IMarker.java

/*******************************************************************************
 *  Copyright (c) 2000, 2009 IBM Corporation and others.
 *  All rights reserved. This program and the accompanying materials
 *  are made available under the terms of the Eclipse Public License v1.0
 *  which accompanies this distribution, and is available at
 *  http://www.eclipse.org/legal/epl-v10.html
 * 
 *  Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.core.resources;

import java.util.Map;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IAdaptable;

/**
 * Markers are a general mechanism for associating notes and meta-data with resources.
 * <p>
 * Markers themselves are handles in the same way as <code>IResources</code> are handles. Instances
 * of <code>IMarker</code> do not hold the attributes themselves but rather uniquely refer to the
 * attribute container. As such, their state may change underneath the handle with no warning to the
 * holder of the handle.
 * </p>
 * The Resources plug-in provides a general framework for defining and manipulating markers and
 * provides several standard marker types. </p>
 * <p>
 * Each marker has:
 * <ul>
 * <li>a type string, specifying its type (e.g. <code>"org.eclipse.core.resources.taskmarker"</code>
 * ),</li>
 * <li>an identifier which is unique (relative to a particular resource)</li>
 * </ul>
 * Specific types of markers may carry additional information.
 * </p>
 * <p>
 * The resources plug-in defines five standard types:
 * <ul>
 * <li><code>org.eclipse.core.resources.marker</code></li>
 * <li><code>org.eclipse.core.resources.taskmarker</code></li>
 * <li><code>org.eclipse.core.resources.problemmarker</code></li>
 * <li><code>org.eclipse.core.resources.bookmark</code></li>
 * <li><code>org.eclipse.core.resources.textmarker</code></li>
 * </ul>
 * The plug-in also provides an extension point ( <code>org.eclipse.core.resources.markers</code>)
 * into which other plug-ins can install marker type declaration extensions.
 * </p>
 * <p>
 * Marker types are declared within a multiple inheritance type system. New markers are defined in
 * the <code>plugin.xml</code> file of the declaring plug-in. A valid declaration contains elements
 * as defined by the extension point DTD:
 * <ul>
 * <li><i>type</i> - the unique name of the marker type</li>
 * <li><i>super</i> - the list of marker types of which this marker is to be considered a sub-type</li>
 * <li><i>attributes</i> - the list of standard attributes which may be present on this type of
 * marker</li>
 * <li><i>persistent</i> - whether markers of this type should be persisted by the platform</li>
 * </li>
 * </p>
 * <p>
 * All markers declared as <code>persistent</code> are saved when the workspace is saved, except
 * those explicitly set as transient (the <code>TRANSIENT</code> attribute is set as
 * <code>true</code>). A plug-in which defines a persistent marker is not directly involved in
 * saving and restoring the marker. Markers are not under version and configuration management, and
 * cannot be shared via VCM repositories.
 * </p>
 * <p>
 * Markers implement the <code>IAdaptable</code> interface; extensions are managed by the platform's
 * adapter manager.
 * </p>
 * 
 * @noimplement This interface is not intended to be implemented by clients.
 * @noextend This interface is not intended to be extended by clients.
 */
public interface IMarker extends IAdaptable {

	/*====================================================================
	 * Marker types:
	 *====================================================================*/

	/**
	 * Base marker type.
	 * 
	 * @see #getType()
	 */
	public static final String MARKER= ResourcesPlugin.PI_RESOURCES + ".marker"; //$NON-NLS-1$

	/**
	 * Task marker type.
	 * 
	 * @see #getType()
	 */
	public static final String TASK= ResourcesPlugin.PI_RESOURCES + ".taskmarker"; //$NON-NLS-1$

	/**
	 * Problem marker type.
	 * 
	 * @see #getType()
	 */
	public static final String PROBLEM= ResourcesPlugin.PI_RESOURCES + ".problemmarker"; //$NON-NLS-1$

	/**
	 * Text marker type.
	 * 
	 * @see #getType()
	 */
	public static final String TEXT= ResourcesPlugin.PI_RESOURCES + ".textmarker"; //$NON-NLS-1$

