/*******************************************************************************
 * Copyright (c) 2000, 2004 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     IBM Corporation - added J2SE 1.5 support
 *******************************************************************************/
package org.eclipse.jdt.core;

import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.jdt.core.dom.CompilationUnit;
import org.eclipse.jdt.core.dom.AST;


/**
 * Represents an entire Java compilation unit (<code>.java</code> source file).
 * Compilation unit elements need to be opened before they can be navigated or manipulated.
 * The children are of type <code>IPackageDeclaration</code>,
 * <code>IImportContainer</code>, and <code>IType</code>,
 * and appear in the order in which they are declared in the source.
 * If a <code>.java</code> file cannot be parsed, its structure remains unknown.
 * Use <code>IJavaElement.isStructureKnown</code> to determine whether this is 
 * the case.
 * <p>
 * This interface is not intended to be implemented by clients.
 * </p>
 */
public interface ICompilationUnit extends IJavaElement, ISourceReference, IParent, IOpenable, IWorkingCopy, ISourceManipulation, ICodeAssist {
/**
 * Constant indicating that a reconcile operation should not return an AST.
 * @since 3.0
 */
public static final int NO_AST = 0;

/**
 * Changes this compilation unit handle into a working copy. A new <code>IBuffer</code> is
 * created using this compilation unit handle's owner. Uses the primary owner is none was
 * specified when this compilation unit handle was created.
 * <p>
 * When switching to working copy mode, problems are reported to given 
 * <code>IProblemRequestor</code>.
 * </p>
 * <p>
 * Once in working copy mode, changes to this compilation unit or its children are done in memory.
 * Only the new buffer is affected. Using <code>commitWorkingCopy(boolean, IProgressMonitor)</code>
 * will bring the underlying resource in sync with this compilation unit.
 * </p>
 * <p>
 * If this compilation unit was already in working copy mode, an internal counter is incremented and no
 * other action is taken on this compilation unit. To bring this compilation unit back into the original mode 
 * (where it reflects the underlying resource), <code>discardWorkingCopy</code> must be call as many 
 * times as <code>becomeWorkingCopy</code>.
 * </p>
 * 
 * @param problemRequestor a requestor which will get notified of problems detected during
 * 	reconciling as they are discovered. The requestor can be set to <code>null</code> indicating
 * 	that the client is not interested in problems.
 * @param monitor a progress monitor used to report progress while opening this compilation unit
 * 	or <code>null</code> if no progress should be reported 
 * @throws JavaModelException if this compilation unit could not become a working copy.
 * @see #discardWorkingCopy()
 * @since 3.0
 */
void becomeWorkingCopy(IProblemRequestor problemRequestor, IProgressMonitor monitor) throws JavaModelException;
/**
 * Commits the contents of this working copy to its underlying resource.
 *
 * <p>It is possible that the contents of the original resource have changed
 * since this working copy was created, in which case there is an update conflict.
 * The value of the <code>force</code> parameter effects the resolution of
 * such a conflict:<ul>
 * <li> <code>true</code> - in this case the contents of this working copy are applied to
 * 	the underlying resource even though this working copy was created before
 *		a subsequent change in the resource</li>
 * <li> <code>false</code> - in this case a <code>JavaModelException</code> is thrown</li>
 * </ul>
 * <p>
 * Since 2.1, a working copy can be created on a not-yet existing compilation
 * unit. In particular, such a working copy can then be committed in order to create
 * the corresponding compilation unit.
 * </p>
 * @param force a flag to handle the cases when the contents of the original resource have changed
 * since this working copy was created
 * @param monitor the given progress monitor
 * @throws JavaModelException if this working copy could not commit. Reasons include:
 * <ul>
 * <li> A <code>CoreException</code> occurred while updating an underlying resource
 * <li> This element is not a working copy (INVALID_ELEMENT_TYPES)
 * <li> A update conflict (described above) (UPDATE_CONFLICT)
 * </ul>
 * @since 3.0
 */
void commitWorkingCopy(boolean force, IProgressMonitor monitor) throws JavaModelException;
/**
 * Creates and returns an non-static import declaration in this compilation unit
 * with the given name. This method is equivalent to 
 * <code>createImport(name, Flags.AccDefault, sibling, monitor)</code>.
