Refactor null-safe length query code into new IOUtils methods.

Author: Gary Gregory

src/main/java/org/apache/commons/io/IOUtils.java

@@ -3290,4 +3290,48 @@ public IOUtils() {
         super();
     }
 
+    /**
+     * Returns the length of the given array in a null-safe manner.
+     *
+     * @param array an array or null
+     * @return the array length or null if the given array is null.
+     * @since 2.7
+     */
+    public static int length(final byte[] array) {
+        return array == null ? 0 : array.length;
+    }
+
+    /**
+     * Returns the length of the given array in a null-safe manner.
+     *
+     * @param array an array or null
+     * @return the array length or null if the given array is null.
+     * @since 2.7
+     */
+    public static int length(final char[] array) {
+        return array == null ? 0 : array.length;
+    }
+
+    /**
+     * Returns the length of the given CharSequence in a null-safe manner.
+     *
+     * @param csq a CharSequence or null
+     * @return the CharSequence length or null if the given CharSequence is null.
+     * @since 2.7
+     */
+    public static int length(final CharSequence csq) {
+        return csq == null ? 0 : csq.length();
+    }
+
+    /**
+     * Returns the length of the given array in a null-safe manner.
+     *
+     * @param array an array or null
+     * @return the array length or null if the given array is null.
+     * @since 2.7
+     */
+    public static int length(final Object[] array) {
+        return array == null ? 0 : array.length;
+    }
+
 }

src/main/java/org/apache/commons/io/input/BOMInputStream.java

@@ -26,6 +26,7 @@
 import java.util.List;
 
 import org.apache.commons.io.ByteOrderMark;
+import org.apache.commons.io.IOUtils;
 
 /**
  * This class is used to wrap a stream that includes an encoded {@link ByteOrderMark} as its first bytes.
@@ -164,7 +165,7 @@ public int compare(final ByteOrderMark bom1, final ByteOrderMark bom2) {
      */
     public BOMInputStream(final InputStream delegate, final boolean include, final ByteOrderMark... boms) {
         super(delegate);
-        if (boms == null || boms.length == 0) {
+        if (IOUtils.length(boms) == 0) {
             throw new IllegalArgumentException("No BOMs specified");
         }
         this.include = include;

src/main/java/org/apache/commons/io/input/ProxyInputStream.java

@@ -22,6 +22,8 @@
 import java.io.IOException;
 import java.io.InputStream;
 
+import org.apache.commons.io.IOUtils;
+
 /**
  * A Proxy stream which acts as expected, that is it passes the method
  * calls on to the proxied stream and doesn't change which methods are
@@ -74,7 +76,7 @@ public int read() throws IOException {
     @Override
     public int read(final byte[] bts) throws IOException {
         try {
-            beforeRead(bts != null ? bts.length : 0);
+            beforeRead(IOUtils.length(bts));
             final int n = in.read(bts);
             afterRead(n);
             return n;

src/main/java/org/apache/commons/io/input/ProxyReader.java

@@ -23,6 +23,8 @@
 import java.io.Reader;
 import java.nio.CharBuffer;
 
+import org.apache.commons.io.IOUtils;
+
 /**
  * A Proxy stream which acts as expected, that is it passes the method
  * calls on to the proxied stream and doesn't change which methods are
@@ -72,7 +74,7 @@ public int read() throws IOException {
     @Override
     public int read(final char[] chr) throws IOException {
         try {
-            beforeRead(chr != null ? chr.length : 0);
+            beforeRead(IOUtils.length(chr));
             final int n = in.read(chr);
             afterRead(n);
             return n;
@@ -113,7 +115,7 @@ public int read(final char[] chr, final int st, final int len) throws IOExceptio
     @Override
     public int read(final CharBuffer target) throws IOException {
         try {
-            beforeRead(target != null ? target.length() : 0);
+            beforeRead(IOUtils.length(target));
             final int n = in.read(target);
             afterRead(n);
             return n;

src/main/java/org/apache/commons/io/output/ProxyOutputStream.java

@@ -20,6 +20,8 @@
 import java.io.IOException;
 import java.io.OutputStream;
 
+import org.apache.commons.io.IOUtils;
+
 /**
  * A Proxy stream which acts as expected, that is it passes the method
  * calls on to the proxied stream and doesn't change which methods are
@@ -66,7 +68,7 @@ public void write(final int idx) throws IOException {
     @Override
     public void write(final byte[] bts) throws IOException {
         try {
-            final int len = bts != null ? bts.length : 0;
+            final int len = IOUtils.length(bts);
             beforeWrite(len);
             out.write(bts);
             afterWrite(len);

src/main/java/org/apache/commons/io/output/ProxyWriter.java

@@ -20,6 +20,8 @@
 import java.io.IOException;
 import java.io.Writer;
 
+import org.apache.commons.io.IOUtils;
+
 /**
  * A Proxy stream which acts as expected, that is it passes the method
  * calls on to the proxied stream and doesn't change which methods are
@@ -90,11 +92,7 @@ public Writer append(final CharSequence csq, final int start, final int end) thr
     @Override
     public Writer append(final CharSequence csq) throws IOException {
         try {
-            int len = 0;
-            if (csq != null) {
-                len = csq.length();
-            }
-
+            int len = IOUtils.length(csq);
             beforeWrite(len);
             out.append(csq);
             afterWrite(len);
@@ -128,11 +126,7 @@ public void write(final int c) throws IOException {
     @Override
     public void write(final char[] cbuf) throws IOException {
         try {
-            int len = 0;
-            if (cbuf != null) {
-                len = cbuf.length;
-            }
-
+            int len = IOUtils.length(cbuf);
             beforeWrite(len);
             out.write(cbuf);
             afterWrite(len);
@@ -167,11 +161,7 @@ public void write(final char[] cbuf, final int off, final int len) throws IOExce
     @Override
     public void write(final String str) throws IOException {
         try {
-            int len = 0;
-            if (str != null) {
-                len = str.length();
-            }
-
+            int len = IOUtils.length(str);
             beforeWrite(len);
             out.write(str);
             afterWrite(len);