	/**
	 * Bookmark marker type.
	 * 
	 * @see #getType()
	 */
	public static final String BOOKMARK= ResourcesPlugin.PI_RESOURCES + ".bookmark"; //$NON-NLS-1$

	/*====================================================================
	 * Marker attributes:
	 *====================================================================*/

	/**
	 * Severity marker attribute. A number from the set of error, warning and info severities
	 * defined by the platform.
	 * 
	 * @see #SEVERITY_ERROR
	 * @see #SEVERITY_WARNING
	 * @see #SEVERITY_INFO
	 * @see #getAttribute(String, int)
	 */
	public static final String SEVERITY= "severity"; //$NON-NLS-1$

	/**
	 * Message marker attribute. A localized string describing the nature of the marker (e.g., a
	 * name for a bookmark or task). The content and form of this attribute is not specified or
	 * interpreted by the platform.
	 * 
	 * @see #getAttribute(String, String)
	 */
	public static final String MESSAGE= "message"; //$NON-NLS-1$

	/**
	 * Location marker attribute. The location is a human-readable (localized) string which can be
	 * used to distinguish between markers on a resource. As such it should be concise and aimed at
	 * users. The content and form of this attribute is not specified or interpreted by the
	 * platform.
	 * 
	 * @see #getAttribute(String, String)
	 */
	public static final String LOCATION= "location"; //$NON-NLS-1$

	/**
	 * Priority marker attribute. A number from the set of high, normal and low priorities defined
	 * by the platform.
	 * 
	 * @see #PRIORITY_HIGH
	 * @see #PRIORITY_NORMAL
	 * @see #PRIORITY_LOW
	 * @see #getAttribute(String, int)
	 */
	public static final String PRIORITY= "priority"; //$NON-NLS-1$

	/**
	 * Done marker attribute. A boolean value indicating whether the marker (e.g., a task) is
	 * considered done.
	 * 
	 * @see #getAttribute(String, String)
	 */
	public static final String DONE= "done"; //$NON-NLS-1$

	/**
	 * Character start marker attribute. An integer value indicating where a text marker starts.
	 * This attribute is zero-relative and inclusive.
	 * 
	 * @see #getAttribute(String, String)
	 */
	public static final String CHAR_START= "charStart"; //$NON-NLS-1$

	/**
	 * Character end marker attribute. An integer value indicating where a text marker ends. This
	 * attribute is zero-relative and exclusive.
	 * 
	 * @see #getAttribute(String, String)
	 */
	public static final String CHAR_END= "charEnd"; //$NON-NLS-1$

	/**
	 * Line number marker attribute. An integer value indicating the line number for a text marker.
	 * This attribute is 1-relative.
	 * 
	 * @see #getAttribute(String, String)
	 */
	public static final String LINE_NUMBER= "lineNumber"; //$NON-NLS-1$

	/**
	 * Transient marker attribute. A boolean value indicating whether the marker (e. g., a task) is
	 * considered transient even if its type is declared as persistent.
	 * 
	 * @see #getAttribute(String, String)
	 * @since 2.1
	 */
	public static final String TRANSIENT= "transient"; //$NON-NLS-1$

	/**
	 * User editable marker attribute. A boolean value indicating whether a user should be able to
	 * manually change the marker (e.g. a task). The default is <code>true</code>. Note that the
	 * value of this attribute is to be used by the UI as a suggestion and its value will NOT be
	 * interpreted by Core in any manner and will not be enforced by Core when performing any
	 * operations on markers.
	 * 
	 * @see #getAttribute(String, String)
	 * @since 2.1
	 */
	public static final String USER_EDITABLE= "userEditable"; //$NON-NLS-1$

	/**
	 * Source id attribute. A string attribute that can be used by tools that generate markers to
	 * indicate the source of the marker. Use of this attribute is optional and its format or
	 * existence is not enforced. This attribute is intended to improve serviceability by providing
	 * a value that product support personnel or automated tools can use to determine appropriate
	 * help and resolutions for markers.
	 * 
	 * @see #getAttribute(String, String)
	 * @since 3.3
	 */
	public static final String SOURCE_ID= "sourceId"; //$NON-NLS-1$

