feat(http-client-configration): add proxy support

Author: hamzamahmood

src/main/java/io/apimatic/core/configurations/http/client/CoreHttpClientConfiguration.java

@@ -1,5 +1,6 @@
 package io.apimatic.core.configurations.http.client;
 
+import io.apimatic.coreinterfaces.http.proxy.ProxyConfiguration;
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.Set;
@@ -122,6 +123,12 @@ public final class CoreHttpClientConfiguration implements ClientConfiguration {
      */
     private final boolean skipSslCertVerification;
 
+    /**
+     * The proxy configuration used to route network requests through a proxy server.
+     * Contains details such as address, port, and optional authentication credentials.
+     */
+    private final ProxyConfiguration proxyConfiguration;
+
     /**
      * @param timeout
      * @param numberOfRetries
@@ -140,7 +147,7 @@ private CoreHttpClientConfiguration(final long timeout, final int numberOfRetrie
             final boolean skipSslCertVerification, final Set<Integer> httpStatusCodesToRetry,
             final Set<Method> httpMethodsToRetry, final long maximumRetryWaitTime,
             final boolean shouldRetryOnTimeout, final okhttp3.OkHttpClient httpClientInstance,
-            final boolean overrideHttpClientConfigurations) {
+            final boolean overrideHttpClientConfigurations, final ProxyConfiguration proxyConfiguration) {
         this.timeout = timeout;
         this.numberOfRetries = numberOfRetries;
         this.backOffFactor = backOffFactor;
@@ -152,6 +159,7 @@ private CoreHttpClientConfiguration(final long timeout, final int numberOfRetrie
         this.httpClientInstance = httpClientInstance;
         this.overrideHttpClientConfigurations = overrideHttpClientConfigurations;
         this.skipSslCertVerification = skipSslCertVerification;
+        this.proxyConfiguration = proxyConfiguration;
     }
 
     /**
@@ -243,6 +251,14 @@ public boolean skipSslCertVerification() {
         return skipSslCertVerification;
     }
 
+    /**
+     * Returns the proxy configuration used to route requests through a proxy server.
+     * This includes the proxy address, port, and any authentication credentials.
+     *
+     * @return the {@link ProxyConfiguration}, or {@code null} if no proxy is configured
+     */
+    public ProxyConfiguration getProxyConfiguration() { return proxyConfiguration; }
+
     /**
      * Converts this HttpClientConfiguration into string format.
      * @return String representation of this class.
@@ -255,7 +271,8 @@ public String toString() {
                 + ", httpMethodsToRetry=" + httpMethodsToRetry + ", maximumRetryWaitTime="
                 + maximumRetryWaitTime + ", shouldRetryOnTimeout=" + shouldRetryOnTimeout
                 + ", httpClientInstance=" + httpClientInstance
-                + ", overrideHttpClientConfigurations=" + overrideHttpClientConfigurations + "]";
+                + ", overrideHttpClientConfigurations=" + overrideHttpClientConfigurations
+                + ", proxy=" + proxyConfiguration + "]";
     }
 
     /**
@@ -269,7 +286,8 @@ public Builder newBuilder() {
                 .httpStatusCodesToRetry(httpStatusCodesToRetry)
                 .httpMethodsToRetry(httpMethodsToRetry).maximumRetryWaitTime(maximumRetryWaitTime)
                 .shouldRetryOnTimeout(shouldRetryOnTimeout)
-                .httpClientInstance(httpClientInstance, overrideHttpClientConfigurations);
+                .httpClientInstance(httpClientInstance, overrideHttpClientConfigurations)
+                .proxyConfiguration(proxyConfiguration);
     }
 
     /**
@@ -322,6 +340,11 @@ public static class Builder {
          * Skip Ssl certification.
          */
         private boolean skipSslCertVerification;
+        /**
+         * The proxy configuration used to route network requests through a proxy server.
+         * Contains details such as address, port, and optional authentication credentials.
+         */
+        private ProxyConfiguration proxyConfiguration;
 
         /**
          * Default Constructor to initiate builder with default properties.
@@ -463,6 +486,17 @@ public Builder skipSslCertVerification(boolean skipSslCertVerification) {
             return this;
         }
 
