[seam-commits] Seam SVN: r10599 - in modules/trunk/security/src/main/java/org/jboss/seam/security: callbacks and 3 other directories.

Author: shane.bryzak(a)jboss.com Date: 2009-04-22 20:37:40 -0400 (Wed, 22 Apr 2009) New Revision: 10599 Added: modules/trunk/security/src/main/java/org/jboss/seam/security/callbacks/ modules/trunk/security/src/main/java/org/jboss/seam/security/callbacks/AuthenticatorCallback.java modules/trunk/security/src/main/java/org/jboss/seam/security/callbacks/IdentityCallback.java modules/trunk/security/src/main/java/org/jboss/seam/security/callbacks/IdentityManagerCallback.java modules/trunk/security/src/main/java/org/jboss/seam/security/util/ modules/trunk/security/src/main/java/org/jboss/seam/security/util/Strings.java Modified: modules/trunk/security/src/main/java/org/jboss/seam/security/Authenticator.java modules/trunk/security/src/main/java/org/jboss/seam/security/Credentials.java modules/trunk/security/src/main/java/org/jboss/seam/security/Identity.java modules/trunk/security/src/main/java/org/jboss/seam/security/JaasConfiguration.java modules/trunk/security/src/main/java/org/jboss/seam/security/jaas/SeamLoginModule.java modules/trunk/security/src/main/java/org/jboss/seam/security/management/IdentityManager.java Log: fix SeamLoginModule Modified: modules/trunk/security/src/main/java/org/jboss/seam/security/Authenticator.java =================================================================== --- modules/trunk/security/src/main/java/org/jboss/seam/security/Authenticator.java 2009-04-22 22:55:46 UTC (rev 10598) +++ modules/trunk/security/src/main/java/org/jboss/seam/security/Authenticator.java 2009-04-23 00:37:40 UTC (rev 10599) @@ -7,5 +7,5 @@ */ public interface Authenticator { - void authenticate(); + boolean authenticate(); } Modified: modules/trunk/security/src/main/java/org/jboss/seam/security/Credentials.java =================================================================== --- modules/trunk/security/src/main/java/org/jboss/seam/security/Credentials.java 2009-04-22 22:55:46 UTC (rev 10598) +++ modules/trunk/security/src/main/java/org/jboss/seam/security/Credentials.java 2009-04-23 00:37:40 UTC (rev 10599) @@ -109,37 +109,5 @@ public String toString() { return "Credentials[" + username + "]"; - } - - - /** - * Creates a callback handler that can handle a standard username/password - * callback, using the username and password properties. - */ - public CallbackHandler createCallbackHandler() - { - return new CallbackHandler() - { - public void handle(Callback[] callbacks) - throws IOException, UnsupportedCallbackException - { - for (int i=0; i < callbacks.length; i++) - { - if (callbacks[i] instanceof NameCallback) - { - ( (NameCallback) callbacks[i] ).setName(getUsername()); - } - else if (callbacks[i] instanceof PasswordCallback) - { - ( (PasswordCallback) callbacks[i] ).setPassword( getPassword() != null ? - getPassword().toCharArray() : null ); - } - else - { - log.warn("Unsupported callback " + callbacks[i]); - } - } - } - }; - } + } } Modified: modules/trunk/security/src/main/java/org/jboss/seam/security/Identity.java =================================================================== --- modules/trunk/security/src/main/java/org/jboss/seam/security/Identity.java 2009-04-22 22:55:46 UTC (rev 10598) +++ modules/trunk/security/src/main/java/org/jboss/seam/security/Identity.java 2009-04-23 00:37:40 UTC (rev 10599) @@ -1,5 +1,6 @@ package org.jboss.seam.security; +import java.io.IOException; import java.io.Serializable; import java.security.Principal; import java.security.acl.Group; @@ -7,18 +8,29 @@ import java.util.Collection; import java.util.Enumeration; import java.util.List; +import java.util.Set; import javax.annotation.Named; import javax.context.SessionScoped; import javax.inject.Current; import javax.inject.Initializer; +import javax.inject.manager.Bean; import javax.inject.manager.Manager; import javax.security.auth.Subject; +import javax.security.auth.callback.Callback; +import javax.security.auth.callback.CallbackHandler; +import javax.security.auth.callback.NameCallback; +import javax.security.auth.callback.PasswordCallback; +import javax.security.auth.callback.UnsupportedCallbackException; +import