jni jnienv GetBooleanField example c c++ java

Get<type>Field Routines - GetBooleanField

NativeType Get<type>Field(JNIEnv *env, jobject obj,
jfieldID fieldID);

This family of accessor routines returns the value of an instance (nonstatic) field of an object. The field to access is specified by a field ID obtained by calling GetFieldID(). (GetBooleanField)

The following table describes the Get<type>Field routine name and result type. You should replace type in Get<type>Field with the Java type of the field, or use one of the actual routine names from the table, and replace NativeType with the corresponding native type for that routine.

Table 4-1a Get<type>Field Family of Accessor Routines

Get<type>Field Routine Name	Native Type
GetObjectField()	jobject
GetBooleanField()	jboolean
GetByteField()	jbyte
GetCharField()	jchar
GetShortField()	jshort
GetIntField()	jint
GetLongField()	jlong
GetFloatField()	jfloat
GetDoubleField()	jdouble

LINKAGE:

Indices in the JNIEnv interface function table:

Table 4-1b Get<type>Field Family of Accessor Routines

Get<type>Field Routine Name	Index
GetObjectField()	95
GetBooleanField()	96
GetByteField()	97
GetCharField()	98
GetShortField()	99
GetIntField()	100
GetLongField()	101
GetFloatField()	102
GetDoubleField()	103

PARAMETERS:

env: the JNI interface pointer.

obj: a Java object (must not be NULL).

fieldID: a valid field ID.

RETURNS:

Returns the content of the field.

Example - GetBooleanField

static void initSocketNative(JNIEnv *env, jobject obj) {
102	#ifdef HAVE_BLUETOOTH
103	LOGV(__FUNCTION__);
104	#ifdef USE_BM3_BLUETOOTH
105	// BM3: RFCOMM-only assumption
106	jint type;
107	type = env->GetIntField(obj, field_mType);
108	if (TYPE_RFCOMM != type) {
109	jniThrowIOException(env, ENOSYS);
110	return;
111	}
112
113	int fd = 0; /* Bogus value for now--for BM3 we initialize the socket on connect/bind */
114	#else
115	int fd;
116	int lm = 0;
117	int sndbuf;
118	jboolean auth;
119	jboolean encrypt;
120	jint type;
121
122	type = env->GetIntField(obj, field_mType);
123
124	switch (type) {
125	case TYPE_RFCOMM:
126	fd = socket(PF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM);
127	break;
128	case TYPE_SCO:
129	fd = socket(PF_BLUETOOTH, SOCK_SEQPACKET, BTPROTO_SCO);
130	break;
131	case TYPE_L2CAP:
132	fd = socket(PF_BLUETOOTH, SOCK_SEQPACKET, BTPROTO_L2CAP);
133	break;
134	default:
135	jniThrowIOException(env, ENOSYS);
136	return;
137	}
138
139	if (fd < 0) {
140	LOGV("socket() failed, throwing");
141	jniThrowIOException(env, errno);
142	return;
143	}
144
145	auth = env->GetBooleanField(obj, field_mAuth);
146	encrypt = env->GetBooleanField(obj, field_mEncrypt);
147
148	/* kernel does not yet support LM for SCO */
149	switch (type) {
150	case TYPE_RFCOMM:
151	lm |= auth ? RFCOMM_LM_AUTH : 0;
152	lm |= encrypt ? RFCOMM_LM_ENCRYPT : 0;
153	lm |= (auth && encrypt) ? RFCOMM_LM_SECURE : 0;
154	break;
155	case TYPE_L2CAP:
156	lm |= auth ? L2CAP_LM_AUTH : 0;
157	lm |= encrypt ? L2CAP_LM_ENCRYPT : 0;
158	lm |= (auth && encrypt) ? L2CAP_LM_SECURE : 0;
159	break;
160	}
161
162	if (lm) {
163	if (setsockopt(fd, SOL_RFCOMM, RFCOMM_LM, &lm, sizeof(lm))) {
164	LOGV("setsockopt(RFCOMM_LM) failed, throwing");
165	jniThrowIOException(env, errno);
166	return;
167	}
168	}
169
170	if (type == TYPE_RFCOMM) {
171	sndbuf = RFCOMM_SO_SNDBUF;
172	if (setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &sndbuf, sizeof(sndbuf))) {
173	LOGV("setsockopt(SO_SNDBUF) failed, throwing");
174	jniThrowIOException(env, errno);
175	return;
176	}
177	}
178
179	LOGV("...fd %d created (%s, lm = %x)", fd, TYPE_AS_STR(type), lm);
180	#endif /* USE_BM3_BLUETOOTH */
181	initSocketFromFdNative(env, obj, fd);
182	return;
183	#endif
184	jniThrowIOException(env, ENOSYS);
185	}