 *
 * @param name the name of the import declaration to add as defined by JLS2 7.5. (For example: <code>"java.io.File"</code> or
 *  <code>"java.awt.*"</code>)
 * @param sibling the existing element which the import declaration will be inserted immediately before (if
 *	<code> null </code>, then this import will be inserted as the last import declaration.
 * @param monitor the progress monitor to notify
 * @return the newly inserted import declaration (or the previously existing one in case attempting to create a duplicate)
 *
 * @throws JavaModelException if the element could not be created. Reasons include:
 * <ul>
 * <li> This Java element does not exist or the specified sibling does not exist (ELEMENT_DOES_NOT_EXIST)</li>
 * <li> A <code>CoreException</code> occurred while updating an underlying resource
 * <li> The specified sibling is not a child of this compilation unit (INVALID_SIBLING)
 * <li> The name is not a valid import name (INVALID_NAME)
 * </ul>
 * @see #createImport(String, IJavaElement, int, IProgressMonitor)
 */
IImportDeclaration createImport(String name, IJavaElement sibling, IProgressMonitor monitor) throws JavaModelException;

/**
 * Creates and returns an import declaration in this compilation unit
 * with the given name.
 * <p>
 * Optionally, the new element can be positioned before the specified
 * sibling. If no sibling is specified, the element will be inserted
 * as the last import declaration in this compilation unit.
 * <p>
 * If the compilation unit already includes the specified import declaration,
 * the import is not generated (it does not generate duplicates).
 * Note that it is valid to specify both a single-type import and an on-demand import
 * for the same package, for example <code>"java.io.File"</code> and
 * <code>"java.io.*"</code>, in which case both are preserved since the semantics
 * of this are not the same as just importing <code>"java.io.*"</code>.
 * Importing <code>"java.lang.*"</code>, or the package in which the compilation unit
 * is defined, are not treated as special cases.  If they are specified, they are
 * included in the result.
 * <p>
 * Note: Static imports are an experimental language feature 
 * under discussion in JSR-201 and under consideration for inclusion
 * in the 1.5 release of J2SE. The support here is therefore tentative
 * and subject to change.
 * </p>
 *
 * @param name the name of the import declaration to add as defined by JLS2 7.5. (For example: <code>"java.io.File"</code> or
 *  <code>"java.awt.*"</code>)
 * @param sibling the existing element which the import declaration will be inserted immediately before (if
 *	<code> null </code>, then this import will be inserted as the last import declaration.
 * @param flags <code>Flags.AccStatic</code> for static imports, or
 * <code>Flags.AccDefault</code> for regular imports; other modifier flags
 * are ignored
 * @param monitor the progress monitor to notify
 * @return the newly inserted import declaration (or the previously existing one in case attempting to create a duplicate)
 *
 * @throws JavaModelException if the element could not be created. Reasons include:
 * <ul>
 * <li> This Java element does not exist or the specified sibling does not exist (ELEMENT_DOES_NOT_EXIST)</li>
 * <li> A <code>CoreException</code> occurred while updating an underlying resource
 * <li> The specified sibling is not a child of this compilation unit (INVALID_SIBLING)
 * <li> The name is not a valid import name (INVALID_NAME)
 * </ul>
 * @see Flags
 * @since 3.0
 */
IImportDeclaration createImport(String name, IJavaElement sibling, int flags, IProgressMonitor monitor) throws JavaModelException;

/**
 * Creates and returns a package declaration in this compilation unit
 * with the given package name.
 *
 * <p>If the compilation unit already includes the specified package declaration,
 * it is not generated (it does not generate duplicates).
