface types in the type namespace. Imported |
| * type names must be unique. When used (e.g. in a parameter declaration, |
| * cast expression, etc.) a type name must be the name of the candidate |
| * class, the name of a class or interface imported by method |
| * <code>declareImports</code>, or denote a class or interface from the same |
| * package as the candidate class. |
| * <P>The method <code>setClass</code> introduces the names of the candidate class fields. |
| * <P>The method <code>declareParameters</code> introduces the names of the |
| * parameters. A name introduced by <code>declareParameters</code> hides the name |
| * of a candidate class field of the same name. Parameter names must be unique. |
| * <P>The method <code>declareVariables</code> introduces the names of the variables. |
| * A name introduced by <code>declareVariables</code> hides the name of a candidate |
| * class field if equal. Variable names must be unique and must not |
| * conflict with parameter names. |
| * <P>The result of the query by default is a list of result class instances, |
| * but might be specified via <code>setResult</code>. The class of the result |
| * by default is the candidate class, but might be specified via |
| * <code>setResultClass</code>. |
| * <P>A hidden field may be accessed using the 'this' qualifier: |
| * <code>this.fieldName</code>. |
| * <P>The <code>Query</code> interface provides methods which execute the query |
| * based on the parameters given. They return a single instance or a |
| * <code>List</code> of result class instances which the |
| * user can iterate to get results. The signature |
| * of the <code>execute</code> methods specifies that they return an <code>Object</code> which |
| * must be cast to the appropriate result by the user. |
| * <P>Any parameters passed to the <code>execute</code> methods are used only for |
| * this execution, and are not remembered for future execution. |
| * @version 2.0 |
| */ |
| |
| public interface Query extends Serializable { |
| |
| /** |
| * The string constant used as the first argument to {@link |
| * PersistenceManager#newQuery(String,Object)} to identify that |
| * the created query should obey the JDOQL syntax and semantic |
| * rules. |
| * <p>This is the default query language used when creating a |
| * query with any of the other {@link |
| * PersistenceManager#newQuery} methods, except {@link |
| * PersistenceManager#newQuery(Object)}, which uses the query |
| * language of the compiled query template object passed to that |
| * method.</p> |
| * @since 2.0 |
| */ |
| String JDOQL = "javax.jdo.query.JDOQL"; |
| |
| /** |
| * The string constant used as the first argument to {@link |
| * PersistenceManager#newQuery(String,Object)} to identify that |
| * the created query should use SQL semantics. This is only |
| * meaningful for relational JDO implementations. |
| * <p>If this is used, the <code>Object</code> argument to the |
| * {@link PersistenceManager#newQuery(String,Object)} method |
| * should be a <code>String</code> containing a SQL |
| * <code>SELECT</code> statement.</p> |
| * @since 2.0 |
| */ |
| String SQL = "javax.jdo.query.SQL"; |
| |
| /** Set the class of the candidate instances of the query. |
| * <P>The class specifies the class |
| * of the candidates of the query. Elements of the candidate collection |
| * that are of the specified class are filtered before being |
| * put into the result <code>Collection</code>. |
| * |
| * @param cls the <code>Class</code> of the candidate instances. |
| */ |
| void setClass(Class cls); |
| |
| /** Set the candidate <code>Extent</code> to query. |
| * @param pcs the candidate <code>Extent</code>. |
| */ |
| void setCandidates(Extent pcs); |
| |
| /** Set the candidate <code>Collection</code> to query. |
| * @param pcs the candidate <code>Collection</code>. |
| */ |
| void setCandidates(Collection pcs); |
| |
| /** Set the filter for the query. |
| * |
| * <P>The filter specification is a <code>String</code> containing a Boolean |
| * expression that is to be evaluated for each of the instances |
| * in the candidate collection. If the filter is not specified, |
| * then it defaults to "true", which has the effect of filtering |
| * the input <code>Collection</code> only for class type. |
| * <P>An element of the candidate collection is returned in the result if: |
| * <ul><li>it is assignment compatible to the candidate <code>Class</code> of the <code>Query</code>; and |
| * <li>for all variables there exists a value for which the filter |
| * expression evaluates to <code>true</code>. |
| * </ul> |
| * <P>The user may denote uniqueness in the filter expression by |
| * explicitly declaring an expression (for example, <code>e1 != e2</code>). |
| * <P>Rules for constructing valid expressions follow the Java |
| * language, except for these differences: |
| * <ul> |
| * <li>Equality and ordering comparisons between primitives and instances |
| * of wrapper classes are valid. |