	/*====================================================================
	 * Marker attributes values:
	 *====================================================================*/

	/**
	 * High priority constant (value 2).
	 * 
	 * @see #getAttribute(String, int)
	 */
	public static final int PRIORITY_HIGH= 2;

	/**
	 * Normal priority constant (value 1).
	 * 
	 * @see #getAttribute(String, int)
	 */
	public static final int PRIORITY_NORMAL= 1;

	/**
	 * Low priority constant (value 0).
	 * 
	 * @see #getAttribute(String, int)
	 */
	public static final int PRIORITY_LOW= 0;

	/**
	 * Error severity constant (value 2) indicating an error state.
	 * 
	 * @see #getAttribute(String, int)
	 */
	public static final int SEVERITY_ERROR= 2;

	/**
	 * Warning severity constant (value 1) indicating a warning.
	 * 
	 * @see #getAttribute(String, int)
	 */
	public static final int SEVERITY_WARNING= 1;

	/**
	 * Info severity constant (value 0) indicating information only.
	 * 
	 * @see #getAttribute(String, int)
	 */
	public static final int SEVERITY_INFO= 0;

	/**
	 * Deletes this marker from its associated resource. This method has no effect if this marker
	 * does not exist.
	 * 
	 * @exception CoreException if this marker could not be deleted. Reasons include:
	 *                <ul>
	 *                <li>Resource changes are disallowed during certain types of resource change
	 *                event notification. See <code>IResourceChangeEvent</code> for more details.</li>
	 *                </ul>
	 * @see IResourceRuleFactory#markerRule(IResource)
	 */
	public void delete() throws CoreException;

	/**
	 * Tests this marker for equality with the given object. Two markers are equal if their id and
	 * resource are both equal.
	 * 
	 * @param object the other object
	 * @return an indication of whether the objects are equal
	 */
	public boolean equals(Object object);

	/**
	 * Returns whether this marker exists in the workspace. A marker exists if its resource exists
	 * and has a marker with the marker's id.
	 * 
	 * @return <code>true</code> if this marker exists, otherwise <code>false</code>
	 */
	public boolean exists();

	/**
	 * Returns the attribute with the given name. The result is an instance of one of the following
	 * classes: <code>String</code>, <code>Integer</code>, or <code>Boolean</code>. Returns
	 * <code>null</code> if the attribute is undefined.
	 * 
	 * @param attributeName the name of the attribute
	 * @return the value, or <code>null</code> if the attribute is undefined.
	 * @exception CoreException if this method fails. Reasons include:
	 *                <ul>
	 *                <li>This marker does not exist.</li>
	 *                </ul>
	 */
	public Object getAttribute(String attributeName) throws CoreException;

	/**
	 * Returns the integer-valued attribute with the given name. Returns the given default value if
	 * the attribute is undefined. or the marker does not exist or is not an integer value.
	 * 
	 * @param attributeName the name of the attribute
	 * @param defaultValue the value to use if no value is found
	 * @return the value or the default value if no value was found.
	 */
	public int getAttribute(String attributeName, int defaultValue);

	/**
	 * Returns the string-valued attribute with the given name. Returns the given default value if
	 * the attribute is undefined or the marker does not exist or is not a string value.
	 * 
	 * @param attributeName the name of the attribute
	 * @param defaultValue the value to use if no value is found
	 * @return the value or the default value if no value was found.
	 */
	public String getAttribute(String attributeName, String defaultValue);

	/**
	 * Returns the boolean-valued attribute with the given name. Returns the given default value if
	 * the attribute is undefined or the marker does not exist or is not a boolean value.
	 * 
	 * @param attributeName the name of the attribute
	 * @param defaultValue the value to use if no value is found
	 * @return the value or the default value if no value was found.
	 */
	public boolean getAttribute(String attributeName, boolean defaultValue);