 *
 * @param name the name of the package declaration to add as defined by JLS2 7.4. (For example, <code>"java.lang"</code>)
 * @param monitor the progress monitor to notify
 * @return the newly inserted package declaration (or the previously existing one in case attempting to create a duplicate)
 *
 * @throws JavaModelException if the element could not be created. Reasons include:
 * <ul>
 * <li>This Java element does not exist (ELEMENT_DOES_NOT_EXIST)</li>
 * <li> A <code>CoreException</code> occurred while updating an underlying resource
 * <li> The name is not a valid package name (INVALID_NAME)
 * </ul>
 */
 IPackageDeclaration createPackageDeclaration(String name, IProgressMonitor monitor) throws JavaModelException;   
/**
 * Creates and returns a type in this compilation unit with the
 * given contents. If this compilation unit does not exist, one
 * will be created with an appropriate package declaration.
 * <p>
 * Optionally, the new type can be positioned before the specified
 * sibling. If <code>sibling</code> is <code>null</code>, the type will be appended
 * to the end of this compilation unit.
 *
 * <p>It is possible that a type with the same name already exists in this compilation unit.
 * The value of the <code>force</code> parameter effects the resolution of
 * such a conflict:<ul>
 * <li> <code>true</code> - in this case the type is created with the new contents</li>
 * <li> <code>false</code> - in this case a <code>JavaModelException</code> is thrown</li>
 * </ul>
 *
 * @param contents the source contents of the type declaration to add.
 * @param sibling the existing element which the type will be inserted immediately before (if
 *	<code> null </code>, then this type will be inserted as the last type declaration.
 * @param force a <code> boolean </code> flag indicating how to deal with duplicates
 * @param monitor the progress monitor to notify
 * @return the newly inserted type
 *
 * @throws JavaModelException if the element could not be created. Reasons include:
 * <ul>
 * <li>The specified sibling element does not exist (ELEMENT_DOES_NOT_EXIST)</li>
 * <li> A <code>CoreException</code> occurred while updating an underlying resource
 * <li> The specified sibling is not a child of this compilation unit (INVALID_SIBLING)
 * <li> The contents could not be recognized as a type declaration (INVALID_CONTENTS)
 * <li> There was a naming collision with an existing type (NAME_COLLISION)
 * </ul>
 */
IType createType(String contents, IJavaElement sibling, boolean force, IProgressMonitor monitor) throws JavaModelException;
/**
 * Changes this compilation unit in working copy mode back to its original mode.
 * <p>
 * This has no effect if this compilation unit was not in working copy mode.
 * </p>
 * <p>
 * If <code>becomeWorkingCopy</code> was called several times on this
 * compilation unit, <code>discardWorkingCopy</code> must be called as 
 * many times before it switches back to the original mode.
 * </p>
 * 
 * @throws JavaModelException if this working copy could not return in its original mode.
 * @see #becomeWorkingCopy(IProblemRequestor, IProgressMonitor)
 * @since 3.0
 */
void discardWorkingCopy() throws JavaModelException;
/** 
 * Finds the elements in this compilation unit that correspond to
 * the given element.
 * An element A corresponds to an element B if:
 * <ul>
 * <li>A has the same element name as B.
 * <li>If A is a method, A must have the same number of arguments as
 *     B and the simple names of the argument types must be equals.
 * <li>The parent of A corresponds to the parent of B recursively up to
 *     their respective compilation units.
 * <li>A exists.
 * </ul>
 * Returns <code>null</code> if no such java elements can be found
 * or if the given element is not included in a compilation unit.
 * 
 * @param element the given element
 * @return the found elements in this compilation unit that correspond to the given element
 * @since 3.0 
 */
IJavaElement[] findElements(IJavaElement element);
/**
 * Finds the primary type of this compilation unit (that is, the type with the same name as the
 * compilation unit), or <code>null</code> if no such a type exists.
 * 
 * @return the found primary type of this compilation unit, or <code>null</code> if no such a type exists
 * @since 3.0
 */
IType findPrimaryType();
/**
 * Finds the working copy for this compilation unit, given a <code>WorkingCopyOwner</code>. 