| * <li>Equality and ordering comparisons of <code>Date</code> fields and <code>Date</code> |
| * parameters are valid. |
| * <li>White space (non-printing characters space, tab, carriage |
| * return, and line feed) is a separator and is otherwise ignored. |
| * <li>The assignment operators <code>=</code>, <code>+=</code>, etc. and pre- and post-increment |
| * and -decrement are not supported. Therefore, there are no side |
| * effects from evaluation of any expressions. |
| * <li>Methods, including object construction, are not supported, except |
| * for <code>Collection.contains(Object o)</code>, <code>Collection.isEmpty()</code>, |
| * <code>String.startsWith(String s)</code>, and <code>String.endsWith(String e)</code>. |
| * Implementations might choose to support non-mutating method |
| * calls as non-standard extensions. |
| * <li>Navigation through a <code>null</code>-valued field, which would throw |
| * <code>NullPointerException</code>, is treated as if the filter expression |
| * returned <code>false</code> for the evaluation of the current set of variable |
| * values. Other values for variables might still qualify the candidate |
| * instance for inclusion in the result set. |
| * <li>Navigation through multi-valued fields (<code>Collection</code> types) is |
| * specified using a variable declaration and the |
| * <code>Collection.contains(Object o)</code> method. |
| * </ul> |
| * <P>Identifiers in the expression are considered to be in the name |
| * space of the specified class, with the addition of declared imports, |
| * parameters and variables. As in the Java language, <code>this</code> is a reserved |
| * word which means the element of the collection being evaluated. |
| * <P>Navigation through single-valued fields is specified by the Java |
| * language syntax of <code>field_name.field_name....field_name</code>. |
| * <P>A JDO implementation is allowed to reorder the filter expression |
| * for optimization purposes. |
| * @param filter the query filter. |
| */ |
| void setFilter(String filter); |
| |
| /** Set the import statements to be used to identify the fully qualified name of |
| * variables or parameters. Parameters and unbound variables might |
| * come from a different class from the candidate class, and the names |
| * need to be declared in an import statement to eliminate ambiguity. |
| * Import statements are specified as a <code>String</code> with semicolon-separated |
| * statements. |
| * <P>The <code>String</code> parameter to this method follows the syntax of the |
| * import statement of the Java language. |
| * @param imports import statements separated by semicolons. |
| */ |
| void declareImports(String imports); |
| |
| /** Declare the list of parameters query execution. |
| * |
| * The parameter declaration is a <code>String</code> containing one or more query |
| * parameter declarations separated with commas. Each parameter named |
| * in the parameter declaration must be bound to a value when |
| * the query is executed. |
| * <P>The <code>String</code> parameter to this method follows the syntax for formal |
| * parameters in the Java language. |
| * @param parameters the list of parameters separated by commas. |
| */ |
| void declareParameters(String parameters); |
| |
| /** Declare the unbound variables to be used in the query. Variables |
| * might be used in the filter, and these variables must be declared |
| * with their type. The unbound variable declaration is a <code>String</code> |
| * containing one or more unbound variable declarations separated |
| * with semicolons. It follows the syntax for local variables in |
| * the Java language. |
| * @param variables the variables separated by semicolons. |
| */ |
| void declareVariables(String variables); |
| |
| /** Set the ordering specification for the result <code>Collection</code>. The |
| * ordering specification is a <code>String</code> containing one or more ordering |
| * declarations separated by commas. |
| * |
| * <P>Each ordering declaration is the name of the field on which |
| * to order the results followed by one of the following words: |
| * "<code>ascending</code>" or "<code>descending</code>". |
| * |
| *<P>The field must be declared in the candidate class or must be |
| * a navigation expression starting with a field in the candidate class. |
| * |
| *<P>Valid field types are primitive types except <code>boolean</code>; wrapper types |
| * except <code>Boolean</code>; <code>BigDecimal</code>; <code>BigInteger</code>; |
| * <code>String</code>; and <code>Date</code>. |
| * @param ordering the ordering specification. |
| */ |
| void setOrdering(String ordering); |
| |
| /** Set the ignoreCache option. The default value for this option was |
| * set by the <code>PersistenceManagerFactory</code> or the |
| * <code>PersistenceManager</code> used to create this <code>Query</code>. |
| * |
| * The ignoreCache option setting specifies whether the query should execute |
