/* | |
* $Header: /cvshome/build/org.osgi.service.condpermadmin/src/org/osgi/service/condpermadmin/ConditionInfo.java,v 1.12 2006/03/14 01:20:40 hargrave Exp $ | |
* | |
* Copyright (c) OSGi Alliance (2004, 2005). All Rights Reserved. | |
* | |
* 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. | |
*/ | |
package org.osgi.service.condpermadmin; | |
import java.util.ArrayList; | |
/** | |
* Condition representation used by the Conditional Permission Admin service. | |
* | |
* <p> | |
* This class encapsulates two pieces of information: a Condition <i>type</i> | |
* (class name), which must implement <code>Condition</code>, and the | |
* arguments passed to its constructor. | |
* | |
* <p> | |
* In order for a Condition represented by a <code>ConditionInfo</code> to be | |
* instantiated and considered during a permission check, its Condition class | |
* must be available from the system classpath. | |
* | |
* <p> | |
* The Condition class must either: | |
* <ul> | |
* <li>Declare a public static <code>getCondition</code> method that takes a | |
* <code>Bundle</code> object and a <code>ConditionInfo</code> object as | |
* arguments. That method must return an object that implements the | |
* <code>Condition</code> interface.</li> | |
* <li>Implement the <code>Condition</code> interface and define a public | |
* constructor that takes a <code>Bundle</code> object and a | |
* <code>ConditionInfo</code> object as arguments. | |
* </ul> | |
* | |
* @version $Revision: 1.12 $ | |
*/ | |
public class ConditionInfo { | |
private String type; | |
private String[] args; | |
/** | |
* Constructs a <code>ConditionInfo</code> from the specified type and | |
* args. | |
* | |
* @param type The fully qualified class name of the Condition represented | |
* by this <code>ConditionInfo</code>. | |
* @param args The arguments for the Condition. These arguments are | |
* available to the newly created Condition by calling the | |
* {@link #getArgs()} method. | |
* @throws java.lang.NullPointerException If <code>type</code> is | |
* <code>null</code>. | |
*/ | |
public ConditionInfo(String type, String[] args) { | |
this.type = type; | |
this.args = args != null ? args : new String[0]; | |
if (type == null) { | |
throw new NullPointerException("type is null"); | |
} | |
} | |
/** | |
* Constructs a <code>ConditionInfo</code> object from the specified | |
* encoded <code>ConditionInfo</code> string. White space in the encoded | |
* <code>ConditionInfo</code> string is ignored. | |
* | |
* @param encodedCondition The encoded <code>ConditionInfo</code>. | |
* @see #getEncoded | |
* @throws java.lang.IllegalArgumentException If the | |
* <code>encodedCondition</code> is not properly formatted. | |
*/ | |
public ConditionInfo(String encodedCondition) { | |
if (encodedCondition == null) { | |
throw new NullPointerException("missing encoded condition"); | |
} | |
if (encodedCondition.length() == 0) { | |
throw new IllegalArgumentException("empty encoded condition"); | |
} | |
try { | |
char[] encoded = encodedCondition.toCharArray(); | |
int length = encoded.length; | |
int pos = 0; | |
/* skip whitespace */ | |
while (Character.isWhitespace(encoded[pos])) { | |
pos++; | |
} | |
/* the first character must be '[' */ | |
if (encoded[pos] != '[') { | |
throw new IllegalArgumentException("expecting open bracket"); | |
} | |
pos++; | |
/* skip whitespace */ | |
while (Character.isWhitespace(encoded[pos])) { | |
pos++; | |
} | |
/* type is not quoted or encoded */ | |
int begin = pos; | |
while (!Character.isWhitespace(encoded[pos]) | |
&& (encoded[pos] != ']')) { | |
pos++; | |
} | |
if (pos == begin || encoded[begin] == '"') { | |
throw new IllegalArgumentException("expecting type"); | |
} | |
this.type = new String(encoded, begin, pos - begin); | |
/* skip whitespace */ | |
while (Character.isWhitespace(encoded[pos])) { | |
pos++; | |
} | |
/* type may be followed by args which are quoted and encoded */ | |
ArrayList argsList = new ArrayList(); | |
while (encoded[pos] == '"') { | |
pos++; | |
begin = pos; | |
while (encoded[pos] != '"') { | |
if (encoded[pos] == '\\') { | |
pos++; | |
} | |
pos++; | |
} | |
argsList.add(unescapeString(encoded, begin, pos)); | |
pos++; | |
if (Character.isWhitespace(encoded[pos])) { | |
/* skip whitespace */ | |
while (Character.isWhitespace(encoded[pos])) { | |
pos++; | |
} | |
} | |
} | |
this.args = (String[]) argsList | |
.toArray(new String[argsList.size()]); | |
/* the final character must be ']' */ | |
char c = encoded[pos]; | |
pos++; | |
while ((pos < length) && Character.isWhitespace(encoded[pos])) { | |
pos++; | |
} | |
if ((c != ']') || (pos != length)) { | |
throw new IllegalArgumentException("expecting close bracket"); | |