javax.security.auth.login.Configuration; import javax.security.auth.login.LoginContext; import javax.security.auth.login.LoginException; import org.jboss.webbeans.log.LogProvider; import org.jboss.webbeans.log.Logging; +import org.jboss.seam.security.callbacks.AuthenticatorCallback; +import org.jboss.seam.security.callbacks.IdentityCallback; +import org.jboss.seam.security.callbacks.IdentityManagerCallback; import org.jboss.seam.security.events.AlreadyLoggedInEvent; import org.jboss.seam.security.events.LoggedInEvent; import org.jboss.seam.security.events.LoggedOutEvent; @@ -28,6 +40,7 @@ import org.jboss.seam.security.events.PostAuthenticateEvent; import org.jboss.seam.security.events.PreAuthenticateEvent; import org.jboss.seam.security.events.QuietLoginEvent; +import org.jboss.seam.security.management.IdentityManager; import org.jboss.seam.security.permission.PermissionMapper; /** @@ -78,12 +91,6 @@ { securityEnabled = enabled; } - - public static Identity instance() - { - // TODO - implement - return null; - } /** * Simple check that returns true if the user is logged in, without attempting to authenticate @@ -348,13 +355,75 @@ if (getJaasConfigName() != null) { return new LoginContext(getJaasConfigName(), getSubject(), - credentials.createCallbackHandler()); + createCallbackHandler()); } + Bean<Configuration> configBean = manager.resolveByType(Configuration.class).iterator().next(); + Configuration config = manager.getInstance(configBean); + return new LoginContext(JaasConfiguration.DEFAULT_JAAS_CONFIG_NAME, getSubject(), - credentials.createCallbackHandler(), JaasConfiguration.instance()); + createCallbackHandler(), config); } + + /** + * Creates a callback handler that can handle a standard username/password + * callback, using the credentials username and password properties + */ + public CallbackHandler createCallbackHandler() + { + final Identity identity = this; + final Authenticator authenticator; + final IdentityManager identityManager = manager.getInstanceByType(IdentityManager.class); + + Set<Bean<Authenticator>> authenticators = manager.resolveByType(Authenticator.class); + if (authenticators.size() > 0) + { + Bean<Authenticator> authenticatorBean = authenticators.iterator().next(); + authenticator = manager.getInstance(authenticatorBean); + } + else + { + authenticator = null; + } + + return new CallbackHandler() + { + public void handle(Callback[] callbacks) + throws IOException, UnsupportedCallbackException + { + for (int i=0; i < callbacks.length; i++) + { + if (callbacks[i] instanceof NameCallback) + { + ( (NameCallback) callbacks[i] ).setName(credentials.getUsername()); + } + else if (callbacks[i] instanceof PasswordCallback) + { + ( (PasswordCallback) callbacks[i] ).setPassword( credentials.getPassword() != null ? + credentials.getPassword().toCharArray() : null ); + } + else if (callbacks[i] instanceof IdentityCallback) + { + ((IdentityCallback ) callbacks[i]).setIdentity(identity); + } + else if (callbacks[i] instanceof AuthenticatorCallback) + { + ((AuthenticatorCallback) callbacks[i]).setAuthenticator(authenticator); + } + else if (callbacks[i] instanceof IdentityManagerCallback) + { + ((IdentityManagerCallback) callbacks[i]).setIdentityManager(identityManager); + } + else + { + log.warn("Unsupported callback " + callbacks[i]); + } + } + } + }; + } + public void logout() { if (isLoggedIn()) Modified: modules/trunk/security/src/main/java/org/jboss/seam/security/JaasConfiguration.java =================================================================== --- modules/trunk/security/src/main/java/org/jboss/seam/security/JaasConfiguration.java 2009-04-22 22:55:46 UTC (rev 10598) +++ modules/trunk/security/src/main/java/org/jboss/seam/security/JaasConfiguration.java 2009-04-23 00:37:40 UTC (rev 10599) @@ -5,12 +5,13 @@ import javax.context.ApplicationScoped; import javax.inject.Produces; import javax.security.auth.login.AppConfigurationEntry; +import javax.security.auth.login.Configuration; import javax.security.auth.login.AppConfigurationEntry.LoginModuleControlFlag; import org.jboss.seam.security.jaas.SeamLoginModule; /** - * Factory for the JAAS Configuration used by Seam Security. + * Producer for