| * entirely in the back end, instead of in the cache. If this flag is set |
| * to <code>true</code>, an implementation might be able to optimize the query |
| * execution by ignoring changed values in the cache. For optimistic |
| * transactions, this can dramatically improve query response times. |
| * @param ignoreCache the setting of the ignoreCache option. |
| */ |
| void setIgnoreCache(boolean ignoreCache); |
| |
| /** Get the ignoreCache option setting. |
| * @return the ignoreCache option setting. |
| * @see #setIgnoreCache |
| */ |
| boolean getIgnoreCache(); |
| |
| /** Verify the elements of the query and provide a hint to the query to |
| * prepare and optimize an execution plan. |
| */ |
| void compile(); |
| |
| /** Execute the query and return the filtered Collection. |
| * @return the filtered <code>Collection</code>. |
| * @see #executeWithArray(Object[] parameters) |
| */ |
| Object execute(); |
| |
| /** Execute the query and return the filtered <code>Collection</code>. |
| * @return the filtered <code>Collection</code>. |
| * @see #executeWithArray(Object[] parameters) |
| * @param p1 the value of the first parameter declared. |
| */ |
| Object execute(Object p1); |
| |
| /** Execute the query and return the filtered <code>Collection</code>. |
| * @return the filtered <code>Collection</code>. |
| * @see #executeWithArray(Object[] parameters) |
| * @param p1 the value of the first parameter declared. |
| * @param p2 the value of the second parameter declared. |
| */ |
| Object execute(Object p1, Object p2); |
| |
| /** Execute the query and return the filtered <code>Collection</code>. |
| * @return the filtered <code>Collection</code>. |
| * @see #executeWithArray(Object[] parameters) |
| * @param p1 the value of the first parameter declared. |
| * @param p2 the value of the second parameter declared. |
| * @param p3 the value of the third parameter declared. |
| */ |
| Object execute(Object p1, Object p2, Object p3); |
| |
| /** Execute the query and return the filtered <code>Collection</code>. The query |
| * is executed with the parameters set by the <code>Map</code> values. Each <code>Map</code> entry |
| * consists of a key which is the name of the parameter in the |
| * <code>declareParameters</code> method, and a value which is the value used in |
| * the <code>execute</code> method. The keys in the <code>Map</code> and the declared parameters |
| * must exactly match or a <code>JDOUserException</code> is thrown. |
| * @return the filtered <code>Collection</code>. |
| * @see #executeWithArray(Object[] parameters) |
| * @param parameters the <code>Map</code> containing all of the parameters. |
| */ |
| Object executeWithMap (Map parameters); |
| |
| /** Execute the query and return the filtered <code>Collection</code>. |
| * |
| * <P>The execution of the query obtains the values of the parameters and |
| * matches them against the declared parameters in order. The names |
| * of the declared parameters are ignored. The type of |
| * the declared parameters must match the type of the passed parameters, |
| * except that the passed parameters might need to be unwrapped to get |
| * their primitive values. |
| * |
| * <P>The filter, import, declared parameters, declared variables, and |
| * ordering statements are verified for consistency. |
| * |
| * <P>Each element in the candidate <code>Collection</code> is examined to see that it |
| * is assignment compatible to the <code>Class</code> of the query. It is then evaluated |
| * by the Boolean expression of the filter. The element passes the filter |
| * if there exist unique values for all variables for which the filter |
| * expression evaluates to <code>true</code>. |
| * @return the filtered <code>Collection</code>. |
| * @param parameters the <code>Object</code> array with all of the parameters. |
| */ |
| Object executeWithArray (Object[] parameters); |
| |
| /** Get the <code>PersistenceManager</code> associated with this <code>Query</code>. |
| * |
| * <P>If this <code>Query</code> was restored from a serialized form, it has no |
| * <code>PersistenceManager</code>, and this method returns <code>null</code>. |
| * @return the <code>PersistenceManager</code> associated with this <code>Query</code>. |
| */ |
| PersistenceManager getPersistenceManager(); |
| |
| /** Close a query result and release any resources associated with it. The |
| * parameter is the return from <code>execute(...)</code> and might have iterators open on it. |
| * Iterators associated with the query result are invalidated: they return <code>false</code> |
| * to <code>hasNext()</code> and throw <code>NoSuchElementException</code> to <code>next()</code>. |
| * @param queryResult the result of <code>execute(...)</code> on this <code>Query</code> instance. |
| */ |
| void close (Object queryResult); |
| |
| /** Close all query results associated with this <code>Query</code> instance, and release all |
| * resources associated with them. The query results might have iterators open |