	/**
	 * Returns a map with all the attributes for the marker. If the marker has no attributes then
	 * <code>null</code> is returned.
	 * 
	 * @return a map of attribute keys and values (key type : <code>String</code> value type :
	 *         <code>String</code>, <code>Integer</code>, or <code>Boolean</code>) or
	 *         <code>null</code>.
	 * @exception CoreException if this method fails. Reasons include:
	 *                <ul>
	 *                <li>This marker does not exist.</li>
	 *                </ul>
	 */
	public Map getAttributes() throws CoreException;

	/**
	 * Returns the attributes with the given names. The result is an an array whose elements
	 * correspond to the elements of the given attribute name array. Each element is
	 * <code>null</code> or an instance of one of the following classes: <code>String</code>,
	 * <code>Integer</code>, or <code>Boolean</code>.
	 * 
	 * @param attributeNames the names of the attributes
	 * @return the values of the given attributes.
	 * @exception CoreException if this method fails. Reasons include:
	 *                <ul>
	 *                <li>This marker does not exist.</li>
	 *                </ul>
	 */
	public Object[] getAttributes(String[] attributeNames) throws CoreException;

	/**
	 * Returns the time at which this marker was created.
	 * 
	 * @return the difference, measured in milliseconds, between the time at which this marker was
	 *         created and midnight, January 1, 1970 UTC, or <code>0L</code> if the creation time is
	 *         not known (this can occur in workspaces created using v2.0 or earlier).
	 * @exception CoreException if this method fails. Reasons include:
	 *                <ul>
	 *                <li>This marker does not exist.</li>
	 *                </ul>
	 * @since 2.1
	 */
	public long getCreationTime() throws CoreException;

	/**
	 * Returns the id of the marker. The id of a marker is unique relative to the resource with
	 * which the marker is associated. Marker ids are not globally unique.
	 * 
	 * @return the id of the marker
	 * @see IResource#findMarker(long)
	 */
	public long getId();

	/**
	 * Returns the resource with which this marker is associated.
	 * 
	 * @return the resource with which this marker is associated
	 */
	public IResource getResource();

	/**
	 * Returns the type of this marker. The returned marker type will not be <code>null</code>.
	 * 
	 * @return the type of this marker
	 * @exception CoreException if this method fails. Reasons include:
	 *                <ul>
	 *                <li>This marker does not exist.</li>
	 *                </ul>
	 */
	public String getType() throws CoreException;

	/**
	 * Returns whether the type of this marker is considered to be a sub-type of the given marker
	 * type.
	 * 
	 * @return boolean <code>true</code>if the marker's type is the same as (or a sub-type of) the
	 *         given type.
	 * @exception CoreException if this method fails. Reasons include:
	 *                <ul>
	 *                <li>This marker does not exist.</li>
	 *                </ul>
	 */
	public boolean isSubtypeOf(String superType) throws CoreException;

	/**
	 * Sets the integer-valued attribute with the given name.
	 * <p>
	 * This method changes resources; these changes will be reported in a subsequent resource change
	 * event, including an indication that this marker has been modified.
	 * </p>
	 * 
	 * @param attributeName the name of the attribute
	 * @param value the value
	 * @exception CoreException if this method fails. Reasons include:
	 *                <ul>
	 *                <li>This marker does not exist.</li>
	 *                <li>Resource changes are disallowed during certain types of resource change
	 *                event notification. See <code>IResourceChangeEvent</code> for more details.</li>
	 *                </ul>
	 * @see IResourceRuleFactory#markerRule(IResource)
	 */
	public void setAttribute(String attributeName, int value) throws CoreException;