the JAAS Configuration used by Seam Security. * * @author Shane Bryzak * @@ -19,9 +20,9 @@ { static final String DEFAULT_JAAS_CONFIG_NAME = "default"; - protected javax.security.auth.login.Configuration createConfiguration() + protected Configuration createConfiguration() { - return new javax.security.auth.login.Configuration() + return new Configuration() { private AppConfigurationEntry[] aces = { createAppConfigurationEntry() }; @@ -45,7 +46,7 @@ ); } - @Produces @ApplicationScoped javax.security.auth.login.Configuration getConfiguration() + @Produces @ApplicationScoped Configuration getConfiguration() { return createConfiguration(); } Added: modules/trunk/security/src/main/java/org/jboss/seam/security/callbacks/AuthenticatorCallback.java =================================================================== --- modules/trunk/security/src/main/java/org/jboss/seam/security/callbacks/AuthenticatorCallback.java (rev 0) +++ modules/trunk/security/src/main/java/org/jboss/seam/security/callbacks/AuthenticatorCallback.java 2009-04-23 00:37:40 UTC (rev 10599) @@ -0,0 +1,29 @@ +package org.jboss.seam.security.callbacks; + +import java.io.Serializable; + +import javax.security.auth.callback.Callback; + +import org.jboss.seam.security.Authenticator; + +/** + * This callback implementation is used to provide an instance of the Authenticator bean to the LoginModule + * + * @author Shane Bryzak + */ +public class AuthenticatorCallback implements Serializable, Callback +{ + private static final long serialVersionUID = -6186364148255506167L; + + private Authenticator authenticator; + + public Authenticator getAuthenticator() + { + return authenticator; + } + + public void setAuthenticator(Authenticator authenticator) + { + this.authenticator = authenticator; + } +} Added: modules/trunk/security/src/main/java/org/jboss/seam/security/callbacks/IdentityCallback.java =================================================================== --- modules/trunk/security/src/main/java/org/jboss/seam/security/callbacks/IdentityCallback.java (rev 0) +++ modules/trunk/security/src/main/java/org/jboss/seam/security/callbacks/IdentityCallback.java 2009-04-23 00:37:40 UTC (rev 10599) @@ -0,0 +1,29 @@ +package org.jboss.seam.security.callbacks; + +import java.io.Serializable; + +import javax.security.auth.callback.Callback; + +import org.jboss.seam.security.Identity; + +/** + * This callback implementation is used to provide an instance of the Identity bean to the LoginModule + * + * @author Shane Bryzak + */ +public class IdentityCallback implements Serializable, Callback +{ + private static final long serialVersionUID = 5720975438991518059L; + + private Identity identity; + + public void setIdentity(Identity identity) + { + this.identity = identity; + } + + public Identity getIdentity() + { + return identity; + } +} Added: modules/trunk/security/src/main/java/org/jboss/seam/security/callbacks/IdentityManagerCallback.java =================================================================== --- modules/trunk/security/src/main/java/org/jboss/seam/security/callbacks/IdentityManagerCallback.java (rev 0) +++ modules/trunk/security/src/main/java/org/jboss/seam/security/callbacks/IdentityManagerCallback.java 2009-04-23 00:37:40 UTC (rev 10599) @@ -0,0 +1,29 @@ +package org.jboss.seam.security.callbacks; + +import java.io.Serializable; + +import javax.security.auth.callback.Callback; + +import org.jboss.seam.security.management.IdentityManager; + +/** + * This callback implementation is used to provide an instance of the IdentityManager bean to the LoginModule + * + * @author Shane Bryzak + */ +public class IdentityManagerCallback implements Serializable, Callback +{ + private static final long serialVersionUID = 8430300053672194472L; + + private IdentityManager identityManager; + + public IdentityManager getIdentityManager() + { + return identityManager; + } + + public void setIdentityManager(IdentityManager identityManager) + { + this.identityManager = identityManager; + } +} Modified: modules/trunk/security/src/main/java/org/jboss/seam/security/jaas/SeamLoginModule.java =================================================================== --- modules/trunk/security/src/main/java/org/jboss/seam/security/jaas/SeamLoginModule.java 