| * on them. Iterators associated with the query results are invalidated: |
| * they return <code>false</code> to <code>hasNext()</code> and throw |
| * <code>NoSuchElementException</code> to <code>next()</code>. |
| */ |
| void closeAll (); |
| |
| /** |
| * Set the grouping expressions, optionally including a "having" |
| * clause. When grouping is specified, each result expression |
| * must either be an expression contained in the grouping, or an |
| * aggregate evaluated once per group. |
| * |
| * @param group a comma-delimited list of expressions, optionally |
| * followed by the "having" keyword and a boolean expression |
| * @since 2.0 |
| */ |
| void setGrouping (String group); |
| |
| /** |
| * Specify that only the first result of the query should be |
| * returned, rather than a collection. The execute method will |
| * return null if the query result size is 0. |
| * @since 2.0 |
| * @param unique if true, only one element is returned |
| */ |
| void setUnique (boolean unique); |
| |
| /** |
| * Specifies what type of data this query should return. If this |
| * is unset or set to <code>null</code>, this query returns |
| * instances of the query's candidate class. If set, this query |
| * will return expressions, including field values (projections) and |
| * aggregate function results. |
| * @param data a comma-delimited list of expressions |
| * (fields, functions on fields, or aggregate functions) |
| * to return from this query |
| * @since 2.0 |
| */ |
| void setResult (String data); |
| |
| /** |
| * Specify the type of object in which to return each element of |
| * the result of invoking {@link #execute} or one of its siblings. |
| * If the result is not set or set to null, the result class defaults |
| * to the candidate class of the query. If the result consists of one |
| * expression, the result class defaults to the type of that expression. |
| * If the result consists of more than one expression, the result class |
| * defaults to Object[]. |
| * The result class may be specified to be one of the java.lang classes |
| * Character, Boolean, Byte, Short, Integer, Long, Float, Double, String, |
| * or Object[]; or one of the java.math classes BigInteger or BigDecimal; |
| * or the java.util class Date; or one of the java.sql classes Date, |
| * Time, or Timestamp; or a user-defined class. |
| * <P>If there are multiple result expressions, the result class |
| * must be able to hold all elements of the result specification |
| * or a JDOUserException is thrown. |
| *<P>If there is only one result expression, the result class must be |
| * assignable from the type of the result expression or must be able |
| * to hold all elements of the result specification. A single value |
| * must be able to be coerced into the specified result class |
| * (treating wrapper classes as equivalent to their unwrapped |
| * primitive types) or by matching. If the result class does not satisfy |
| * these conditions, a JDOUserException is thrown. |
| *<P>A constructor of a result class specified in the setResult method |
| * will be used if the results specification matches the parameters |
| * of the constructor by position and type. If more than one constructor |
| * satisfies the requirements, the JDO implementation chooses one of them. |
| * If no constructor satisfies the results requirements, or if the result |
| * class is specified via the setResultClass method, the following |
| * requirements apply: |
| * <ul> |
| * <li>A user-defined result class must have a no-args constructor and |
| * one or more public <code>set</code> or <code>put</code> methods or fields. |
| * <li>Each result expression must match one of: |
| * <ul> |
| * <li>a public field that matches the name of the result expression |
| * and is of the type (treating wrapper types equivalent to primitive |
| * types) of the result expression; |
| * <li>or if no public field matches the name and type, a public |
| * <code>set</code method that returns void and matches the name of the |
| * result expression and takes a single parameter which is the |
| * exact type of the result expression; |
| * <li>or if neither of the above applies,a public method must be found |
| * with the signature <code>void put(Object, Object)</code>. |
| * During processing of the results, |
| * the first argument is the name of the result expression and |
| * the second argument is the value from the query result. |
| * </ul> |
| * </ul> |
| * Portable result classes do not invoke any persistence behavior |
| * during their no-args constructor or <code>set</code methods. |
| * @param cls the result class |
| * @since 2.0 |
| */ |
| void setResultClass (Class cls); |
| |
| /** |
| * Set the range of results to return. The execution of the query is |
| * modified to return only a subset of results. If the filter would |
| * normally return 100 instances, and fromIncl is set to 50, and |
| * toExcl is set to 70, then the first 50 results that would have |