	/**
	 * Sets the attribute with the given name. The value must be <code>null</code> or an instance of
	 * one of the following classes: <code>String</code>, <code>Integer</code>, or
	 * <code>Boolean</code>. If the value is <code>null</code>, the attribute is considered to be
	 * undefined.
	 * 
	 * <p>
	 * The attribute value cannot be <code>String</code> whose UTF encoding exceeds 65535 bytes. On
	 * persistent markers this limit is enforced by an assertion.
	 * </p>
	 * 
	 * <p>
	 * This method changes resources; these changes will be reported in a subsequent resource change
	 * event, including an indication that this marker has been modified.
	 * </p>
	 * 
	 * @param attributeName the name of the attribute
	 * @param value the value, or <code>null</code> if the attribute is to be undefined
	 * @exception CoreException if this method fails. Reasons include:
	 *                <ul>
	 *                <li>This marker does not exist.</li>
	 *                <li>Resource changes are disallowed during certain types of resource change
	 *                event notification. See <code>IResourceChangeEvent</code> for more details.</li>
	 *                </ul>
	 * @see IResourceRuleFactory#markerRule(IResource)
	 */
	public void setAttribute(String attributeName, Object value) throws CoreException;

	/**
	 * Sets the boolean-valued attribute with the given name.
	 * <p>
	 * This method changes resources; these changes will be reported in a subsequent resource change
	 * event, including an indication that this marker has been modified.
	 * </p>
	 * 
	 * @param attributeName the name of the attribute
	 * @param value the value
	 * @exception CoreException if this method fails. Reasons include:
	 *                <ul>
	 *                <li>This marker does not exist.</li>
	 *                <li>Resource changes are disallowed during certain types of resource change
	 *                event notification. See <code>IResourceChangeEvent</code> for more details.</li>
	 *                </ul>
	 * @see IResourceRuleFactory#markerRule(IResource)
	 */
	public void setAttribute(String attributeName, boolean value) throws CoreException;

	/**
	 * Sets the given attribute key-value pairs on this marker. The values must be <code>null</code>
	 * or an instance of one of the following classes: <code>String</code>, <code>Integer</code>, or
	 * <code>Boolean</code>. If a value is <code>null</code>, the new value of the attribute is
	 * considered to be undefined.
	 * 
	 * <p>
	 * The values of the attributes cannot be <code>String</code> whose UTF encoding exceeds 65535
	 * bytes. On persistent markers this limit is enforced by an assertion.
	 * </p>
	 * 
	 * <p>
	 * This method changes resources; these changes will be reported in a subsequent resource change
	 * event, including an indication that this marker has been modified.
	 * </p>
	 * 
	 * @param attributeNames an array of attribute names
	 * @param values an array of attribute values
	 * @exception CoreException if this method fails. Reasons include:
	 *                <ul>
	 *                <li>This marker does not exist.</li>
	 *                <li>Resource changes are disallowed during certain types of resource change
	 *                event notification. See <code>IResourceChangeEvent</code> for more details.</li>
	 *                </ul>
	 * @see IResourceRuleFactory#markerRule(IResource)
	 */
	public void setAttributes(String[] attributeNames, Object[] values) throws CoreException;

	/**
	 * Sets the attributes for this marker to be the ones contained in the given table. The values
	 * must be an instance of one of the following classes: <code>String</code>,
	 * <code>Integer</code>, or <code>Boolean</code>. Attributes previously set on the marker but
	 * not included in the given map are considered to be removals. Setting the given map to be
	 * <code>null</code> is equivalent to removing all marker attributes.
	 * 
	 * <p>
	 * The values of the attributes cannot be <code>String</code> whose UTF encoding exceeds 65535
	 * bytes. On persistent markers this limit is enforced by an assertion.
	 * </p>
	 * 
	 * <p>
	 * This method changes resources; these changes will be reported in a subsequent resource change
	 * event, including an indication that this marker has been modified.
	 * </p>
	 * 
	 * @param attributes a map of attribute names to attribute values (key type :
	 *            <code>String</code> value type : <code>String</code>, <code>Integer</code>, or
	 *            <code>Boolean</code>) or <code>null</code>
	 * @exception CoreException if this method fails. Reasons include:
	 *                <ul>
	 *                <li>This marker does not exist.</li>
	 *                <li>Resource changes are disallowed during certain types of resource change
	 *                event notification. See <code>IResourceChangeEvent</code> for more details.</li>
	 *                </ul>
	 * @see IResourceRuleFactory#markerRule(IResource)
	 */
	public void setAttributes(Map attributes) throws CoreException;
}