 * If no working copy has been created for this compilation unit associated with this
 * working copy owner, returns <code>null</code>.
 * <p>
 * Users of this method must not destroy the resulting working copy. 
 * 
 * @param owner the given <code>WorkingCopyOwner</code>
 * @return the found working copy for this compilation unit, <code>null</code> if none
 * @see WorkingCopyOwner
 * @since 3.0
 */
ICompilationUnit findWorkingCopy(WorkingCopyOwner owner);
/**
 * Returns all types declared in this compilation unit in the order
 * in which they appear in the source. 
 * This includes all top-level types and nested member types.
 * It does NOT include local types (types defined in methods).
 *
 * @return the array of top-level and member types defined in a compilation unit, in declaration order.
 * @throws JavaModelException if this element does not exist or if an
 *		exception occurs while accessing its corresponding resource
 */
IType[] getAllTypes() throws JavaModelException;
/**
 * Returns the smallest element within this compilation unit that 
 * includes the given source position (that is, a method, field, etc.), or
 * <code>null</code> if there is no element other than the compilation
 * unit itself at the given position, or if the given position is not
 * within the source range of this compilation unit.
 *
 * @param position a source position inside the compilation unit
 * @return the innermost Java element enclosing a given source position or <code>null</code>
 *	if none (excluding the compilation unit).
 * @throws JavaModelException if the compilation unit does not exist or if an
 *		exception occurs while accessing its corresponding resource
 */
IJavaElement getElementAt(int position) throws JavaModelException;
/**
 * Returns the first import declaration in this compilation unit with the given name.
 * This is a handle-only method. The import declaration may or may not exist. This
 * is a convenience method - imports can also be accessed from a compilation unit's
 * import container.
 *
 * @param name the name of the import to find as defined by JLS2 7.5. (For example: <code>"java.io.File"</code> 
 * 	or <code>"java.awt.*"</code>)
 * @return a handle onto the corresponding import declaration. The import declaration may or may not exist.
 */
IImportDeclaration getImport(String name) ;
/**
 * Returns the import container for this compilation unit.
 * This is a handle-only method. The import container may or
 * may not exist. The import container can used to access the 
 * imports.
 * @return a handle onto the corresponding import container. The 
 *		import contain may or may not exist.
 */
IImportContainer getImportContainer();
/**
 * Returns the import declarations in this compilation unit
 * in the order in which they appear in the source. This is
 * a convenience method - import declarations can also be
 * accessed from a compilation unit's import container.
 *
 * @return the import declarations in this compilation unit
 * @throws JavaModelException if this element does not exist or if an
 *		exception occurs while accessing its corresponding resource
 */
IImportDeclaration[] getImports() throws JavaModelException;
/**
 * Returns the primary compilation unit (whose owner is the primary owner)
 * this working copy was created from, or this compilation unit if this a primary
 * compilation unit.
 * <p>
 * Note that the returned primary compilation unit can be in working copy mode.
 * </p>
 * 
 * @return the primary compilation unit this working copy was created from,
 * or this compilation unit if it is primary
 * @since 3.0
 */
ICompilationUnit getPrimary();
/**
 * Returns the working copy owner of this working copy.
 * Returns null if it is not a working copy or if it has no owner.
 * 
 * @return WorkingCopyOwner the owner of this working copy or <code>null</code>
 * @since 3.0
 */
WorkingCopyOwner getOwner();
/**
 * Returns the first package declaration in this compilation unit with the given package name
 * (there normally is at most one package declaration).
 * This is a handle-only method. The package declaration may or may not exist.
 *
 * @param name the name of the package declaration as defined by JLS2 7.4. (For example, <code>"java.lang"</code>)
 * @return the first package declaration in this compilation unit with the given package name
 */
IPackageDeclaration getPackageDeclaration(String name);
/**
 * Returns the package declarations in this compilation unit
 * in the order in which they appear in the source.
 * There normally is at most one package declaration.