2009-04-22 22:55:46 UTC (rev 10598) +++ modules/trunk/security/src/main/java/org/jboss/seam/security/jaas/SeamLoginModule.java 2009-04-23 00:37:40 UTC (rev 10599) @@ -7,7 +7,6 @@ import java.util.Map; import java.util.Set; -import javax.inject.manager.Manager; import javax.security.auth.Subject; import javax.security.auth.callback.Callback; import javax.security.auth.callback.CallbackHandler; @@ -16,15 +15,17 @@ import javax.security.auth.login.LoginException; import javax.security.auth.spi.LoginModule; -import org.jboss.webbeans.log.LogProvider; -import org.jboss.webbeans.log.Logging; -import org.jboss.seam.security.Identity; import org.jboss.seam.security.SimpleGroup; import org.jboss.seam.security.SimplePrincipal; +import org.jboss.seam.security.callbacks.AuthenticatorCallback; +import org.jboss.seam.security.callbacks.IdentityCallback; +import org.jboss.seam.security.callbacks.IdentityManagerCallback; import org.jboss.seam.security.management.IdentityManager; +import org.jboss.webbeans.log.LogProvider; +import org.jboss.webbeans.log.Logging; /** - * Performs authentication using a Seam component + * Performs authentication using a Seam component or Identity Management * * @author Shane Bryzak */ @@ -82,74 +83,63 @@ public boolean login() throws LoginException - { + { + PasswordCallback cbPassword = null; try { NameCallback cbName = new NameCallback("Enter username"); - PasswordCallback cbPassword = new PasswordCallback("Enter password", false); - - // Get the username and password from the callback handler - callbackHandler.handle(new Callback[] { cbName, cbPassword }); - username = cbName.getName(); - } - catch (Exception ex) - { - log.error("Error logging in", ex); - LoginException le = new LoginException(ex.getMessage()); - le.initCause(ex); - throw le; - } + cbPassword = new PasswordCallback("Enter password", false); + + IdentityCallback idCallback = new IdentityCallback(); + AuthenticatorCallback authCallback = new AuthenticatorCallback(); + IdentityManagerCallback idmCallback = new IdentityManagerCallback(); - // If an authentication method has been specified, use that to authenticate - MethodExpression mb = Identity.instance().getAuthenticateMethod(); - if (mb != null) - { - try - { - return (Boolean) mb.invoke(); - } - catch (Exception ex) - { - log.error("Error invoking login method", ex); - throw new LoginException(ex.getMessage()); - } - } - - // Otherwise if identity management is enabled, use it. - IdentityManager identityManager = IdentityManager.instance(); - if (identityManager != null && identityManager.isEnabled()) - { - Identity identity = Identity.instance(); + // Get the username, password and identity from the callback handler + callbackHandler.handle(new Callback[] { cbName, cbPassword, idCallback, authCallback, idmCallback }); - try + username = cbName.getName(); + + // If an authenticator method has been specified, use that to authenticate + if (authCallback.getAuthenticator() != null) { - boolean success = identityManager.authenticate(username, identity.getCredentials().getPassword()); + return authCallback.getAuthenticator().authenticate(); + } + + // Otherwise if identity management is enabled, use it. + IdentityManager identityManager = idmCallback.getIdentityManager(); + if (identityManager != null && identityManager.isEnabled()) + { + boolean success = identityManager.authenticate(username, + new String(cbPassword.getPassword())); if (success) { for (String role : identityManager.getImpliedRoles(username)) { - identity.addRole(role); + idCallback.getIdentity().addRole(role); } } return success; } - catch (Exception ex) + else { - log.error("Error invoking login method", ex); - LoginException le = new LoginException(ex.getMessage()); - le.initCause(ex); - throw le; + log.error("No authentication method defined - " + + "please define authenticate-method for <security:identity/> in components.xml"); + throw new LoginException("No authentication method defined"); } } - else + catch (Exception ex) { - log.error("No authentication method defined - " + - "please define authenticate-method for <security:identity/> in components.xml"); - throw new