} | |
} | |
catch (ArrayIndexOutOfBoundsException e) { | |
throw new IllegalArgumentException("parsing terminated abruptly"); | |
} | |
} | |
/** | |
* Returns the string encoding of this <code>ConditionInfo</code> in a | |
* form suitable for restoring this <code>ConditionInfo</code>. | |
* | |
* <p> | |
* The encoding format is: | |
* | |
* <pre> | |
* [type "arg0" "arg1" ...] | |
* </pre> | |
* | |
* where <i>argN</i> are strings that are encoded for proper parsing. | |
* Specifically, the <code>"</code>, <code>\</code>, carriage return, | |
* and linefeed characters are escaped using <code>\"</code>, | |
* <code>\\</code>, <code>\r</code>, and <code>\n</code>, | |
* respectively. | |
* | |
* <p> | |
* The encoded string contains no leading or trailing whitespace characters. | |
* A single space character is used between type and "<i>arg0</i>" and | |
* between the arguments. | |
* | |
* @return The string encoding of this <code>ConditionInfo</code>. | |
*/ | |
public final String getEncoded() { | |
StringBuffer output = new StringBuffer(); | |
output.append('['); | |
output.append(type); | |
for (int i = 0; i < args.length; i++) { | |
output.append(" \""); | |
escapeString(args[i], output); | |
output.append('\"'); | |
} | |
output.append(']'); | |
return output.toString(); | |
} | |
/** | |
* Returns the string representation of this <code>ConditionInfo</code>. | |
* The string is created by calling the <code>getEncoded</code> method on | |
* this <code>ConditionInfo</code>. | |
* | |
* @return The string representation of this <code>ConditionInfo</code>. | |
*/ | |
public String toString() { | |
return getEncoded(); | |
} | |
/** | |
* Returns the fully qualified class name of the condition represented by | |
* this <code>ConditionInfo</code>. | |
* | |
* @return The fully qualified class name of the condition represented by | |
* this <code>ConditionInfo</code>. | |
*/ | |
public final String getType() { | |
return type; | |
} | |
/** | |
* Returns arguments of this <code>ConditionInfo</code>. | |
* | |
* @return The arguments of this <code>ConditionInfo</code>. An empty | |
* array is returned if the <code>ConditionInfo</code> has no | |
* arguments. | |
*/ | |
public final String[] getArgs() { | |
return args; | |
} | |
/** | |
* Determines the equality of two <code>ConditionInfo</code> objects. | |
* | |
* This method checks that specified object has the same type and args as | |
* this <code>ConditionInfo</code> object. | |
* | |
* @param obj The object to test for equality with this | |
* <code>ConditionInfo</code> object. | |
* @return <code>true</code> if <code>obj</code> is a | |
* <code>ConditionInfo</code>, and has the same type and args as | |
* this <code>ConditionInfo</code> object; <code>false</code> | |
* otherwise. | |
*/ | |
public boolean equals(Object obj) { | |
if (obj == this) { | |
return true; | |
} | |
if (!(obj instanceof ConditionInfo)) { | |
return false; | |
} | |
ConditionInfo other = (ConditionInfo) obj; | |
if (!type.equals(other.type) || args.length != other.args.length) | |
return false; | |
for (int i = 0; i < args.length; i++) { | |
if (!args[i].equals(other.args[i])) | |
return false; | |
} | |
return true; | |
} | |
/** | |
* Returns the hash code value for this object. | |
* | |
* @return A hash code value for this object. | |
*/ | |
public int hashCode() { | |
int hash = type.hashCode(); | |
for (int i = 0; i < args.length; i++) { | |
hash ^= args[i].hashCode(); | |
} | |
return hash; | |
} | |
/** | |
* This escapes the quotes, backslashes, \n, and \r in the string using a | |
* backslash and appends the newly escaped string to a StringBuffer. | |
*/ | |
private static void escapeString(String str, StringBuffer output) { | |
int len = str.length(); | |
for (int i = 0; i < len; i++) { | |
char c = str.charAt(i); | |
switch (c) { | |
case '"' : | |
case '\\' : | |
output.append('\\'); | |
output.append(c); | |
break; | |
case '\r' : | |
output.append("\\r"); | |
break; | |
case '\n' : | |
output.append("\\n"); | |
break; | |
default : | |
output.append(c); | |
break; | |
} | |
} | |
} | |
/** | |
* Takes an encoded character array and decodes it into a new String. | |
*/ | |
private static String unescapeString(char[] str, int begin, int end) { | |
StringBuffer output = new StringBuffer(end - begin); | |
for (int i = begin; i < end; i++) { | |
char c = str[i]; | |
if (c == '\\') { | |
i++; | |
if (i < end) { | |
c = str[i]; | |
switch (c) { | |
case '"' : | |
case '\\' : | |
break; | |
case 'r' : | |
c = '\r'; | |
break; | |
case 'n' : | |
c = '\n'; | |
break; | |
default : | |
c = '\\'; | |
i--; | |
break; | |
} | |
} | |
} | |
output.append(c); | |
} | |
return output.toString(); | |
} | |
} |