 *
 * @return an array of package declaration (normally of size one)
 *
 * @throws JavaModelException if this element does not exist or if an
 *		exception occurs while accessing its corresponding resource
 */
IPackageDeclaration[] getPackageDeclarations() throws JavaModelException;
/**
 * Returns the top-level type declared in this compilation unit with the given simple type name.
 * The type name has to be a valid compilation unit name.
 * This is a handle-only method. The type may or may not exist.
 *
 * @param name the simple name of the requested type in the compilation unit
 * @return a handle onto the corresponding type. The type may or may not exist.
 * @see JavaConventions#validateCompilationUnitName(String name)
 */
IType getType(String name);
/**
 * Returns the top-level types declared in this compilation unit
 * in the order in which they appear in the source.
 *
 * @return the top-level types declared in this compilation unit
 * @throws JavaModelException if this element does not exist or if an
 *		exception occurs while accessing its corresponding resource
 */
IType[] getTypes() throws JavaModelException;
/**
 * Returns a new working copy of this compilation unit if it is a primary compilation unit, 
 * or this compilation unit if it is already a non-primary working copy.
 * <p>
 * Note: if intending to share a working copy amongst several clients, then 
 * <code>#getWorkingCopy(WorkingCopyOwner, IProblemRequestor, IProgressMonitor)</code> 
 * should be used instead.
 * </p><p>
 * When the working copy instance is created, an ADDED IJavaElementDelta is 
 * reported on this working copy.
 * </p><p>
 * Once done with the working copy, users of this method must discard it using 
 * <code>discardWorkingCopy()</code>.
 * </p><p>
 * Since 2.1, a working copy can be created on a not-yet existing compilation
 * unit. In particular, such a working copy can then be committed in order to create
 * the corresponding compilation unit.
 * </p>
* @param monitor a progress monitor used to report progress while opening this compilation unit
 *                 or <code>null</code> if no progress should be reported 
 * @throws JavaModelException if the contents of this element can
 *   not be determined. 
 * @return a new working copy of this element if this element is not
 * a working copy, or this element if this element is already a working copy
 * @since 3.0
 */
ICompilationUnit getWorkingCopy(IProgressMonitor monitor) throws JavaModelException;
/**
 * Returns a shared working copy on this compilation unit using the given working copy owner to create
 * the buffer, or this compilation unit if it is already a non-primary working copy.
 * This API can only answer an already existing working copy if it is based on the same
 * original compilation unit AND was using the same working copy owner (that is, as defined by <code>Object.equals</code>).	 
 * <p>
 * The life time of a shared working copy is as follows:
 * <ul>
 * <li>The first call to <code>getWorkingCopy(WorkingCopyOwner, IProblemRequestor, IProgressMonitor)</code> 
 * 	creates a new working copy for this element</li>
 * <li>Subsequent calls increment an internal counter.</li>
 * <li>A call to <code>discardWorkingCopy()</code> decrements the internal counter.</li>
 * <li>When this counter is 0, the working copy is discarded.
 * </ul>
 * So users of this method must discard exactly once the working copy.
 * <p>
 * Note that the working copy owner will be used for the life time of this working copy, that is if the 
 * working copy is closed then reopened, this owner will be used.
 * The buffer will be automatically initialized with the original's compilation unit content
 * upon creation.
 * <p>
 * When the shared working copy instance is created, an ADDED IJavaElementDelta is reported on this
 * working copy.
 * </p><p>
 * Since 2.1, a working copy can be created on a not-yet existing compilation
 * unit. In particular, such a working copy can then be committed in order to create
 * the corresponding compilation unit.
 * </p>
 * @param owner the working copy owner that creates a buffer that is used to get the content 
 * 				of the working copy
 * @param problemRequestor a requestor which will get notified of problems detected during
 * 	reconciling as they are discovered. The requestor can be set to <code>null</code> indicating
 * 	that the client is not interested in problems.