LoginException("No authentication method defined"); + log.error("Error logging in", ex); + LoginException le = new LoginException(ex.getMessage()); + le.initCause(ex); + throw le; + } + finally + { + cbPassword.clearPassword(); } - } public boolean logout() throws LoginException Modified: modules/trunk/security/src/main/java/org/jboss/seam/security/management/IdentityManager.java =================================================================== --- modules/trunk/security/src/main/java/org/jboss/seam/security/management/IdentityManager.java 2009-04-22 22:55:46 UTC (rev 10598) +++ modules/trunk/security/src/main/java/org/jboss/seam/security/management/IdentityManager.java 2009-04-23 00:37:40 UTC (rev 10599) @@ -1,37 +1,33 @@ package org.jboss.seam.security.management; -import static org.jboss.seam.ScopeType.EVENT; -import static org.jboss.seam.annotations.Install.BUILT_IN; - import java.io.Serializable; import java.security.Principal; import java.util.Collections; import java.util.Comparator; import java.util.List; -import org.jboss.seam.Component; -import org.jboss.seam.annotations.Create; -import org.jboss.seam.annotations.Install; -import org.jboss.seam.annotations.Name; -import org.jboss.seam.annotations.Scope; -import org.jboss.seam.annotations.intercept.BypassInterceptors; -import org.jboss.seam.contexts.Contexts; -import org.jboss.seam.log.LogProvider; -import org.jboss.seam.log.Logging; +import javax.annotation.Named; +import javax.context.RequestScoped; +import javax.inject.Current; +import javax.inject.Initializer; +import javax.inject.manager.Manager; + +import org.jboss.webbeans.log.LogProvider; +import org.jboss.webbeans.log.Logging; import org.jboss.seam.security.Identity; -import org.jboss.seam.util.Strings; +import org.jboss.seam.security.util.Strings; /** * Identity Management API, deals with user name/password-based identity management. * * @author Shane Bryzak */ -@Scope(EVENT) -(a)Name(&quot;org.jboss.seam.security.identityManager&quot;) -@Install(precedence = BUILT_IN) -@BypassInterceptors +@Named +@RequestScoped public class IdentityManager implements Serializable { + private static final long serialVersionUID = 6864253169970552893L; + public static final String USER_PERMISSION_NAME = "seam.user"; public static final String ROLE_PERMISSION_NAME = "seam.role"; @@ -45,7 +41,10 @@ private IdentityStore identityStore; private IdentityStore roleIdentityStore; - @Create + @Current Manager manager; + @Current Identity identity; + + @Initializer public void create() { initIdentityStore(); @@ -55,7 +54,7 @@ { // Default to JpaIdentityStore if (identityStore == null) - { + { identityStore = (IdentityStore) Component.getInstance(JpaIdentityStore.class, true); } @@ -71,24 +70,6 @@ } } - public static IdentityManager instance() - { - if ( !Contexts.isEventContextActive() ) - { - throw new IllegalStateException("No active event context"); - } - - IdentityManager instance = (IdentityManager) Component.getInstance( - IdentityManager.class, EVENT); - - if (instance == null) - { - throw new IllegalStateException("No IdentityManager could be created"); - } - - return instance; - } - public boolean createUser(String name, String password) { return createUser(name, password, null, null); @@ -96,79 +77,79 @@ public boolean createUser(String name, String password, String firstname, String lastname) { - Identity.instance().checkPermission(USER_PERMISSION_NAME, PERMISSION_CREATE); + identity.checkPermission(USER_PERMISSION_NAME, PERMISSION_CREATE); return identityStore.createUser(name, password, firstname, lastname); } public boolean deleteUser(String name) { - Identity.instance().checkPermission(USER_PERMISSION_NAME, PERMISSION_DELETE); + identity.checkPermission(USER_PERMISSION_NAME, PERMISSION_DELETE); return identityStore.deleteUser(name); } public boolean enableUser(String name) { - Identity.instance().checkPermission(USER_PERMISSION_NAME, PERMISSION_UPDATE); + identity.checkPermission(USER_PERMISSION_NAME, PERMISSION_UPDATE); return identityStore.enableUser(name); } public boolean disableUser(String name) { - Identity.instance().checkPermission(USER_PERMISSION_NAME, PERMISSION_UPDATE); + identity.checkPermission(USER_PERMISSION_NAME, PERMISSION_UPDATE); return