+        /**
+         * Sets the proxy configuration to be used for routing requests through a proxy server.
+         *
+         * @param proxyConfiguration the {@link ProxyConfiguration} instance to use
+         * @return the builder instance
+         */
+        public Builder proxyConfiguration(ProxyConfiguration proxyConfiguration) {
+            this.proxyConfiguration = proxyConfiguration;
+            return this;
+        }
+
         /**
          * Builds a new HttpClientConfiguration object using the set fields.
          * @return {@link CoreHttpClientConfiguration}.
@@ -471,7 +505,7 @@ public CoreHttpClientConfiguration build() {
             return new CoreHttpClientConfiguration(timeout, numberOfRetries, backOffFactor,
                     retryInterval, skipSslCertVerification, httpStatusCodesToRetry,
                     httpMethodsToRetry, maximumRetryWaitTime, shouldRetryOnTimeout,
-                    httpClientInstance, overrideHttpClientConfigurations);
+                    httpClientInstance, overrideHttpClientConfigurations, proxyConfiguration);
         }
     }
 }

src/main/java/io/apimatic/core/configurations/http/client/CoreProxyConfiguration.java

@@ -0,0 +1,151 @@
+package io.apimatic.core.configurations.http.client;
+
+import io.apimatic.coreinterfaces.http.proxy.ProxyConfiguration;
+
+/**
+ * Represents a proxy configuration with address, port, and optional authentication credentials.
+ * This class is an implementation of the {@link ProxyConfiguration} interface.
+ */
+public class CoreProxyConfiguration implements ProxyConfiguration {
+
+    /**
+     * The proxy server address (e.g., IP or domain name).
+     */
+    private final String address;
+
+    /**
+     * The port on which the proxy server is listening.
+     */
+    private final int port;
+
+    /**
+     * The username for proxy authentication, if required.
+     */
+    private final String username;
+
+    /**
+     * The password for proxy authentication, if required.
+     */
+    private final String password;
+
+    /**
+     * Creates a new instance of {@code CoreProxyConfiguration} with the specified address,
+     * port, and optional authentication credentials.
+     *
+     * @param address  The proxy server address.
+     * @param port     The proxy server port.
+     * @param username The username for proxy authentication (can be {@code null}).
+     * @param password The password for proxy authentication (can be {@code null}).
+     */
+    private CoreProxyConfiguration(String address, int port, String username, String password) {
+        this.address = address;
+        this.port = port;
+        this.username = username;
+        this.password = password;
+    }
+
+    @Override
+    public String getAddress() {
+        return address;
+    }
+
+    @Override
+    public int getPort() {
+        return port;
+    }
+
+    @Override
+    public String getUsername() {
+        return username;
+    }
+
+    @Override
+    public String getPassword() {
+        return password;
+    }
+
+    /**
+     * Creates a new builder initialized with the current configuration's values.
+     * @return a new {@link Builder} instance
+     */
+    public Builder newBuilder() {
+        return new Builder()
+          .address(this.address)
+          .port(this.port)
+          .username(this.username)
+          .password(this.password);
+    }
+
+    /**
+     * Returns a string representation of this proxy configuration.
+     * @return string representation of this object
+     */
+    @Override
+    public String toString() {
+        return "CoreProxyConfiguration [" +
+          "address=" + address +
+          ", port=" + port +
+          ", username=" + (username != null ? username : "null") +
+          ", password=" + (password != null ? password : "null") +
+          "]";
+    }
+
+    /**
+     * Builder class for constructing {@link CoreProxyConfiguration} instances.
+     */
+    public static class Builder {
+
+        private String address;
+        private int port;
+        private String username;
+        private String password;
+
+        /**
+         * Sets the proxy server address.
+         * @param address the address to set
+         * @return the builder instance
+         */
+        public Builder address(String address) {
+            this.address = address;
+            return this;
+        }
+
+        /**
+         * Sets the proxy server port.
+         * @param port the port to set
+         * @return the builder instance
+         */
+        public Builder port(int port) {
+            this.port = port;
+            return this;
+        }
+
+        /**
+         * Sets the proxy username for authentication.
+         * @param username the username to set
+         * @return the builder instance
+         */
+        public Builder username(String username) {
+            this.username = username;
+            return this;
+        }
+
+        /**
+         * Sets the proxy password for authentication.
+         * @param password the password to set
+         * @return the builder instance
+         */
+        public Builder password(String password) {
+            this.password = password;
+            return this;
+        }
+
+        /**
+         * Builds a new {@link CoreProxyConfiguration} instance using the set fields.
+         * @return the built {@link CoreProxyConfiguration}
+         */
+        public CoreProxyConfiguration build() {
+            return new CoreProxyConfiguration(address, port, username, password);
+        }
+    }
+}