 * @param monitor a progress monitor used to report progress while opening this compilation unit
 *                 or <code>null</code> if no progress should be reported 
 * @throws JavaModelException if the contents of this element can
 *   not be determined. 
 * @return a new working copy of this element using the given factory to create
 * the buffer, or this element if this element is already a working copy
 * @since 3.0
 */
ICompilationUnit getWorkingCopy(WorkingCopyOwner owner, IProblemRequestor problemRequestor, IProgressMonitor monitor) throws JavaModelException;
/**
 * Returns whether the resource of this working copy has changed since the
 * inception of this working copy.
 * Returns <code>false</code> if this compilation unit is not in working copy mode.
 * 
 * @return whether the resource has changed
 * @since 3.0
 */
public boolean hasResourceChanged();
/**
 * Returns whether this element is a working copy.
 * 
 * @return true if this element is a working copy, false otherwise
 * @since 3.0
 */
boolean isWorkingCopy();

/**
 * Reconciles the contents of this working copy, sends out a Java delta
 * notification indicating the nature of the change of the working copy since
 * the last time it was either reconciled or made consistent 
 * (see <code>IOpenable#makeConsistent()</code>), and returns a
 * compilation unit AST if requested.
 * <p>
 * It performs the reconciliation by locally caching the contents of 
 * the working copy, updating the contents, then creating a delta 
 * over the cached contents and the new contents, and finally firing
 * this delta.
 * <p>
 * The boolean argument allows to force problem detection even if the
 * working copy is already consistent.
 * </p>
 * <p>
 * This functionality allows to specify a working copy owner which is used
 * during problem detection. All references contained in the working copy are
 * resolved against other units; for which corresponding owned working copies
 * are going to take precedence over their original compilation units. If
 * <code>null</code> is passed in, then the primary working copy owner is used.
 * </p>
 * <p>
 * Compilation problems found in the new contents are notified through the
 * <code>IProblemRequestor</code> interface which was passed at
 * creation, and no longer as transient markers.
 * </p>
 * <p>
 * Note: Since 3.0, added/removed/changed inner types generate change deltas.
 * </p>
 * <p>
 * If requested, a DOM AST representing the compilation unit is returned.
 * Its bindings are computed only if the problem requestor is active, or if the
 * problem detection is forced. This method returns <code>null</code> if the
 * creation of the DOM AST was not requested, or if the requested level of AST
 * API is not supported, or if the working copy was already consistent.
 * </p>
 *
 * @param astLevel either {@link #NO_AST} if no AST is wanted,
 * or the {@linkplain AST#AST(int) AST API level} of the AST if one is wanted
 * @param forceProblemDetection boolean indicating whether problem should be 
 *   recomputed even if the source hasn't changed
 * @param owner the owner of working copies that take precedence over the 
 *   original compilation units, or <code>null</code> if the primary working
 *   copy owner should be used
 * @param monitor a progress monitor
 * @return the compilation unit AST or <code>null</code> if not requested, 
 *    or if the requested level of AST API is not supported,
 *    or if the working copy was consistent
 * @throws JavaModelException if the contents of the original element
 *		cannot be accessed. Reasons include:
 * <ul>
 * <li> The original Java element does not exist (ELEMENT_DOES_NOT_EXIST)</li>
 * </ul>
 * @since 3.0
 */
CompilationUnit reconcile(int astLevel, boolean forceProblemDetection, WorkingCopyOwner owner, IProgressMonitor monitor) throws JavaModelException;

/**
 * Restores the contents of this working copy to the current contents of
 * this working copy's original element. Has no effect if this element
 * is not a working copy.
 *
 * <p>Note: This is the inverse of committing the content of the
 * working copy to the original element with <code>commit(boolean, IProgressMonitor)</code>.
 *
 * @throws JavaModelException if the contents of the original element
 *		cannot be accessed.  Reasons include:
 * <ul>
 * <li> The original Java element does not exist (ELEMENT_DOES_NOT_EXIST)</li>
 * </ul>
 * @since 3.0
 */
void restore() throws JavaModelException;
}