| * been returned are skipped, the next 20 results are returned and the |
| * remaining 30 results are ignored. An implementation should execute |
| * the query such that the range algorithm is done at the data store. |
| * @param fromIncl 0-based inclusive start index |
| * @param toExcl 0-based exclusive end index, or |
| * {@link Long#MAX_VALUE} for no limit. |
| * @since 2.0 |
| */ |
| void setRange (long fromIncl, long toExcl); |
| |
| /** |
| * Set the range of results to return. The parameter is a String |
| * containing a comma-separated fromIncl and toExcl. The fromIncl and |
| * toExcl can be either String representations of long values, or can |
| * be parameters identified with a leading ":". For example, |
| * <code>setRange("50, 70");</code> or |
| * <code>setRange(":from, :to");</code> or |
| * <code>setRange("50, :to");</code>. |
| * The execution of the query is |
| * modified to return only a subset of results. If the filter would |
| * normally return 100 instances, and fromIncl is set to 50, and |
| * toExcl is set to 70, then the first 50 results that would have |
| * been returned are skipped, the next 20 results are returned and the |
| * remaining 30 results are ignored. An implementation should execute |
| * the query such that the range algorithm is done at the data store. |
| * @param fromInclToExcl comma-separated fromIncl and toExcl values |
| * @see #setRange(long, long) |
| * @since 2.0 |
| */ |
| void setRange (String fromInclToExcl); |
| |
| /** |
| * Add a vendor-specific extension to this query. The key and value |
| * are not standard. |
| * An implementation must ignore keys that are not recognized. |
| * @param key the key of the extension |
| * @param value the value of the extension |
| * @since 2.0 |
| */ |
| void addExtension (String key, Object value); |
| |
| /** |
| * Set multiple extensions, or use null to clear all extensions. |
| * Map keys and values are not standard. |
| * An implementation must ignore entries that are not recognized. |
| * @param extensions the map of extensions |
| * @see #addExtension |
| * @since 2.0 |
| */ |
| void setExtensions (Map extensions); |
| |
| /** |
| * Returns the <code>FetchPlan</code> used by this |
| * <code>Query</code>. Modifications of the returned fetch plan will not |
| * cause this query's owning <code>PersistenceManager</code>'s |
| * <code>FetchPlan</code> to be modified. |
| * @since 2.0 |
| * @return the fetch plan used by this query |
| */ |
| FetchPlan getFetchPlan (); |
| |
| /** |
| * Deletes all the instances of the candidate class that pass the |
| * filter. |
| * @see #deletePersistentAll() |
| * @param parameters for the query |
| * @return the number of instances of the candidate class that were deleted |
| * @since 2.0 |
| */ |
| long deletePersistentAll (Object[] parameters); |
| |
| /** |
| * Deletes all the instances of the candidate class that pass the |
| * filter. |
| * @see #deletePersistentAll() |
| * @param parameters for the query |
| * @return the number of instances of the candidate class that were deleted |
| * @since 2.0 |
| */ |
| long deletePersistentAll (Map parameters); |
| |
| /** |
| * Deletes all the instances of the candidate class that pass the |
| * filter. Returns the number of instances of the candidate |
| * class that were deleted, specifically not including the number |
| * of dependent and embedded instances. |
| * <P>Dirty instances of affected classes in the cache are first |
| * flushed to the datastore. Instances in the cache or brought into |
| * the cache as a result of executing one of the |
| * <code>deletePersistentAll</code> |
| * methods undergo life cycle changes as if <code>deletePersistent</code> |
| * were called on them. |
| * <P>Specifically, if the class of deleted instances implements the |
| * delete callback interface, the corresponding callback methods |
| * are called on the deleted instances. Similarly, if there are |
| * lifecycle listeners registered for delete events on affected |
| * classes, the listener is called for each appropriate deleted instance. |
| * <P>Before returning control to the application, instances of affected |
| * classes in the cache are refreshed to reflect whether they were |
| * deleted from the datastore. |
| * |
| * @return the number of instances of the candidate class that were deleted |
| * @since 2.0 |
| */ |
| long deletePersistentAll (); |
| |
| /** |
| * The unmodifiable flag, when set, disallows further |
| * modification of the query, except for specifying the range, |
| * result class, and ignoreCache option. |
| * The unmodifiable flag can also be set in metadata. |
| * @since 2.0 |
| */ |
| void setUnmodifiable(); |
| |
| /** |
| * The unmodifiable flag, when set, disallows further |
| * modification of the query, except for specifying the range, |
| * result class, and ignoreCache option. |
| * @return the current setting of the flag |
| * @since 2.0 |
| */ |
| boolean isUnmodifiable(); |
| |
| } |
| |