identityStore.disableUser(name); } public boolean changePassword(String name, String password) { - Identity.instance().checkPermission(USER_PERMISSION_NAME, PERMISSION_UPDATE); + identity.checkPermission(USER_PERMISSION_NAME, PERMISSION_UPDATE); return identityStore.changePassword(name, password); } public boolean isUserEnabled(String name) { - Identity.instance().checkPermission(USER_PERMISSION_NAME, PERMISSION_READ); + identity.checkPermission(USER_PERMISSION_NAME, PERMISSION_READ); return identityStore.isUserEnabled(name); } public boolean grantRole(String name, String role) { - Identity.instance().checkPermission(USER_PERMISSION_NAME, PERMISSION_UPDATE); + identity.checkPermission(USER_PERMISSION_NAME, PERMISSION_UPDATE); return roleIdentityStore.grantRole(name, role); } public boolean revokeRole(String name, String role) { - Identity.instance().checkPermission(USER_PERMISSION_NAME, PERMISSION_UPDATE); + identity.checkPermission(USER_PERMISSION_NAME, PERMISSION_UPDATE); return roleIdentityStore.revokeRole(name, role); } public boolean createRole(String role) { - Identity.instance().checkPermission(ROLE_PERMISSION_NAME, PERMISSION_CREATE); + identity.checkPermission(ROLE_PERMISSION_NAME, PERMISSION_CREATE); return roleIdentityStore.createRole(role); } public boolean deleteRole(String role) { - Identity.instance().checkPermission(ROLE_PERMISSION_NAME, PERMISSION_DELETE); + identity.checkPermission(ROLE_PERMISSION_NAME, PERMISSION_DELETE); return roleIdentityStore.deleteRole(role); } public boolean addRoleToGroup(String role, String group) { - Identity.instance().checkPermission(ROLE_PERMISSION_NAME, PERMISSION_UPDATE); + identity.checkPermission(ROLE_PERMISSION_NAME, PERMISSION_UPDATE); return roleIdentityStore.addRoleToGroup(role, group); } public boolean removeRoleFromGroup(String role, String group) { - Identity.instance().checkPermission(ROLE_PERMISSION_NAME, PERMISSION_UPDATE); + identity.checkPermission(ROLE_PERMISSION_NAME, PERMISSION_UPDATE); return roleIdentityStore.removeRoleFromGroup(role, group); } public boolean userExists(String name) { - Identity.instance().checkPermission(USER_PERMISSION_NAME, PERMISSION_READ); + identity.checkPermission(USER_PERMISSION_NAME, PERMISSION_READ); return identityStore.userExists(name); } @@ -179,7 +160,7 @@ public List<String> listUsers() { - Identity.instance().checkPermission(USER_PERMISSION_NAME, PERMISSION_READ); + identity.checkPermission(USER_PERMISSION_NAME, PERMISSION_READ); List<String> users = identityStore.listUsers(); Collections.sort(users, new Comparator<String>() { @@ -193,7 +174,7 @@ public List<String> listUsers(String filter) { - Identity.instance().checkPermission(USER_PERMISSION_NAME, PERMISSION_READ); + identity.checkPermission(USER_PERMISSION_NAME, PERMISSION_READ); List<String> users = identityStore.listUsers(filter); Collections.sort(users, new Comparator<String>() { @@ -207,7 +188,7 @@ public List<String> listRoles() { - Identity.instance().checkPermission(ROLE_PERMISSION_NAME, PERMISSION_READ); + identity.checkPermission(ROLE_PERMISSION_NAME, PERMISSION_READ); List<String> roles = roleIdentityStore.listRoles(); Collections.sort(roles, new Comparator<String>() { @@ -256,7 +237,7 @@ public List<Principal> listMembers(String role) { - Identity.instance().checkPermission(ROLE_PERMISSION_NAME, PERMISSION_READ); + identity.checkPermission(ROLE_PERMISSION_NAME, PERMISSION_READ); return roleIdentityStore.listMembers(role); } Added: modules/trunk/security/src/main/java/org/jboss/seam/security/util/Strings.java =================================================================== --- modules/trunk/security/src/main/java/org/jboss/seam/security/util/Strings.java (rev 0) +++ modules/trunk/security/src/main/java/org/jboss/seam/security/util/Strings.java 2009-04-23 00:37:40 UTC (rev 10599) @@ -0,0 +1,22 @@ +package org.jboss.seam.security.util; + +public class Strings +{ + public static boolean isEmpty(String string) + { + int len; + if (string == null || (len = string.length()) == 0) + { + return true; + } + + for (int i = 0; i < len; i++) + { + if ((Character.isWhitespace(string.charAt(i)) == false)) + { + return false; + } + } + return true; + } +}